Commit f30664e2 authored by Sebastian Ott's avatar Sebastian Ott Committed by Martin Schwidefsky

s390: add scm block driver

Block device driver for Storage Class Memory (SCM). This driver
provides a block device interface for each available SCM increment.
Signed-off-by: default avatarSebastian Ott <sebott@linux.vnet.ibm.com>
Signed-off-by: default avatarMartin Schwidefsky <schwidefsky@de.ibm.com>
parent 2e73c2cf
......@@ -70,3 +70,14 @@ config DASD_EER
This driver provides a character device interface to the
DASD extended error reporting. This is only needed if you want to
use applications written for the EER facility.
config SCM_BLOCK
def_tristate m
prompt "Support for Storage Class Memory"
depends on S390 && BLOCK && EADM_SCH && SCM_BUS
help
Block device driver for Storage Class Memory (SCM). This driver
provides a block device interface for each available SCM increment.
To compile this driver as a module, choose M here: the
module will be called scm_block.
......@@ -17,3 +17,6 @@ obj-$(CONFIG_DASD_ECKD) += dasd_eckd_mod.o
obj-$(CONFIG_DASD_FBA) += dasd_fba_mod.o
obj-$(CONFIG_BLK_DEV_XPRAM) += xpram.o
obj-$(CONFIG_DCSSBLK) += dcssblk.o
scm_block-objs := scm_drv.o scm_blk.o
obj-$(CONFIG_SCM_BLOCK) += scm_block.o
/*
* Block driver for s390 storage class memory.
*
* Copyright IBM Corp. 2012
* Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "scm_block"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/genhd.h>
#include <linux/slab.h>
#include <linux/list.h>
#include <asm/eadm.h>
#include "scm_blk.h"
debug_info_t *scm_debug;
static int scm_major;
static DEFINE_SPINLOCK(list_lock);
static LIST_HEAD(inactive_requests);
static unsigned int nr_requests = 64;
static atomic_t nr_devices = ATOMIC_INIT(0);
module_param(nr_requests, uint, S_IRUGO);
MODULE_PARM_DESC(nr_requests, "Number of parallel requests.");
MODULE_DESCRIPTION("Block driver for s390 storage class memory.");
MODULE_LICENSE("GPL");
MODULE_ALIAS("scm:scmdev*");
static void __scm_free_rq(struct scm_request *scmrq)
{
struct aob_rq_header *aobrq = to_aobrq(scmrq);
free_page((unsigned long) scmrq->aob);
free_page((unsigned long) scmrq->aidaw);
kfree(aobrq);
}
static void scm_free_rqs(void)
{
struct list_head *iter, *safe;
struct scm_request *scmrq;
spin_lock_irq(&list_lock);
list_for_each_safe(iter, safe, &inactive_requests) {
scmrq = list_entry(iter, struct scm_request, list);
list_del(&scmrq->list);
__scm_free_rq(scmrq);
}
spin_unlock_irq(&list_lock);
}
static int __scm_alloc_rq(void)
{
struct aob_rq_header *aobrq;
struct scm_request *scmrq;
aobrq = kzalloc(sizeof(*aobrq) + sizeof(*scmrq), GFP_KERNEL);
if (!aobrq)
return -ENOMEM;
scmrq = (void *) aobrq->data;
scmrq->aidaw = (void *) get_zeroed_page(GFP_DMA);
scmrq->aob = (void *) get_zeroed_page(GFP_DMA);
if (!scmrq->aob || !scmrq->aidaw) {
__scm_free_rq(scmrq);
return -ENOMEM;
}
INIT_LIST_HEAD(&scmrq->list);
spin_lock_irq(&list_lock);
list_add(&scmrq->list, &inactive_requests);
spin_unlock_irq(&list_lock);
return 0;
}
static int scm_alloc_rqs(unsigned int nrqs)
{
int ret = 0;
while (nrqs-- && !ret)
ret = __scm_alloc_rq();
return ret;
}
static struct scm_request *scm_request_fetch(void)
{
struct scm_request *scmrq = NULL;
spin_lock(&list_lock);
if (list_empty(&inactive_requests))
goto out;
scmrq = list_first_entry(&inactive_requests, struct scm_request, list);
list_del(&scmrq->list);
out:
spin_unlock(&list_lock);
return scmrq;
}
static void scm_request_done(struct scm_request *scmrq)
{
unsigned long flags;
spin_lock_irqsave(&list_lock, flags);
list_add(&scmrq->list, &inactive_requests);
spin_unlock_irqrestore(&list_lock, flags);
}
static int scm_open(struct block_device *blkdev, fmode_t mode)
{
return scm_get_ref();
}
static int scm_release(struct gendisk *gendisk, fmode_t mode)
{
scm_put_ref();
return 0;
}
static const struct block_device_operations scm_blk_devops = {
.owner = THIS_MODULE,
.open = scm_open,
.release = scm_release,
};
static void scm_request_prepare(struct scm_request *scmrq)
{
struct scm_blk_dev *bdev = scmrq->bdev;
struct scm_device *scmdev = bdev->gendisk->private_data;
struct aidaw *aidaw = scmrq->aidaw;
struct msb *msb = &scmrq->aob->msb[0];
struct req_iterator iter;
struct bio_vec *bv;
msb->bs = MSB_BS_4K;
scmrq->aob->request.msb_count = 1;
msb->scm_addr = scmdev->address +
((u64) blk_rq_pos(scmrq->request) << 9);
msb->oc = (rq_data_dir(scmrq->request) == READ) ?
