Merge branch 'message-callback' into kbuild/kconfig

[mirror_ubuntu-focal-kernel.git] / drivers / media / video / videobuf-dma-sg.c

/*
 * helper functions for SG DMA video4linux capture buffers
 *
 * The functions expect the hardware being able to scatter gather
 * (i.e. the buffers are not linear in physical memory, but fragmented
 * into PAGE_SIZE chunks).  They also assume the driver does not need
 * to touch the video data.
 *
 * (c) 2007 Mauro Carvalho Chehab, <mchehab@infradead.org>
 *
 * Highly based on video-buf written originally by:
 * (c) 2001,02 Gerd Knorr <kraxel@bytesex.org>
 * (c) 2006 Mauro Carvalho Chehab, <mchehab@infradead.org>
 * (c) 2006 Ted Walther and John Sokol
 *
 * 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
 */

#include <linux/init.h>
#include <linux/module.h>
#include <linux/moduleparam.h>
#include <linux/sched.h>
#include <linux/slab.h>
#include <linux/interrupt.h>

#include <linux/dma-mapping.h>
#include <linux/vmalloc.h>
#include <linux/pagemap.h>
#include <linux/scatterlist.h>
#include <asm/page.h>
#include <asm/pgtable.h>

#include <media/videobuf-dma-sg.h>

#define MAGIC_DMABUF 0x19721112
#define MAGIC_SG_MEM 0x17890714

#define MAGIC_CHECK(is, should)                                         \
        if (unlikely((is) != (should))) {                               \
                printk(KERN_ERR "magic mismatch: %x (expected %x)\n",   \
                                is, should);                            \
                BUG();                                                  \
        }

static int debug;
module_param(debug, int, 0644);

MODULE_DESCRIPTION("helper module to manage video4linux dma sg buffers");
MODULE_AUTHOR("Mauro Carvalho Chehab <mchehab@infradead.org>");
MODULE_LICENSE("GPL");

#define dprintk(level, fmt, arg...)                                     \
        if (debug >= level)                                             \
                printk(KERN_DEBUG "vbuf-sg: " fmt , ## arg)

/* --------------------------------------------------------------------- */

/*
 * Return a scatterlist for some page-aligned vmalloc()'ed memory
 * block (NULL on errors).  Memory for the scatterlist is allocated
 * using kmalloc.  The caller must free the memory.
 */
static struct scatterlist *videobuf_vmalloc_to_sg(unsigned char *virt,
                                                  int nr_pages)
{
        struct scatterlist *sglist;
        struct page *pg;
        int i;

        sglist = vmalloc(nr_pages * sizeof(*sglist));
        if (NULL == sglist)
                return NULL;
        memset(sglist, 0, nr_pages * sizeof(*sglist));
        sg_init_table(sglist, nr_pages);
        for (i = 0; i < nr_pages; i++, virt += PAGE_SIZE) {
                pg = vmalloc_to_page(virt);
                if (NULL == pg)
                        goto err;
                BUG_ON(PageHighMem(pg));
                sg_set_page(&sglist[i], pg, PAGE_SIZE, 0);
        }
        return sglist;

err:
        vfree(sglist);
        return NULL;
}

/*
 * Return a scatterlist for a an array of userpages (NULL on errors).
 * Memory for the scatterlist is allocated using kmalloc.  The caller
 * must free the memory.
 */
static struct scatterlist *videobuf_pages_to_sg(struct page **pages,
                                                int nr_pages, int offset)
{
        struct scatterlist *sglist;
        int i;

        if (NULL == pages[0])
                return NULL;
        sglist = vmalloc(nr_pages * sizeof(*sglist));
        if (NULL == sglist)
                return NULL;
        sg_init_table(sglist, nr_pages);

        if (PageHighMem(pages[0]))
                /* DMA to highmem pages might not work */
                goto highmem;
        sg_set_page(&sglist[0], pages[0], PAGE_SIZE - offset, offset);
        for (i = 1; i < nr_pages; i++) {
                if (NULL == pages[i])
                        goto nopage;
                if (PageHighMem(pages[i]))
                        goto highmem;
                sg_set_page(&sglist[i], pages[i], PAGE_SIZE, 0);
        }
        return sglist;

nopage:
        dprintk(2, "sgl: oops - no page\n");
        vfree(sglist);
        return NULL;

highmem:
        dprintk(2, "sgl: oops - highmem page\n");
        vfree(sglist);
        return NULL;
}

