summaryrefslogtreecommitdiffstats
path: root/drivers/mmc/host/mmc_hsq.c
diff options
context:
space:
mode:
Diffstat (limited to 'drivers/mmc/host/mmc_hsq.c')
-rw-r--r--drivers/mmc/host/mmc_hsq.c365
1 files changed, 365 insertions, 0 deletions
diff --git a/drivers/mmc/host/mmc_hsq.c b/drivers/mmc/host/mmc_hsq.c
new file mode 100644
index 0000000000..424dc7b078
--- /dev/null
+++ b/drivers/mmc/host/mmc_hsq.c
@@ -0,0 +1,365 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ *
+ * MMC software queue support based on command queue interfaces
+ *
+ * Copyright (C) 2019 Linaro, Inc.
+ * Author: Baolin Wang <baolin.wang@linaro.org>
+ */
+
+#include <linux/mmc/card.h>
+#include <linux/mmc/host.h>
+#include <linux/module.h>
+
+#include "mmc_hsq.h"
+
+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;
+
+ mmc->ops->request(mmc, hsq->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);
+
+ /* Make sure we are not already running a request now */
+ if (hsq->mrq || hsq->recovery_halt) {
+ spin_unlock_irqrestore(&hsq->lock, flags);
+ return;
+ }
+
+ /* Make sure there are remain requests need to pump */
+ if (!hsq->qcnt || !hsq->enabled) {
+ spin_unlock_irqrestore(&hsq->lock, flags);
+ return;
+ }
+
+ slot = &hsq->slot[hsq->next_tag];
+ hsq->mrq = slot->mrq;
+ hsq->qcnt--;
+
+ spin_unlock_irqrestore(&hsq->lock, flags);
+
+ if (mmc->ops->request_atomic)
+ 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 just give a warning for other error cases, since the host
+ * driver will handle them.
+ */
+ if (ret == -EBUSY)
+ schedule_work(&hsq->retry_work);
+ else
+ WARN_ON_ONCE(ret);
+}
+
+static void mmc_hsq_update_next_tag(struct mmc_hsq *hsq, int remains)
+{
+ int tag;
+
+ /*
+ * If there are no remain requests in software queue, then set a invalid
+ * tag.
+ */
+ if (!remains) {
+ hsq->next_tag = HSQ_INVALID_TAG;
+ hsq->tail_tag = HSQ_INVALID_TAG;
+ return;
+ }
+
+ tag = hsq->tag_slot[hsq->next_tag];
+ hsq->tag_slot[hsq->next_tag] = HSQ_INVALID_TAG;
+ hsq->next_tag = tag;
+}
+
+static void mmc_hsq_post_request(struct mmc_hsq *hsq)
+{
+ unsigned long flags;
+ int remains;
+
+ spin_lock_irqsave(&hsq->lock, flags);
+
+ remains = hsq->qcnt;
+ hsq->mrq = NULL;
+
+ /* Update the next available tag to be queued. */
+ mmc_hsq_update_next_tag(hsq, remains);
+
+ if (hsq->waiting_for_idle && !remains) {
+ hsq->waiting_for_idle = false;
+ wake_up(&hsq->wait_queue);
+ }
+
+ /* Do not pump new request in recovery mode. */
+ if (hsq->recovery_halt) {
+ spin_unlock_irqrestore(&hsq->lock, flags);
+ return;
+ }
+
+ spin_unlock_irqrestore(&hsq->lock, flags);
+
+ /*
+ * Try to pump new request to host controller as fast as possible,
+ * after completing previous request.
+ */
+ if (remains > 0)
+ mmc_hsq_pump_requests(hsq);
+}
+
+/**
+ * mmc_hsq_finalize_request - finalize one request if the request is done
+ * @mmc: the host controller
+ * @mrq: the request need to be finalized
+ *
+ * Return true if we finalized the corresponding request in software queue,
+ * otherwise return false.
+ */
+bool mmc_hsq_finalize_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ struct mmc_hsq *hsq = mmc->cqe_private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hsq->lock, flags);
+
+ if (!hsq->enabled || !hsq->mrq || hsq->mrq != mrq) {
+ spin_unlock_irqrestore(&hsq->lock, flags);
+ return false;
+ }
+
+ /*
+ * Clear current completed slot request to make a room for new request.
+ */
+ hsq->slot[hsq->next_tag].mrq = NULL;
+
+ spin_unlock_irqrestore(&hsq->lock, flags);
+
+ mmc_cqe_request_done(mmc, hsq->mrq);
+
+ mmc_hsq_post_request(hsq);
+
+ return true;
+}
+EXPORT_SYMBOL_GPL(mmc_hsq_finalize_request);
+
+static void mmc_hsq_recovery_start(struct mmc_host *mmc)
+{
+ struct mmc_hsq *hsq = mmc->cqe_private;
+ unsigned long flags;
+
+ spin_lock_irqsave(&hsq->lock, flags);
+
+ hsq->recovery_halt = true;
+
+ spin_unlock_irqrestore(&hsq->lock, flags);
+}
+
+static void mmc_hsq_recovery_finish(struct mmc_host *mmc)
+{
+ struct mmc_hsq *hsq = mmc->cqe_private;
+ int remains;
+
+ spin_lock_irq(&hsq->lock);
+
+ hsq->recovery_halt = false;
+ remains = hsq->qcnt;
+
+ spin_unlock_irq(&hsq->lock);
+
+ /*
+ * Try to pump new request if there are request pending in software
+ * queue after finishing recovery.
