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SubjectRe: [PATCH] mmc: core: Initial support for SD express card/host
On Thu, Jul 16, 2020 at 07:04:21PM +0200, Ulf Hansson wrote:
> On Thu, 16 Jul 2020 at 18:14, Greg Kroah-Hartman
> <gregkh@linuxfoundation.org> wrote:
> >
> > On Thu, Jul 16, 2020 at 04:15:34PM +0200, Ulf Hansson wrote:
> > > +int mmc_send_if_cond_pcie(struct mmc_host *host, u32 ocr)
> > > +{
> > > + u32 resp = 0;
> > > + u8 pcie_bits = 0;
> > > + int ret;
> > > +
> > > + if (host->caps2 & MMC_CAP2_SD_EXP) {
> > > + /* Probe card for SD express support via PCIe. */
> > > + pcie_bits = 0x10;
> > > + if (host->caps2 & MMC_CAP2_SD_EXP_1_2V)
> > > + /* Probe also for 1.2V support. */
> > > + pcie_bits = 0x30;
> > > + }
> > > +
> > > + ret = __mmc_send_if_cond(host, ocr, pcie_bits, &resp);
> > > + if (ret)
> > > + return 0;
> > > +
> > > + /* Continue with the SD express init, if the card supports it. */
> > > + resp &= 0x3000;
> > > + if (pcie_bits && resp) {
> > > + if (resp == 0x3000)
> >
> > 0x3000 should be some defined value, right? Otherwise it just looks
> > like magic bits :)
>
> Yeah, I was considering that, but there are already lots of magic bits
> around here in this code. On top of that, the bits are shifted,
> depending on how they are used.
>
> We should probably look into doing a cleanup, so this gets clearer overall.
>
> >
> > > --- a/include/linux/mmc/host.h
> > > +++ b/include/linux/mmc/host.h
> > > @@ -60,6 +60,8 @@ struct mmc_ios {
> > > #define MMC_TIMING_MMC_DDR52 8
> > > #define MMC_TIMING_MMC_HS200 9
> > > #define MMC_TIMING_MMC_HS400 10
> > > +#define MMC_TIMING_SD_EXP 11
> > > +#define MMC_TIMING_SD_EXP_1_2V 12
> > >
> > > unsigned char signal_voltage; /* signalling voltage (1.8V or 3.3V) */
> > >
> > > @@ -172,6 +174,9 @@ struct mmc_host_ops {
> > > */
> > > int (*multi_io_quirk)(struct mmc_card *card,
> > > unsigned int direction, int blk_size);
> > > +
> > > + /* Initialize an SD express card, mandatory for MMC_CAP2_SD_EXP. */
> > > + int (*init_sd_express)(struct mmc_host *host, struct mmc_ios *ios);
> > > };
> > >
> > > struct mmc_cqe_ops {
> > > @@ -357,6 +362,8 @@ struct mmc_host {
> > > #define MMC_CAP2_HS200_1_2V_SDR (1 << 6) /* can support */
> > > #define MMC_CAP2_HS200 (MMC_CAP2_HS200_1_8V_SDR | \
> > > MMC_CAP2_HS200_1_2V_SDR)
> > > +#define MMC_CAP2_SD_EXP (1 << 7) /* SD express via PCIe */
> >
> > BIT(7)?
> >
> > > +#define MMC_CAP2_SD_EXP_1_2V (1 << 8) /* SD express 1.2V */
> >
> > BIT(8)?
>
> I can change to that, but it wouldn't be consistent with existing
> code. Again, probably better targeted as a separate bigger cleanup on
> top.

Ah, good point.

Ok, no objection from me!

Reviewed-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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