mm, fs: reduce fault, page_mkwrite, and pfn_mkwrite to take only vmf

[mirror_ubuntu-jammy-kernel.git] / arch / powerpc / platforms / cell / spufs / file.c

/*
 * SPU file system -- file contents
 *
 * (C) Copyright IBM Deutschland Entwicklung GmbH 2005
 *
 * Author: Arnd Bergmann <arndb@de.ibm.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#undef DEBUG

#include <linux/fs.h>
#include <linux/ioctl.h>
#include <linux/export.h>
#include <linux/pagemap.h>
#include <linux/poll.h>
#include <linux/ptrace.h>
#include <linux/seq_file.h>
#include <linux/slab.h>

#include <asm/io.h>
#include <asm/time.h>
#include <asm/spu.h>
#include <asm/spu_info.h>
#include <linux/uaccess.h>

#include "spufs.h"
#include "sputrace.h"

#define SPUFS_MMAP_4K (PAGE_SIZE == 0x1000)

/* Simple attribute files */
struct spufs_attr {
        int (*get)(void *, u64 *);
        int (*set)(void *, u64);
        char get_buf[24];       /* enough to store a u64 and "\n\0" */
        char set_buf[24];
        void *data;
        const char *fmt;        /* format for read operation */
        struct mutex mutex;     /* protects access to these buffers */
};

static int spufs_attr_open(struct inode *inode, struct file *file,
                int (*get)(void *, u64 *), int (*set)(void *, u64),
                const char *fmt)
{
        struct spufs_attr *attr;

        attr = kmalloc(sizeof(*attr), GFP_KERNEL);
        if (!attr)
                return -ENOMEM;

        attr->get = get;
        attr->set = set;
        attr->data = inode->i_private;
        attr->fmt = fmt;
        mutex_init(&attr->mutex);
        file->private_data = attr;

        return nonseekable_open(inode, file);
}

static int spufs_attr_release(struct inode *inode, struct file *file)
{
       kfree(file->private_data);
        return 0;
}

static ssize_t spufs_attr_read(struct file *file, char __user *buf,
                size_t len, loff_t *ppos)
{
        struct spufs_attr *attr;
        size_t size;
        ssize_t ret;

        attr = file->private_data;
        if (!attr->get)
                return -EACCES;

        ret = mutex_lock_interruptible(&attr->mutex);
        if (ret)
                return ret;

        if (*ppos) {            /* continued read */
                size = strlen(attr->get_buf);
        } else {                /* first read */
                u64 val;
                ret = attr->get(attr->data, &val);
                if (ret)
                        goto out;

                size = scnprintf(attr->get_buf, sizeof(attr->get_buf),
                                 attr->fmt, (unsigned long long)val);
        }

        ret = simple_read_from_buffer(buf, len, ppos, attr->get_buf, size);
out:
        mutex_unlock(&attr->mutex);
        return ret;
}

static ssize_t spufs_attr_write(struct file *file, const char __user *buf,
                size_t len, loff_t *ppos)
{
        struct spufs_attr *attr;
        u64 val;
        size_t size;
        ssize_t ret;

        attr = file->private_data;
        if (!attr->set)
                return -EACCES;

        ret = mutex_lock_interruptible(&attr->mutex);
        if (ret)
                return ret;

        ret = -EFAULT;
        size = min(sizeof(attr->set_buf) - 1, len);
        if (copy_from_user(attr->set_buf, buf, size))
                goto out;

        ret = len; /* claim we got the whole input */
        attr->set_buf[size] = '\0';
        val = simple_strtol(attr->set_buf, NULL, 0);
        attr->set(attr->data, val);
out:
        mutex_unlock(&attr->mutex);
        return ret;
}

#define DEFINE_SPUFS_SIMPLE_ATTRIBUTE(__fops, __get, __set, __fmt)      \
static int __fops ## _open(struct inode *inode, struct file *file)      \
{                                                                       \
        __simple_attr_check_format(__fmt, 0ull);                        \
        return spufs_attr_open(inode, file, __get, __set, __fmt);       \
}                                                                       \
static const struct file_operations __fops = {                          \
        .open    = __fops ## _open,                                     \
        .release = spufs_attr_release,                                  \
        .read    = spufs_attr_read,                                     \
        .write   = spufs_attr_write,                                    \
        .llseek  = generic_file_llseek,                                 \
};


static int
spufs_mem_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        file->private_data = ctx;
        if (!i->i_openers++)
                ctx->local_store = inode->i_mapping;
        mutex_unlock(&ctx->mapping_lock);
        return 0;
}

static int
spufs_mem_release(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        if (!--i->i_openers)
                ctx->local_store = NULL;
        mutex_unlock(&ctx->mapping_lock);
        return 0;
}

static ssize_t
__spufs_mem_read(struct spu_context *ctx, char __user *buffer,
                        size_t size, loff_t *pos)
{
        char *local_store = ctx->ops->get_ls(ctx);
        return simple_read_from_buffer(buffer, size, pos, local_store,
                                        LS_SIZE);
}

static ssize_t
spufs_mem_read(struct file *file, char __user *buffer,
                                size_t size, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        ssize_t ret;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        ret = __spufs_mem_read(ctx, buffer, size, pos);
        spu_release(ctx);

        return ret;
}

static ssize_t
spufs_mem_write(struct file *file, const char __user *buffer,
                                        size_t size, loff_t *ppos)
{
        struct spu_context *ctx = file->private_data;
        char *local_store;
        loff_t pos = *ppos;
        int ret;

        if (pos > LS_SIZE)
                return -EFBIG;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;

        local_store = ctx->ops->get_ls(ctx);
        size = simple_write_to_buffer(local_store, LS_SIZE, ppos, buffer, size);
        spu_release(ctx);

        return size;
}

static int
spufs_mem_mmap_fault(struct vm_fault *vmf)
{
        struct vm_area_struct *vma = vmf->vma;
        struct spu_context *ctx = vma->vm_file->private_data;
        unsigned long pfn, offset;

        offset = vmf->pgoff << PAGE_SHIFT;
        if (offset >= LS_SIZE)
                return VM_FAULT_SIGBUS;

        pr_debug("spufs_mem_mmap_fault address=0x%lx, offset=0x%lx\n",
                        vmf->address, offset);

        if (spu_acquire(ctx))
                return VM_FAULT_NOPAGE;

        if (ctx->state == SPU_STATE_SAVED) {
                vma->vm_page_prot = pgprot_cached(vma->vm_page_prot);
                pfn = vmalloc_to_pfn(ctx->csa.lscsa->ls + offset);
        } else {
                vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);
                pfn = (ctx->spu->local_store_phys + offset) >> PAGE_SHIFT;
        }
        vm_insert_pfn(vma, vmf->address, pfn);

        spu_release(ctx);

        return VM_FAULT_NOPAGE;
}

static int spufs_mem_mmap_access(struct vm_area_struct *vma,
                                unsigned long address,
                                void *buf, int len, int write)
{
        struct spu_context *ctx = vma->vm_file->private_data;
        unsigned long offset = address - vma->vm_start;
        char *local_store;

        if (write && !(vma->vm_flags & VM_WRITE))
                return -EACCES;
        if (spu_acquire(ctx))
                return -EINTR;
        if ((offset + len) > vma->vm_end)
                len = vma->vm_end - offset;
        local_store = ctx->ops->get_ls(ctx);
        if (write)
                memcpy_toio(local_store + offset, buf, len);
        else
                memcpy_fromio(buf, local_store + offset, len);
        spu_release(ctx);
        return len;
}

static const struct vm_operations_struct spufs_mem_mmap_vmops = {
        .fault = spufs_mem_mmap_fault,
        .access = spufs_mem_mmap_access,
};

static int spufs_mem_mmap(struct file *file, struct vm_area_struct *vma)
{
        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        vma->vm_flags |= VM_IO | VM_PFNMAP;
        vma->vm_page_prot = pgprot_noncached_wc(vma->vm_page_prot);

        vma->vm_ops = &spufs_mem_mmap_vmops;
        return 0;
}

static const struct file_operations spufs_mem_fops = {
        .open                   = spufs_mem_open,
        .release                = spufs_mem_release,
        .read                   = spufs_mem_read,
        .write                  = spufs_mem_write,
        .llseek                 = generic_file_llseek,
        .mmap                   = spufs_mem_mmap,
};

static int spufs_ps_fault(struct vm_fault *vmf,
                                    unsigned long ps_offs,
                                    unsigned long ps_size)
{
        struct spu_context *ctx = vmf->vma->vm_file->private_data;
        unsigned long area, offset = vmf->pgoff << PAGE_SHIFT;
        int ret = 0;

        spu_context_nospu_trace(spufs_ps_fault__enter, ctx);

        if (offset >= ps_size)
                return VM_FAULT_SIGBUS;

        if (fatal_signal_pending(current))
                return VM_FAULT_SIGBUS;

        /*
         * Because we release the mmap_sem, the context may be destroyed while
         * we're in spu_wait. Grab an extra reference so it isn't destroyed
         * in the meantime.
         */
        get_spu_context(ctx);