/* --------------------------------------------------------------------- */

struct videobuf_dmabuf *videobuf_to_dma(struct videobuf_buffer *buf)
{
        struct videobuf_dma_sg_memory *mem = buf->priv;
        BUG_ON(!mem);

        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);

        return &mem->dma;
}
EXPORT_SYMBOL_GPL(videobuf_to_dma);

void videobuf_dma_init(struct videobuf_dmabuf *dma)
{
        memset(dma, 0, sizeof(*dma));
        dma->magic = MAGIC_DMABUF;
}
EXPORT_SYMBOL_GPL(videobuf_dma_init);

static int videobuf_dma_init_user_locked(struct videobuf_dmabuf *dma,
                        int direction, unsigned long data, unsigned long size)
{
        unsigned long first, last;
        int err, rw = 0;

        dma->direction = direction;
        switch (dma->direction) {
        case DMA_FROM_DEVICE:
                rw = READ;
                break;
        case DMA_TO_DEVICE:
                rw = WRITE;
                break;
        default:
                BUG();
        }

        first = (data          & PAGE_MASK) >> PAGE_SHIFT;
        last  = ((data+size-1) & PAGE_MASK) >> PAGE_SHIFT;
        dma->offset   = data & ~PAGE_MASK;
        dma->nr_pages = last-first+1;
        dma->pages = kmalloc(dma->nr_pages * sizeof(struct page *), GFP_KERNEL);
        if (NULL == dma->pages)
                return -ENOMEM;

        dprintk(1, "init user [0x%lx+0x%lx => %d pages]\n",
                data, size, dma->nr_pages);

        err = get_user_pages(current, current->mm,
                             data & PAGE_MASK, dma->nr_pages,
                             rw == READ, 1, /* force */
                             dma->pages, NULL);

        if (err != dma->nr_pages) {
                dma->nr_pages = (err >= 0) ? err : 0;
                dprintk(1, "get_user_pages: err=%d [%d]\n", err, dma->nr_pages);
                return err < 0 ? err : -EINVAL;
        }
        return 0;
}

int videobuf_dma_init_user(struct videobuf_dmabuf *dma, int direction,
                           unsigned long data, unsigned long size)
{
        int ret;

        down_read(&current->mm->mmap_sem);
        ret = videobuf_dma_init_user_locked(dma, direction, data, size);
        up_read(&current->mm->mmap_sem);

        return ret;
}
EXPORT_SYMBOL_GPL(videobuf_dma_init_user);

int videobuf_dma_init_kernel(struct videobuf_dmabuf *dma, int direction,
                             int nr_pages)
{
        dprintk(1, "init kernel [%d pages]\n", nr_pages);

        dma->direction = direction;
        dma->vaddr = vmalloc_32(nr_pages << PAGE_SHIFT);
        if (NULL == dma->vaddr) {
                dprintk(1, "vmalloc_32(%d pages) failed\n", nr_pages);
                return -ENOMEM;
        }

        dprintk(1, "vmalloc is at addr 0x%08lx, size=%d\n",
                                (unsigned long)dma->vaddr,
                                nr_pages << PAGE_SHIFT);

        memset(dma->vaddr, 0, nr_pages << PAGE_SHIFT);
        dma->nr_pages = nr_pages;

        return 0;
}
EXPORT_SYMBOL_GPL(videobuf_dma_init_kernel);

int videobuf_dma_init_overlay(struct videobuf_dmabuf *dma, int direction,
                              dma_addr_t addr, int nr_pages)
{
        dprintk(1, "init overlay [%d pages @ bus 0x%lx]\n",
                nr_pages, (unsigned long)addr);
        dma->direction = direction;

        if (0 == addr)
                return -EINVAL;

        dma->bus_addr = addr;
        dma->nr_pages = nr_pages;

        return 0;
}
EXPORT_SYMBOL_GPL(videobuf_dma_init_overlay);

int videobuf_dma_map(struct device *dev, struct videobuf_dmabuf *dma)
{
        MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
        BUG_ON(0 == dma->nr_pages);

