HW reset will reset eMMC card. So after reset, card should also be
reinitialized. Add two new callbacks to implement reset and reinitialize.
MMC core layer will check whether occurs a timeout error in the new added
routine mmc_handle_timeout_error
mmc_handle_timeout_error: check whether occurs a timeout error. If
occurs,use HW reset callbacks to do reset and reinitialize
hardware_reset: trigger a RST_n signal for host to reset card. This callback
was just defined in header file, not implemented in this patch.
Signed-off-by: Chuanxiao Dong <chuanxiao.dong@xxxxxxxxx>
---
drivers/mmc/core/core.c | 45 +++++++++++++++++++++++++++++++++++++++++++++
drivers/mmc/core/core.h | 9 +++++++++
drivers/mmc/core/mmc.c | 31 +++++++++++++++++++++++++++++++
include/linux/mmc/core.h | 1 +
include/linux/mmc/host.h | 13 +++++++++++++
5 files changed, 99 insertions(+), 0 deletions(-)
diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
index 6286898..530fc35 100644
--- a/drivers/mmc/core/core.c
+++ b/drivers/mmc/core/core.c
@@ -82,6 +82,51 @@ static void mmc_flush_scheduled_work(void)
}
/**
+ * mmc_handle_timeout_error - handle command and data timeout
+ * errors.
+ * @host: MMC host used to handle error
+ * @error: error condition
+ *
+ * check whether there is a command or data timeout error occured,
+ * if so, reset and reinit eMMC card if card has such capability.
+ * 1. let host controller do a specific hardware reset for eMMC
+ * card (trigger RST_n signal).
+ * 2. after reset done, reinit eMMC card.
+ */
+void mmc_handle_timeout_error(struct mmc_host *host, int error)
+{
+ struct mmc_card *card = host->card;
+
+ /*
+ * If error condition is not timeout, do nothing
+ */
+ if (error != -ETIMEDOUT)
+ return;
+ /*
+ * make sure mmc_reqeust is not NULL
+ * make sure mmc_card has HW reset capability
+ */
+ if (!card || !card->ext_csd.rst)
+ return;
+
+ /* check whether host has such callback */
+ if (!host->ops->hardware_reset ||
+ !host->bus_ops->reinit)
+ return;
+
+ /*
+ * if there occurs any timeout error, HW reset
+ * eMMC card and reinit again.
+ */
+ if (host->ops->hardware_reset(host))
+ pr_warn("MMC card reset failed\n");
+ else
+ if (host->bus_ops->reinit(host))
+ pr_warn("MMC card reinit failed\n");
+}
+EXPORT_SYMBOL(mmc_handle_timeout_error);
+
+/**
* mmc_request_done - finish processing an MMC request
* @host: MMC host which completed request
* @mrq: MMC request which request
diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
index 026c975..4980e2f 100644
--- a/drivers/mmc/core/core.h
+++ b/drivers/mmc/core/core.h
@@ -24,6 +24,15 @@ struct mmc_bus_ops {
int (*resume)(struct mmc_host *);
int (*power_save)(struct mmc_host *);
int (*power_restore)(struct mmc_host *);
+ /*
+ * New added callback
+ * Used to reinit card when HW reset occurs
+ *
+ * return value:
+ * 0: successfully reinit card.
+ * negative value: failed to reinit
+ */
+ int (*reinit)(struct mmc_host *);
};
void mmc_attach_bus(struct mmc_host *host, const struct mmc_bus_ops *ops);
diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
index 1d138b3..b3eb8a6 100644
--- a/drivers/mmc/core/mmc.c
+++ b/drivers/mmc/core/mmc.c
@@ -732,6 +732,35 @@ static int mmc_awake(struct mmc_host *host)
return err;
}
+/**
+ * mmc_reinit_card - reinitialize card after HW reset
+ *
+ * this callback is used to reinitialize card after a HW
+ * reset occurs.
+ * Reture value:
+ * 0: successfully reinitialize
+ * other: failed to reinitialize
+ *
+ * claim_host should be called before using this callback.
+ */
+static int mmc_reinit_card(struct mmc_host *host)
+{
+ int err;
+ /*
+ * Before init card, set the clock to be
+ * the init frequency
+ */
+ host->ios.clock = host->f_init;
+ mmc_set_clock(host, host->ios.clock);
+
+ err = mmc_init_card(host, host->ocr, host->card);
+ if (err)
+ pr_err("%s: Error %d while reinit card\n",
+ mmc_hostname(host), err);
+
+ return err;
+}
+
static const struct mmc_bus_ops mmc_ops = {
.awake = mmc_awake,
.sleep = mmc_sleep,
@@ -740,6 +769,7 @@ static const struct mmc_bus_ops mmc_ops = {
.suspend = NULL,
.resume = NULL,
.power_restore = mmc_power_restore,
+ .reinit = mmc_reinit_card,
};
static const struct mmc_bus_ops mmc_ops_unsafe = {
@@ -750,6 +780,7 @@ static const struct mmc_bus_ops mmc_ops_unsafe = {
.suspend = mmc_suspend,
.resume = mmc_resume,
.power_restore = mmc_power_restore,
+ .reinit = mmc_reinit_card,
};
static void mmc_attach_bus_ops(struct mmc_host *host)
diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
index 64e013f..115d589 100644
--- a/include/linux/mmc/core.h
+++ b/include/linux/mmc/core.h
@@ -131,6 +131,7 @@ struct mmc_request {
struct mmc_host;
struct mmc_card;
+extern void mmc_handle_timeout_error(struct mmc_host *, int);
extern void mmc_wait_for_req(struct mmc_host *, struct mmc_request *);
extern int mmc_wait_for_cmd(struct mmc_host *, struct mmc_command *, int);
extern int mmc_wait_for_app_cmd(struct mmc_host *, struct mmc_card *,
diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
index 4a9d9d2..f1dffcb 100644
--- a/include/linux/mmc/host.h
+++ b/include/linux/mmc/host.h
@@ -117,6 +117,19 @@ struct mmc_host_ops {
/* optional callback for HC quirks */
void (*init_card)(struct mmc_host *host, struct mmc_card *card);
+
+ /*
+ * eMMC4.4 HW reset feature callback
+ *
+ * eMMC4.4 card can be reset if host triggers a RST_n signal
+ * This callback will be used to for host to trigger such
+ * signal.
+ *
+ * return value:
+ * 0: successfully reset the eMMC card.
+ * -ENODEV: no valid hardware to do so.
+ */
+ int (*hardware_reset)(struct mmc_host *host);
};
struct mmc_card;
--
1.6.6.1
--
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