        /*
         * We have to wait for context to be loaded before we have
         * pages to hand out to the user, but we don't want to wait
         * with the mmap_sem held.
         * It is possible to drop the mmap_sem here, but then we need
         * to return VM_FAULT_NOPAGE because the mappings may have
         * hanged.
         */
        if (spu_acquire(ctx))
                goto refault;

        if (ctx->state == SPU_STATE_SAVED) {
                up_read(&current->mm->mmap_sem);
                spu_context_nospu_trace(spufs_ps_fault__sleep, ctx);
                ret = spufs_wait(ctx->run_wq, ctx->state == SPU_STATE_RUNNABLE);
                spu_context_trace(spufs_ps_fault__wake, ctx, ctx->spu);
                down_read(&current->mm->mmap_sem);
        } else {
                area = ctx->spu->problem_phys + ps_offs;
                vm_insert_pfn(vmf->vma, vmf->address, (area + offset) >> PAGE_SHIFT);
                spu_context_trace(spufs_ps_fault__insert, ctx, ctx->spu);
        }

        if (!ret)
                spu_release(ctx);

refault:
        put_spu_context(ctx);
        return VM_FAULT_NOPAGE;
}

#if SPUFS_MMAP_4K
static int spufs_cntl_mmap_fault(struct vm_fault *vmf)
{
        return spufs_ps_fault(vmf, 0x4000, SPUFS_CNTL_MAP_SIZE);
}

static const struct vm_operations_struct spufs_cntl_mmap_vmops = {
        .fault = spufs_cntl_mmap_fault,
};

/*
 * mmap support for problem state control area [0x4000 - 0x4fff].
 */
static int spufs_cntl_mmap(struct file *file, struct vm_area_struct *vma)
{
        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        vma->vm_flags |= VM_IO | VM_PFNMAP;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        vma->vm_ops = &spufs_cntl_mmap_vmops;
        return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_cntl_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_cntl_get(void *data, u64 *val)
{
        struct spu_context *ctx = data;
        int ret;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        *val = ctx->ops->status_read(ctx);
        spu_release(ctx);

        return 0;
}

static int spufs_cntl_set(void *data, u64 val)
{
        struct spu_context *ctx = data;
        int ret;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        ctx->ops->runcntl_write(ctx, val);
        spu_release(ctx);

        return 0;
}

static int spufs_cntl_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        file->private_data = ctx;
        if (!i->i_openers++)
                ctx->cntl = inode->i_mapping;
        mutex_unlock(&ctx->mapping_lock);
        return simple_attr_open(inode, file, spufs_cntl_get,
                                        spufs_cntl_set, "0x%08lx");
}

static int
spufs_cntl_release(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        simple_attr_release(inode, file);

        mutex_lock(&ctx->mapping_lock);
        if (!--i->i_openers)
                ctx->cntl = NULL;
        mutex_unlock(&ctx->mapping_lock);
        return 0;
}

static const struct file_operations spufs_cntl_fops = {
        .open = spufs_cntl_open,
        .release = spufs_cntl_release,
        .read = simple_attr_read,
        .write = simple_attr_write,
        .llseek = generic_file_llseek,
        .mmap = spufs_cntl_mmap,
};

static int
spufs_regs_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        file->private_data = i->i_ctx;
        return 0;
}

static ssize_t
__spufs_regs_read(struct spu_context *ctx, char __user *buffer,
                        size_t size, loff_t *pos)
{
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        return simple_read_from_buffer(buffer, size, pos,
                                      lscsa->gprs, sizeof lscsa->gprs);
}

static ssize_t
spufs_regs_read(struct file *file, char __user *buffer,
                size_t size, loff_t *pos)
{
        int ret;
        struct spu_context *ctx = file->private_data;

        /* pre-check for file position: if we'd return EOF, there's no point
         * causing a deschedule */
        if (*pos >= sizeof(ctx->csa.lscsa->gprs))
                return 0;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        ret = __spufs_regs_read(ctx, buffer, size, pos);
        spu_release_saved(ctx);
        return ret;
}

static ssize_t
spufs_regs_write(struct file *file, const char __user *buffer,
                 size_t size, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        int ret;

        if (*pos >= sizeof(lscsa->gprs))
                return -EFBIG;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;

        size = simple_write_to_buffer(lscsa->gprs, sizeof(lscsa->gprs), pos,
                                        buffer, size);

        spu_release_saved(ctx);
        return size;
}

static const struct file_operations spufs_regs_fops = {
        .open    = spufs_regs_open,
        .read    = spufs_regs_read,
        .write   = spufs_regs_write,
        .llseek  = generic_file_llseek,
};

static ssize_t
__spufs_fpcr_read(struct spu_context *ctx, char __user * buffer,
                        size_t size, loff_t * pos)
{
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        return simple_read_from_buffer(buffer, size, pos,
                                      &lscsa->fpcr, sizeof(lscsa->fpcr));
}

static ssize_t
spufs_fpcr_read(struct file *file, char __user * buffer,
                size_t size, loff_t * pos)
{
        int ret;
        struct spu_context *ctx = file->private_data;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        ret = __spufs_fpcr_read(ctx, buffer, size, pos);
        spu_release_saved(ctx);
        return ret;
}

static ssize_t
spufs_fpcr_write(struct file *file, const char __user * buffer,
                 size_t size, loff_t * pos)
{
        struct spu_context *ctx = file->private_data;
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        int ret;

        if (*pos >= sizeof(lscsa->fpcr))
                return -EFBIG;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;

        size = simple_write_to_buffer(&lscsa->fpcr, sizeof(lscsa->fpcr), pos,
                                        buffer, size);

        spu_release_saved(ctx);
        return size;
}

static const struct file_operations spufs_fpcr_fops = {
        .open = spufs_regs_open,
        .read = spufs_fpcr_read,
        .write = spufs_fpcr_write,
        .llseek = generic_file_llseek,
};

/* generic open function for all pipe-like files */
static int spufs_pipe_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        file->private_data = i->i_ctx;

        return nonseekable_open(inode, file);
}

/*
 * Read as many bytes from the mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - no more data available in the mailbox
 * - end of the user provided buffer
 * - end of the mapped area
 */
static ssize_t spufs_mbox_read(struct file *file, char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        u32 mbox_data, __user *udata;
        ssize_t count;

        if (len < 4)
                return -EINVAL;

        if (!access_ok(VERIFY_WRITE, buf, len))
                return -EFAULT;

        udata = (void __user *)buf;

        count = spu_acquire(ctx);
        if (count)
                return count;

        for (count = 0; (count + 4) <= len; count += 4, udata++) {
                int ret;
                ret = ctx->ops->mbox_read(ctx, &mbox_data);
                if (ret == 0)
                        break;

                /*
                 * at the end of the mapped area, we can fault
                 * but still need to return the data we have
                 * read successfully so far.
                 */
                ret = __put_user(mbox_data, udata);
                if (ret) {
                        if (!count)
                                count = -EFAULT;
                        break;
                }
        }
        spu_release(ctx);

        if (!count)
                count = -EAGAIN;

        return count;
}

static const struct file_operations spufs_mbox_fops = {
        .open   = spufs_pipe_open,
        .read   = spufs_mbox_read,
        .llseek = no_llseek,
};

static ssize_t spufs_mbox_stat_read(struct file *file, char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        ssize_t ret;
        u32 mbox_stat;

        if (len < 4)
                return -EINVAL;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;

        mbox_stat = ctx->ops->mbox_stat_read(ctx) & 0xff;

        spu_release(ctx);

        if (copy_to_user(buf, &mbox_stat, sizeof mbox_stat))
                return -EFAULT;

        return 4;
}

static const struct file_operations spufs_mbox_stat_fops = {
        .open   = spufs_pipe_open,
        .read   = spufs_mbox_stat_read,
        .llseek = no_llseek,
};

/* low-level ibox access function */
size_t spu_ibox_read(struct spu_context *ctx, u32 *data)
{
        return ctx->ops->ibox_read(ctx, data);
}

static int spufs_ibox_fasync(int fd, struct file *file, int on)
{
        struct spu_context *ctx = file->private_data;

        return fasync_helper(fd, file, on, &ctx->ibox_fasync);
}

/* interrupt-level ibox callback function. */
void spufs_ibox_callback(struct spu *spu)
{
        struct spu_context *ctx = spu->ctx;

        if (!ctx)
                return;

        wake_up_all(&ctx->ibox_wq);
        kill_fasync(&ctx->ibox_fasync, SIGIO, POLLIN);
}

/*
 * Read as many bytes from the interrupt mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - no more data available in the mailbox
 * - end of the user provided buffer
 * - end of the mapped area
 *
 * If the file is opened without O_NONBLOCK, we wait here until
 * any data is available, but return when we have been able to
 * read something.
 */
static ssize_t spufs_ibox_read(struct file *file, char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        u32 ibox_data, __user *udata;
        ssize_t count;

        if (len < 4)
                return -EINVAL;

        if (!access_ok(VERIFY_WRITE, buf, len))
                return -EFAULT;

        udata = (void __user *)buf;

        count = spu_acquire(ctx);
        if (count)
                goto out;

        /* wait only for the first element */
        count = 0;
        if (file->f_flags & O_NONBLOCK) {
                if (!spu_ibox_read(ctx, &ibox_data)) {
                        count = -EAGAIN;
                        goto out_unlock;
                }
        } else {
                count = spufs_wait(ctx->ibox_wq, spu_ibox_read(ctx, &ibox_data));
                if (count)
                        goto out;
        }