        if (dma->pages) {
                dma->sglist = videobuf_pages_to_sg(dma->pages, dma->nr_pages,
                                                   dma->offset);
        }
        if (dma->vaddr) {
                dma->sglist = videobuf_vmalloc_to_sg(dma->vaddr,
                                                     dma->nr_pages);
        }
        if (dma->bus_addr) {
                dma->sglist = vmalloc(sizeof(*dma->sglist));
                if (NULL != dma->sglist) {
                        dma->sglen = 1;
                        sg_dma_address(&dma->sglist[0]) = dma->bus_addr
                                                        & PAGE_MASK;
                        dma->sglist[0].offset = dma->bus_addr & ~PAGE_MASK;
                        sg_dma_len(&dma->sglist[0]) = dma->nr_pages * PAGE_SIZE;
                }
        }
        if (NULL == dma->sglist) {
                dprintk(1, "scatterlist is NULL\n");
                return -ENOMEM;
        }
        if (!dma->bus_addr) {
                dma->sglen = dma_map_sg(dev, dma->sglist,
                                        dma->nr_pages, dma->direction);
                if (0 == dma->sglen) {
                        printk(KERN_WARNING
                               "%s: videobuf_map_sg failed\n", __func__);
                        vfree(dma->sglist);
                        dma->sglist = NULL;
                        dma->sglen = 0;
                        return -ENOMEM;
                }
        }

        return 0;
}
EXPORT_SYMBOL_GPL(videobuf_dma_map);

int videobuf_dma_unmap(struct device *dev, struct videobuf_dmabuf *dma)
{
        MAGIC_CHECK(dma->magic, MAGIC_DMABUF);

        if (!dma->sglen)
                return 0;

        dma_unmap_sg(dev, dma->sglist, dma->sglen, dma->direction);

        vfree(dma->sglist);
        dma->sglist = NULL;
        dma->sglen = 0;

        return 0;
}
EXPORT_SYMBOL_GPL(videobuf_dma_unmap);

int videobuf_dma_free(struct videobuf_dmabuf *dma)
{
        int i;
        MAGIC_CHECK(dma->magic, MAGIC_DMABUF);
        BUG_ON(dma->sglen);

        if (dma->pages) {
                for (i = 0; i < dma->nr_pages; i++)
                        page_cache_release(dma->pages[i]);
                kfree(dma->pages);
                dma->pages = NULL;
        }

        vfree(dma->vaddr);
        dma->vaddr = NULL;

        if (dma->bus_addr)
                dma->bus_addr = 0;
        dma->direction = DMA_NONE;

        return 0;
}
EXPORT_SYMBOL_GPL(videobuf_dma_free);

/* --------------------------------------------------------------------- */

static void videobuf_vm_open(struct vm_area_struct *vma)
{
        struct videobuf_mapping *map = vma->vm_private_data;

        dprintk(2, "vm_open %p [count=%d,vma=%08lx-%08lx]\n", map,
                map->count, vma->vm_start, vma->vm_end);

        map->count++;
}

static void videobuf_vm_close(struct vm_area_struct *vma)
{
        struct videobuf_mapping *map = vma->vm_private_data;
        struct videobuf_queue *q = map->q;
        struct videobuf_dma_sg_memory *mem;
        int i;

        dprintk(2, "vm_close %p [count=%d,vma=%08lx-%08lx]\n", map,
                map->count, vma->vm_start, vma->vm_end);

        map->count--;
        if (0 == map->count) {
                dprintk(1, "munmap %p q=%p\n", map, q);
                mutex_lock(&q->vb_lock);
                for (i = 0; i < VIDEO_MAX_FRAME; i++) {
                        if (NULL == q->bufs[i])
                                continue;
                        mem = q->bufs[i]->priv;
                        if (!mem)
                                continue;

                        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);

                        if (q->bufs[i]->map != map)
                                continue;
                        q->bufs[i]->map   = NULL;
                        q->bufs[i]->baddr = 0;
                        q->ops->buf_release(q, q->bufs[i]);
                }
                mutex_unlock(&q->vb_lock);
                kfree(map);
        }
        return;
}

/*
 * Get a anonymous page for the mapping.  Make sure we can DMA to that
 * memory location with 32bit PCI devices (i.e. don't use highmem for
 * now ...).  Bounce buffers don't work very well for the data rates
 * video capture has.
 */
static int videobuf_vm_fault(struct vm_area_struct *vma, struct vm_fault *vmf)
{
        struct page *page;

        dprintk(3, "fault: fault @ %08lx [vma %08lx-%08lx]\n",
                (unsigned long)vmf->virtual_address,
                vma->vm_start, vma->vm_end);

        page = alloc_page(GFP_USER | __GFP_DMA32);
        if (!page)
                return VM_FAULT_OOM;
        clear_user_highpage(page, (unsigned long)vmf->virtual_address);
        vmf->page = page;

        return 0;
}

static const struct vm_operations_struct videobuf_vm_ops = {
        .open   = videobuf_vm_open,
        .close  = videobuf_vm_close,
        .fault  = videobuf_vm_fault,
};

