block: IBM RamSan 70/80 device driver

This patch includes the device driver for the IBM RamSan
family of PCI SSD flash storage cards. This driver will
include support for the RamSan 70 and 80. The driver
presents a block device for device I/O.

Signed-off-by: Philip J Kelleher <pjk1939@linux.vnet.ibm.com>
Signed-off-by: Jens Axboe <axboe@kernel.dk>

1 files changed, 367 insertions, 0 deletions

diff --git a/drivers/block/rsxx/dev.c b/drivers/block/rsxx/dev.c
new file mode 100644
index 0000000..96df053
--- /dev/null
+++ b/drivers/block/rsxx/dev.c
@@ -0,0 +1,367 @@
+/*
+* Filename: dev.c
+*
+*
+* Authors: Joshua Morris <josh.h.morris@us.ibm.com>
+*	Philip Kelleher <pjk1939@linux.vnet.ibm.com>
+*
+* (C) Copyright 2013 IBM Corporation
+*
+* 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 of the
+* License, 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., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+*/
+
+#include <linux/kernel.h>
+#include <linux/interrupt.h>
+#include <linux/module.h>
+#include <linux/pci.h>
+#include <linux/slab.h>
+
+#include <linux/hdreg.h>
+#include <linux/genhd.h>
+#include <linux/blkdev.h>
+#include <linux/bio.h>
+
+#include <linux/fs.h>
+
+#include "rsxx_priv.h"
+
+static unsigned int blkdev_minors = 64;
+module_param(blkdev_minors, uint, 0444);
+MODULE_PARM_DESC(blkdev_minors, "Number of minors(partitions)");
+
+/*
+ * For now I'm making this tweakable in case any applications hit this limit.
+ * If you see a "bio too big" error in the log you will need to raise this
+ * value.
+ */
+static unsigned int blkdev_max_hw_sectors = 1024;
+module_param(blkdev_max_hw_sectors, uint, 0444);
+MODULE_PARM_DESC(blkdev_max_hw_sectors, "Max hw sectors for a single BIO");
+
+static unsigned int enable_blkdev = 1;
+module_param(enable_blkdev , uint, 0444);
+MODULE_PARM_DESC(enable_blkdev, "Enable block device interfaces");
+
+
+struct rsxx_bio_meta {
+	struct bio	*bio;
+	atomic_t	pending_dmas;
+	atomic_t	error;
+	unsigned long	start_time;
+};
+
+static struct kmem_cache *bio_meta_pool;
+
+/*----------------- Block Device Operations -----------------*/
+static int rsxx_blkdev_ioctl(struct block_device *bdev,
+				 fmode_t mode,
+				 unsigned int cmd,
+				 unsigned long arg)
+{
+	struct rsxx_cardinfo *card = bdev->bd_disk->private_data;
+
+	switch (cmd) {
+	case RSXX_GETREG:
+		return rsxx_reg_access(card, (void __user *)arg, 1);
+	case RSXX_SETREG:
+		return rsxx_reg_access(card, (void __user *)arg, 0);
+	}
+
+	return -ENOTTY;
+}
+
+static int rsxx_getgeo(struct block_device *bdev, struct hd_geometry *geo)
+{
+	struct rsxx_cardinfo *card = bdev->bd_disk->private_data;
+	u64 blocks = card->size8 >> 9;
+
+	/*
+	 * get geometry: Fake it. I haven't found any drivers that set
+	 * geo->start, so we won't either.