        /* if we can't write at all, return -EFAULT */
        count = __put_user(ibox_data, udata);
        if (count)
                goto out_unlock;

        for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) {
                int ret;
                ret = ctx->ops->ibox_read(ctx, &ibox_data);
                if (ret == 0)
                        break;
                /*
                 * at the end of the mapped area, we can fault
                 * but still need to return the data we have
                 * read successfully so far.
                 */
                ret = __put_user(ibox_data, udata);
                if (ret)
                        break;
        }

out_unlock:
        spu_release(ctx);
out:
        return count;
}

static unsigned int spufs_ibox_poll(struct file *file, poll_table *wait)
{
        struct spu_context *ctx = file->private_data;
        unsigned int mask;

        poll_wait(file, &ctx->ibox_wq, wait);

        /*
         * For now keep this uninterruptible and also ignore the rule
         * that poll should not sleep.  Will be fixed later.
         */
        mutex_lock(&ctx->state_mutex);
        mask = ctx->ops->mbox_stat_poll(ctx, POLLIN | POLLRDNORM);
        spu_release(ctx);

        return mask;
}

static const struct file_operations spufs_ibox_fops = {
        .open   = spufs_pipe_open,
        .read   = spufs_ibox_read,
        .poll   = spufs_ibox_poll,
        .fasync = spufs_ibox_fasync,
        .llseek = no_llseek,
};

static ssize_t spufs_ibox_stat_read(struct file *file, char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        ssize_t ret;
        u32 ibox_stat;

        if (len < 4)
                return -EINVAL;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        ibox_stat = (ctx->ops->mbox_stat_read(ctx) >> 16) & 0xff;
        spu_release(ctx);

        if (copy_to_user(buf, &ibox_stat, sizeof ibox_stat))
                return -EFAULT;

        return 4;
}

static const struct file_operations spufs_ibox_stat_fops = {
        .open   = spufs_pipe_open,
        .read   = spufs_ibox_stat_read,
        .llseek = no_llseek,
};

/* low-level mailbox write */
size_t spu_wbox_write(struct spu_context *ctx, u32 data)
{
        return ctx->ops->wbox_write(ctx, data);
}

static int spufs_wbox_fasync(int fd, struct file *file, int on)
{
        struct spu_context *ctx = file->private_data;
        int ret;

        ret = fasync_helper(fd, file, on, &ctx->wbox_fasync);

        return ret;
}

/* interrupt-level wbox callback function. */
void spufs_wbox_callback(struct spu *spu)
{
        struct spu_context *ctx = spu->ctx;

        if (!ctx)
                return;

        wake_up_all(&ctx->wbox_wq);
        kill_fasync(&ctx->wbox_fasync, SIGIO, POLLOUT);
}

/*
 * Write as many bytes to the interrupt mailbox as possible, until
 * one of the conditions becomes true:
 *
 * - the mailbox is full
 * - end of the user provided buffer
 * - end of the mapped area
 *
 * If the file is opened without O_NONBLOCK, we wait here until
 * space is available, but return when we have been able to
 * write something.
 */
static ssize_t spufs_wbox_write(struct file *file, const char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        u32 wbox_data, __user *udata;
        ssize_t count;

        if (len < 4)
                return -EINVAL;

        udata = (void __user *)buf;
        if (!access_ok(VERIFY_READ, buf, len))
                return -EFAULT;

        if (__get_user(wbox_data, udata))
                return -EFAULT;

        count = spu_acquire(ctx);
        if (count)
                goto out;

        /*
         * make sure we can at least write one element, by waiting
         * in case of !O_NONBLOCK
         */
        count = 0;
        if (file->f_flags & O_NONBLOCK) {
                if (!spu_wbox_write(ctx, wbox_data)) {
                        count = -EAGAIN;
                        goto out_unlock;
                }
        } else {
                count = spufs_wait(ctx->wbox_wq, spu_wbox_write(ctx, wbox_data));
                if (count)
                        goto out;
        }


        /* write as much as possible */
        for (count = 4, udata++; (count + 4) <= len; count += 4, udata++) {
                int ret;
                ret = __get_user(wbox_data, udata);
                if (ret)
                        break;

                ret = spu_wbox_write(ctx, wbox_data);
                if (ret == 0)
                        break;
        }

out_unlock:
        spu_release(ctx);
out:
        return count;
}

static unsigned int spufs_wbox_poll(struct file *file, poll_table *wait)
{
        struct spu_context *ctx = file->private_data;
        unsigned int mask;

        poll_wait(file, &ctx->wbox_wq, wait);

        /*
         * For now keep this uninterruptible and also ignore the rule
         * that poll should not sleep.  Will be fixed later.
         */
        mutex_lock(&ctx->state_mutex);
        mask = ctx->ops->mbox_stat_poll(ctx, POLLOUT | POLLWRNORM);
        spu_release(ctx);

        return mask;
}

static const struct file_operations spufs_wbox_fops = {
        .open   = spufs_pipe_open,
        .write  = spufs_wbox_write,
        .poll   = spufs_wbox_poll,
        .fasync = spufs_wbox_fasync,
        .llseek = no_llseek,
};

static ssize_t spufs_wbox_stat_read(struct file *file, char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        ssize_t ret;
        u32 wbox_stat;

        if (len < 4)
                return -EINVAL;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        wbox_stat = (ctx->ops->mbox_stat_read(ctx) >> 8) & 0xff;
        spu_release(ctx);

        if (copy_to_user(buf, &wbox_stat, sizeof wbox_stat))
                return -EFAULT;

        return 4;
}

static const struct file_operations spufs_wbox_stat_fops = {
        .open   = spufs_pipe_open,
        .read   = spufs_wbox_stat_read,
        .llseek = no_llseek,
};

static int spufs_signal1_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        file->private_data = ctx;
        if (!i->i_openers++)
                ctx->signal1 = inode->i_mapping;
        mutex_unlock(&ctx->mapping_lock);
        return nonseekable_open(inode, file);
}

static int
spufs_signal1_release(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        if (!--i->i_openers)
                ctx->signal1 = NULL;
        mutex_unlock(&ctx->mapping_lock);
        return 0;
}

static ssize_t __spufs_signal1_read(struct spu_context *ctx, char __user *buf,
                        size_t len, loff_t *pos)
{
        int ret = 0;
        u32 data;

        if (len < 4)
                return -EINVAL;

        if (ctx->csa.spu_chnlcnt_RW[3]) {
                data = ctx->csa.spu_chnldata_RW[3];
                ret = 4;
        }

        if (!ret)
                goto out;

        if (copy_to_user(buf, &data, 4))
                return -EFAULT;

out:
        return ret;
}

static ssize_t spufs_signal1_read(struct file *file, char __user *buf,
                        size_t len, loff_t *pos)
{
        int ret;
        struct spu_context *ctx = file->private_data;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        ret = __spufs_signal1_read(ctx, buf, len, pos);
        spu_release_saved(ctx);

        return ret;
}

static ssize_t spufs_signal1_write(struct file *file, const char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx;
        ssize_t ret;
        u32 data;

        ctx = file->private_data;

        if (len < 4)
                return -EINVAL;

        if (copy_from_user(&data, buf, 4))
                return -EFAULT;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        ctx->ops->signal1_write(ctx, data);
        spu_release(ctx);

        return 4;
}

static int
spufs_signal1_mmap_fault(struct vm_fault *vmf)
{
#if SPUFS_SIGNAL_MAP_SIZE == 0x1000
        return spufs_ps_fault(vmf, 0x14000, SPUFS_SIGNAL_MAP_SIZE);
#elif SPUFS_SIGNAL_MAP_SIZE == 0x10000
        /* For 64k pages, both signal1 and signal2 can be used to mmap the whole
         * signal 1 and 2 area
         */
        return spufs_ps_fault(vmf, 0x10000, SPUFS_SIGNAL_MAP_SIZE);
#else
#error unsupported page size
#endif
}

static const struct vm_operations_struct spufs_signal1_mmap_vmops = {
        .fault = spufs_signal1_mmap_fault,
};

static int spufs_signal1_mmap(struct file *file, struct vm_area_struct *vma)
{
        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        vma->vm_flags |= VM_IO | VM_PFNMAP;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        vma->vm_ops = &spufs_signal1_mmap_vmops;
        return 0;
}

static const struct file_operations spufs_signal1_fops = {
        .open = spufs_signal1_open,
        .release = spufs_signal1_release,
        .read = spufs_signal1_read,
        .write = spufs_signal1_write,
        .mmap = spufs_signal1_mmap,
        .llseek = no_llseek,
};

static const struct file_operations spufs_signal1_nosched_fops = {
        .open = spufs_signal1_open,
        .release = spufs_signal1_release,
        .write = spufs_signal1_write,
        .mmap = spufs_signal1_mmap,
        .llseek = no_llseek,
};

static int spufs_signal2_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        file->private_data = ctx;
        if (!i->i_openers++)
                ctx->signal2 = inode->i_mapping;
        mutex_unlock(&ctx->mapping_lock);
        return nonseekable_open(inode, file);
}

static int
spufs_signal2_release(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        if (!--i->i_openers)
                ctx->signal2 = NULL;
        mutex_unlock(&ctx->mapping_lock);
        return 0;
}

static ssize_t __spufs_signal2_read(struct spu_context *ctx, char __user *buf,
                        size_t len, loff_t *pos)
{
        int ret = 0;
        u32 data;