+ */
+ if (remains > 0)
+ mmc_hsq_pump_requests(hsq);
+}
+
+static int mmc_hsq_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ struct mmc_hsq *hsq = mmc->cqe_private;
+ int tag = mrq->tag;
+
+ spin_lock_irq(&hsq->lock);
+
+ if (!hsq->enabled) {
+ spin_unlock_irq(&hsq->lock);
+ return -ESHUTDOWN;
+ }
+
+ /* Do not queue any new requests in recovery mode. */
+ if (hsq->recovery_halt) {
+ spin_unlock_irq(&hsq->lock);
+ return -EBUSY;
+ }
+
+ hsq->slot[tag].mrq = mrq;
+
+ /*
+ * Set the next tag as current request tag if no available
+ * next tag.
+ */
+ if (hsq->next_tag == HSQ_INVALID_TAG) {
+ hsq->next_tag = tag;
+ hsq->tail_tag = tag;
+ hsq->tag_slot[hsq->tail_tag] = HSQ_INVALID_TAG;
+ } else {
+ hsq->tag_slot[hsq->tail_tag] = tag;
+ hsq->tail_tag = tag;
+ }
+
+ hsq->qcnt++;
+
+ spin_unlock_irq(&hsq->lock);
+
+ mmc_hsq_pump_requests(hsq);
+
+ return 0;
+}
+
+static void mmc_hsq_post_req(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ if (mmc->ops->post_req)
+ mmc->ops->post_req(mmc, mrq, 0);
+}
+
+static bool mmc_hsq_queue_is_idle(struct mmc_hsq *hsq, int *ret)
+{
+ bool is_idle;
+
+ spin_lock_irq(&hsq->lock);
+
+ is_idle = (!hsq->mrq && !hsq->qcnt) ||
+ hsq->recovery_halt;
+
+ *ret = hsq->recovery_halt ? -EBUSY : 0;
+ hsq->waiting_for_idle = !is_idle;
+
+ spin_unlock_irq(&hsq->lock);
+
+ return is_idle;
+}
+
+static int mmc_hsq_wait_for_idle(struct mmc_host *mmc)
+{
+ struct mmc_hsq *hsq = mmc->cqe_private;
+ int ret;
+
+ wait_event(hsq->wait_queue,
+ mmc_hsq_queue_is_idle(hsq, &ret));
+
+ return ret;
+}
+
+static void mmc_hsq_disable(struct mmc_host *mmc)
+{
+ struct mmc_hsq *hsq = mmc->cqe_private;
+ u32 timeout = 500;
+ int ret;
+
+ spin_lock_irq(&hsq->lock);
+
+ if (!hsq->enabled) {
+ spin_unlock_irq(&hsq->lock);
+ return;
+ }
+
+ spin_unlock_irq(&hsq->lock);
+
+ ret = wait_event_timeout(hsq->wait_queue,
+ mmc_hsq_queue_is_idle(hsq, &ret),
+ msecs_to_jiffies(timeout));
+ if (ret == 0) {
+ pr_warn("could not stop mmc software queue\n");
+ return;
+ }
+
+ spin_lock_irq(&hsq->lock);
+
+ hsq->enabled = false;
+
+ spin_unlock_irq(&hsq->lock);
+}
+
+static int mmc_hsq_enable(struct mmc_host *mmc, struct mmc_card *card)
+{
+ struct mmc_hsq *hsq = mmc->cqe_private;
+
+ spin_lock_irq(&hsq->lock);
+
+ if (hsq->enabled) {
+ spin_unlock_irq(&hsq->lock);
+ return -EBUSY;
+ }
+
+ hsq->enabled = true;
+
+ spin_unlock_irq(&hsq->lock);
+
+ return 0;
+}
+
+static const struct mmc_cqe_ops mmc_hsq_ops = {
+ .cqe_enable = mmc_hsq_enable,
+ .cqe_disable = mmc_hsq_disable,
+ .cqe_request = mmc_hsq_request,
+ .cqe_post_req = mmc_hsq_post_req,
+ .cqe_wait_for_idle = mmc_hsq_wait_for_idle,
+ .cqe_recovery_start = mmc_hsq_recovery_start,
+ .cqe_recovery_finish = mmc_hsq_recovery_finish,
+};
+
+int mmc_hsq_init(struct mmc_hsq *hsq, struct mmc_host *mmc)
+{
+ int i;
+ hsq->num_slots = HSQ_NUM_SLOTS;
+ hsq->next_tag = HSQ_INVALID_TAG;
+ hsq->tail_tag = HSQ_INVALID_TAG;
+
+ hsq->slot = devm_kcalloc(mmc_dev(mmc), hsq->num_slots,
+ sizeof(struct hsq_slot), GFP_KERNEL);
+ if (!hsq->slot)
+ return -ENOMEM;
+
+ hsq->mmc = mmc;
+ hsq->mmc->cqe_private = hsq;
+ mmc->cqe_ops = &mmc_hsq_ops;
+
+ for (i = 0; i < HSQ_NUM_SLOTS; i++)
+ hsq->tag_slot[i] = HSQ_INVALID_TAG;
+
+ INIT_WORK(&hsq->retry_work, mmc_hsq_retry_handler);
+ spin_lock_init(&hsq->lock);
+ init_waitqueue_head(&hsq->wait_queue);
+
+ return 0;
+}
+EXPORT_SYMBOL_GPL(mmc_hsq_init);
+
+void mmc_hsq_suspend(struct mmc_host *mmc)
+{
+ mmc_hsq_disable(mmc);
+}
+EXPORT_SYMBOL_GPL(mmc_hsq_suspend);
+
+int mmc_hsq_resume(struct mmc_host *mmc)
+{
+ return mmc_hsq_enable(mmc, NULL);
+}
+EXPORT_SYMBOL_GPL(mmc_hsq_resume);
+
+MODULE_DESCRIPTION("MMC Host Software Queue support");
+MODULE_LICENSE("GPL v2");