+	 */
+	if (card->size8) {
+		geo->heads = 64;
+		geo->sectors = 16;
+		do_div(blocks, (geo->heads * geo->sectors));
+		geo->cylinders = blocks;
+	} else {
+		geo->heads = 0;
+		geo->sectors = 0;
+		geo->cylinders = 0;
+	}
+	return 0;
+}
+
+static const struct block_device_operations rsxx_fops = {
+	.owner		= THIS_MODULE,
+	.getgeo		= rsxx_getgeo,
+	.ioctl		= rsxx_blkdev_ioctl,
+};
+
+static void disk_stats_start(struct rsxx_cardinfo *card, struct bio *bio)
+{
+	struct hd_struct *part0 = &card->gendisk->part0;
+	int rw = bio_data_dir(bio);
+	int cpu;
+
+	cpu = part_stat_lock();
+
+	part_round_stats(cpu, part0);
+	part_inc_in_flight(part0, rw);
+
+	part_stat_unlock();
+}
+
+static void disk_stats_complete(struct rsxx_cardinfo *card,
+				struct bio *bio,
+				unsigned long start_time)
+{
+	struct hd_struct *part0 = &card->gendisk->part0;
+	unsigned long duration = jiffies - start_time;
+	int rw = bio_data_dir(bio);
+	int cpu;
+
+	cpu = part_stat_lock();
+
+	part_stat_add(cpu, part0, sectors[rw], bio_sectors(bio));
+	part_stat_inc(cpu, part0, ios[rw]);
+	part_stat_add(cpu, part0, ticks[rw], duration);
+
+	part_round_stats(cpu, part0);
+	part_dec_in_flight(part0, rw);
+
+	part_stat_unlock();
+}
+
+static void bio_dma_done_cb(struct rsxx_cardinfo *card,
+			    void *cb_data,
+			    unsigned int error)
+{
+	struct rsxx_bio_meta *meta = (struct rsxx_bio_meta *)cb_data;
+
+	if (error)
+		atomic_set(&meta->error, 1);
+
+	if (atomic_dec_and_test(&meta->pending_dmas)) {
+		disk_stats_complete(card, meta->bio, meta->start_time);
+
+		bio_endio(meta->bio, atomic_read(&meta->error) ? -EIO : 0);
+		kmem_cache_free(bio_meta_pool, meta);
+	}
+}
+
+static void rsxx_make_request(struct request_queue *q, struct bio *bio)
+{
+	struct rsxx_cardinfo *card = q->queuedata;
+	struct rsxx_bio_meta *bio_meta;
+	int st = -EINVAL;
+
+	might_sleep();
+
+	if (unlikely(card->halt)) {
+		st = -EFAULT;
+		goto req_err;
+	}
+
+	if (unlikely(card->dma_fault)) {
+		st = (-EFAULT);
+		goto req_err;
+	}
+
+	if (bio->bi_size == 0) {
+		dev_err(CARD_TO_DEV(card), "size zero BIO!\n");
+		goto req_err;
+	}
+
+	bio_meta = kmem_cache_alloc(bio_meta_pool, GFP_KERNEL);
+	if (!bio_meta) {
+		st = -ENOMEM;
+		goto req_err;
+	}
+
+	bio_meta->bio = bio;
+	atomic_set(&bio_meta->error, 0);
+	atomic_set(&bio_meta->pending_dmas, 0);
+	bio_meta->start_time = jiffies;
+
+	disk_stats_start(card, bio);
+
+	dev_dbg(CARD_TO_DEV(card), "BIO[%c]: meta: %p addr8: x%llx size: %d\n",
+		 bio_data_dir(bio) ? 'W' : 'R', bio_meta,
+		 (u64)bio->bi_sector << 9, bio->bi_size);
+
+	st = rsxx_dma_queue_bio(card, bio, &bio_meta->pending_dmas,
+				    bio_dma_done_cb, bio_meta);
+	if (st)
+		goto queue_err;
+
+	return;
+
+queue_err:
+	kmem_cache_free(bio_meta_pool, bio_meta);
+req_err:
+	bio_endio(bio, st);
+}
+
+/*----------------- Device Setup -------------------*/
+static bool rsxx_discard_supported(struct rsxx_cardinfo *card)
+{
+	unsigned char pci_rev;
+
+	pci_read_config_byte(card->dev, PCI_REVISION_ID, &pci_rev);
+
+	return (pci_rev >= RSXX_DISCARD_SUPPORT);
+}
+
+static unsigned short rsxx_get_logical_block_size(
+					struct rsxx_cardinfo *card)
+{
+	u32 capabilities = 0;
+	int st;
+
+	st = rsxx_get_card_capabilities(card, &capabilities);
+	if (st)
+		dev_warn(CARD_TO_DEV(card),