        if (len < 4)
                return -EINVAL;

        if (ctx->csa.spu_chnlcnt_RW[4]) {
                data =  ctx->csa.spu_chnldata_RW[4];
                ret = 4;
        }

        if (!ret)
                goto out;

        if (copy_to_user(buf, &data, 4))
                return -EFAULT;

out:
        return ret;
}

static ssize_t spufs_signal2_read(struct file *file, char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        int ret;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        ret = __spufs_signal2_read(ctx, buf, len, pos);
        spu_release_saved(ctx);

        return ret;
}

static ssize_t spufs_signal2_write(struct file *file, const char __user *buf,
                        size_t len, loff_t *pos)
{
        struct spu_context *ctx;
        ssize_t ret;
        u32 data;

        ctx = file->private_data;

        if (len < 4)
                return -EINVAL;

        if (copy_from_user(&data, buf, 4))
                return -EFAULT;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        ctx->ops->signal2_write(ctx, data);
        spu_release(ctx);

        return 4;
}

#if SPUFS_MMAP_4K
static int
spufs_signal2_mmap_fault(struct vm_fault *vmf)
{
#if SPUFS_SIGNAL_MAP_SIZE == 0x1000
        return spufs_ps_fault(vmf, 0x1c000, SPUFS_SIGNAL_MAP_SIZE);
#elif SPUFS_SIGNAL_MAP_SIZE == 0x10000
        /* For 64k pages, both signal1 and signal2 can be used to mmap the whole
         * signal 1 and 2 area
         */
        return spufs_ps_fault(vmf, 0x10000, SPUFS_SIGNAL_MAP_SIZE);
#else
#error unsupported page size
#endif
}

static const struct vm_operations_struct spufs_signal2_mmap_vmops = {
        .fault = spufs_signal2_mmap_fault,
};

static int spufs_signal2_mmap(struct file *file, struct vm_area_struct *vma)
{
        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        vma->vm_flags |= VM_IO | VM_PFNMAP;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        vma->vm_ops = &spufs_signal2_mmap_vmops;
        return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_signal2_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static const struct file_operations spufs_signal2_fops = {
        .open = spufs_signal2_open,
        .release = spufs_signal2_release,
        .read = spufs_signal2_read,
        .write = spufs_signal2_write,
        .mmap = spufs_signal2_mmap,
        .llseek = no_llseek,
};

static const struct file_operations spufs_signal2_nosched_fops = {
        .open = spufs_signal2_open,
        .release = spufs_signal2_release,
        .write = spufs_signal2_write,
        .mmap = spufs_signal2_mmap,
        .llseek = no_llseek,
};

/*
 * This is a wrapper around DEFINE_SIMPLE_ATTRIBUTE which does the
 * work of acquiring (or not) the SPU context before calling through
 * to the actual get routine. The set routine is called directly.
 */
#define SPU_ATTR_NOACQUIRE      0
#define SPU_ATTR_ACQUIRE        1
#define SPU_ATTR_ACQUIRE_SAVED  2

#define DEFINE_SPUFS_ATTRIBUTE(__name, __get, __set, __fmt, __acquire)  \
static int __##__get(void *data, u64 *val)                              \
{                                                                       \
        struct spu_context *ctx = data;                                 \
        int ret = 0;                                                    \
                                                                        \
        if (__acquire == SPU_ATTR_ACQUIRE) {                            \
                ret = spu_acquire(ctx);                                 \
                if (ret)                                                \
                        return ret;                                     \
                *val = __get(ctx);                                      \
                spu_release(ctx);                                       \
        } else if (__acquire == SPU_ATTR_ACQUIRE_SAVED) {               \
                ret = spu_acquire_saved(ctx);                           \
                if (ret)                                                \
                        return ret;                                     \
                *val = __get(ctx);                                      \
                spu_release_saved(ctx);                                 \
        } else                                                          \
                *val = __get(ctx);                                      \
                                                                        \
        return 0;                                                       \
}                                                                       \
DEFINE_SPUFS_SIMPLE_ATTRIBUTE(__name, __##__get, __set, __fmt);

static int spufs_signal1_type_set(void *data, u64 val)
{
        struct spu_context *ctx = data;
        int ret;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        ctx->ops->signal1_type_set(ctx, val);
        spu_release(ctx);

        return 0;
}

static u64 spufs_signal1_type_get(struct spu_context *ctx)
{
        return ctx->ops->signal1_type_get(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_signal1_type, spufs_signal1_type_get,
                       spufs_signal1_type_set, "%llu\n", SPU_ATTR_ACQUIRE);


static int spufs_signal2_type_set(void *data, u64 val)
{
        struct spu_context *ctx = data;
        int ret;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        ctx->ops->signal2_type_set(ctx, val);
        spu_release(ctx);

        return 0;
}

static u64 spufs_signal2_type_get(struct spu_context *ctx)
{
        return ctx->ops->signal2_type_get(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_signal2_type, spufs_signal2_type_get,
                       spufs_signal2_type_set, "%llu\n", SPU_ATTR_ACQUIRE);

#if SPUFS_MMAP_4K
static int
spufs_mss_mmap_fault(struct vm_fault *vmf)
{
        return spufs_ps_fault(vmf, 0x0000, SPUFS_MSS_MAP_SIZE);
}

static const struct vm_operations_struct spufs_mss_mmap_vmops = {
        .fault = spufs_mss_mmap_fault,
};

/*
 * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
 */
static int spufs_mss_mmap(struct file *file, struct vm_area_struct *vma)
{
        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        vma->vm_flags |= VM_IO | VM_PFNMAP;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        vma->vm_ops = &spufs_mss_mmap_vmops;
        return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_mss_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_mss_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        file->private_data = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        if (!i->i_openers++)
                ctx->mss = inode->i_mapping;
        mutex_unlock(&ctx->mapping_lock);
        return nonseekable_open(inode, file);
}

static int
spufs_mss_release(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        if (!--i->i_openers)
                ctx->mss = NULL;
        mutex_unlock(&ctx->mapping_lock);
        return 0;
}

static const struct file_operations spufs_mss_fops = {
        .open    = spufs_mss_open,
        .release = spufs_mss_release,
        .mmap    = spufs_mss_mmap,
        .llseek  = no_llseek,
};

static int
spufs_psmap_mmap_fault(struct vm_fault *vmf)
{
        return spufs_ps_fault(vmf, 0x0000, SPUFS_PS_MAP_SIZE);
}

static const struct vm_operations_struct spufs_psmap_mmap_vmops = {
        .fault = spufs_psmap_mmap_fault,
};

/*
 * mmap support for full problem state area [0x00000 - 0x1ffff].
 */
static int spufs_psmap_mmap(struct file *file, struct vm_area_struct *vma)
{
        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        vma->vm_flags |= VM_IO | VM_PFNMAP;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        vma->vm_ops = &spufs_psmap_mmap_vmops;
        return 0;
}

static int spufs_psmap_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        file->private_data = i->i_ctx;
        if (!i->i_openers++)
                ctx->psmap = inode->i_mapping;
        mutex_unlock(&ctx->mapping_lock);
        return nonseekable_open(inode, file);
}

static int
spufs_psmap_release(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        if (!--i->i_openers)
                ctx->psmap = NULL;
        mutex_unlock(&ctx->mapping_lock);
        return 0;
}

static const struct file_operations spufs_psmap_fops = {
        .open    = spufs_psmap_open,
        .release = spufs_psmap_release,
        .mmap    = spufs_psmap_mmap,
        .llseek  = no_llseek,
};


#if SPUFS_MMAP_4K
static int
spufs_mfc_mmap_fault(struct vm_fault *vmf)
{
        return spufs_ps_fault(vmf, 0x3000, SPUFS_MFC_MAP_SIZE);
}

static const struct vm_operations_struct spufs_mfc_mmap_vmops = {
        .fault = spufs_mfc_mmap_fault,
};

/*
 * mmap support for problem state MFC DMA area [0x0000 - 0x0fff].
 */
static int spufs_mfc_mmap(struct file *file, struct vm_area_struct *vma)
{
        if (!(vma->vm_flags & VM_SHARED))
                return -EINVAL;

        vma->vm_flags |= VM_IO | VM_PFNMAP;
        vma->vm_page_prot = pgprot_noncached(vma->vm_page_prot);

        vma->vm_ops = &spufs_mfc_mmap_vmops;
        return 0;
}
#else /* SPUFS_MMAP_4K */
#define spufs_mfc_mmap NULL
#endif /* !SPUFS_MMAP_4K */

static int spufs_mfc_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        /* we don't want to deal with DMA into other processes */
        if (ctx->owner != current->mm)
                return -EINVAL;

        if (atomic_read(&inode->i_count) != 1)
                return -EBUSY;

        mutex_lock(&ctx->mapping_lock);
        file->private_data = ctx;
        if (!i->i_openers++)
                ctx->mfc = inode->i_mapping;
        mutex_unlock(&ctx->mapping_lock);
        return nonseekable_open(inode, file);
}

static int
spufs_mfc_release(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;

        mutex_lock(&ctx->mapping_lock);
        if (!--i->i_openers)
                ctx->mfc = NULL;
        mutex_unlock(&ctx->mapping_lock);
        return 0;
}

