/*
* 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/moduleparam.h>
#include <linux/slab.h>
#include <linux/pmem.h>
#include <linux/nd.h>
#include "nd.h"
struct pmem_device {
struct request_queue *pmem_queue;
struct gendisk *pmem_disk;
/* One contiguous memory region per device */
phys_addr_t phys_addr;
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);
size_t pmem_off = sector << 9;
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 void 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, 0);
}
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);
page_endio(page, rw & WRITE, 0);
return 0;
}
static long pmem_direct_access(struct block_device *bdev, sector_t sector,
void **kaddr, unsigned long *pfn, long size)
{
struct pmem_device *pmem = bdev->bd_disk->private_data;
size_t offset = sector << 9;
if (!pmem)
return -ENODEV;
/* FIXME convert DAX to comprehend that this mapping has a lifetime */
*kaddr = (void __force *) pmem->virt_addr + offset;
*pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
return pmem->size - offset;
}
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 = kzalloc(sizeof(*pmem), GFP_KERNEL);
if (!pmem)
return ERR_PTR(-ENOMEM);
pmem->phys_addr = res->start;
pmem->size = resource_size(res);
if (!arch_has_pmem_api())
dev_warn(dev, "unable to guarantee persistence of writes\n");
if (!request_mem_region(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);
kfree(pmem);
return ERR_PTR(-EBUSY);
}
pmem->virt_addr = memremap_pmem(pmem->phys_addr, pmem->size);
if (!pmem->virt_addr) {
release_mem_region(pmem->phys_addr, pmem->size);
kfree(pmem);
return ERR_PTR(-ENXIO);
}
return pmem;
}
static void pmem_detach_disk(struct pmem_device *pmem)
{
del_gendisk(pmem->pmem_disk);
put_disk(pmem->pmem_disk);
blk_cleanup_queue(pmem->pmem_queue);
}
static int pmem_attach_disk(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 = &ndns->dev;
set_capacity(disk, pmem->size >> 9);
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 void pmem_free(struct pmem_device *pmem)
{
memunmap_pmem(pmem->virt_addr);
release_mem_region(pmem->phys_addr, pmem->size);
kfree(pmem);
}
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;
int rc;
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);
dev_set_drvdata(dev, pmem);
ndns->rw_bytes = pmem_rw_bytes;
if (is_nd_btt(dev))
rc = nvdimm_namespace_attach_btt(ndns);
else if (nd_btt_probe(ndns, pmem) == 0) {
/* we'll come back as btt-pmem */
rc = -ENXIO;
} else
rc = pmem_attach_disk(ndns, pmem);
if (rc)
pmem_free(pmem);
return rc;
}
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(to_nd_btt(dev)->ndns);
else
pmem_detach_disk(pmem);
pmem_free(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");