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Subject[PATCH v4 2/3] mmc: host: sdhci: Implement the request_atomic() API
Date
Implement the request_atomic() ops for the sdhci driver to process
one request in the atomic context if the card is nonremovable.

Moreover, add a boolean parameter for sdhci_send_command() function
to indicate if need poll the inhibit bits, which can avoid
time-consuming polling in interrupt context by returning BUSY if
we met this unusual case through request_atomic() API.

Signed-off-by: Baolin Wang <baolin.wang7@gmail.com>
---
drivers/mmc/host/sdhci.c | 65 +++++++++++++++++++++++++++++++++++-------------
drivers/mmc/host/sdhci.h | 4 ++-
2 files changed, 51 insertions(+), 18 deletions(-)

diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
index 3f71646..1e67b1a 100644
--- a/drivers/mmc/host/sdhci.c
+++ b/drivers/mmc/host/sdhci.c
@@ -1539,14 +1539,15 @@ static void sdhci_finish_data(struct sdhci_host *host)
} else {
/* Avoid triggering warning in sdhci_send_command() */
host->cmd = NULL;
- sdhci_send_command(host, data->stop);
+ sdhci_send_command(host, data->stop, true);
}
} else {
__sdhci_finish_mrq(host, data->mrq);
}
}

-void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
+int sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd,
+ bool polling)
{
int flags;
u32 mask;
@@ -1574,13 +1575,26 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
mask &= ~SDHCI_DATA_INHIBIT;

while (sdhci_readl(host, SDHCI_PRESENT_STATE) & mask) {
- if (timeout == 0) {
+ if (!polling) {
+ pr_err("%s: Controller has not released inhibit bit(s), try again.\n",
+ mmc_hostname(host->mmc));
+
+ /*
+ * HSQ may send a command in interrupt context without
+ * polling the busy signaling, which means we should
+ * return BUSY if controller has not released inhibit
+ * bits to allow HSQ trying to send request again in
+ * non-atomic context. so we should not finish this
+ * request here.
+ */
+ return -EBUSY;
+ } else if (timeout == 0) {
pr_err("%s: Controller never released inhibit bit(s).\n",
mmc_hostname(host->mmc));
sdhci_dumpregs(host);
cmd->error = -EIO;
sdhci_finish_mrq(host, cmd->mrq);
- return;
+ return -EIO;
}
timeout--;
mdelay(1);
@@ -1610,7 +1624,7 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
mmc_hostname(host->mmc));
cmd->error = -EINVAL;
sdhci_finish_mrq(host, cmd->mrq);
- return;
+ return -EINVAL;
}

if (!(cmd->flags & MMC_RSP_PRESENT))
@@ -1645,6 +1659,8 @@ void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd)
sdhci_external_dma_pre_transfer(host, cmd);

sdhci_writew(host, SDHCI_MAKE_CMD(cmd->opcode, flags), SDHCI_COMMAND);
+
+ return 0;
}
EXPORT_SYMBOL_GPL(sdhci_send_command);

@@ -1707,7 +1723,7 @@ static void sdhci_finish_command(struct sdhci_host *host)

/* Finished CMD23, now send actual command. */
if (cmd == cmd->mrq->sbc) {
- sdhci_send_command(host, cmd->mrq->cmd);
+ sdhci_send_command(host, cmd->mrq->cmd, true);
} else {

/* Processed actual command. */
@@ -2035,16 +2051,12 @@ void sdhci_set_power_and_bus_voltage(struct sdhci_host *host,
* *
\*****************************************************************************/

-void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
+static int sdhci_start_request(struct mmc_host *mmc, struct mmc_request *mrq,
+ int present, bool polling)
{
- struct sdhci_host *host;
- int present;
+ struct sdhci_host *host = mmc_priv(mmc);
unsigned long flags;
-
- host = mmc_priv(mmc);
-
- /* Firstly check card presence */
- present = mmc->ops->get_cd(mmc);
+ int ret;

spin_lock_irqsave(&host->lock, flags);

@@ -2052,15 +2064,34 @@ void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)

if (!present || host->flags & SDHCI_DEVICE_DEAD) {
mrq->cmd->error = -ENOMEDIUM;
+ ret = -ENOMEDIUM;
sdhci_finish_mrq(host, mrq);
} else {
if (mrq->sbc && !(host->flags & SDHCI_AUTO_CMD23))
- sdhci_send_command(host, mrq->sbc);
+ ret = sdhci_send_command(host, mrq->sbc, polling);
else
- sdhci_send_command(host, mrq->cmd);
+ ret = sdhci_send_command(host, mrq->cmd, polling);
}

spin_unlock_irqrestore(&host->lock, flags);
+
+ return ret;
+}
+
+int sdhci_request_atomic(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ return sdhci_start_request(mmc, mrq, 1, false);
+}
+EXPORT_SYMBOL_GPL(sdhci_request_atomic);
+
+void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq)
+{
+ int present;
+
+ /* Firstly check card presence */
+ present = mmc->ops->get_cd(mmc);
+
+ sdhci_start_request(mmc, mrq, present, true);
}
EXPORT_SYMBOL_GPL(sdhci_request);

@@ -2600,7 +2631,7 @@ void sdhci_send_tuning(struct sdhci_host *host, u32 opcode)
*/
sdhci_writew(host, SDHCI_TRNS_READ, SDHCI_TRANSFER_MODE);

- sdhci_send_command(host, &cmd);
+ sdhci_send_command(host, &cmd, true);

host->cmd = NULL;

diff --git a/drivers/mmc/host/sdhci.h b/drivers/mmc/host/sdhci.h
index 79dffbb..f2d255c 100644
--- a/drivers/mmc/host/sdhci.h
+++ b/drivers/mmc/host/sdhci.h
@@ -757,7 +757,8 @@ void __sdhci_read_caps(struct sdhci_host *host, const u16 *ver,
int __sdhci_add_host(struct sdhci_host *host);
int sdhci_add_host(struct sdhci_host *host);
void sdhci_remove_host(struct sdhci_host *host, int dead);
-void sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd);
+int sdhci_send_command(struct sdhci_host *host, struct mmc_command *cmd,
+ bool polling);

static inline void sdhci_read_caps(struct sdhci_host *host)
{
@@ -776,6 +777,7 @@ void sdhci_set_power_and_bus_voltage(struct sdhci_host *host,
void sdhci_set_power_noreg(struct sdhci_host *host, unsigned char mode,
unsigned short vdd);
void sdhci_request(struct mmc_host *mmc, struct mmc_request *mrq);
+int sdhci_request_atomic(struct mmc_host *mmc, struct mmc_request *mrq);
void sdhci_set_bus_width(struct sdhci_host *host, int width);
void sdhci_reset(struct sdhci_host *host, u8 mask);
void sdhci_set_uhs_signaling(struct sdhci_host *host, unsigned timing);
--
1.9.1
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