/* interrupt-level mfc callback function. */
void spufs_mfc_callback(struct spu *spu)
{
        struct spu_context *ctx = spu->ctx;

        if (!ctx)
                return;

        wake_up_all(&ctx->mfc_wq);

        pr_debug("%s %s\n", __func__, spu->name);
        if (ctx->mfc_fasync) {
                u32 free_elements, tagstatus;
                unsigned int mask;

                /* no need for spu_acquire in interrupt context */
                free_elements = ctx->ops->get_mfc_free_elements(ctx);
                tagstatus = ctx->ops->read_mfc_tagstatus(ctx);

                mask = 0;
                if (free_elements & 0xffff)
                        mask |= POLLOUT;
                if (tagstatus & ctx->tagwait)
                        mask |= POLLIN;

                kill_fasync(&ctx->mfc_fasync, SIGIO, mask);
        }
}

static int spufs_read_mfc_tagstatus(struct spu_context *ctx, u32 *status)
{
        /* See if there is one tag group is complete */
        /* FIXME we need locking around tagwait */
        *status = ctx->ops->read_mfc_tagstatus(ctx) & ctx->tagwait;
        ctx->tagwait &= ~*status;
        if (*status)
                return 1;

        /* enable interrupt waiting for any tag group,
           may silently fail if interrupts are already enabled */
        ctx->ops->set_mfc_query(ctx, ctx->tagwait, 1);
        return 0;
}

static ssize_t spufs_mfc_read(struct file *file, char __user *buffer,
                        size_t size, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        int ret = -EINVAL;
        u32 status;

        if (size != 4)
                goto out;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;

        ret = -EINVAL;
        if (file->f_flags & O_NONBLOCK) {
                status = ctx->ops->read_mfc_tagstatus(ctx);
                if (!(status & ctx->tagwait))
                        ret = -EAGAIN;
                else
                        /* XXX(hch): shouldn't we clear ret here? */
                        ctx->tagwait &= ~status;
        } else {
                ret = spufs_wait(ctx->mfc_wq,
                           spufs_read_mfc_tagstatus(ctx, &status));
                if (ret)
                        goto out;
        }
        spu_release(ctx);

        ret = 4;
        if (copy_to_user(buffer, &status, 4))
                ret = -EFAULT;

out:
        return ret;
}

static int spufs_check_valid_dma(struct mfc_dma_command *cmd)
{
        pr_debug("queueing DMA %x %llx %x %x %x\n", cmd->lsa,
                 cmd->ea, cmd->size, cmd->tag, cmd->cmd);

        switch (cmd->cmd) {
        case MFC_PUT_CMD:
        case MFC_PUTF_CMD:
        case MFC_PUTB_CMD:
        case MFC_GET_CMD:
        case MFC_GETF_CMD:
        case MFC_GETB_CMD:
                break;
        default:
                pr_debug("invalid DMA opcode %x\n", cmd->cmd);
                return -EIO;
        }

        if ((cmd->lsa & 0xf) != (cmd->ea &0xf)) {
                pr_debug("invalid DMA alignment, ea %llx lsa %x\n",
                                cmd->ea, cmd->lsa);
                return -EIO;
        }

        switch (cmd->size & 0xf) {
        case 1:
                break;
        case 2:
                if (cmd->lsa & 1)
                        goto error;
                break;
        case 4:
                if (cmd->lsa & 3)
                        goto error;
                break;
        case 8:
                if (cmd->lsa & 7)
                        goto error;
                break;
        case 0:
                if (cmd->lsa & 15)
                        goto error;
                break;
        error:
        default:
                pr_debug("invalid DMA alignment %x for size %x\n",
                        cmd->lsa & 0xf, cmd->size);
                return -EIO;
        }

        if (cmd->size > 16 * 1024) {
                pr_debug("invalid DMA size %x\n", cmd->size);
                return -EIO;
        }

        if (cmd->tag & 0xfff0) {
                /* we reserve the higher tag numbers for kernel use */
                pr_debug("invalid DMA tag\n");
                return -EIO;
        }

        if (cmd->class) {
                /* not supported in this version */
                pr_debug("invalid DMA class\n");
                return -EIO;
        }

        return 0;
}

static int spu_send_mfc_command(struct spu_context *ctx,
                                struct mfc_dma_command cmd,
                                int *error)
{
        *error = ctx->ops->send_mfc_command(ctx, &cmd);
        if (*error == -EAGAIN) {
                /* wait for any tag group to complete
                   so we have space for the new command */
                ctx->ops->set_mfc_query(ctx, ctx->tagwait, 1);
                /* try again, because the queue might be
                   empty again */
                *error = ctx->ops->send_mfc_command(ctx, &cmd);
                if (*error == -EAGAIN)
                        return 0;
        }
        return 1;
}

static ssize_t spufs_mfc_write(struct file *file, const char __user *buffer,
                        size_t size, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        struct mfc_dma_command cmd;
        int ret = -EINVAL;

        if (size != sizeof cmd)
                goto out;

        ret = -EFAULT;
        if (copy_from_user(&cmd, buffer, sizeof cmd))
                goto out;

        ret = spufs_check_valid_dma(&cmd);
        if (ret)
                goto out;

        ret = spu_acquire(ctx);
        if (ret)
                goto out;

        ret = spufs_wait(ctx->run_wq, ctx->state == SPU_STATE_RUNNABLE);
        if (ret)
                goto out;

        if (file->f_flags & O_NONBLOCK) {
                ret = ctx->ops->send_mfc_command(ctx, &cmd);
        } else {
                int status;
                ret = spufs_wait(ctx->mfc_wq,
                                 spu_send_mfc_command(ctx, cmd, &status));
                if (ret)
                        goto out;
                if (status)
                        ret = status;
        }

        if (ret)
                goto out_unlock;

        ctx->tagwait |= 1 << cmd.tag;
        ret = size;

out_unlock:
        spu_release(ctx);
out:
        return ret;
}

static unsigned int spufs_mfc_poll(struct file *file,poll_table *wait)
{
        struct spu_context *ctx = file->private_data;
        u32 free_elements, tagstatus;
        unsigned int mask;

        poll_wait(file, &ctx->mfc_wq, wait);

        /*
         * For now keep this uninterruptible and also ignore the rule
         * that poll should not sleep.  Will be fixed later.
         */
        mutex_lock(&ctx->state_mutex);
        ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2);
        free_elements = ctx->ops->get_mfc_free_elements(ctx);
        tagstatus = ctx->ops->read_mfc_tagstatus(ctx);
        spu_release(ctx);

        mask = 0;
        if (free_elements & 0xffff)
                mask |= POLLOUT | POLLWRNORM;
        if (tagstatus & ctx->tagwait)
                mask |= POLLIN | POLLRDNORM;

        pr_debug("%s: free %d tagstatus %d tagwait %d\n", __func__,
                free_elements, tagstatus, ctx->tagwait);

        return mask;
}

static int spufs_mfc_flush(struct file *file, fl_owner_t id)
{
        struct spu_context *ctx = file->private_data;
        int ret;

        ret = spu_acquire(ctx);
        if (ret)
                goto out;
#if 0
/* this currently hangs */
        ret = spufs_wait(ctx->mfc_wq,
                         ctx->ops->set_mfc_query(ctx, ctx->tagwait, 2));
        if (ret)
                goto out;
        ret = spufs_wait(ctx->mfc_wq,
                         ctx->ops->read_mfc_tagstatus(ctx) == ctx->tagwait);
        if (ret)
                goto out;
#else
        ret = 0;
#endif
        spu_release(ctx);
out:
        return ret;
}

static int spufs_mfc_fsync(struct file *file, loff_t start, loff_t end, int datasync)
{
        struct inode *inode = file_inode(file);
        int err = filemap_write_and_wait_range(inode->i_mapping, start, end);
        if (!err) {
                inode_lock(inode);
                err = spufs_mfc_flush(file, NULL);
                inode_unlock(inode);
        }
        return err;
}

static int spufs_mfc_fasync(int fd, struct file *file, int on)
{
        struct spu_context *ctx = file->private_data;

        return fasync_helper(fd, file, on, &ctx->mfc_fasync);
}

static const struct file_operations spufs_mfc_fops = {
        .open    = spufs_mfc_open,
        .release = spufs_mfc_release,
        .read    = spufs_mfc_read,
        .write   = spufs_mfc_write,
        .poll    = spufs_mfc_poll,
        .flush   = spufs_mfc_flush,
        .fsync   = spufs_mfc_fsync,
        .fasync  = spufs_mfc_fasync,
        .mmap    = spufs_mfc_mmap,
        .llseek  = no_llseek,
};

static int spufs_npc_set(void *data, u64 val)
{
        struct spu_context *ctx = data;
        int ret;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;
        ctx->ops->npc_write(ctx, val);
        spu_release(ctx);

        return 0;
}

static u64 spufs_npc_get(struct spu_context *ctx)
{
        return ctx->ops->npc_read(ctx);
}
DEFINE_SPUFS_ATTRIBUTE(spufs_npc_ops, spufs_npc_get, spufs_npc_set,
                       "0x%llx\n", SPU_ATTR_ACQUIRE);

static int spufs_decr_set(void *data, u64 val)
{
        struct spu_context *ctx = data;
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        int ret;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        lscsa->decr.slot[0] = (u32) val;
        spu_release_saved(ctx);

