[PATCH 5/5] mmc: sdhci: add quirk SDHCI_QUIRK_FIX_NO_INT_IN_MULTI_BLK_IO

[Zhu Richard-R65037]

Hi Wolfsang:
Maybe I don't describe my thoughts clearly and exactly.
I feel it's not easy to add the the IO-accessors in every cmd execution procedure, to make
a double check why a IO-accessor is needed or not.

Best Regards
Richard Zhu


> -----Original Message-----
> From: Wolfram Sang [mailto:w.sang at pengutronix.de]
> Sent: Monday, February 21, 2011 7:16 PM
> To: Russell King - ARM Linux
> Cc: Zhu Richard-R65037; Zhao Richard-B20223; cjb at laptop.org;
> eric at eukrea.com; linux-mmc at vger.kernel.org; kernel at pengutronix.de;
> avorontsov at ru.mvista.com; linux-arm-kernel at lists.infradead.org;
> linuxzsc at gmail.com
> Subject: Re: [PATCH 5/5] mmc: sdhci: add quirk
> SDHCI_QUIRK_FIX_NO_INT_IN_MULTI_BLK_IO
>
> On Mon, Feb 21, 2011 at 11:09:05AM +0000, Russell King - ARM Linux wrote:
> > On Mon, Feb 21, 2011 at 11:46:08AM +0100, Wolfram Sang wrote:
> > > > > > -   if (cpu_is_mx35() || cpu_is_mx51())
> > > > > > +   if (cpu_is_mx53())
> > > > > > +           host->quirks |=
> > > > > > + SDHCI_QUIRK_FIX_NO_INT_IN_MULTI_BLK_IO;
> > > > >
> > > > > Have you tried it doing it via IO-accessors?
> > > > Richard Zhu: This quirk is used to fix a mechanism problem in the
> MMC CMDs execution procedure.
> > > > It would be very abrupt and ugly, if the IO-accessors are added
> into these original procedures.
> > >
> > > Please don't get it personal, but IMHO it is pretty ugly the way it
> > > is now. This quirk is very imx-specific and calling something like
> > > SDHCI_VENDOR_SPEC in sdhci.c looks clearly wrong to me. By the way,
> > > what does this bit do, the description doesn't say so?
> >
> > SDHCI_QUIRK_FIX_NO_INT_IN_MULTI_BLK_IO is rather too verbose.  Isn't
> > there a shorter version which could be used?
> > SDHCI_QUIRK_SDIO_MULTIBLK_INT maybe?
>
> As I understand, the non-SDIO part is handled here:
Yes, it is. The following codes are used to solve non-sdio part.
That bit is introduced by imx53 latest spec.
I think so too that the SDHCI_VENDOR_SPEC shouldn't be used in sdhci.c file, but
I don't have better idea to fix the issue in this situation.
Option:
Make a double check when issue every MMC CMD, to figure out whether a IO-accessor is needed or not?
Two checkpoints would be needed, one is in the sdhci_send_command function, the other should be in sdhci_data_finish func.
How do you think this method?

>
> +       /*Set the CMD_TYPE of the CMD12, fix no INT in MULTI_BLK IO */
> +       if (host->quirks & SDHCI_QUIRK_FIX_NO_INT_IN_MULTI_BLK_IO) {
> +               if (cmd->opcode == 12)
> +                       flags |= SDHCI_CMD_ABORTCMD;
> +       }
>
> But I'd really like to avoid the quirk bit. Maybe we'll get a better idea
> once we understand what that magic bit actually does. For a start, we
> might simply set SDHCI_QUIRK_NO_MULTIBLOCK for mx53 like we do for other
> imx.
As I know that, this bit is used to make the machine stat of the eSDHC IC to be a correct stat after SDIO Multi-Read.
>
> Regards,
>
>    Wolfram
>
> --
> Pengutronix e.K.                           | Wolfram Sang
> |
> Industrial Linux Solutions                 | http://www.pengutronix.de/
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