[mirror_ubuntu-bionic-kernel.git] / drivers / nvdimm / pmem.c

/*
 * Persistent Memory Driver
 *
 * Copyright (c) 2014-2015, Intel Corporation.
 * Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
 * Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
 *
 * This program is free software; you can redistribute it and/or modify it
 * under the terms and conditions of the GNU General Public License,
 * version 2, as published by the Free Software Foundation.
 *
 * This program is distributed in the hope 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.
 */

#include <asm/cacheflush.h>
#include <linux/blkdev.h>
#include <linux/hdreg.h>
#include <linux/init.h>
#include <linux/platform_device.h>
#include <linux/module.h>
#include <linux/memory_hotplug.h>
#include <linux/moduleparam.h>
#include <linux/vmalloc.h>
#include <linux/slab.h>
#include <linux/pmem.h>
#include <linux/nd.h>
#include "pfn.h"
#include "nd.h"

struct pmem_device {
        struct request_queue    *pmem_queue;
        struct gendisk          *pmem_disk;
        struct nd_namespace_common *ndns;

        /* One contiguous memory region per device */
        phys_addr_t             phys_addr;
        /* when non-zero this device is hosting a 'pfn' instance */
        phys_addr_t             data_offset;
        void __pmem             *virt_addr;
        size_t                  size;
};

static int pmem_major;

static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
                        unsigned int len, unsigned int off, int rw,
                        sector_t sector)
{
        void *mem = kmap_atomic(page);
        phys_addr_t pmem_off = sector * 512 + pmem->data_offset;
        void __pmem *pmem_addr = pmem->virt_addr + pmem_off;

        if (rw == READ) {
                memcpy_from_pmem(mem + off, pmem_addr, len);
                flush_dcache_page(page);
        } else {
                flush_dcache_page(page);
                memcpy_to_pmem(pmem_addr, mem + off, len);
        }

        kunmap_atomic(mem);
}

static blk_qc_t pmem_make_request(struct request_queue *q, struct bio *bio)
{
        bool do_acct;
        unsigned long start;
        struct bio_vec bvec;
        struct bvec_iter iter;
        struct block_device *bdev = bio->bi_bdev;
        struct pmem_device *pmem = bdev->bd_disk->private_data;

        do_acct = nd_iostat_start(bio, &start);
        bio_for_each_segment(bvec, bio, iter)
                pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset,
                                bio_data_dir(bio), iter.bi_sector);
        if (do_acct)
                nd_iostat_end(bio, start);

        if (bio_data_dir(bio))
                wmb_pmem();

        bio_endio(bio);
        return BLK_QC_T_NONE;
}

static int pmem_rw_page(struct block_device *bdev, sector_t sector,
                       struct page *page, int rw)
{
        struct pmem_device *pmem = bdev->bd_disk->private_data;

        pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
        if (rw & WRITE)
                wmb_pmem();
        page_endio(page, rw & WRITE, 0);

        return 0;
}

static long pmem_direct_access(struct block_device *bdev, sector_t sector,
                      void __pmem **kaddr, unsigned long *pfn)
{
        struct pmem_device *pmem = bdev->bd_disk->private_data;
        resource_size_t offset = sector * 512 + pmem->data_offset;
        resource_size_t size;

        if (pmem->data_offset) {
                /*
                 * Limit the direct_access() size to what is covered by
                 * the memmap
                 */
                size = (pmem->size - offset) & ~ND_PFN_MASK;
        } else
                size = pmem->size - offset;

        /* FIXME convert DAX to comprehend that this mapping has a lifetime */
        *kaddr = pmem->virt_addr + offset;
        *pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;

        return size;
}

static const struct block_device_operations pmem_fops = {
        .owner =                THIS_MODULE,
        .rw_page =              pmem_rw_page,
        .direct_access =        pmem_direct_access,
        .revalidate_disk =      nvdimm_revalidate_disk,
};

static struct pmem_device *pmem_alloc(struct device *dev,
                struct resource *res, int id)
{
        struct pmem_device *pmem;

        pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
        if (!pmem)
                return ERR_PTR(-ENOMEM);

        pmem->phys_addr = res->start;
        pmem->size = resource_size(res);
        if (!arch_has_wmb_pmem())
                dev_warn(dev, "unable to guarantee persistence of writes\n");

        if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size,
                        dev_name(dev))) {
                dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
                                &pmem->phys_addr, pmem->size);
                return ERR_PTR(-EBUSY);
        }

        if (pmem_should_map_pages(dev)) {
                void *addr = devm_memremap_pages(dev, res);

                if (IS_ERR(addr))
                        return addr;
                pmem->virt_addr = (void __pmem *) addr;
        } else {
                pmem->virt_addr = memremap_pmem(dev, pmem->phys_addr,
                                pmem->size);
                if (!pmem->virt_addr)
                        return ERR_PTR(-ENXIO);
        }