        return 0;
}

static u64 spufs_decr_get(struct spu_context *ctx)
{
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        return lscsa->decr.slot[0];
}
DEFINE_SPUFS_ATTRIBUTE(spufs_decr_ops, spufs_decr_get, spufs_decr_set,
                       "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED);

static int spufs_decr_status_set(void *data, u64 val)
{
        struct spu_context *ctx = data;
        int ret;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        if (val)
                ctx->csa.priv2.mfc_control_RW |= MFC_CNTL_DECREMENTER_RUNNING;
        else
                ctx->csa.priv2.mfc_control_RW &= ~MFC_CNTL_DECREMENTER_RUNNING;
        spu_release_saved(ctx);

        return 0;
}

static u64 spufs_decr_status_get(struct spu_context *ctx)
{
        if (ctx->csa.priv2.mfc_control_RW & MFC_CNTL_DECREMENTER_RUNNING)
                return SPU_DECR_STATUS_RUNNING;
        else
                return 0;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_decr_status_ops, spufs_decr_status_get,
                       spufs_decr_status_set, "0x%llx\n",
                       SPU_ATTR_ACQUIRE_SAVED);

static int spufs_event_mask_set(void *data, u64 val)
{
        struct spu_context *ctx = data;
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        int ret;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        lscsa->event_mask.slot[0] = (u32) val;
        spu_release_saved(ctx);

        return 0;
}

static u64 spufs_event_mask_get(struct spu_context *ctx)
{
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        return lscsa->event_mask.slot[0];
}

DEFINE_SPUFS_ATTRIBUTE(spufs_event_mask_ops, spufs_event_mask_get,
                       spufs_event_mask_set, "0x%llx\n",
                       SPU_ATTR_ACQUIRE_SAVED);

static u64 spufs_event_status_get(struct spu_context *ctx)
{
        struct spu_state *state = &ctx->csa;
        u64 stat;
        stat = state->spu_chnlcnt_RW[0];
        if (stat)
                return state->spu_chnldata_RW[0];
        return 0;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_event_status_ops, spufs_event_status_get,
                       NULL, "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED)

static int spufs_srr0_set(void *data, u64 val)
{
        struct spu_context *ctx = data;
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        int ret;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        lscsa->srr0.slot[0] = (u32) val;
        spu_release_saved(ctx);

        return 0;
}

static u64 spufs_srr0_get(struct spu_context *ctx)
{
        struct spu_lscsa *lscsa = ctx->csa.lscsa;
        return lscsa->srr0.slot[0];
}
DEFINE_SPUFS_ATTRIBUTE(spufs_srr0_ops, spufs_srr0_get, spufs_srr0_set,
                       "0x%llx\n", SPU_ATTR_ACQUIRE_SAVED)

static u64 spufs_id_get(struct spu_context *ctx)
{
        u64 num;

        if (ctx->state == SPU_STATE_RUNNABLE)
                num = ctx->spu->number;
        else
                num = (unsigned int)-1;

        return num;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_id_ops, spufs_id_get, NULL, "0x%llx\n",
                       SPU_ATTR_ACQUIRE)

static u64 spufs_object_id_get(struct spu_context *ctx)
{
        /* FIXME: Should there really be no locking here? */
        return ctx->object_id;
}

static int spufs_object_id_set(void *data, u64 id)
{
        struct spu_context *ctx = data;
        ctx->object_id = id;

        return 0;
}

DEFINE_SPUFS_ATTRIBUTE(spufs_object_id_ops, spufs_object_id_get,
                       spufs_object_id_set, "0x%llx\n", SPU_ATTR_NOACQUIRE);

static u64 spufs_lslr_get(struct spu_context *ctx)
{
        return ctx->csa.priv2.spu_lslr_RW;
}
DEFINE_SPUFS_ATTRIBUTE(spufs_lslr_ops, spufs_lslr_get, NULL, "0x%llx\n",
                       SPU_ATTR_ACQUIRE_SAVED);

static int spufs_info_open(struct inode *inode, struct file *file)
{
        struct spufs_inode_info *i = SPUFS_I(inode);
        struct spu_context *ctx = i->i_ctx;
        file->private_data = ctx;
        return 0;
}

static int spufs_caps_show(struct seq_file *s, void *private)
{
        struct spu_context *ctx = s->private;

        if (!(ctx->flags & SPU_CREATE_NOSCHED))
                seq_puts(s, "sched\n");
        if (!(ctx->flags & SPU_CREATE_ISOLATE))
                seq_puts(s, "step\n");
        return 0;
}

static int spufs_caps_open(struct inode *inode, struct file *file)
{
        return single_open(file, spufs_caps_show, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_caps_fops = {
        .open           = spufs_caps_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static ssize_t __spufs_mbox_info_read(struct spu_context *ctx,
                        char __user *buf, size_t len, loff_t *pos)
{
        u32 data;

        /* EOF if there's no entry in the mbox */
        if (!(ctx->csa.prob.mb_stat_R & 0x0000ff))
                return 0;

        data = ctx->csa.prob.pu_mb_R;

        return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
}

static ssize_t spufs_mbox_info_read(struct file *file, char __user *buf,
                                   size_t len, loff_t *pos)
{
        int ret;
        struct spu_context *ctx = file->private_data;

        if (!access_ok(VERIFY_WRITE, buf, len))
                return -EFAULT;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        spin_lock(&ctx->csa.register_lock);
        ret = __spufs_mbox_info_read(ctx, buf, len, pos);
        spin_unlock(&ctx->csa.register_lock);
        spu_release_saved(ctx);

        return ret;
}

static const struct file_operations spufs_mbox_info_fops = {
        .open = spufs_info_open,
        .read = spufs_mbox_info_read,
        .llseek  = generic_file_llseek,
};

static ssize_t __spufs_ibox_info_read(struct spu_context *ctx,
                                char __user *buf, size_t len, loff_t *pos)
{
        u32 data;

        /* EOF if there's no entry in the ibox */
        if (!(ctx->csa.prob.mb_stat_R & 0xff0000))
                return 0;

        data = ctx->csa.priv2.puint_mb_R;

        return simple_read_from_buffer(buf, len, pos, &data, sizeof data);
}

static ssize_t spufs_ibox_info_read(struct file *file, char __user *buf,
                                   size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        int ret;

        if (!access_ok(VERIFY_WRITE, buf, len))
                return -EFAULT;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        spin_lock(&ctx->csa.register_lock);
        ret = __spufs_ibox_info_read(ctx, buf, len, pos);
        spin_unlock(&ctx->csa.register_lock);
        spu_release_saved(ctx);

        return ret;
}

static const struct file_operations spufs_ibox_info_fops = {
        .open = spufs_info_open,
        .read = spufs_ibox_info_read,
        .llseek  = generic_file_llseek,
};

static ssize_t __spufs_wbox_info_read(struct spu_context *ctx,
                        char __user *buf, size_t len, loff_t *pos)
{
        int i, cnt;
        u32 data[4];
        u32 wbox_stat;

        wbox_stat = ctx->csa.prob.mb_stat_R;
        cnt = 4 - ((wbox_stat & 0x00ff00) >> 8);
        for (i = 0; i < cnt; i++) {
                data[i] = ctx->csa.spu_mailbox_data[i];
        }

        return simple_read_from_buffer(buf, len, pos, &data,
                                cnt * sizeof(u32));
}

static ssize_t spufs_wbox_info_read(struct file *file, char __user *buf,
                                   size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        int ret;

        if (!access_ok(VERIFY_WRITE, buf, len))
                return -EFAULT;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        spin_lock(&ctx->csa.register_lock);
        ret = __spufs_wbox_info_read(ctx, buf, len, pos);
        spin_unlock(&ctx->csa.register_lock);
        spu_release_saved(ctx);

        return ret;
}

static const struct file_operations spufs_wbox_info_fops = {
        .open = spufs_info_open,
        .read = spufs_wbox_info_read,
        .llseek  = generic_file_llseek,
};

static ssize_t __spufs_dma_info_read(struct spu_context *ctx,
                        char __user *buf, size_t len, loff_t *pos)
{
        struct spu_dma_info info;
        struct mfc_cq_sr *qp, *spuqp;
        int i;

        info.dma_info_type = ctx->csa.priv2.spu_tag_status_query_RW;
        info.dma_info_mask = ctx->csa.lscsa->tag_mask.slot[0];
        info.dma_info_status = ctx->csa.spu_chnldata_RW[24];
        info.dma_info_stall_and_notify = ctx->csa.spu_chnldata_RW[25];
        info.dma_info_atomic_command_status = ctx->csa.spu_chnldata_RW[27];
        for (i = 0; i < 16; i++) {
                qp = &info.dma_info_command_data[i];
                spuqp = &ctx->csa.priv2.spuq[i];

                qp->mfc_cq_data0_RW = spuqp->mfc_cq_data0_RW;
                qp->mfc_cq_data1_RW = spuqp->mfc_cq_data1_RW;
                qp->mfc_cq_data2_RW = spuqp->mfc_cq_data2_RW;
                qp->mfc_cq_data3_RW = spuqp->mfc_cq_data3_RW;
        }

        return simple_read_from_buffer(buf, len, pos, &info,
                                sizeof info);
}

static ssize_t spufs_dma_info_read(struct file *file, char __user *buf,
                              size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        int ret;

