[PATCH] mmc: mediatek: fix request blocked by cancel_delayed_work

Chaotian Jing
2016-04-18T07:13:29Z

there are 2 points will cause could not call mmc_request_done()
and eventually cause the caller thread blocked.

A. if card was busy, cancel_delayed_work() will return false because
the delay work has not been scheduled, in this case, need put
mod_delayed_work() in front of msdc_cmd_is_ready()

B. if a request really need more than 5s(Some Sandisk TF card), it will
use cancel_delayed_work() to cancel itself, and also return false, so use
in_interrupt() to avoid this case

Signed-off-by: Chaotian Jing <chaotian.jing@mediatek.com>
---
drivers/mmc/host/mtk-sd.c | 11 ++++++++---
1 file changed, 8 insertions(+), 3 deletions(-)

diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
index b17f30d..1511b1b 100644
--- a/drivers/mmc/host/mtk-sd.c
+++ b/drivers/mmc/host/mtk-sd.c
@@ -724,7 +724,7 @@ static void msdc_request_done(struct msdc_host *host, struct mmc_request *mrq)
bool ret;

ret = cancel_delayed_work(&host->req_timeout);
- if (!ret) {
+ if (!ret && in_interrupt()) {
/* delay work already running */
return;
}
@@ -824,7 +824,12 @@ static inline bool msdc_cmd_is_ready(struct msdc_host *host,
}

if (mmc_resp_type(cmd) == MMC_RSP_R1B || cmd->data) {
- tmo = jiffies + msecs_to_jiffies(20);
+ /*
+ * 2550ms is from EXT_CSD[248], after switch to hs200,
+ * using CMD13 to polling card status, it will get response
+ * of 0x800, but EMMC still pull-low DAT0.
+ */
+ tmo = jiffies + msecs_to_jiffies(2550);
/* R1B or with data, should check SDCBUSY */
while ((readl(host->base + SDC_STS) & SDC_STS_SDCBUSY) &&
time_before(jiffies, tmo))
@@ -847,6 +852,7 @@ static void msdc_start_command(struct msdc_host *host,
WARN_ON(host->cmd);
host->cmd = cmd;

+ mod_delayed_work(system_wq, &host->req_timeout, DAT_TIMEOUT);
if (!msdc_cmd_is_ready(host, mrq, cmd))
return;

@@ -858,7 +864,6 @@ static void msdc_start_command(struct msdc_host *host,

cmd->error = 0;
rawcmd = msdc_cmd_prepare_raw_cmd(host, mrq, cmd);
- mod_delayed_work(system_wq, &host->req_timeout, DAT_TIMEOUT);

sdr_set_bits(host->base + MSDC_INTEN, cmd_ints_mask);
writel(cmd->arg, host->base + SDC_ARG);
--
1.8.1.1.dirty