MSB_OC_READ : MSB_OC_WRITE;
msb->flags |= MSB_FLAG_IDA;
msb->data_addr = (u64) aidaw;
rq_for_each_segment(bv, scmrq->request, iter) {
WARN_ON(bv->bv_offset);
msb->blk_count += bv->bv_len >> 12;
aidaw->data_addr = (u64) page_address(bv->bv_page);
aidaw++;
}
}
static inline void scm_request_init(struct scm_blk_dev *bdev,
struct scm_request *scmrq,
struct request *req)
{
struct aob_rq_header *aobrq = to_aobrq(scmrq);
struct aob *aob = scmrq->aob;
memset(aob, 0, sizeof(*aob));
memset(scmrq->aidaw, 0, PAGE_SIZE);
aobrq->scmdev = bdev->scmdev;
aob->request.cmd_code = ARQB_CMD_MOVE;
aob->request.data = (u64) aobrq;
scmrq->request = req;
scmrq->bdev = bdev;
scmrq->retries = 4;
scmrq->error = 0;
}
static void scm_ensure_queue_restart(struct scm_blk_dev *bdev)
{
if (atomic_read(&bdev->queued_reqs)) {
/* Queue restart is triggered by the next interrupt. */
return;
}
blk_delay_queue(bdev->rq, SCM_QUEUE_DELAY);
}
static void scm_request_requeue(struct scm_request *scmrq)
{
struct scm_blk_dev *bdev = scmrq->bdev;
blk_requeue_request(bdev->rq, scmrq->request);
scm_request_done(scmrq);
scm_ensure_queue_restart(bdev);
}
static void scm_request_finish(struct scm_request *scmrq)
{
blk_end_request_all(scmrq->request, scmrq->error);
scm_request_done(scmrq);
}
static void scm_blk_request(struct request_queue *rq)
{
struct scm_device *scmdev = rq->queuedata;
struct scm_blk_dev *bdev = dev_get_drvdata(&scmdev->dev);
struct scm_request *scmrq;
struct request *req;
int ret;
while ((req = blk_peek_request(rq))) {
if (req->cmd_type != REQ_TYPE_FS)
continue;
scmrq = scm_request_fetch();
if (!scmrq) {
SCM_LOG(5, "no request");
scm_ensure_queue_restart(bdev);
return;
}
scm_request_init(bdev, scmrq, req);
scm_request_prepare(scmrq);
blk_start_request(req);
ret = scm_start_aob(scmrq->aob);
if (ret) {
SCM_LOG(5, "no subchannel");
scm_request_requeue(scmrq);
return;
}
atomic_inc(&bdev->queued_reqs);
}
}
static void __scmrq_log_error(struct scm_request *scmrq)
{
struct aob *aob = scmrq->aob;
if (scmrq->error == -ETIMEDOUT)
SCM_LOG(1, "Request timeout");
else {
SCM_LOG(1, "Request error");
SCM_LOG_HEX(1, &aob->response, sizeof(aob->response));
}
if (scmrq->retries)
SCM_LOG(1, "Retry request");
else
pr_err("An I/O operation to SCM failed with rc=%d\n",
scmrq->error);
}
void scm_blk_irq(struct scm_device *scmdev, void *data, int error)
{
struct scm_request *scmrq = data;
struct scm_blk_dev *bdev = scmrq->bdev;
scmrq->error = error;
if (error)
__scmrq_log_error(scmrq);
spin_lock(&bdev->lock);
list_add_tail(&scmrq->list, &bdev->finished_requests);
spin_unlock(&bdev->lock);
tasklet_hi_schedule(&bdev->tasklet);
}
static void scm_blk_tasklet(struct scm_blk_dev *bdev)
{
struct scm_request *scmrq;
unsigned long flags;
spin_lock_irqsave(&bdev->lock, flags);
while (!list_empty(&bdev->finished_requests)) {
scmrq = list_first_entry(&bdev->finished_requests,
struct scm_request, list);
list_del(&scmrq->list);
spin_unlock_irqrestore(&bdev->lock, flags);
if (scmrq->error && scmrq->retries-- > 0) {
if (scm_start_aob(scmrq->aob)) {
spin_lock_irqsave(&bdev->rq_lock, flags);
scm_request_requeue(scmrq);
spin_unlock_irqrestore(&bdev->rq_lock, flags);
}
/* Request restarted or requeued, handle next. */