        if (!access_ok(VERIFY_WRITE, buf, len))
                return -EFAULT;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        spin_lock(&ctx->csa.register_lock);
        ret = __spufs_dma_info_read(ctx, buf, len, pos);
        spin_unlock(&ctx->csa.register_lock);
        spu_release_saved(ctx);

        return ret;
}

static const struct file_operations spufs_dma_info_fops = {
        .open = spufs_info_open,
        .read = spufs_dma_info_read,
        .llseek = no_llseek,
};

static ssize_t __spufs_proxydma_info_read(struct spu_context *ctx,
                        char __user *buf, size_t len, loff_t *pos)
{
        struct spu_proxydma_info info;
        struct mfc_cq_sr *qp, *puqp;
        int ret = sizeof info;
        int i;

        if (len < ret)
                return -EINVAL;

        if (!access_ok(VERIFY_WRITE, buf, len))
                return -EFAULT;

        info.proxydma_info_type = ctx->csa.prob.dma_querytype_RW;
        info.proxydma_info_mask = ctx->csa.prob.dma_querymask_RW;
        info.proxydma_info_status = ctx->csa.prob.dma_tagstatus_R;
        for (i = 0; i < 8; i++) {
                qp = &info.proxydma_info_command_data[i];
                puqp = &ctx->csa.priv2.puq[i];

                qp->mfc_cq_data0_RW = puqp->mfc_cq_data0_RW;
                qp->mfc_cq_data1_RW = puqp->mfc_cq_data1_RW;
                qp->mfc_cq_data2_RW = puqp->mfc_cq_data2_RW;
                qp->mfc_cq_data3_RW = puqp->mfc_cq_data3_RW;
        }

        return simple_read_from_buffer(buf, len, pos, &info,
                                sizeof info);
}

static ssize_t spufs_proxydma_info_read(struct file *file, char __user *buf,
                                   size_t len, loff_t *pos)
{
        struct spu_context *ctx = file->private_data;
        int ret;

        ret = spu_acquire_saved(ctx);
        if (ret)
                return ret;
        spin_lock(&ctx->csa.register_lock);
        ret = __spufs_proxydma_info_read(ctx, buf, len, pos);
        spin_unlock(&ctx->csa.register_lock);
        spu_release_saved(ctx);

        return ret;
}

static const struct file_operations spufs_proxydma_info_fops = {
        .open = spufs_info_open,
        .read = spufs_proxydma_info_read,
        .llseek = no_llseek,
};

static int spufs_show_tid(struct seq_file *s, void *private)
{
        struct spu_context *ctx = s->private;

        seq_printf(s, "%d\n", ctx->tid);
        return 0;
}

static int spufs_tid_open(struct inode *inode, struct file *file)
{
        return single_open(file, spufs_show_tid, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_tid_fops = {
        .open           = spufs_tid_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static const char *ctx_state_names[] = {
        "user", "system", "iowait", "loaded"
};

static unsigned long long spufs_acct_time(struct spu_context *ctx,
                enum spu_utilization_state state)
{
        unsigned long long time = ctx->stats.times[state];

        /*
         * In general, utilization statistics are updated by the controlling
         * thread as the spu context moves through various well defined
         * state transitions, but if the context is lazily loaded its
         * utilization statistics are not updated as the controlling thread
         * is not tightly coupled with the execution of the spu context.  We
         * calculate and apply the time delta from the last recorded state
         * of the spu context.
         */
        if (ctx->spu && ctx->stats.util_state == state) {
                time += ktime_get_ns() - ctx->stats.tstamp;
        }

        return time / NSEC_PER_MSEC;
}

static unsigned long long spufs_slb_flts(struct spu_context *ctx)
{
        unsigned long long slb_flts = ctx->stats.slb_flt;

        if (ctx->state == SPU_STATE_RUNNABLE) {
                slb_flts += (ctx->spu->stats.slb_flt -
                             ctx->stats.slb_flt_base);
        }

        return slb_flts;
}

static unsigned long long spufs_class2_intrs(struct spu_context *ctx)
{
        unsigned long long class2_intrs = ctx->stats.class2_intr;

        if (ctx->state == SPU_STATE_RUNNABLE) {
                class2_intrs += (ctx->spu->stats.class2_intr -
                                 ctx->stats.class2_intr_base);
        }

        return class2_intrs;
}


static int spufs_show_stat(struct seq_file *s, void *private)
{
        struct spu_context *ctx = s->private;
        int ret;

        ret = spu_acquire(ctx);
        if (ret)
                return ret;

        seq_printf(s, "%s %llu %llu %llu %llu "
                      "%llu %llu %llu %llu %llu %llu %llu %llu\n",
                ctx_state_names[ctx->stats.util_state],
                spufs_acct_time(ctx, SPU_UTIL_USER),
                spufs_acct_time(ctx, SPU_UTIL_SYSTEM),
                spufs_acct_time(ctx, SPU_UTIL_IOWAIT),
                spufs_acct_time(ctx, SPU_UTIL_IDLE_LOADED),
                ctx->stats.vol_ctx_switch,
                ctx->stats.invol_ctx_switch,
                spufs_slb_flts(ctx),
                ctx->stats.hash_flt,
                ctx->stats.min_flt,
                ctx->stats.maj_flt,
                spufs_class2_intrs(ctx),
                ctx->stats.libassist);
        spu_release(ctx);
        return 0;
}

static int spufs_stat_open(struct inode *inode, struct file *file)
{
        return single_open(file, spufs_show_stat, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_stat_fops = {
        .open           = spufs_stat_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

static inline int spufs_switch_log_used(struct spu_context *ctx)
{
        return (ctx->switch_log->head - ctx->switch_log->tail) %
                SWITCH_LOG_BUFSIZE;
}

static inline int spufs_switch_log_avail(struct spu_context *ctx)
{
        return SWITCH_LOG_BUFSIZE - spufs_switch_log_used(ctx);
}

static int spufs_switch_log_open(struct inode *inode, struct file *file)
{
        struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
        int rc;

        rc = spu_acquire(ctx);
        if (rc)
                return rc;

        if (ctx->switch_log) {
                rc = -EBUSY;
                goto out;
        }

        ctx->switch_log = kmalloc(sizeof(struct switch_log) +
                SWITCH_LOG_BUFSIZE * sizeof(struct switch_log_entry),
                GFP_KERNEL);

        if (!ctx->switch_log) {
                rc = -ENOMEM;
                goto out;
        }

        ctx->switch_log->head = ctx->switch_log->tail = 0;
        init_waitqueue_head(&ctx->switch_log->wait);
        rc = 0;

out:
        spu_release(ctx);
        return rc;
}

static int spufs_switch_log_release(struct inode *inode, struct file *file)
{
        struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
        int rc;

        rc = spu_acquire(ctx);
        if (rc)
                return rc;

        kfree(ctx->switch_log);
        ctx->switch_log = NULL;
        spu_release(ctx);

        return 0;
}

static int switch_log_sprint(struct spu_context *ctx, char *tbuf, int n)
{
        struct switch_log_entry *p;

        p = ctx->switch_log->log + ctx->switch_log->tail % SWITCH_LOG_BUFSIZE;

        return snprintf(tbuf, n, "%u.%09u %d %u %u %llu\n",
                        (unsigned int) p->tstamp.tv_sec,
                        (unsigned int) p->tstamp.tv_nsec,
                        p->spu_id,
                        (unsigned int) p->type,
                        (unsigned int) p->val,
                        (unsigned long long) p->timebase);
}

static ssize_t spufs_switch_log_read(struct file *file, char __user *buf,
                             size_t len, loff_t *ppos)
{
        struct inode *inode = file_inode(file);
        struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
        int error = 0, cnt = 0;

        if (!buf)
                return -EINVAL;

        error = spu_acquire(ctx);
        if (error)
                return error;

        while (cnt < len) {
                char tbuf[128];
                int width;

                if (spufs_switch_log_used(ctx) == 0) {
                        if (cnt > 0) {
                                /* If there's data ready to go, we can
                                 * just return straight away */
                                break;

                        } else if (file->f_flags & O_NONBLOCK) {
                                error = -EAGAIN;
                                break;

                        } else {
                                /* spufs_wait will drop the mutex and
                                 * re-acquire, but since we're in read(), the
                                 * file cannot be _released (and so
                                 * ctx->switch_log is stable).
                                 */
                                error = spufs_wait(ctx->switch_log->wait,
                                                spufs_switch_log_used(ctx) > 0);

                                /* On error, spufs_wait returns without the
                                 * state mutex held */
                                if (error)
                                        return error;

                                /* We may have had entries read from underneath
                                 * us while we dropped the mutex in spufs_wait,
                                 * so re-check */
                                if (spufs_switch_log_used(ctx) == 0)
                                        continue;
                        }
                }

                width = switch_log_sprint(ctx, tbuf, sizeof(tbuf));
                if (width < len)
                        ctx->switch_log->tail =
                                (ctx->switch_log->tail + 1) %
                                 SWITCH_LOG_BUFSIZE;
                else
                        /* If the record is greater than space available return
                         * partial buffer (so far) */
                        break;

                error = copy_to_user(buf + cnt, tbuf, width);
                if (error)
                        break;
                cnt += width;
        }

        spu_release(ctx);

        return cnt == 0 ? error : cnt;
}

static unsigned int spufs_switch_log_poll(struct file *file, poll_table *wait)
{
        struct inode *inode = file_inode(file);
        struct spu_context *ctx = SPUFS_I(inode)->i_ctx;
        unsigned int mask = 0;
        int rc;

        poll_wait(file, &ctx->switch_log->wait, wait);

        rc = spu_acquire(ctx);
        if (rc)
                return rc;

        if (spufs_switch_log_used(ctx) > 0)
                mask |= POLLIN;

        spu_release(ctx);

        return mask;
}

static const struct file_operations spufs_switch_log_fops = {
        .open           = spufs_switch_log_open,
        .read           = spufs_switch_log_read,
        .poll           = spufs_switch_log_poll,
        .release        = spufs_switch_log_release,
        .llseek         = no_llseek,
};

