Re: [PATCH 1/3] tmio: add a platform flag to disable card

[Magnus Damm <magnus.damm@gmail.com>]

On Tue, May 11, 2010 at 9:15 PM, Guennadi Liakhovetski
<g.liakhovetski@gmx.de> wrote:
> On Tue, 11 May 2010, Magnus Damm wrote:
>
>> Hi Guennadi,
>>
>> Many thanks for your work on this!
>>
>> On Tue, May 11, 2010 at 6:52 PM, Guennadi Liakhovetski
>> <g.liakhovetski@gmx.de> wrote:
>> > Write-protection status is not always available, e.g., micro-SD cards do not
>> > have a write-protection switch at all. This patch adds a flag to let platforms
>> > force tmio_mmc to consider the card writable.
>> >
>> > Signed-off-by: Guennadi Liakhovetski <g.liakhovetski@gmx.de>
>> > ---
>> >  drivers/mmc/host/tmio_mmc.c |    5 ++++-
>> >  include/linux/mfd/tmio.h    |    4 ++++
>> >  2 files changed, 8 insertions(+), 1 deletions(-)
>> >
>> > diff --git a/drivers/mmc/host/tmio_mmc.c b/drivers/mmc/host/tmio_mmc.c
>> > index 7e79ba4..11c19b0 100644
>> > --- a/drivers/mmc/host/tmio_mmc.c
>> > +++ b/drivers/mmc/host/tmio_mmc.c
>> > @@ -640,8 +640,11 @@ static void tmio_mmc_set_ios(struct mmc_host *mmc, struct mmc_ios *ios)
>> >  static int tmio_mmc_get_ro(struct mmc_host *mmc)
>> >  {
>> >        struct tmio_mmc_host *host = mmc_priv(mmc);
>> > +       struct mfd_cell *cell = host->pdev->dev.platform_data;
>> > +       struct tmio_mmc_data *pdata = cell->driver_data;
>> >
>> > -       return (sd_ctrl_read32(host, CTL_STATUS) & TMIO_STAT_WRPROTECT) ? 0 : 1;
>> > +       return ((pdata->flags & TMIO_MMC_WRPROTECT_DISABLE) ||
>> > +               (sd_ctrl_read32(host, CTL_STATUS) & TMIO_STAT_WRPROTECT)) ? 0 : 1;
>> >  }
>>
>> It's a bit late so perhaps I'm thinking backwards, but isn't this
>> logic inverted?
>>
>> Fact: The WP signal is missing from the micro-sd slot on the kfr2r09
>> board, and the card incorrectly comes up write protected.
>>
>> Solution: TMIO_MMC_WRPROTECT_DISABLE is set to make sure the card is
>> _not_ write protected by mistake.
>>
>> But: The code using the ->reg_ro() callback assumes that the card is
>> read-only if 1 is returned according to drivers/mmc/core/sd.c. The
>> code above returns 1 if TMIO_MMC_WRPROTECT_DISABLE is set. So the card
>> will be forced read-only on kfr2r09 unless i'm mistaken, and this does
>> not help so much. =)
>
> I think above is right, please, look again. If TMIO_MMC_WRPROTECT_DISABLE
> is set, the function returns 0.

Err, yeah, you are correct. I overlooked the "?" part... Looking good!

Thanks,

/ magnus