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/block.c b/drivers/mmc/core/block.c
index 7874c3b..7275ac5 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -112,6 +112,7 @@ struct mmc_blk_data {
#define MMC_BLK_WRITE BIT(1)
#define MMC_BLK_DISCARD BIT(2)
#define MMC_BLK_SECDISCARD BIT(3)
+#define MMC_BLK_CQE_RECOVERY BIT(4)
/*
* Only set in main mmc_blk_data associated
@@ -1730,6 +1731,138 @@ static void mmc_blk_data_prep(struct mmc_queue *mq, struct mmc_queue_req *mqrq,
*do_data_tag_p = do_data_tag;
}
+#define MMC_CQE_RETRIES 2
+
+static void mmc_blk_cqe_complete_rq(struct mmc_queue *mq, struct request *req)
+{
+ struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
+ struct mmc_request *mrq = &mqrq->brq.mrq;
+ struct request_queue *q = req->q;
+ struct mmc_host *host = mq->card->host;
+ unsigned long flags;
+ bool put_card;
+ int err;
+
+ mmc_cqe_post_req(host, mrq);
+
+ if (mrq->cmd && mrq->cmd->error)
+ err = mrq->cmd->error;
+ else if (mrq->data && mrq->data->error)
+ err = mrq->data->error;
+ else
+ err = 0;
+
+ if (err) {
+ if (mqrq->retries++ < MMC_CQE_RETRIES)
+ blk_mq_requeue_request(req, true);
+ else
+ blk_mq_end_request(req, BLK_STS_IOERR);
+ } else if (mrq->data) {
+ if (blk_update_request(req, BLK_STS_OK, mrq->data->bytes_xfered))
+ blk_mq_requeue_request(req, true);
+ else
+ __blk_mq_end_request(req, BLK_STS_OK);
+ } else {
+ blk_mq_end_request(req, BLK_STS_OK);
+ }
+
+ spin_lock_irqsave(q->queue_lock, flags);
+
+ mq->in_flight[mmc_issue_type(mq, req)] -= 1;
+
+ put_card = (mmc_tot_in_flight(mq) == 0);
+
+ mmc_cqe_check_busy(mq);
+
+ spin_unlock_irqrestore(q->queue_lock, flags);
+
+ if (!mq->cqe_busy)
+ blk_mq_run_hw_queues(q, true);
+
+ if (put_card)
+ mmc_put_card(mq->card, &mq->ctx);
+}
+
+void mmc_blk_cqe_recovery(struct mmc_queue *mq)
+{
+ struct mmc_card *card = mq->card;
+ struct mmc_host *host = card->host;
+ int err;
+
+ pr_debug("%s: CQE recovery start\n", mmc_hostname(host));
+
+ err = mmc_cqe_recovery(host);
+ if (err)
+ mmc_blk_reset(mq->blkdata, host, MMC_BLK_CQE_RECOVERY);
+ else
+ mmc_blk_reset_success(mq->blkdata, MMC_BLK_CQE_RECOVERY);
+
+ pr_debug("%s: CQE recovery done\n", mmc_hostname(host));
+}
+
+static void mmc_blk_cqe_req_done(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;
+
+ /*
+ * Block layer timeouts race with completions which means the normal
+ * completion path cannot be used during recovery.
+ */
+ if (mq->in_recovery)
+ mmc_blk_cqe_complete_rq(mq, req);
+ else
+ blk_mq_complete_request(req);
+}
+
+static int mmc_blk_cqe_start_req(struct mmc_host *host, struct mmc_request *mrq)
+{
+ mrq->done = mmc_blk_cqe_req_done;
+ mrq->recovery_notifier = mmc_cqe_recovery_notifier;
+
+ return mmc_cqe_start_req(host, mrq);
+}
+
+static struct mmc_request *mmc_blk_cqe_prep_dcmd(struct mmc_queue_req *mqrq,
+ struct request *req)
+{
+ struct mmc_blk_request *brq = &mqrq->brq;
+
+ memset(brq, 0, sizeof(*brq));
+
+ brq->mrq.cmd = &brq->cmd;
+ brq->mrq.tag = req->tag;
+
+ return &brq->mrq;
+}
+
+static int mmc_blk_cqe_issue_flush(struct mmc_queue *mq, struct request *req)
+{
+ struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
+ struct mmc_request *mrq = mmc_blk_cqe_prep_dcmd(mqrq, req);
+
+ mrq->cmd->opcode = MMC_SWITCH;
+ mrq->cmd->arg = (MMC_SWITCH_MODE_WRITE_BYTE << 24) |
+ (EXT_CSD_FLUSH_CACHE << 16) |
+ (1 << 8) |
+ EXT_CSD_CMD_SET_NORMAL;
+ mrq->cmd->flags = MMC_CMD_AC | MMC_RSP_R1B;
+
+ return mmc_blk_cqe_start_req(mq->card->host, mrq);
+}
+
+static int mmc_blk_cqe_issue_rw_rq(struct mmc_queue *mq, struct request *req)
+{
+ struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
+
+ mmc_blk_data_prep(mq, mqrq, 0, NULL, NULL);
+
+ return mmc_blk_cqe_start_req(mq->card->host, &mqrq->brq.mrq);
+}
+
static void mmc_blk_rw_rq_prep(struct mmc_queue_req *mqrq,
struct mmc_card *card,
int disable_multi,
@@ -2038,7 +2171,10 @@ void mmc_blk_mq_complete(struct request *req)
{
struct mmc_queue *mq = req->q->queuedata;
- mmc_blk_mq_complete_rq(mq, req);
+ if (mq->use_cqe)
+ mmc_blk_cqe_complete_rq(mq, req);
+ else
+ mmc_blk_mq_complete_rq(mq, req);
}
static void mmc_blk_mq_poll_completion(struct mmc_queue *mq,
@@ -2212,6 +2348,9 @@ static int mmc_blk_mq_issue_rw_rq(struct mmc_queue *mq,
static int mmc_blk_wait_for_idle(struct mmc_queue *mq, struct mmc_host *host)
{
+ if (mq->use_cqe)
+ return host->cqe_ops->cqe_wait_for_idle(host);
+
return mmc_blk_rw_wait(mq, NULL);
}
@@ -2250,11 +2389,18 @@ enum mmc_issued mmc_blk_mq_issue_rq(struct mmc_queue *mq, struct request *req)
return MMC_REQ_FAILED_TO_START;
}
return MMC_REQ_FINISHED;
+ case MMC_ISSUE_DCMD:
case MMC_ISSUE_ASYNC:
switch (req_op(req)) {
+ case REQ_OP_FLUSH:
+ ret = mmc_blk_cqe_issue_flush(mq, req);
+ break;
case REQ_OP_READ:
case REQ_OP_WRITE:
- ret = mmc_blk_mq_issue_rw_rq(mq, req);
+ if (mq->use_cqe)
+ ret = mmc_blk_cqe_issue_rw_rq(mq, req);
+ else
+ ret = mmc_blk_mq_issue_rw_rq(mq, req);
break;
default:
WARN_ON_ONCE(1);