/**
 * Log a context switch event to a switch log reader.
 *
 * Must be called with ctx->state_mutex held.
 */
void spu_switch_log_notify(struct spu *spu, struct spu_context *ctx,
                u32 type, u32 val)
{
        if (!ctx->switch_log)
                return;

        if (spufs_switch_log_avail(ctx) > 1) {
                struct switch_log_entry *p;

                p = ctx->switch_log->log + ctx->switch_log->head;
                ktime_get_ts(&p->tstamp);
                p->timebase = get_tb();
                p->spu_id = spu ? spu->number : -1;
                p->type = type;
                p->val = val;

                ctx->switch_log->head =
                        (ctx->switch_log->head + 1) % SWITCH_LOG_BUFSIZE;
        }

        wake_up(&ctx->switch_log->wait);
}

static int spufs_show_ctx(struct seq_file *s, void *private)
{
        struct spu_context *ctx = s->private;
        u64 mfc_control_RW;

        mutex_lock(&ctx->state_mutex);
        if (ctx->spu) {
                struct spu *spu = ctx->spu;
                struct spu_priv2 __iomem *priv2 = spu->priv2;

                spin_lock_irq(&spu->register_lock);
                mfc_control_RW = in_be64(&priv2->mfc_control_RW);
                spin_unlock_irq(&spu->register_lock);
        } else {
                struct spu_state *csa = &ctx->csa;

                mfc_control_RW = csa->priv2.mfc_control_RW;
        }

        seq_printf(s, "%c flgs(%lx) sflgs(%lx) pri(%d) ts(%d) spu(%02d)"
                " %c %llx %llx %llx %llx %x %x\n",
                ctx->state == SPU_STATE_SAVED ? 'S' : 'R',
                ctx->flags,
                ctx->sched_flags,
                ctx->prio,
                ctx->time_slice,
                ctx->spu ? ctx->spu->number : -1,
                !list_empty(&ctx->rq) ? 'q' : ' ',
                ctx->csa.class_0_pending,
                ctx->csa.class_0_dar,
                ctx->csa.class_1_dsisr,
                mfc_control_RW,
                ctx->ops->runcntl_read(ctx),
                ctx->ops->status_read(ctx));

        mutex_unlock(&ctx->state_mutex);

        return 0;
}

static int spufs_ctx_open(struct inode *inode, struct file *file)
{
        return single_open(file, spufs_show_ctx, SPUFS_I(inode)->i_ctx);
}

static const struct file_operations spufs_ctx_fops = {
        .open           = spufs_ctx_open,
        .read           = seq_read,
        .llseek         = seq_lseek,
        .release        = single_release,
};

const struct spufs_tree_descr spufs_dir_contents[] = {
        { "capabilities", &spufs_caps_fops, 0444, },
        { "mem",  &spufs_mem_fops,  0666, LS_SIZE, },
        { "regs", &spufs_regs_fops,  0666, sizeof(struct spu_reg128[128]), },
        { "mbox", &spufs_mbox_fops, 0444, },
        { "ibox", &spufs_ibox_fops, 0444, },
        { "wbox", &spufs_wbox_fops, 0222, },
        { "mbox_stat", &spufs_mbox_stat_fops, 0444, sizeof(u32), },
        { "ibox_stat", &spufs_ibox_stat_fops, 0444, sizeof(u32), },
        { "wbox_stat", &spufs_wbox_stat_fops, 0444, sizeof(u32), },
        { "signal1", &spufs_signal1_fops, 0666, },
        { "signal2", &spufs_signal2_fops, 0666, },
        { "signal1_type", &spufs_signal1_type, 0666, },
        { "signal2_type", &spufs_signal2_type, 0666, },
        { "cntl", &spufs_cntl_fops,  0666, },
        { "fpcr", &spufs_fpcr_fops, 0666, sizeof(struct spu_reg128), },
        { "lslr", &spufs_lslr_ops, 0444, },
        { "mfc", &spufs_mfc_fops, 0666, },
        { "mss", &spufs_mss_fops, 0666, },
        { "npc", &spufs_npc_ops, 0666, },
        { "srr0", &spufs_srr0_ops, 0666, },
        { "decr", &spufs_decr_ops, 0666, },
        { "decr_status", &spufs_decr_status_ops, 0666, },
        { "event_mask", &spufs_event_mask_ops, 0666, },
        { "event_status", &spufs_event_status_ops, 0444, },
        { "psmap", &spufs_psmap_fops, 0666, SPUFS_PS_MAP_SIZE, },
        { "phys-id", &spufs_id_ops, 0666, },
        { "object-id", &spufs_object_id_ops, 0666, },
        { "mbox_info", &spufs_mbox_info_fops, 0444, sizeof(u32), },
        { "ibox_info", &spufs_ibox_info_fops, 0444, sizeof(u32), },
        { "wbox_info", &spufs_wbox_info_fops, 0444, sizeof(u32), },
        { "dma_info", &spufs_dma_info_fops, 0444,
                sizeof(struct spu_dma_info), },
        { "proxydma_info", &spufs_proxydma_info_fops, 0444,
                sizeof(struct spu_proxydma_info)},
        { "tid", &spufs_tid_fops, 0444, },
        { "stat", &spufs_stat_fops, 0444, },
        { "switch_log", &spufs_switch_log_fops, 0444 },
        {},
};

const struct spufs_tree_descr spufs_dir_nosched_contents[] = {
        { "capabilities", &spufs_caps_fops, 0444, },
        { "mem",  &spufs_mem_fops,  0666, LS_SIZE, },
        { "mbox", &spufs_mbox_fops, 0444, },
        { "ibox", &spufs_ibox_fops, 0444, },
        { "wbox", &spufs_wbox_fops, 0222, },
        { "mbox_stat", &spufs_mbox_stat_fops, 0444, sizeof(u32), },
        { "ibox_stat", &spufs_ibox_stat_fops, 0444, sizeof(u32), },
        { "wbox_stat", &spufs_wbox_stat_fops, 0444, sizeof(u32), },
        { "signal1", &spufs_signal1_nosched_fops, 0222, },
        { "signal2", &spufs_signal2_nosched_fops, 0222, },
        { "signal1_type", &spufs_signal1_type, 0666, },
        { "signal2_type", &spufs_signal2_type, 0666, },
        { "mss", &spufs_mss_fops, 0666, },
        { "mfc", &spufs_mfc_fops, 0666, },
        { "cntl", &spufs_cntl_fops,  0666, },
        { "npc", &spufs_npc_ops, 0666, },
        { "psmap", &spufs_psmap_fops, 0666, SPUFS_PS_MAP_SIZE, },
        { "phys-id", &spufs_id_ops, 0666, },
        { "object-id", &spufs_object_id_ops, 0666, },
        { "tid", &spufs_tid_fops, 0444, },
        { "stat", &spufs_stat_fops, 0444, },
        {},
};

const struct spufs_tree_descr spufs_dir_debug_contents[] = {
        { ".ctx", &spufs_ctx_fops, 0444, },
        {},
};

const struct spufs_coredump_reader spufs_coredump_read[] = {
        { "regs", __spufs_regs_read, NULL, sizeof(struct spu_reg128[128])},
        { "fpcr", __spufs_fpcr_read, NULL, sizeof(struct spu_reg128) },
        { "lslr", NULL, spufs_lslr_get, 19 },
        { "decr", NULL, spufs_decr_get, 19 },
        { "decr_status", NULL, spufs_decr_status_get, 19 },
        { "mem", __spufs_mem_read, NULL, LS_SIZE, },
        { "signal1", __spufs_signal1_read, NULL, sizeof(u32) },
        { "signal1_type", NULL, spufs_signal1_type_get, 19 },
        { "signal2", __spufs_signal2_read, NULL, sizeof(u32) },
        { "signal2_type", NULL, spufs_signal2_type_get, 19 },
        { "event_mask", NULL, spufs_event_mask_get, 19 },
        { "event_status", NULL, spufs_event_status_get, 19 },
        { "mbox_info", __spufs_mbox_info_read, NULL, sizeof(u32) },
        { "ibox_info", __spufs_ibox_info_read, NULL, sizeof(u32) },
        { "wbox_info", __spufs_wbox_info_read, NULL, 4 * sizeof(u32)},
        { "dma_info", __spufs_dma_info_read, NULL, sizeof(struct spu_dma_info)},
        { "proxydma_info", __spufs_proxydma_info_read,
                           NULL, sizeof(struct spu_proxydma_info)},
        { "object-id", NULL, spufs_object_id_get, 19 },
        { "npc", NULL, spufs_npc_get, 19 },
        { NULL },
};