+			"Failed reading card capabilities register\n");
+
+	/* Earlier firmware did not have support for 512 byte accesses */
+	if (capabilities & CARD_CAP_SUBPAGE_WRITES)
+		return 512;
+	else
+		return RSXX_HW_BLK_SIZE;
+}
+
+int rsxx_attach_dev(struct rsxx_cardinfo *card)
+{
+	mutex_lock(&card->dev_lock);
+
+	/* The block device requires the stripe size from the config. */
+	if (enable_blkdev) {
+		if (card->config_valid)
+			set_capacity(card->gendisk, card->size8 >> 9);
+		else
+			set_capacity(card->gendisk, 0);
+		add_disk(card->gendisk);
+
+		card->bdev_attached = 1;
+	}
+
+	mutex_unlock(&card->dev_lock);
+
+	return 0;
+}
+
+void rsxx_detach_dev(struct rsxx_cardinfo *card)
+{
+	mutex_lock(&card->dev_lock);
+
+	if (card->bdev_attached) {
+		del_gendisk(card->gendisk);
+		card->bdev_attached = 0;
+	}
+
+	mutex_unlock(&card->dev_lock);
+}
+
+int rsxx_setup_dev(struct rsxx_cardinfo *card)
+{
+	unsigned short blk_size;
+
+	mutex_init(&card->dev_lock);
+
+	if (!enable_blkdev)
+		return 0;
+
+	card->major = register_blkdev(0, DRIVER_NAME);
+	if (card->major < 0) {
+		dev_err(CARD_TO_DEV(card), "Failed to get major number\n");
+		return -ENOMEM;
+	}
+
+	card->queue = blk_alloc_queue(GFP_KERNEL);
+	if (!card->queue) {
+		dev_err(CARD_TO_DEV(card), "Failed queue alloc\n");
+		unregister_blkdev(card->major, DRIVER_NAME);
+		return -ENOMEM;
+	}
+
+	card->gendisk = alloc_disk(blkdev_minors);
+	if (!card->gendisk) {
+		dev_err(CARD_TO_DEV(card), "Failed disk alloc\n");
+		blk_cleanup_queue(card->queue);
+		unregister_blkdev(card->major, DRIVER_NAME);
+		return -ENOMEM;
+	}
+
+	blk_size = rsxx_get_logical_block_size(card);
+
+	blk_queue_make_request(card->queue, rsxx_make_request);
+	blk_queue_bounce_limit(card->queue, BLK_BOUNCE_ANY);
+	blk_queue_dma_alignment(card->queue, blk_size - 1);
+	blk_queue_max_hw_sectors(card->queue, blkdev_max_hw_sectors);
+	blk_queue_logical_block_size(card->queue, blk_size);
+	blk_queue_physical_block_size(card->queue, RSXX_HW_BLK_SIZE);
+
+	queue_flag_set_unlocked(QUEUE_FLAG_NONROT, card->queue);
+	if (rsxx_discard_supported(card)) {
+		queue_flag_set_unlocked(QUEUE_FLAG_DISCARD, card->queue);
+		blk_queue_max_discard_sectors(card->queue,
+						RSXX_HW_BLK_SIZE >> 9);
+		card->queue->limits.discard_granularity = RSXX_HW_BLK_SIZE;
+		card->queue->limits.discard_alignment   = RSXX_HW_BLK_SIZE;
+		card->queue->limits.discard_zeroes_data = 1;
+	}
+
+	card->queue->queuedata = card;
+
+	snprintf(card->gendisk->disk_name, sizeof(card->gendisk->disk_name),
+		 "rsxx%d", card->disk_id);
+	card->gendisk->driverfs_dev = &card->dev->dev;
+	card->gendisk->major = card->major;
+	card->gendisk->first_minor = 0;
+	card->gendisk->fops = &rsxx_fops;
+	card->gendisk->private_data = card;
+	card->gendisk->queue = card->queue;
+
+	return 0;
+}
+
+void rsxx_destroy_dev(struct rsxx_cardinfo *card)
+{
+	if (!enable_blkdev)
+		return;
+
+	put_disk(card->gendisk);
+	card->gendisk = NULL;
+
+	blk_cleanup_queue(card->queue);
+	unregister_blkdev(card->major, DRIVER_NAME);
+}
+
+int rsxx_dev_init(void)
+{
+	bio_meta_pool = KMEM_CACHE(rsxx_bio_meta, SLAB_HWCACHE_ALIGN);
+	if (!bio_meta_pool)
+		return -ENOMEM;
+
+	return 0;
+}
+
+void rsxx_dev_cleanup(void)
+{
+	kmem_cache_destroy(bio_meta_pool);
+}
+
+