mmc: block: Add CQE support
Add CQE support to the block driver, including:
- optionally using DCMD for flush requests
- "manually" issuing discard requests
- issuing read / write requests to the CQE
- supporting block-layer timeouts
- handling recovery
- supporting re-tuning
CQE offers 25% - 50% better random multi-threaded I/O. There is a slight
(e.g. 2%) drop in sequential read speed but no observable change to sequential
write.
CQE automatically sends the commands to complete requests. However it only
supports reads / writes and so-called "direct commands" (DCMD). Furthermore
DCMD is limited to one command at a time, but discards require 3 commands.
That makes issuing discards through CQE very awkward, but some CQE's don't
support DCMD anyway. So for discards, the existing non-CQE approach is
taken, where the mmc core code issues the 3 commands one at a time i.e.
mmc_erase(). Where DCMD is used, is for issuing flushes.
Signed-off-by: Adrian Hunter <adrian.hunter@intel.com>
Acked-by: Linus Walleij <linus.walleij@linaro.org>
Signed-off-by: Ulf Hansson <ulf.hansson@linaro.org>
Tested-by: Linus Walleij <linus.walleij@linaro.org>
diff --git a/drivers/mmc/core/queue.c b/drivers/mmc/core/queue.c
index 54bec4c..8d632d2 100644
--- a/drivers/mmc/core/queue.c
+++ b/drivers/mmc/core/queue.c
@@ -40,18 +40,142 @@
return BLKPREP_OK;
}
+static inline bool mmc_cqe_dcmd_busy(struct mmc_queue *mq)
+{
+ /* Allow only 1 DCMD at a time */
+ return mq->in_flight[MMC_ISSUE_DCMD];
+}
+
+void mmc_cqe_check_busy(struct mmc_queue *mq)
+{
+ if ((mq->cqe_busy & MMC_CQE_DCMD_BUSY) && !mmc_cqe_dcmd_busy(mq))
+ mq->cqe_busy &= ~MMC_CQE_DCMD_BUSY;
+
+ mq->cqe_busy &= ~MMC_CQE_QUEUE_FULL;
+}
+
+static inline bool mmc_cqe_can_dcmd(struct mmc_host *host)
+{
+ return host->caps2 & MMC_CAP2_CQE_DCMD;
+}
+
+enum mmc_issue_type mmc_cqe_issue_type(struct mmc_host *host,
+ struct request *req)
+{
+ switch (req_op(req)) {
+ case REQ_OP_DRV_IN:
+ case REQ_OP_DRV_OUT:
+ case REQ_OP_DISCARD:
+ case REQ_OP_SECURE_ERASE:
+ return MMC_ISSUE_SYNC;
+ case REQ_OP_FLUSH:
+ return mmc_cqe_can_dcmd(host) ? MMC_ISSUE_DCMD : MMC_ISSUE_SYNC;
+ default:
+ return MMC_ISSUE_ASYNC;
+ }
+}
+
enum mmc_issue_type mmc_issue_type(struct mmc_queue *mq, struct request *req)
{
+ struct mmc_host *host = mq->card->host;
+
+ if (mq->use_cqe)
+ return mmc_cqe_issue_type(host, req);
+
if (req_op(req) == REQ_OP_READ || req_op(req) == REQ_OP_WRITE)
return MMC_ISSUE_ASYNC;
return MMC_ISSUE_SYNC;
}
+static void __mmc_cqe_recovery_notifier(struct mmc_queue *mq)
+{
+ if (!mq->recovery_needed) {
+ mq->recovery_needed = true;
+ schedule_work(&mq->recovery_work);
+ }
+}
+
+void mmc_cqe_recovery_notifier(struct mmc_request *mrq)
+{
+ struct mmc_queue_req *mqrq = container_of(mrq, struct mmc_queue_req,
+ brq.mrq);
+ struct request *req = mmc_queue_req_to_req(mqrq);
+ struct request_queue *q = req->q;
+ struct mmc_queue *mq = q->queuedata;
+ unsigned long flags;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+ __mmc_cqe_recovery_notifier(mq);
+ spin_unlock_irqrestore(q->queue_lock, flags);
+}
+
+static enum blk_eh_timer_return mmc_cqe_timed_out(struct request *req)
+{
+ struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
+ struct mmc_request *mrq = &mqrq->brq.mrq;
+ struct mmc_queue *mq = req->q->queuedata;
+ struct mmc_host *host = mq->card->host;
+ enum mmc_issue_type issue_type = mmc_issue_type(mq, req);
+ bool recovery_needed = false;