/* ---------------------------------------------------------------------
 * SG handlers for the generic methods
 */

/* Allocated area consists on 3 parts:
        struct video_buffer
        struct <driver>_buffer (cx88_buffer, saa7134_buf, ...)
        struct videobuf_dma_sg_memory
 */

static struct videobuf_buffer *__videobuf_alloc_vb(size_t size)
{
        struct videobuf_dma_sg_memory *mem;
        struct videobuf_buffer *vb;

        vb = kzalloc(size + sizeof(*mem), GFP_KERNEL);
        if (!vb)
                return vb;

        mem = vb->priv = ((char *)vb) + size;
        mem->magic = MAGIC_SG_MEM;

        videobuf_dma_init(&mem->dma);

        dprintk(1, "%s: allocated at %p(%ld+%ld) & %p(%ld)\n",
                __func__, vb, (long)sizeof(*vb), (long)size - sizeof(*vb),
                mem, (long)sizeof(*mem));

        return vb;
}

static void *__videobuf_to_vaddr(struct videobuf_buffer *buf)
{
        struct videobuf_dma_sg_memory *mem = buf->priv;
        BUG_ON(!mem);

        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);

        return mem->dma.vaddr;
}

static int __videobuf_iolock(struct videobuf_queue *q,
                             struct videobuf_buffer *vb,
                             struct v4l2_framebuffer *fbuf)
{
        int err, pages;
        dma_addr_t bus;
        struct videobuf_dma_sg_memory *mem = vb->priv;
        BUG_ON(!mem);

        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);

        switch (vb->memory) {
        case V4L2_MEMORY_MMAP:
        case V4L2_MEMORY_USERPTR:
                if (0 == vb->baddr) {
                        /* no userspace addr -- kernel bounce buffer */
                        pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
                        err = videobuf_dma_init_kernel(&mem->dma,
                                                       DMA_FROM_DEVICE,
                                                       pages);
                        if (0 != err)
                                return err;
                } else if (vb->memory == V4L2_MEMORY_USERPTR) {
                        /* dma directly to userspace */
                        err = videobuf_dma_init_user(&mem->dma,
                                                     DMA_FROM_DEVICE,
                                                     vb->baddr, vb->bsize);
                        if (0 != err)
                                return err;
                } else {
                        /* NOTE: HACK: videobuf_iolock on V4L2_MEMORY_MMAP
                        buffers can only be called from videobuf_qbuf
                        we take current->mm->mmap_sem there, to prevent
                        locking inversion, so don't take it here */

                        err = videobuf_dma_init_user_locked(&mem->dma,
                                                      DMA_FROM_DEVICE,
                                                      vb->baddr, vb->bsize);
                        if (0 != err)
                                return err;
                }
                break;
        case V4L2_MEMORY_OVERLAY:
                if (NULL == fbuf)
                        return -EINVAL;
                /* FIXME: need sanity checks for vb->boff */
                /*
                 * Using a double cast to avoid compiler warnings when
                 * building for PAE. Compiler doesn't like direct casting
                 * of a 32 bit ptr to 64 bit integer.
                 */
                bus   = (dma_addr_t)(unsigned long)fbuf->base + vb->boff;
                pages = PAGE_ALIGN(vb->size) >> PAGE_SHIFT;
                err = videobuf_dma_init_overlay(&mem->dma, DMA_FROM_DEVICE,
                                                bus, pages);
                if (0 != err)
                        return err;
                break;
        default:
                BUG();
        }
        err = videobuf_dma_map(q->dev, &mem->dma);
        if (0 != err)
                return err;

        return 0;
}

static int __videobuf_sync(struct videobuf_queue *q,
                           struct videobuf_buffer *buf)
{
        struct videobuf_dma_sg_memory *mem = buf->priv;
        BUG_ON(!mem || !mem->dma.sglen);