        return pmem;
}

static void pmem_detach_disk(struct pmem_device *pmem)
{
        if (!pmem->pmem_disk)
                return;

        del_gendisk(pmem->pmem_disk);
        put_disk(pmem->pmem_disk);
        blk_cleanup_queue(pmem->pmem_queue);
}

static int pmem_attach_disk(struct device *dev,
                struct nd_namespace_common *ndns, struct pmem_device *pmem)
{
        struct gendisk *disk;

        pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
        if (!pmem->pmem_queue)
                return -ENOMEM;

        blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
        blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE);
        blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
        blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
        queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);

        disk = alloc_disk(0);
        if (!disk) {
                blk_cleanup_queue(pmem->pmem_queue);
                return -ENOMEM;
        }

        disk->major             = pmem_major;
        disk->first_minor       = 0;
        disk->fops              = &pmem_fops;
        disk->private_data      = pmem;
        disk->queue             = pmem->pmem_queue;
        disk->flags             = GENHD_FL_EXT_DEVT;
        nvdimm_namespace_disk_name(ndns, disk->disk_name);
        disk->driverfs_dev = dev;
        set_capacity(disk, (pmem->size - pmem->data_offset) / 512);
        pmem->pmem_disk = disk;

        add_disk(disk);
        revalidate_disk(disk);

        return 0;
}

static int pmem_rw_bytes(struct nd_namespace_common *ndns,
                resource_size_t offset, void *buf, size_t size, int rw)
{
        struct pmem_device *pmem = dev_get_drvdata(ndns->claim);

        if (unlikely(offset + size > pmem->size)) {
                dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
                return -EFAULT;
        }

        if (rw == READ)
                memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
        else {
                memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
                wmb_pmem();
        }

        return 0;
}

static int nd_pfn_init(struct nd_pfn *nd_pfn)
{
        struct nd_pfn_sb *pfn_sb = kzalloc(sizeof(*pfn_sb), GFP_KERNEL);
        struct pmem_device *pmem = dev_get_drvdata(&nd_pfn->dev);
        struct nd_namespace_common *ndns = nd_pfn->ndns;
        struct nd_region *nd_region;
        unsigned long npfns;
        phys_addr_t offset;
        u64 checksum;
        int rc;

        if (!pfn_sb)
                return -ENOMEM;

        nd_pfn->pfn_sb = pfn_sb;
        rc = nd_pfn_validate(nd_pfn);
        if (rc == 0 || rc == -EBUSY)
                return rc;

        /* section alignment for simple hotplug */
        if (nvdimm_namespace_capacity(ndns) < ND_PFN_ALIGN
                        || pmem->phys_addr & ND_PFN_MASK)
                return -ENODEV;

        nd_region = to_nd_region(nd_pfn->dev.parent);
        if (nd_region->ro) {
                dev_info(&nd_pfn->dev,
                                "%s is read-only, unable to init metadata\n",
                                dev_name(&nd_region->dev));
                goto err;
        }

        memset(pfn_sb, 0, sizeof(*pfn_sb));
        npfns = (pmem->size - SZ_8K) / SZ_4K;
        /*
         * Note, we use 64 here for the standard size of struct page,
         * debugging options may cause it to be larger in which case the
         * implementation will limit the pfns advertised through
         * ->direct_access() to those that are included in the memmap.
         */
        if (nd_pfn->mode == PFN_MODE_PMEM)
                offset = ALIGN(SZ_8K + 64 * npfns, PMD_SIZE);
        else if (nd_pfn->mode == PFN_MODE_RAM)
                offset = SZ_8K;
        else
                goto err;

        npfns = (pmem->size - offset) / SZ_4K;
        pfn_sb->mode = cpu_to_le32(nd_pfn->mode);
        pfn_sb->dataoff = cpu_to_le64(offset);
        pfn_sb->npfns = cpu_to_le64(npfns);
        memcpy(pfn_sb->signature, PFN_SIG, PFN_SIG_LEN);
        memcpy(pfn_sb->uuid, nd_pfn->uuid, 16);
        pfn_sb->version_major = cpu_to_le16(1);
        checksum = nd_sb_checksum((struct nd_gen_sb *) pfn_sb);
        pfn_sb->checksum = cpu_to_le64(checksum);

        rc = nvdimm_write_bytes(ndns, SZ_4K, pfn_sb, sizeof(*pfn_sb));
        if (rc)
                goto err;

        return 0;
 err:
        nd_pfn->pfn_sb = NULL;
        kfree(pfn_sb);
        return -ENXIO;
}

static int nvdimm_namespace_detach_pfn(struct nd_namespace_common *ndns)
{
        struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
        struct pmem_device *pmem;

        /* free pmem disk */
        pmem = dev_get_drvdata(&nd_pfn->dev);
        pmem_detach_disk(pmem);