+
+ switch (issue_type) {
+ case MMC_ISSUE_ASYNC:
+ case MMC_ISSUE_DCMD:
+ if (host->cqe_ops->cqe_timeout(host, mrq, &recovery_needed)) {
+ if (recovery_needed)
+ __mmc_cqe_recovery_notifier(mq);
+ return BLK_EH_RESET_TIMER;
+ }
+ /* No timeout */
+ return BLK_EH_HANDLED;
+ default:
+ /* Timeout is handled by mmc core */
+ return BLK_EH_RESET_TIMER;
+ }
+}
+
static enum blk_eh_timer_return mmc_mq_timed_out(struct request *req,
bool reserved)
{
- return BLK_EH_RESET_TIMER;
+ struct request_queue *q = req->q;
+ struct mmc_queue *mq = q->queuedata;
+ unsigned long flags;
+ int ret;
+
+ spin_lock_irqsave(q->queue_lock, flags);
+
+ if (mq->recovery_needed || !mq->use_cqe)
+ ret = BLK_EH_RESET_TIMER;
+ else
+ ret = mmc_cqe_timed_out(req);
+
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ return ret;
+}
+
+static void mmc_mq_recovery_handler(struct work_struct *work)
+{
+ struct mmc_queue *mq = container_of(work, struct mmc_queue,
+ recovery_work);
+ struct request_queue *q = mq->queue;
+
+ mmc_get_card(mq->card, &mq->ctx);
+
+ mq->in_recovery = true;
+
+ mmc_blk_cqe_recovery(mq);
+
+ mq->in_recovery = false;
+
+ spin_lock_irq(q->queue_lock);
+ mq->recovery_needed = false;
+ spin_unlock_irq(q->queue_lock);
+
+ mmc_put_card(mq->card, &mq->ctx);
+
+ blk_mq_run_hw_queues(q, true);
}
static int mmc_queue_thread(void *d)
@@ -223,9 +347,10 @@
struct request_queue *q = req->q;
struct mmc_queue *mq = q->queuedata;
struct mmc_card *card = mq->card;
+ struct mmc_host *host = card->host;
enum mmc_issue_type issue_type;
enum mmc_issued issued;
- bool get_card;
+ bool get_card, cqe_retune_ok;
int ret;
if (mmc_card_removed(mq->card)) {
@@ -237,7 +362,19 @@
spin_lock_irq(q->queue_lock);
+ if (mq->recovery_needed) {
+ spin_unlock_irq(q->queue_lock);
+ return BLK_STS_RESOURCE;
+ }
+
switch (issue_type) {
+ case MMC_ISSUE_DCMD:
+ if (mmc_cqe_dcmd_busy(mq)) {
+ mq->cqe_busy |= MMC_CQE_DCMD_BUSY;
+ spin_unlock_irq(q->queue_lock);
+ return BLK_STS_RESOURCE;
+ }
+ break;
case MMC_ISSUE_ASYNC:
break;
default:
@@ -254,6 +391,7 @@
mq->in_flight[issue_type] += 1;
get_card = (mmc_tot_in_flight(mq) == 1);
+ cqe_retune_ok = (mmc_cqe_qcnt(mq) == 1);
spin_unlock_irq(q->queue_lock);
@@ -265,6 +403,11 @@
if (get_card)
mmc_get_card(card, &mq->ctx);
+ if (mq->use_cqe) {
+ host->retune_now = host->need_retune && cqe_retune_ok &&
+ !host->hold_retune;
+ }
+
blk_mq_start_request(req);
issued = mmc_blk_mq_issue_rq(mq, req);
@@ -326,6 +469,7 @@
/* Initialize thread_sem even if it is not used */
sema_init(&mq->thread_sem, 1);
+ INIT_WORK(&mq->recovery_work, mmc_mq_recovery_handler);
INIT_WORK(&mq->complete_work, mmc_blk_mq_complete_work);
mutex_init(&mq->complete_lock);
@@ -375,10 +519,18 @@
static int mmc_mq_init(struct mmc_queue *mq, struct mmc_card *card,
spinlock_t *lock)
{
+ struct mmc_host *host = card->host;
int q_depth;
int ret;
- q_depth = MMC_QUEUE_DEPTH;
+ /*
+ * The queue depth for CQE must match the hardware because the request
+ * tag is used to index the hardware queue.
+ */
+ if (mq->use_cqe)
+ q_depth = min_t(int, card->ext_csd.cmdq_depth, host->cqe_qdepth);
+ else
+ q_depth = MMC_QUEUE_DEPTH;
ret = mmc_mq_init_queue(mq, q_depth, &mmc_mq_ops, lock);
if (ret)
@@ -408,7 +560,9 @@
mq->card = card;
- if (mmc_host_use_blk_mq(host))
+ mq->use_cqe = host->cqe_enabled;
+
+ if (mq->use_cqe || mmc_host_use_blk_mq(host))
return mmc_mq_init(mq, card, lock);
mq->queue = blk_alloc_queue(GFP_KERNEL);