Re: [PATCH 4/4] mmc: core: Send HPI only till it is successful

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On Fri, Apr 13, 2012 at 8:09 PM, Namjae Jeon <linkinjeon@xxxxxxxxx> wrote:
> Hi. Venkatraman.
>
> You fixed 10 times. why is it 10 times ?
There's no right number - I haven't seen it fail much in my tests but
should allow a few retries.

> and checking err from mmc_send_status is not needed ? is it  also
> infinite case ?
Check again - the loop will break if the send_status returns an error
(even once), or if the card comes out of PRG state.

>
> Thanks.
>
> 2012/4/13 Venkatraman S <svenkatr@xxxxxx>:
>> Try to send HPI only a fixed number of times till it is
>> successful. One successful transfer is enough - but wait
>> till the card comes out of transfer state.
>> Return an error if the card was not in programming state to
>> begin with - so that the caller knows that HPI was not sent.
>>
>> Reported-by: Alex Lemberg <Alex.Lemberg@xxxxxxxxxxx>
>> Signed-off-by: Venkatraman S <svenkatr@xxxxxx>
>> ---
>>  drivers/mmc/core/core.c |   34 ++++++++++++++++++----------------
>>  1 file changed, 18 insertions(+), 16 deletions(-)
>>
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index e541efb..ceabef5 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -401,7 +401,7 @@ EXPORT_SYMBOL(mmc_wait_for_req);
>>  */
>>  int mmc_interrupt_hpi(struct mmc_card *card)
>>  {
>> -       int err;
>> +       int err, i;
>>        u32 status;
>>
>>        BUG_ON(!card);
>> @@ -421,27 +421,29 @@ int mmc_interrupt_hpi(struct mmc_card *card)
>>        /*
>>         * If the card status is in PRG-state, we can send the HPI command.
>>         */
>> +       err = -EINVAL;
>>        if (R1_CURRENT_STATE(status) == R1_STATE_PRG) {
>> -               do {
>> -                       /*
>> -                        * We don't know when the HPI command will finish
>> -                        * processing, so we need to resend HPI until out
>> -                        * of prg-state, and keep checking the card status
>> -                        * with SEND_STATUS.  If a timeout error occurs when
>> -                        * sending the HPI command, we are already out of
>> -                        * prg-state.
>> -                        */
>> +               /* To prevent an infinite lockout, try to send HPI
>> +                * a fixed number of times and bailout if it can't
>> +                * succeed.
>> +                */
>> +               for (i = 0; i < 10 && err != 0 ; i++)
>>                        err = mmc_send_hpi_cmd(card, &status);
>> -                       if (err)
>> +               /* Once HPI was sent successfully, the card is
>> +                * supposed to be back to transfer state.
>> +                */
>> +               do {
>> +                       if (err) {
>>                                pr_debug("%s: abort HPI (%d error)\n",
>>                                         mmc_hostname(card->host), err);
>> -
>> -                       err = mmc_send_status(card, &status);
>> -                       if (err)
>>                                break;
>> +                       }
>> +                       err = mmc_send_status(card, &status);
>>                } while (R1_CURRENT_STATE(status) == R1_STATE_PRG);
>> -       } else
>> -               pr_debug("%s: Left prg-state\n", mmc_hostname(card->host));
>> +       } else {
>> +               pr_debug("%s: Can't send HPI. State=%d\n",
>> +                       mmc_hostname(card->host), R1_CURRENT_STATE(status));
>> +       }
>>
>>  out:
>>        mmc_release_host(card->host);
>> --
>> 1.7.10.rc2
>>
>> --
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