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Date:   Thu, 9 Nov 2017 17:24:28 +0200
From:   Adrian Hunter <adrian.hunter@...el.com>
To:     Ulf Hansson <ulf.hansson@...aro.org>
Cc:     linux-mmc <linux-mmc@...r.kernel.org>,
        linux-block <linux-block@...r.kernel.org>,
        linux-kernel <linux-kernel@...r.kernel.org>,
        Bough Chen <haibo.chen@....com>,
        Alex Lemberg <alex.lemberg@...disk.com>,
        Mateusz Nowak <mateusz.nowak@...el.com>,
        Yuliy Izrailov <Yuliy.Izrailov@...disk.com>,
        Jaehoon Chung <jh80.chung@...sung.com>,
        Dong Aisheng <dongas86@...il.com>,
        Das Asutosh <asutoshd@...eaurora.org>,
        Zhangfei Gao <zhangfei.gao@...il.com>,
        Sahitya Tummala <stummala@...eaurora.org>,
        Harjani Ritesh <riteshh@...eaurora.org>,
        Venu Byravarasu <vbyravarasu@...dia.com>,
        Linus Walleij <linus.walleij@...aro.org>,
        Shawn Lin <shawn.lin@...k-chips.com>,
        Christoph Hellwig <hch@....de>
Subject: Re: [PATCH V13 09/10] mmc: block: blk-mq: Stop using
 card_busy_detect()

On 09/11/17 15:36, Ulf Hansson wrote:
> On 3 November 2017 at 14:20, Adrian Hunter <adrian.hunter@...el.com> wrote:
>> card_busy_detect() doesn't set a correct timeout, and it doesn't take care
>> of error status bits. Stop using it for blk-mq.
> 
> I think this changelog isn't very descriptive. Could you please work
> on that for the next version.

Ok

> 
>>
>> Signed-off-by: Adrian Hunter <adrian.hunter@...el.com>
>> ---
>>  drivers/mmc/core/block.c | 117 +++++++++++++++++++++++++++++++++++++++++++----
>>  1 file changed, 109 insertions(+), 8 deletions(-)
>>
>> diff --git a/drivers/mmc/core/block.c b/drivers/mmc/core/block.c
>> index 0c29b1d8d545..5c5ff3c34313 100644
>> --- a/drivers/mmc/core/block.c
>> +++ b/drivers/mmc/core/block.c
>> @@ -1426,15 +1426,18 @@ static inline void mmc_apply_rel_rw(struct mmc_blk_request *brq,
>>         }
>>  }
>>
>> -#define CMD_ERRORS                                                     \
>> -       (R1_OUT_OF_RANGE |      /* Command argument out of range */     \
>> -        R1_ADDRESS_ERROR |     /* Misaligned address */                \
>> +#define CMD_ERRORS_EXCL_OOR                                            \
>> +       (R1_ADDRESS_ERROR |     /* Misaligned address */                \
>>          R1_BLOCK_LEN_ERROR |   /* Transferred block length incorrect */\
>>          R1_WP_VIOLATION |      /* Tried to write to protected block */ \
>>          R1_CARD_ECC_FAILED |   /* Card ECC failed */                   \
>>          R1_CC_ERROR |          /* Card controller error */             \
>>          R1_ERROR)              /* General/unknown error */
>>
>> +#define CMD_ERRORS                                                     \
>> +       (CMD_ERRORS_EXCL_OOR |                                          \
>> +        R1_OUT_OF_RANGE)       /* Command argument out of range */     \
>> +
>>  static void mmc_blk_eval_resp_error(struct mmc_blk_request *brq)
>>  {
>>         u32 val;
>> @@ -1951,6 +1954,95 @@ static void mmc_blk_ss_read(struct mmc_queue *mq, struct request *req)
>>         mqrq->retries = MMC_NO_RETRIES;
>>  }
>>
>> +static inline bool mmc_blk_oor_valid(struct mmc_blk_request *brq)
>> +{
>> +       return !!brq->mrq.sbc;
>> +}
>> +
>> +static inline u32 mmc_blk_stop_err_bits(struct mmc_blk_request *brq)
>> +{
>> +       return mmc_blk_oor_valid(brq) ? CMD_ERRORS : CMD_ERRORS_EXCL_OOR;
>> +}
>> +
>> +static inline bool mmc_blk_in_tran_state(u32 status)
>> +{
>> +       /*
>> +        * Some cards mishandle the status bits, so make sure to check both the
>> +        * busy indication and the card state.
>> +        */
>> +       return status & R1_READY_FOR_DATA &&
>> +              (R1_CURRENT_STATE(status) == R1_STATE_TRAN);
>> +}
>> +
>> +static unsigned int mmc_blk_clock_khz(struct mmc_host *host)
>> +{
>> +       if (host->actual_clock)
>> +               return host->actual_clock / 1000;
>> +
>> +       /* Clock may be subject to a divisor, fudge it by a factor of 2. */
>> +       if (host->ios.clock)
>> +               return host->ios.clock / 2000;
>> +
>> +       /* How can there be no clock */
>> +       WARN_ON_ONCE(1);
>> +       return 100; /* 100 kHz is minimum possible value */
>> +}
>> +
>> +static unsigned long mmc_blk_data_timeout_jiffies(struct mmc_host *host,
>> +                                                 struct mmc_data *data)
>> +{
>> +       unsigned int ms = DIV_ROUND_UP(data->timeout_ns, 1000000);
>> +       unsigned int khz;
>> +
>> +       if (data->timeout_clks) {
>> +               khz = mmc_blk_clock_khz(host);
>> +               ms += DIV_ROUND_UP(data->timeout_clks, khz);
>> +       }
>> +
>> +       return msecs_to_jiffies(ms);
>> +}
>> +
>> +static int mmc_blk_card_stuck(struct mmc_card *card, struct request *req,
>> +                             u32 *resp_errs)
>> +{
>> +       struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
>> +       struct mmc_data *data = &mqrq->brq.data;
>> +       unsigned long timeout;
>> +       u32 status;
>> +       int err;
>> +
>> +       timeout = jiffies + mmc_blk_data_timeout_jiffies(card->host, data);
>> +
>> +       while (1) {
>> +               bool done = time_after(jiffies, timeout);
>> +
>> +               err = __mmc_send_status(card, &status, 5);
>> +               if (err) {
>> +                       pr_err("%s: error %d requesting status\n",
>> +                              req->rq_disk->disk_name, err);
>> +                       break;
>> +               }
>> +
>> +               /* Accumulate any response error bits seen */
>> +               if (resp_errs)
>> +                       *resp_errs |= status;
>> +
>> +               if (mmc_blk_in_tran_state(status))
>> +                       break;
>> +
>> +               /* Timeout if the device never becomes ready */
>> +               if (done) {
>> +                       pr_err("%s: Card stuck in wrong state! %s %s\n",
>> +                               mmc_hostname(card->host),
>> +                               req->rq_disk->disk_name, __func__);
>> +                       err = -ETIMEDOUT;
>> +                       break;
>> +               }
>> +       }
>> +
>> +       return err;
>> +}
> 
> The new function here, mmc_blk_card_stuck() looks very similar to
> card_busy_detect().
> 
> Why can't you instead fixup card_busy_detect() so it behaves like the
> new mmc_blk_card_stuck(), rather than re-implementing most of it?

