On Sep 25, 2012, at 12:30 AM, Ulf Hansson <ulf.hansson@xxxxxxxxxx> wrote:
> Hi Johan,
>
> An overall comment; would it be possible to include this patch as a
> piece of patch 1/2 "mmc: core: Proper signal voltage switch".
> They seems like quite tight connected.
>
> Anyway, some comment below.
>
> On 25 September 2012 09:04, Johan Rudholm <johan.rudholm@xxxxxxxxxxxxxx> wrote:
>> Signed-off-by: Johan Rudholm <johan.rudholm@xxxxxxxxxxxxxx>
>> ---
>> drivers/mmc/core/core.c | 2 +-
>> drivers/mmc/core/core.h | 1 +
>> drivers/mmc/core/sd.c | 8 ++++++--
>> 3 files changed, 8 insertions(+), 3 deletions(-)
>>
>> diff --git a/drivers/mmc/core/core.c b/drivers/mmc/core/core.c
>> index dae6744..fb03bd9 100644
>> --- a/drivers/mmc/core/core.c
>> +++ b/drivers/mmc/core/core.c
>> @@ -1348,7 +1348,7 @@ static void mmc_poweroff_notify(struct mmc_host *host)
>> * If a host does all the power sequencing itself, ignore the
>> * initial MMC_POWER_UP stage.
>> */
>> -static void mmc_power_up(struct mmc_host *host)
>> +void mmc_power_up(struct mmc_host *host)
>> {
>> int bit;
>>
>> diff --git a/drivers/mmc/core/core.h b/drivers/mmc/core/core.h
>> index 3bdafbc..5a5170d 100644
>> --- a/drivers/mmc/core/core.h
>> +++ b/drivers/mmc/core/core.h
>> @@ -45,6 +45,7 @@ int mmc_set_signal_voltage(struct mmc_host *host, int signal_voltage,
>> void mmc_set_timing(struct mmc_host *host, unsigned int timing);
>> void mmc_set_driver_type(struct mmc_host *host, unsigned int drv_type);
>> void mmc_power_off(struct mmc_host *host);
>> +void mmc_power_up(struct mmc_host *host);
>>
>> static inline void mmc_delay(unsigned int ms)
>> {
>> diff --git a/drivers/mmc/core/sd.c b/drivers/mmc/core/sd.c
>> index 74972c2..9a165451 100644
>> --- a/drivers/mmc/core/sd.c
>> +++ b/drivers/mmc/core/sd.c
>> @@ -720,6 +720,7 @@ int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr)
>> * state. We wait 1ms to give cards time to
>> * respond.
>> */
>> +try_again:
>> mmc_go_idle(host);
>>
>> /*
>> @@ -748,7 +749,6 @@ int mmc_sd_get_cid(struct mmc_host *host, u32 ocr, u32 *cid, u32 *rocr)
>> if (max_current > 150)
>> ocr |= SD_OCR_XPC;
>>
>> -try_again:
>> err = mmc_send_app_op_cond(host, ocr, rocr);
>> if (err)
>> return err;
>> @@ -761,7 +761,11 @@ try_again:
>> ((*rocr & 0x41000000) == 0x41000000)) {
>> err = mmc_set_signal_voltage(host, MMC_SIGNAL_VOLTAGE_180, true);
>> if (err) {
>> - ocr &= ~SD_OCR_S18R;
>> + /* Power cycle card */
>> + pr_warning("%s: Signal voltage switch failed, "
>> + "power cycling card\n", mmc_hostname(host));
>> + mmc_power_off(host);
>> + mmc_power_up(host);
>
> This mean you will retry forever even if the card is not capable of
> 1.8V. I doubt this really what you want?
>
>> goto try_again;
>> }
>> }
>> --
>> 1.7.10
>>
I did a patch for this problem in sdhci.c when voltage switch failed. It turned off and then
turned on the regulator. The patch worked on the UHS cards I was testing. The fix
has been pulled upstream.
>
> Kind regards
> Ulf Hansson
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