        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);
        MAGIC_CHECK(mem->dma.magic, MAGIC_DMABUF);

        dma_sync_sg_for_cpu(q->dev, mem->dma.sglist,
                            mem->dma.sglen, mem->dma.direction);

        return 0;
}

static int __videobuf_mmap_mapper(struct videobuf_queue *q,
                                  struct videobuf_buffer *buf,
                                  struct vm_area_struct *vma)
{
        struct videobuf_dma_sg_memory *mem = buf->priv;
        struct videobuf_mapping *map;
        unsigned int first, last, size = 0, i;
        int retval;

        retval = -EINVAL;

        /* This function maintains backwards compatibility with V4L1 and will
         * map more than one buffer if the vma length is equal to the combined
         * size of multiple buffers than it will map them together.  See
         * VIDIOCGMBUF in the v4l spec
         *
         * TODO: Allow drivers to specify if they support this mode
         */

        BUG_ON(!mem);
        MAGIC_CHECK(mem->magic, MAGIC_SG_MEM);

        /* look for first buffer to map */
        for (first = 0; first < VIDEO_MAX_FRAME; first++) {
                if (buf == q->bufs[first]) {
                        size = PAGE_ALIGN(q->bufs[first]->bsize);
                        break;
                }
        }

        /* paranoia, should never happen since buf is always valid. */
        if (!size) {
                dprintk(1, "mmap app bug: offset invalid [offset=0x%lx]\n",
                                (vma->vm_pgoff << PAGE_SHIFT));
                goto done;
        }

        last = first;
#ifdef CONFIG_VIDEO_V4L1_COMPAT
        if (size != (vma->vm_end - vma->vm_start)) {
                /* look for last buffer to map */
                for (last = first + 1; last < VIDEO_MAX_FRAME; last++) {
                        if (NULL == q->bufs[last])
                                continue;
                        if (V4L2_MEMORY_MMAP != q->bufs[last]->memory)
                                continue;
                        if (q->bufs[last]->map) {
                                retval = -EBUSY;
                                goto done;
                        }
                        size += PAGE_ALIGN(q->bufs[last]->bsize);
                        if (size == (vma->vm_end - vma->vm_start))
                                break;
                }
                if (VIDEO_MAX_FRAME == last) {
                        dprintk(1, "mmap app bug: size invalid [size=0x%lx]\n",
                                        (vma->vm_end - vma->vm_start));
                        goto done;
                }
        }
#endif

        /* create mapping + update buffer list */
        retval = -ENOMEM;
        map = kmalloc(sizeof(struct videobuf_mapping), GFP_KERNEL);
        if (NULL == map)
                goto done;

        size = 0;
        for (i = first; i <= last; i++) {
                if (NULL == q->bufs[i])
                        continue;
                q->bufs[i]->map   = map;
                q->bufs[i]->baddr = vma->vm_start + size;
                size += PAGE_ALIGN(q->bufs[i]->bsize);
        }

        map->count    = 1;
        map->q        = q;
        vma->vm_ops   = &videobuf_vm_ops;
        vma->vm_flags |= VM_DONTEXPAND | VM_RESERVED;
        vma->vm_flags &= ~VM_IO; /* using shared anonymous pages */
        vma->vm_private_data = map;
        dprintk(1, "mmap %p: q=%p %08lx-%08lx pgoff %08lx bufs %d-%d\n",
                map, q, vma->vm_start, vma->vm_end, vma->vm_pgoff, first, last);
        retval = 0;

done:
        return retval;
}

static struct videobuf_qtype_ops sg_ops = {
        .magic        = MAGIC_QTYPE_OPS,

        .alloc_vb     = __videobuf_alloc_vb,
        .iolock       = __videobuf_iolock,
        .sync         = __videobuf_sync,
        .mmap_mapper  = __videobuf_mmap_mapper,
        .vaddr        = __videobuf_to_vaddr,
};

void *videobuf_sg_alloc(size_t size)
{
        struct videobuf_queue q;

        /* Required to make generic handler to call __videobuf_alloc */
        q.int_ops = &sg_ops;

        q.msize = size;

        return videobuf_alloc_vb(&q);
}
EXPORT_SYMBOL_GPL(videobuf_sg_alloc);

void videobuf_queue_sg_init(struct videobuf_queue *q,
                         const struct videobuf_queue_ops *ops,
                         struct device *dev,
                         spinlock_t *irqlock,
                         enum v4l2_buf_type type,
                         enum v4l2_field field,
                         unsigned int msize,
                         void *priv)
{
        videobuf_queue_core_init(q, ops, dev, irqlock, type, field, msize,
                                 priv, &sg_ops);
}
EXPORT_SYMBOL_GPL(videobuf_queue_sg_init);