From: Baolin Wang <baolin.wang7@gmail.com>
To: adrian.hunter@intel.com, ulf.hansson@linaro.org
Cc: orsonzhai@gmail.com, zhang.lyra@gmail.com,
baolin.wang7@gmail.com, arnd@arndb.de, linux-mmc@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v3 3/4] mmc: host: hsq: Handle an unusual case of returing busy
Date: Thu, 19 Mar 2020 18:54:21 +0800 [thread overview]
Message-ID: <c94b7e9a2fb48ac921fe41dba56df91efcdaa6c4.1584615043.git.baolin.wang7@gmail.com> (raw)
In-Reply-To: <cover.1584615043.git.baolin.wang7@gmail.com>
In-Reply-To: <cover.1584615043.git.baolin.wang7@gmail.com>
There is an unusual case that the card is busy when trying to send a
command, and we can not polling the card status in interrupt context
by using request_atomic() to dispatch requests.
Thus we should queue a work to try again in the non-atomic context
in case the host releases the busy signal later.
Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
---
drivers/mmc/host/mmc_hsq.c | 37 ++++++++++++++++++++++++++++++++++++-
drivers/mmc/host/mmc_hsq.h | 1 +
2 files changed, 37 insertions(+), 1 deletion(-)
diff --git a/drivers/mmc/host/mmc_hsq.c b/drivers/mmc/host/mmc_hsq.c
index fdbaa98..3edad11 100644
--- a/drivers/mmc/host/mmc_hsq.c
+++ b/drivers/mmc/host/mmc_hsq.c
@@ -15,11 +15,33 @@
#define HSQ_NUM_SLOTS 64
#define HSQ_INVALID_TAG HSQ_NUM_SLOTS
+static void mmc_hsq_retry_handler(struct work_struct *work)
+{
+ struct mmc_hsq *hsq = container_of(work, struct mmc_hsq, retry_work);
+ struct mmc_host *mmc = hsq->mmc;
+ struct mmc_request *mrq = hsq->mrq;
+ struct mmc_data *data = mrq->data;
+
+ if (mmc->ops->request) {
+ mmc->ops->request(mmc, mrq);
+ return;
+ }
+
+ /*
+ * If host does not supply the callback in normal context to
+ * handle request, just finish this request.
+ */
+ data->error = -EBUSY;
+ data->bytes_xfered = 0;
+ mmc_hsq_finalize_request(mmc, mrq);
+}
+
static void mmc_hsq_pump_requests(struct mmc_hsq *hsq)
{
struct mmc_host *mmc = hsq->mmc;
struct hsq_slot *slot;
unsigned long flags;
+ int ret = 0;
spin_lock_irqsave(&hsq->lock, flags);
@@ -42,9 +64,21 @@ static void mmc_hsq_pump_requests(struct mmc_hsq *hsq)
spin_unlock_irqrestore(&hsq->lock, flags);
if (mmc->ops->request_atomic)
- mmc->ops->request_atomic(mmc, hsq->mrq);
+ ret = mmc->ops->request_atomic(mmc, hsq->mrq);
else
mmc->ops->request(mmc, hsq->mrq);
+
+ /*
+ * If returning BUSY from request_atomic(), which means the card
+ * may be busy now, and we should change to non-atomic context to
+ * try again for this unusual case, to avoid time-consuming operations
+ * in the atomic context.
+ *
+ * Note: we can ignore other error cases, since the host driver
+ * will handle them.
+ */
+ if (ret == -EBUSY)
+ schedule_work(&hsq->retry_work);
}
static void mmc_hsq_update_next_tag(struct mmc_hsq *hsq, int remains)
@@ -327,6 +361,7 @@ int mmc_hsq_init(struct mmc_hsq *hsq, struct mmc_host *mmc)
hsq->mmc->cqe_private = hsq;
mmc->cqe_ops = &mmc_hsq_ops;
+ INIT_WORK(&hsq->retry_work, mmc_hsq_retry_handler);
spin_lock_init(&hsq->lock);
init_waitqueue_head(&hsq->wait_queue);
diff --git a/drivers/mmc/host/mmc_hsq.h b/drivers/mmc/host/mmc_hsq.h
index d51beb7..81f6c4f 100644
--- a/drivers/mmc/host/mmc_hsq.h
+++ b/drivers/mmc/host/mmc_hsq.h
@@ -12,6 +12,7 @@ struct mmc_hsq {
wait_queue_head_t wait_queue;
struct hsq_slot *slot;
spinlock_t lock;
+ struct work_struct retry_work;
int next_tag;
int num_slots;
--
1.9.1
next prev parent reply other threads:[~2020-03-19 10:55 UTC|newest]
Thread overview: 7+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-03-19 10:54 [PATCH v3 0/4] Introduce the request_atomic() for the host Baolin Wang
2020-03-19 10:54 ` [PATCH v3 1/4] mmc: host: " Baolin Wang
2020-03-19 10:54 ` [PATCH v3 2/4] mmc: host: sdhci: Implement the request_atomic() API Baolin Wang
2020-03-19 10:54 ` Baolin Wang [this message]
2020-04-02 10:45 ` [PATCH v3 3/4] mmc: host: hsq: Handle an unusual case of returing busy Adrian Hunter
2020-04-03 1:21 ` Baolin Wang
2020-03-19 10:54 ` [PATCH v3 4/4] mmc: host: sdhci-sprd: Implement the request_atomic() API Baolin Wang
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