289 lines
7.0 KiB
C
289 lines
7.0 KiB
C
/*
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* Persistent Memory Driver
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*
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* Copyright (c) 2014-2015, Intel Corporation.
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* Copyright (c) 2015, Christoph Hellwig <hch@lst.de>.
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* Copyright (c) 2015, Boaz Harrosh <boaz@plexistor.com>.
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*
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* This program is free software; you can redistribute it and/or modify it
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* under the terms and conditions of the GNU General Public License,
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* version 2, as published by the Free Software Foundation.
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*
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* This program is distributed in the hope it will be useful, but WITHOUT
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* ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
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* FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License for
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* more details.
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*/
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#include <asm/cacheflush.h>
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#include <linux/blkdev.h>
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#include <linux/hdreg.h>
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#include <linux/init.h>
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#include <linux/platform_device.h>
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#include <linux/module.h>
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#include <linux/moduleparam.h>
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#include <linux/slab.h>
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#include <linux/pmem.h>
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#include <linux/nd.h>
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#include "nd.h"
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struct pmem_device {
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struct request_queue *pmem_queue;
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struct gendisk *pmem_disk;
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/* One contiguous memory region per device */
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phys_addr_t phys_addr;
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void __pmem *virt_addr;
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size_t size;
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};
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static int pmem_major;
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static void pmem_do_bvec(struct pmem_device *pmem, struct page *page,
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unsigned int len, unsigned int off, int rw,
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sector_t sector)
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{
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void *mem = kmap_atomic(page);
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size_t pmem_off = sector << 9;
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void __pmem *pmem_addr = pmem->virt_addr + pmem_off;
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if (rw == READ) {
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memcpy_from_pmem(mem + off, pmem_addr, len);
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flush_dcache_page(page);
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} else {
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flush_dcache_page(page);
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memcpy_to_pmem(pmem_addr, mem + off, len);
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}
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kunmap_atomic(mem);
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}
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static void pmem_make_request(struct request_queue *q, struct bio *bio)
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{
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bool do_acct;
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unsigned long start;
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struct bio_vec bvec;
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struct bvec_iter iter;
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struct block_device *bdev = bio->bi_bdev;
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struct pmem_device *pmem = bdev->bd_disk->private_data;
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do_acct = nd_iostat_start(bio, &start);
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bio_for_each_segment(bvec, bio, iter)
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pmem_do_bvec(pmem, bvec.bv_page, bvec.bv_len, bvec.bv_offset,
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bio_data_dir(bio), iter.bi_sector);
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if (do_acct)
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nd_iostat_end(bio, start);
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if (bio_data_dir(bio))
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wmb_pmem();
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bio_endio(bio, 0);
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}
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static int pmem_rw_page(struct block_device *bdev, sector_t sector,
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struct page *page, int rw)
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{
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struct pmem_device *pmem = bdev->bd_disk->private_data;
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pmem_do_bvec(pmem, page, PAGE_CACHE_SIZE, 0, rw, sector);
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page_endio(page, rw & WRITE, 0);
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return 0;
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}
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static long pmem_direct_access(struct block_device *bdev, sector_t sector,
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void **kaddr, unsigned long *pfn, long size)
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{
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struct pmem_device *pmem = bdev->bd_disk->private_data;
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size_t offset = sector << 9;
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if (!pmem)
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return -ENODEV;
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/* FIXME convert DAX to comprehend that this mapping has a lifetime */
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*kaddr = (void __force *) pmem->virt_addr + offset;
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*pfn = (pmem->phys_addr + offset) >> PAGE_SHIFT;
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return pmem->size - offset;
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}
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static const struct block_device_operations pmem_fops = {
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.owner = THIS_MODULE,
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.rw_page = pmem_rw_page,
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.direct_access = pmem_direct_access,
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.revalidate_disk = nvdimm_revalidate_disk,
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};
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static struct pmem_device *pmem_alloc(struct device *dev,
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struct resource *res, int id)
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{
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struct pmem_device *pmem;
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pmem = devm_kzalloc(dev, sizeof(*pmem), GFP_KERNEL);
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if (!pmem)
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return ERR_PTR(-ENOMEM);
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pmem->phys_addr = res->start;
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pmem->size = resource_size(res);
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if (!arch_has_pmem_api())
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dev_warn(dev, "unable to guarantee persistence of writes\n");
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if (!devm_request_mem_region(dev, pmem->phys_addr, pmem->size,
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dev_name(dev))) {
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dev_warn(dev, "could not reserve region [0x%pa:0x%zx]\n",
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&pmem->phys_addr, pmem->size);
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return ERR_PTR(-EBUSY);
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}
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pmem->virt_addr = memremap_pmem(dev, pmem->phys_addr, pmem->size);
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if (!pmem->virt_addr)