spin_lock_irqsave(&bdev->lock, flags);
continue;
}
scm_request_finish(scmrq);
atomic_dec(&bdev->queued_reqs);
spin_lock_irqsave(&bdev->lock, flags);
}
spin_unlock_irqrestore(&bdev->lock, flags);
/* Look out for more requests. */
blk_run_queue(bdev->rq);
}
int scm_blk_dev_setup(struct scm_blk_dev *bdev, struct scm_device *scmdev)
{
struct request_queue *rq;
int len, ret = -ENOMEM;
unsigned int devindex, nr_max_blk;
devindex = atomic_inc_return(&nr_devices) - 1;
/* scma..scmz + scmaa..scmzz */
if (devindex > 701) {
ret = -ENODEV;
goto out;
}
bdev->scmdev = scmdev;
spin_lock_init(&bdev->rq_lock);
spin_lock_init(&bdev->lock);
INIT_LIST_HEAD(&bdev->finished_requests);
atomic_set(&bdev->queued_reqs, 0);
tasklet_init(&bdev->tasklet,
(void (*)(unsigned long)) scm_blk_tasklet,
(unsigned long) bdev);
rq = blk_init_queue(scm_blk_request, &bdev->rq_lock);
if (!rq)
goto out;
bdev->rq = rq;
nr_max_blk = min(scmdev->nr_max_block,
(unsigned int) (PAGE_SIZE / sizeof(struct aidaw)));
blk_queue_logical_block_size(rq, 1 << 12);
blk_queue_max_hw_sectors(rq, nr_max_blk << 3); /* 8 * 512 = blk_size */
blk_queue_max_segments(rq, nr_max_blk);
queue_flag_set_unlocked(QUEUE_FLAG_NONROT, rq);
bdev->gendisk = alloc_disk(SCM_NR_PARTS);
if (!bdev->gendisk)
goto out_queue;
rq->queuedata = scmdev;
bdev->gendisk->driverfs_dev = &scmdev->dev;
bdev->gendisk->private_data = scmdev;
bdev->gendisk->fops = &scm_blk_devops;
bdev->gendisk->queue = rq;
bdev->gendisk->major = scm_major;
bdev->gendisk->first_minor = devindex * SCM_NR_PARTS;
len = snprintf(bdev->gendisk->disk_name, DISK_NAME_LEN, "scm");
if (devindex > 25) {
len += snprintf(bdev->gendisk->disk_name + len,
DISK_NAME_LEN - len, "%c",
'a' + (devindex / 26) - 1);
devindex = devindex % 26;
}
snprintf(bdev->gendisk->disk_name + len, DISK_NAME_LEN - len, "%c",
'a' + devindex);
/* 512 byte sectors */
set_capacity(bdev->gendisk, scmdev->size >> 9);
add_disk(bdev->gendisk);
return 0;
out_queue:
blk_cleanup_queue(rq);
out:
atomic_dec(&nr_devices);
return ret;
}
void scm_blk_dev_cleanup(struct scm_blk_dev *bdev)
{
tasklet_kill(&bdev->tasklet);
del_gendisk(bdev->gendisk);
blk_cleanup_queue(bdev->gendisk->queue);
put_disk(bdev->gendisk);
}
static int __init scm_blk_init(void)
{
int ret;
ret = register_blkdev(0, "scm");
if (ret < 0)
goto out;
scm_major = ret;
if (scm_alloc_rqs(nr_requests))
goto out_unreg;
scm_debug = debug_register("scm_log", 16, 1, 16);
if (!scm_debug)
goto out_free;
debug_register_view(scm_debug, &debug_hex_ascii_view);
debug_set_level(scm_debug, 2);
ret = scm_drv_init();
if (ret)
goto out_dbf;
return ret;
out_dbf:
debug_unregister(scm_debug);
out_free:
scm_free_rqs();
out_unreg:
unregister_blkdev(scm_major, "scm");
out:
return ret;
}
module_init(scm_blk_init);
static void __exit scm_blk_cleanup(void)
{
scm_drv_cleanup();
debug_unregister(scm_debug);
scm_free_rqs();
unregister_blkdev(scm_major, "scm");
}
module_exit(scm_blk_cleanup);
#ifndef SCM_BLK_H
#define SCM_BLK_H
#include <linux/interrupt.h>
#include <linux/spinlock.h>
#include <linux/blkdev.h>
#include <linux/genhd.h>
#include <linux/list.h>
#include <asm/debug.h>
#include <asm/eadm.h>
#define SCM_NR_PARTS 8
#define SCM_QUEUE_DELAY 5
struct scm_blk_dev {
struct tasklet_struct tasklet;
