Re: [PATCH] mmc: mtk-sd: Add support for ignoring cmd response CRC

["Andy-ld Lu (卢东)" <Andy-ld.Lu@mediatek.com>]

On Mon, 2024-11-25 at 14:08 +0100, Ulf Hansson wrote:
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> 
> 
> On Sat, 23 Nov 2024 at 08:10, Andy-ld Lu <andy-ld.lu@mediatek.com>
> wrote:
> > 
> > The current process flow does not handle MMC requests that are
> > indicated
> > to ignore the command response CRC. For instance, cmd12 and cmd48
> > from
> > mmc_cqe_recovery() are marked to ignore CRC, but they are not
> > matched to
> > the appropriate response type in msdc_cmd_find_resp(). As a result,
> > they
> > are defaulted to 'MMC_RSP_NONE', which means no response is
> > expected.
> > 
> > This commit adds a new flag 'MMC_RSP_R1B_NO_CRC' to work alongside
> > the
> > existing 'MMC_RSP_R1_NO_CRC' for the following process flow. It
> > fixes the
> > response type setting in msdc_cmd_find_resp() and adds the logic to
> > ignore
> > CRC in msdc_cmd_done().
> 
> In fact, MMC_RSP_R1_NO_CRC is not being used by the MMC core. So,
> host
> drivers that check this flag shouldn't need to. In other words, we
> should remove that flag entirely.
> 
> That said, introducing MMC_RSP_R1B_NO_CRC as the $subject patch
> suggests, makes sense to me. However, I prefer if we can make it used
> by the mmc core, so please change mmc_cqe_recovery() to use it too.
> 
> Kind regards
> Uffe

Thanks for your review, I will follow your comment in next change.

Best regards
Andy-ld Lu
> 
> > 
> > Signed-off-by: Andy-ld Lu <andy-ld.lu@mediatek.com>
> > ---
> >  drivers/mmc/host/mtk-sd.c | 11 +++++++++--
> >  include/linux/mmc/core.h  |  1 +
> >  2 files changed, 10 insertions(+), 2 deletions(-)
> > 
> > diff --git a/drivers/mmc/host/mtk-sd.c b/drivers/mmc/host/mtk-sd.c
> > index efb0d2d5716b..5d669f985a82 100644
> > --- a/drivers/mmc/host/mtk-sd.c
> > +++ b/drivers/mmc/host/mtk-sd.c
> > @@ -1097,11 +1097,13 @@ static inline u32 msdc_cmd_find_resp(struct
> > msdc_host *host,
> >         u32 resp;
> > 
> >         switch (mmc_resp_type(cmd)) {
> > -               /* Actually, R1, R5, R6, R7 are the same */
> > +       /* Actually, R1, R5, R6, R7 are the same */
> >         case MMC_RSP_R1:
> > +       case MMC_RSP_R1_NO_CRC:
> >                 resp = 0x1;
> >                 break;
> >         case MMC_RSP_R1B:
> > +       case MMC_RSP_R1B_NO_CRC:
> >                 resp = 0x7;
> >                 break;
> >         case MMC_RSP_R2:
> > @@ -1305,6 +1307,7 @@ static bool msdc_cmd_done(struct msdc_host
> > *host, int events,
> >  {
> >         bool done = false;
> >         bool sbc_error;
> > +       bool ignore_crc = false;
> >         unsigned long flags;
> >         u32 *rsp;
> > 
> > @@ -1329,6 +1332,10 @@ static bool msdc_cmd_done(struct msdc_host
> > *host, int events,
> >                 return true;
> >         rsp = cmd->resp;
> > 
> > +       if (mmc_resp_type(cmd) == MMC_RSP_R1_NO_CRC ||
> > +           mmc_resp_type(cmd) == MMC_RSP_R1B_NO_CRC)
> > +               ignore_crc = true;
> > +
> >         sdr_clr_bits(host->base + MSDC_INTEN, cmd_ints_mask);
> > 
> >         if (cmd->flags & MMC_RSP_PRESENT) {
> > @@ -1351,7 +1358,7 @@ static bool msdc_cmd_done(struct msdc_host
> > *host, int events,
> >                          * CRC error.
> >                          */
> >                         msdc_reset_hw(host);
> > -               if (events & MSDC_INT_RSPCRCERR) {
> > +               if (events & MSDC_INT_RSPCRCERR && !ignore_crc) {
> >                         cmd->error = -EILSEQ;
> >                         host->error |= REQ_CMD_EIO;
> >                 } else if (events & MSDC_INT_CMDTMO) {
> > diff --git a/include/linux/mmc/core.h b/include/linux/mmc/core.h
> > index 56972bd78462..076e1c71a07e 100644
> > --- a/include/linux/mmc/core.h
> > +++ b/include/linux/mmc/core.h
> > @@ -66,6 +66,7 @@ struct mmc_command {
> > 
> >  /* Can be used by core to poll after switch to MMC HS mode */
> >  #define MMC_RSP_R1_NO_CRC      (MMC_RSP_PRESENT|MMC_RSP_OPCODE)
> > +#define
> > MMC_RSP_R1B_NO_CRC     (MMC_RSP_PRESENT|MMC_RSP_OPCODE|MMC_RSP_BUSY
> > )
> > 
> >  #define mmc_resp_type(cmd)     ((cmd)->flags &
> > (MMC_RSP_PRESENT|MMC_RSP_136|MMC_RSP_CRC|MMC_RSP_BUSY|MMC_RSP_OPCOD
> > E))
> > 
> > --
> > 2.34.1
> >