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return ERR_PTR(-ENXIO);
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return pmem;
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}
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static void pmem_detach_disk(struct pmem_device *pmem)
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{
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del_gendisk(pmem->pmem_disk);
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put_disk(pmem->pmem_disk);
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blk_cleanup_queue(pmem->pmem_queue);
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}
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static int pmem_attach_disk(struct nd_namespace_common *ndns,
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struct pmem_device *pmem)
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{
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struct gendisk *disk;
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pmem->pmem_queue = blk_alloc_queue(GFP_KERNEL);
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if (!pmem->pmem_queue)
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return -ENOMEM;
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blk_queue_make_request(pmem->pmem_queue, pmem_make_request);
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blk_queue_physical_block_size(pmem->pmem_queue, PAGE_SIZE);
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blk_queue_max_hw_sectors(pmem->pmem_queue, UINT_MAX);
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blk_queue_bounce_limit(pmem->pmem_queue, BLK_BOUNCE_ANY);
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queue_flag_set_unlocked(QUEUE_FLAG_NONROT, pmem->pmem_queue);
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disk = alloc_disk(0);
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if (!disk) {
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blk_cleanup_queue(pmem->pmem_queue);
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return -ENOMEM;
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}
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disk->major = pmem_major;
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disk->first_minor = 0;
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disk->fops = &pmem_fops;
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disk->private_data = pmem;
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disk->queue = pmem->pmem_queue;
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disk->flags = GENHD_FL_EXT_DEVT;
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nvdimm_namespace_disk_name(ndns, disk->disk_name);
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disk->driverfs_dev = &ndns->dev;
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set_capacity(disk, pmem->size >> 9);
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pmem->pmem_disk = disk;
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add_disk(disk);
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revalidate_disk(disk);
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return 0;
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}
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static int pmem_rw_bytes(struct nd_namespace_common *ndns,
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resource_size_t offset, void *buf, size_t size, int rw)
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{
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struct pmem_device *pmem = dev_get_drvdata(ndns->claim);
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if (unlikely(offset + size > pmem->size)) {
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dev_WARN_ONCE(&ndns->dev, 1, "request out of range\n");
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return -EFAULT;
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}
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if (rw == READ)
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memcpy_from_pmem(buf, pmem->virt_addr + offset, size);
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else {
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memcpy_to_pmem(pmem->virt_addr + offset, buf, size);
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wmb_pmem();
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}
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return 0;
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}
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static int nd_pmem_probe(struct device *dev)
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{
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struct nd_region *nd_region = to_nd_region(dev->parent);
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struct nd_namespace_common *ndns;
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struct nd_namespace_io *nsio;
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struct pmem_device *pmem;
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ndns = nvdimm_namespace_common_probe(dev);
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if (IS_ERR(ndns))
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return PTR_ERR(ndns);
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nsio = to_nd_namespace_io(&ndns->dev);
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pmem = pmem_alloc(dev, &nsio->res, nd_region->id);
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if (IS_ERR(pmem))
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return PTR_ERR(pmem);
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dev_set_drvdata(dev, pmem);
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ndns->rw_bytes = pmem_rw_bytes;
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if (is_nd_btt(dev))
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return nvdimm_namespace_attach_btt(ndns);
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if (nd_btt_probe(ndns, pmem) == 0)
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/* we'll come back as btt-pmem */
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return -ENXIO;
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return pmem_attach_disk(ndns, pmem);
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}
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static int nd_pmem_remove(struct device *dev)
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{
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struct pmem_device *pmem = dev_get_drvdata(dev);
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if (is_nd_btt(dev))
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nvdimm_namespace_detach_btt(to_nd_btt(dev)->ndns);
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else
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pmem_detach_disk(pmem);
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return 0;
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}
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MODULE_ALIAS("pmem");
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MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_IO);
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MODULE_ALIAS_ND_DEVICE(ND_DEVICE_NAMESPACE_PMEM);
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static struct nd_device_driver nd_pmem_driver = {
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.probe = nd_pmem_probe,
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.remove = nd_pmem_remove,
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.drv = {
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.name = "nd_pmem",
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},
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.type = ND_DRIVER_NAMESPACE_IO | ND_DRIVER_NAMESPACE_PMEM,
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};
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static int __init pmem_init(void)
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{
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int error;
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pmem_major = register_blkdev(0, "pmem");
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if (pmem_major < 0)
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return pmem_major;
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error = nd_driver_register(&nd_pmem_driver);
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if (error) {
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unregister_blkdev(pmem_major, "pmem");
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return error;
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}
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return 0;
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}
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module_init(pmem_init);
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static void pmem_exit(void)
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{
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driver_unregister(&nd_pmem_driver.drv);
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unregister_blkdev(pmem_major, "pmem");
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}
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module_exit(pmem_exit);
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MODULE_AUTHOR("Ross Zwisler <ross.zwisler@linux.intel.com>");
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MODULE_LICENSE("GPL v2");
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