struct request_queue *rq;
struct gendisk *gendisk;
struct scm_device *scmdev;
spinlock_t rq_lock; /* guard the request queue */
spinlock_t lock; /* guard the rest of the blockdev */
atomic_t queued_reqs;
struct list_head finished_requests;
};
struct scm_request {
struct scm_blk_dev *bdev;
struct request *request;
struct aidaw *aidaw;
struct aob *aob;
struct list_head list;
u8 retries;
int error;
};
#define to_aobrq(rq) container_of((void *) rq, struct aob_rq_header, data)
int scm_blk_dev_setup(struct scm_blk_dev *, struct scm_device *);
void scm_blk_dev_cleanup(struct scm_blk_dev *);
void scm_blk_irq(struct scm_device *, void *, int);
int scm_drv_init(void);
void scm_drv_cleanup(void);
extern debug_info_t *scm_debug;
#define SCM_LOG(imp, txt) do { \
debug_text_event(scm_debug, imp, txt); \
} while (0)
static inline void SCM_LOG_HEX(int level, void *data, int length)
{
if (level > scm_debug->level)
return;
while (length > 0) {
debug_event(scm_debug, level, data, length);
length -= scm_debug->buf_size;
data += scm_debug->buf_size;
}
}
static inline void SCM_LOG_STATE(int level, struct scm_device *scmdev)
{
struct {
u64 address;
u8 oper_state;
u8 rank;
} __packed data = {
.address = scmdev->address,
.oper_state = scmdev->attrs.oper_state,
.rank = scmdev->attrs.rank,
};
SCM_LOG_HEX(level, &data, sizeof(data));
}
#endif /* SCM_BLK_H */
/*
* Device driver for s390 storage class memory.
*
* Copyright IBM Corp. 2012
* Author(s): Sebastian Ott <sebott@linux.vnet.ibm.com>
*/
#define KMSG_COMPONENT "scm_block"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
#include <linux/module.h>
#include <linux/spinlock.h>
#include <linux/slab.h>
#include <asm/eadm.h>
#include "scm_blk.h"
static void notify(struct scm_device *scmdev)
{
pr_info("%lu: The capabilities of the SCM increment changed\n",
(unsigned long) scmdev->address);
SCM_LOG(2, "State changed");
SCM_LOG_STATE(2, scmdev);
}
static int scm_probe(struct scm_device *scmdev)
{
struct scm_blk_dev *bdev;
int ret;
SCM_LOG(2, "probe");
SCM_LOG_STATE(2, scmdev);
if (scmdev->attrs.oper_state != OP_STATE_GOOD)
return -EINVAL;
bdev = kzalloc(sizeof(*bdev), GFP_KERNEL);
if (!bdev)
return -ENOMEM;
spin_lock_irq(&scmdev->lock);
dev_set_drvdata(&scmdev->dev, bdev);
spin_unlock_irq(&scmdev->lock);
ret = scm_blk_dev_setup(bdev, scmdev);
if (ret) {
spin_lock_irq(&scmdev->lock);
dev_set_drvdata(&scmdev->dev, NULL);
spin_unlock_irq(&scmdev->lock);
kfree(bdev);
goto out;
}
out:
return ret;
}
static int scm_remove(struct scm_device *scmdev)
{
struct scm_blk_dev *bdev;
spin_lock_irq(&scmdev->lock);
bdev = dev_get_drvdata(&scmdev->dev);
dev_set_drvdata(&scmdev->dev, NULL);
spin_unlock_irq(&scmdev->lock);
scm_blk_dev_cleanup(bdev);
kfree(bdev);
return 0;
}
static struct scm_driver scm_drv = {
.drv = {
.name = "scm_block",
.owner = THIS_MODULE,
},
.notify = notify,
.probe = scm_probe,
.remove = scm_remove,
.handler = scm_blk_irq,
};
int __init scm_drv_init(void)
{
return scm_driver_register(&scm_drv);
}
void scm_drv_cleanup(void)
{
scm_driver_unregister(&scm_drv);
}
Markdown is supported
0%
or
You are about to add 0 people to the discussion. Proceed with caution.
Finish editing this message first!
Please register or to comment