I saw an advantage in keeping the legacy code separate so that it didn't
then also need testing.

I guess it doesn't hurt to try to fix up the old code.

> 
>> +
>>  static void mmc_blk_rw_recovery(struct mmc_queue *mq, struct request *req)
>>  {
>>         int type = rq_data_dir(req) == READ ? MMC_BLK_READ : MMC_BLK_WRITE;
>> @@ -2097,17 +2189,26 @@ static inline bool mmc_blk_rq_error(struct mmc_blk_request *brq)
>>  static int mmc_blk_card_busy(struct mmc_card *card, struct request *req)
>>  {
>>         struct mmc_queue_req *mqrq = req_to_mmc_queue_req(req);
>> -       bool gen_err = false;
>> +       u32 status = 0;
>>         int err;
>>
>>         if (mmc_host_is_spi(card->host) || rq_data_dir(req) == READ)
>>                 return 0;
>>
>> -       err = card_busy_detect(card, MMC_BLK_TIMEOUT_MS, false, req, &gen_err);
>> +       err = mmc_blk_card_stuck(card, req, &status);
>> +
>> +       /*
>> +        * Do not assume data transferred correctly if there are any error bits
>> +        * set.
>> +        */
>> +       if (!err && status & mmc_blk_stop_err_bits(&mqrq->brq)) {
>> +               mqrq->brq.data.bytes_xfered = 0;
>> +               err = -EIO;
>> +       }
>>
>> -       /* Copy the general error bit so it will be seen later on */
>> -       if (gen_err)
>> -               mqrq->brq.stop.resp[0] |= R1_ERROR;
>> +       /* Copy the exception bit so it will be seen later on */
>> +       if (mmc_card_mmc(card) && status & R1_EXCEPTION_EVENT)
>> +               mqrq->brq.cmd.resp[0] |= R1_EXCEPTION_EVENT;
>>
>>         return err;
>>  }
>> --
>> 1.9.1
>>
> 
> Kind regards
> Uffe
> 

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