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

Ulf Hansson
2016-04-22T12:24:44Z

On 18 April 2016 at 09:13, Chaotian Jing <chaotian.jing@mediatek.com> wrote:
> 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.
> + */

Seems like you are solving a eMMC specific issue on your driver?

Perhaps we should try to use a card quirk instead?

> + 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
>

Kind regards
Uffe