        /* release nd_pfn resources */
        kfree(nd_pfn->pfn_sb);
        nd_pfn->pfn_sb = NULL;

        return 0;
}

static int nvdimm_namespace_attach_pfn(struct nd_namespace_common *ndns)
{
        struct nd_namespace_io *nsio = to_nd_namespace_io(&ndns->dev);
        struct nd_pfn *nd_pfn = to_nd_pfn(ndns->claim);
        struct device *dev = &nd_pfn->dev;
        struct vmem_altmap *altmap;
        struct nd_region *nd_region;
        struct nd_pfn_sb *pfn_sb;
        struct pmem_device *pmem;
        phys_addr_t offset;
        int rc;

        if (!nd_pfn->uuid || !nd_pfn->ndns)
                return -ENODEV;

        nd_region = to_nd_region(dev->parent);
        rc = nd_pfn_init(nd_pfn);
        if (rc)
                return rc;

        if (PAGE_SIZE != SZ_4K) {
                dev_err(dev, "only supported on systems with 4K PAGE_SIZE\n");
                return -ENXIO;
        }
        if (nsio->res.start & ND_PFN_MASK) {
                dev_err(dev, "%s not memory hotplug section aligned\n",
                                dev_name(&ndns->dev));
                return -ENXIO;
        }

        pfn_sb = nd_pfn->pfn_sb;
        offset = le64_to_cpu(pfn_sb->dataoff);
        nd_pfn->mode = le32_to_cpu(nd_pfn->pfn_sb->mode);
        if (nd_pfn->mode == PFN_MODE_RAM) {
                if (offset != SZ_8K)
                        return -EINVAL;
                nd_pfn->npfns = le64_to_cpu(pfn_sb->npfns);
                altmap = NULL;
        } else {
                rc = -ENXIO;
                goto err;
        }

        /* establish pfn range for lookup, and switch to direct map */
        pmem = dev_get_drvdata(dev);
        memunmap_pmem(dev, pmem->virt_addr);
        pmem->virt_addr = (void __pmem *)devm_memremap_pages(dev, &nsio->res);
        if (IS_ERR(pmem->virt_addr)) {
                rc = PTR_ERR(pmem->virt_addr);
                goto err;
        }

        /* attach pmem disk in "pfn-mode" */
        pmem->data_offset = offset;
        rc = pmem_attach_disk(dev, ndns, pmem);
        if (rc)
                goto err;

        return rc;
 err:
        nvdimm_namespace_detach_pfn(ndns);
        return rc;
}

static int nd_pmem_probe(struct device *dev)
{
        struct nd_region *nd_region = to_nd_region(dev->parent);
        struct nd_namespace_common *ndns;
        struct nd_namespace_io *nsio;
        struct pmem_device *pmem;

        ndns = nvdimm_namespace_common_probe(dev);
        if (IS_ERR(ndns))
                return PTR_ERR(ndns);

        nsio = to_nd_namespace_io(&ndns->dev);
        pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
        if (IS_ERR(pmem))
                return PTR_ERR(pmem);

        pmem->ndns = ndns;
        dev_set_drvdata(dev, pmem);
        ndns->rw_bytes = pmem_rw_bytes;

        if (is_nd_btt(dev))
                return nvdimm_namespace_attach_btt(ndns);

        if (is_nd_pfn(dev))
                return nvdimm_namespace_attach_pfn(ndns);

        if (nd_btt_probe(ndns, pmem) == 0) {
                /* we'll come back as btt-pmem */
                return -ENXIO;
        }

        if (nd_pfn_probe(ndns, pmem) == 0) {
                /* we'll come back as pfn-pmem */
                return -ENXIO;
        }

        return pmem_attach_disk(dev, ndns, pmem);
}

static int nd_pmem_remove(struct device *dev)
{
        struct pmem_device *pmem = dev_get_drvdata(dev);

        if (is_nd_btt(dev))
                nvdimm_namespace_detach_btt(pmem->ndns);
        else if (is_nd_pfn(dev))
                nvdimm_namespace_detach_pfn(pmem->ndns);
        else
                pmem_detach_disk(pmem);

        return 0;
}

MODULE_ALIAS("pmem");
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
static struct nd_device_driver nd_pmem_driver = {
        .probe = nd_pmem_probe,
        .remove = nd_pmem_remove,
        .drv = {
                .name = "nd_pmem",
        },
        .type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
};

static int __init pmem_init(void)
{
        int error;

        pmem_major = register_blkdev(0, "pmem");
        if (pmem_major < 0)
                return pmem_major;

        error = nd_driver_register(&nd_pmem_driver);
        if (error) {
                unregister_blkdev(pmem_major, "pmem");
                return error;
        }

        return 0;
}
module_init(pmem_init);

static void pmem_exit(void)
{
        driver_unregister(&nd_pmem_driver.drv);
        unregister_blkdev(pmem_major, "pmem");
}
module_exit(pmem_exit);

MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
MODULE_LICENSE("GPL v2");