On 11 April 2018 at 03:16, Shawn Lin <shawn.lin@xxxxxxxxxxxxxx> wrote:
> Hi Ulf,
>
> On 2018/4/6 4:19, Ulf Hansson wrote:
>>
>> Let's implement the ->sw_reset() bus ops to allow SDIO func drivers, in
>> particular, to make a SW reset without doing a full power cycle of the
>> SDIO
>> card.
>>
>> Signed-off-by: Ulf Hansson <ulf.hansson@xxxxxxxxxx>
>> ---
>> drivers/mmc/core/sdio.c | 13 +++++++++++++
>> 1 file changed, 13 insertions(+)
>>
>> diff --git a/drivers/mmc/core/sdio.c b/drivers/mmc/core/sdio.c
>> index 0124e0e..088c80c 100644
>> --- a/drivers/mmc/core/sdio.c
>> +++ b/drivers/mmc/core/sdio.c
>> @@ -1044,6 +1044,18 @@ static int mmc_sdio_hw_reset(struct mmc_host *host)
>> return mmc_sdio_power_restore(host);
>> }
>> +static int mmc_sdio_sw_reset(struct mmc_host *host)
>> +{
>> + mmc_set_clock(host, host->f_init);
>
>
> This reminds me to think that why we don't fold it
> into mmc_set_initial_state()? See mmc_power_up() calls
> mmc_set_initial_state () and then the clock is set to host->f_init
> later.
I see your point, however mmc_set_inital_state() is also called from
mmc_power_off(), which is when the clock is set to zero.
>
>> + sdio_reset(host);
>> + mmc_go_idle(host);
>> +
>
>
> mmc_sdio_reinit_card() will reset I/O and memory portion internally.
> So maybe we don't need these extra reset ahead?
Are you suggesting the mmc_sdio_reinit_card() should not be doing
sdio_reset() + mmc_go_idle() - or that the above calls should go away?
I don't think dropping the above calls are a good idea (at least both
of them), as changing to the initial state and initial signal voltage,
without first doing a reset may put the card in some undefined error
state. Don't you think?
>
>
>> + mmc_set_initial_state(host);
>> + mmc_set_initial_signal_voltage(host);
>> +
>> + return mmc_sdio_reinit_card(host, 0);
>> +}
>> +
>> static const struct mmc_bus_ops mmc_sdio_ops = {
>> .remove = mmc_sdio_remove,
>> .detect = mmc_sdio_detect,
>> @@ -1055,6 +1067,7 @@ static const struct mmc_bus_ops mmc_sdio_ops = {
>> .power_restore = mmc_sdio_power_restore,
>> .alive = mmc_sdio_alive,
>> .hw_reset = mmc_sdio_hw_reset,
>> + .sw_reset = mmc_sdio_sw_reset,
>> };
>>
>
>
Kind regards
Uffe
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