Best Regards
Jerry Huang
> -----Original Message-----
> From: Wood Scott-B07421
> Sent: Wednesday, September 12, 2012 2:28 AM
> To: Anton Vorontsov
> Cc: Huang Changming-R66093; linuxppc-dev@xxxxxxxxxxxxxxxx; linux-
> mmc@xxxxxxxxxxxxxxx
> Subject: Re: [PATCH 2/3] powerpc/esdhc: add property to disable the CMD23
>
> On 09/11/2012 03:04 AM, Anton Vorontsov wrote:
> > On Tue, Sep 11, 2012 at 12:54:29AM -0700, Anton Vorontsov wrote:
> >> On Tue, Sep 11, 2012 at 03:12:44PM +0800, Chang-
> Ming.Huang@xxxxxxxxxxxxx wrote:
> >>> From: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx>
> >>>
> >>> Below SOCs don't support the cmd23 command for MMC card, therefore,
> >>> disable it in device tree:
> >>> P1020, P1021, P1022, P1024, P1025 and P4080
> >>>
> >>> Signed-off-by: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx>
> >>
> >> Acked-by: Anton Vorontsov <cbouatmailru@xxxxxxxxx>
> >
> > Btw, although the patch is trivial, I guess you still want to let know
> > PowerPC folks about it. Adding Cc and copying the patch:
> >
> > - - - -
> > From: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx>
> >
> > Below SOCs don't support the cmd23 command for MMC card, therefore,
> > disable it in device tree:
> > P1020, P1021, P1022, P1024, P1025 and P4080
> >
> > Signed-off-by: Jerry Huang <Chang-Ming.Huang@xxxxxxxxxxxxx>
> > CC: Anton Vorontsov <cbouatmailru@xxxxxxxxx>
> > ---
> > arch/powerpc/boot/dts/fsl/p1020si-post.dtsi | 1 +
> > arch/powerpc/boot/dts/fsl/p1021si-post.dtsi | 1 +
> > arch/powerpc/boot/dts/fsl/p1022si-post.dtsi | 1 +
> > arch/powerpc/boot/dts/fsl/p4080si-post.dtsi | 1 +
> > 4 files changed, 4 insertions(+)
> >
> > diff --git a/arch/powerpc/boot/dts/fsl/p1020si-post.dtsi
> > b/arch/powerpc/boot/dts/fsl/p1020si-post.dtsi
> > index 68cc5e7..793a30b 100644
> > --- a/arch/powerpc/boot/dts/fsl/p1020si-post.dtsi
> > +++ b/arch/powerpc/boot/dts/fsl/p1020si-post.dtsi
> > @@ -154,6 +154,7 @@
> > sdhc@2e000 {
> > compatible = "fsl,p1020-esdhc", "fsl,esdhc";
> > sdhci,auto-cmd12;
> > + sdhci,no-cmd23;
> > };
> > /include/ "pq3-sec3.3-0.dtsi"
> >
> > diff --git a/arch/powerpc/boot/dts/fsl/p1021si-post.dtsi
> > b/arch/powerpc/boot/dts/fsl/p1021si-post.dtsi
> > index adb82fd..2b7fd2a 100644
> > --- a/arch/powerpc/boot/dts/fsl/p1021si-post.dtsi
> > +++ b/arch/powerpc/boot/dts/fsl/p1021si-post.dtsi
> > @@ -149,6 +149,7 @@
> > /include/ "pq3-esdhc-0.dtsi"
> > sdhc@2e000 {
> > sdhci,auto-cmd12;
> > + sdhci,no-cmd23;
> > };
> >
> > /include/ "pq3-sec3.3-0.dtsi"
> > diff --git a/arch/powerpc/boot/dts/fsl/p1022si-post.dtsi
> > b/arch/powerpc/boot/dts/fsl/p1022si-post.dtsi
> > index 06216b8..2334a52 100644
> > --- a/arch/powerpc/boot/dts/fsl/p1022si-post.dtsi
> > +++ b/arch/powerpc/boot/dts/fsl/p1022si-post.dtsi
> > @@ -215,6 +215,7 @@
> > sdhc@2e000 {
> > compatible = "fsl,p1022-esdhc", "fsl,esdhc";
> > sdhci,auto-cmd12;
> > + sdhci,no-cmd23;
> > };
> >
> > /include/ "pq3-sec3.3-0.dtsi"
> > diff --git a/arch/powerpc/boot/dts/fsl/p4080si-post.dtsi
> > b/arch/powerpc/boot/dts/fsl/p4080si-post.dtsi
> > index 8d35d2c..5b39952 100644
> > --- a/arch/powerpc/boot/dts/fsl/p4080si-post.dtsi
> > +++ b/arch/powerpc/boot/dts/fsl/p4080si-post.dtsi
> > @@ -337,6 +337,7 @@
> > sdhc@114000 {
> > voltage-ranges = <3300 3300>;
> > sdhci,auto-cmd12;
> > + sdhci,no-cmd23;
> > };
> >
> > /include/ "qoriq-i2c-0.dtsi"
> >
>
> This won't help people with old device trees (forked for a custom board,
> tied to an old U-Boot, etc). The driver should infer this from the
> compatible string or version registers (ideally block-specific version
> registers, but if these are absent or inconclusive, SVR can be used).
>
I don't think it is the best way to do it.
For the VVN2.2 or older, some silicon support this feature (mpc8536 and p2020), but other silicones don't support it (e.g. p4080, p102x).
Though, the current p5/p4/p3 has supported this feature, can we sure the future silicon support it?
So I think the best way is to specify it in device tree as 'sdhci,auto-cmd12'
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