From: Ludovic Barre <ludovic.barre@xxxxxx>
After a request a host may be in deadlock state, and wait
a specific action to unstuck the hardware block before
re-sending a new command.
This patch adds an optional callback mmc_hw_unstuck which
allows the host to unstuck the controller. In order to avoid
a critical context, this callback must be called when the
request is completed. Depending the mmc request, the completion
function is defined by mrq->done and could be in block.c or core.c.
mmc_hw_unstuck is called if the host returns an cmd/sbc/stop/data
DEADLK error.
Signed-off-by: Ludovic Barre <ludovic.barre@xxxxxx>
---
drivers/mmc/core/block.c | 11 +++++++++++
drivers/mmc/core/core.c | 35 +++++++++++++++++++++++++++++++++--
include/linux/mmc/core.h | 1 +
include/linux/mmc/host.h | 7 +++++++
4 files changed, 52 insertions(+), 2 deletions(-)
diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
index 2c71a434c915..2f723e2f5fde 100644
--- a/drivers/mmc/core/block.c
+++ b/drivers/mmc/core/block.c
@@ -1799,6 +1799,17 @@ static void mmc_blk_mq_rw_recovery(struct mmc_queue *mq, struct request *req)
u32 blocks;
int err;
+ /*
+ * if the host return a deadlock, it needs to be unstuck
+ * before to send a new command.
+ */
+ if (brq->sbc.error == -EDEADLK || brq->cmd.error == -EDEADLK ||
+ brq->stop.error == -EDEADLK || brq->data.error == -EDEADLK) {
+ pr_err("%s: host is in bad state, must be unstuck\n",
+ req->rq_disk->disk_name);
+ mmc_hw_unstuck(card->host);
+ }
+
/*
* Some errors the host driver might not have seen. Set the number of
* bytes transferred to zero in that case.
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 221127324709..43fe59a7403b 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -397,6 +397,7 @@ static int __mmc_start_req(struct mmc_host *host, struct mmc_request *mrq)
void mmc_wait_for_req_done(struct mmc_host *host, struct mmc_request *mrq)
{
struct mmc_command *cmd;
+ int sbc_err, stop_err, data_err;
while (1) {
wait_for_completion(&mrq->completion);
@@ -420,8 +421,24 @@ void mmc_wait_for_req_done(struct mmc_host *host, struct mmc_request *mrq)
mmc_hostname(host), __func__);
}
}
- if (!cmd->error || !cmd->retries ||
- mmc_card_removed(host->card))
+
+ sbc_err = mrq->sbc ? mrq->sbc->error : 0;
+ stop_err = mrq->stop ? mrq->stop->error : 0;
+ data_err = mrq->data ? mrq->data->error : 0;
+
+ /*
+ * if the host return a deadlock, it needs to be unstuck
+ * before to send a new command.
+ */
+ if (cmd->error == -EDEADLK || sbc_err == -EDEADLK ||
+ stop_err == -EDEADLK || data_err == -EDEADLK) {
+ pr_debug("%s: host is in bad state, must be unstuck\n",
+ mmc_hostname(host));
+ mmc_hw_unstuck(host);
+ }
+
+ if ((!cmd->error && !sbc_err && !stop_err && !data_err) ||
+ !cmd->retries || mmc_card_removed(host->card))
break;
mmc_retune_recheck(host);
@@ -430,6 +447,12 @@ void mmc_wait_for_req_done(struct mmc_host *host, struct mmc_request *mrq)
mmc_hostname(host), cmd->opcode, cmd->error);
cmd->retries--;
cmd->error = 0;
+ if (mrq->sbc)
+ mrq->sbc->error = 0;
+ if (mrq->stop)
+ mrq->stop->error = 0;
+ if (mrq->data)
+ mrq->data->error = 0;
__mmc_start_request(host, mrq);
}
@@ -2161,6 +2184,14 @@ int mmc_sw_reset(struct mmc_host *host)
}
EXPORT_SYMBOL(mmc_sw_reset);
+void mmc_hw_unstuck(struct mmc_host *host)
+{
+ if (!host->ops->hw_unstuck)
+ return;
+ host->ops->hw_unstuck(host);
+}
+EXPORT_SYMBOL(mmc_hw_unstuck);
+
static int mmc_rescan_try_freq(struct mmc_host *host, unsigned freq)
{
host->f_init = freq;
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index b7ba8810a3b5..eb10b8194073 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -173,6 +173,7 @@ void mmc_wait_for_req(struct mmc_host *host, struct mmc_request *mrq);
int mmc_wait_for_cmd(struct mmc_host *host, struct mmc_command *cmd,
int retries);
+void mmc_hw_unstuck(struct mmc_host *host);
int mmc_hw_reset(struct mmc_host *host);
int mmc_sw_reset(struct mmc_host *host);
void mmc_set_data_timeout(struct mmc_data *data, const struct mmc_card *card);
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index ba703384bea0..8b52cafcd1eb 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -163,6 +163,13 @@ struct mmc_host_ops {
void (*hw_reset)(struct mmc_host *host);
void (*card_event)(struct mmc_host *host);
+ /*
+ * Optional callback, if your host could be in deadlock after a command
+ * and need a specific action to unstuck the controller before sending
+ * new command.
+ */
+ void (*hw_unstuck)(struct mmc_host *host);
+
/*
* Optional callback to support controllers with HW issues for multiple
* I/O. Returns the number of supported blocks for the request.
--
2.17.1
