On Wed, 14 Aug 2024 at 09:31, Avri Altman <avri.altman@xxxxxxx> wrote:
>
> ACMD41 was extended to support the host-card handshake during
> initialization. The card expects that the HCS & HO2T bits to be set in
> the command argument, and sets the applicable bits in the R3 returned
> response. On the contrary, if a SDUC card is inserted to a
> non-supporting host, it will never respond to this ACMD41 until
> eventually, the host will timed out and give up.
>
> Tested-by: Ricky WU <ricky_wu@xxxxxxxxxxx>
> Signed-off-by: Avri Altman <avri.altman@xxxxxxx>
> ---
> drivers/mmc/core/sd_ops.c | 19 +++++++++++++++----
> include/linux/mmc/host.h | 6 ++++++
> include/linux/mmc/sd.h | 1 +
> 3 files changed, 22 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/core/sd_ops.c b/drivers/mmc/core/sd_ops.c
> index 8b9b34286ef3..7f6963dac873 100644
> --- a/drivers/mmc/core/sd_ops.c
> +++ b/drivers/mmc/core/sd_ops.c
> @@ -168,12 +168,16 @@ int mmc_send_app_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
> .cmd = &cmd
> };
> int err;
> + u32 sduc_arg = SD_OCR_CCS | SD_OCR_2T;
>
> cmd.opcode = SD_APP_OP_COND;
> + cmd.arg = ocr;
> +
> if (mmc_host_is_spi(host))
> - cmd.arg = ocr & (1 << 30); /* SPI only defines one bit */
> + cmd.arg &= (1 << 30); /* SPI only defines one bit */
> else
> - cmd.arg = ocr;
> + cmd.arg |= sduc_arg;
> +
This code doesn't belong in mmc_send_app_op_cond(), but rather in
mmc_sd_get_cid(), which is where we add one various OCR bits before we
call mmc_send_app_op_cond() with it.
For example, if the response of the SD_SEND_IF_COND commands indicates
an SD 2.0 compliant card, we tag on the SD_OCR_CCS bit. It looks like
that needs to be extended to the SD_OCR_2T bit too.
> cmd.flags = MMC_RSP_SPI_R1 | MMC_RSP_R3 | MMC_CMD_BCR;
>
> err = __mmc_poll_for_busy(host, SD_APP_OP_COND_PERIOD_US,
> @@ -182,8 +186,15 @@ int mmc_send_app_op_cond(struct mmc_host *host, u32 ocr, u32 *rocr)
> if (err)
> return err;
>
> - if (rocr && !mmc_host_is_spi(host))
> - *rocr = cmd.resp[0];
> + if (!mmc_host_is_spi(host)) {
> + if (rocr)
> + *rocr = cmd.resp[0];
> +
> + if ((cmd.resp[0] & sduc_arg) == sduc_arg)
> + host->caps2 |= MMC_CAP2_SD_SDUC;
> + else
> + host->caps2 &= ~MMC_CAP2_SD_SDUC;
Please don't abuse the host->caps2 for this purpose.
Instead let's keep using the card->state to keep track of what type of
card this is. You may have a look at how the MMC_CARD_SDXC bit is
being used and just follow that behaviour for the SDUC cards too.
Moreover, rather than assigning card->state at this point, let's do
that from mmc_decode_csd() instead, when we realize that the card
supports the new CSD structure version 3.
> + }
>
> return 0;
> }
> diff --git a/include/linux/mmc/host.h b/include/linux/mmc/host.h
> index 88c6a76042ee..a9c36a3e1a10 100644
> --- a/include/linux/mmc/host.h
> +++ b/include/linux/mmc/host.h
> @@ -427,6 +427,7 @@ struct mmc_host {
> #define MMC_CAP2_CRYPTO 0
> #endif
> #define MMC_CAP2_ALT_GPT_TEGRA (1 << 28) /* Host with eMMC that has GPT entry at a non-standard location */
> +#define MMC_CAP2_SD_SDUC (1 << 29) /* SD over 2TB */
>
> int fixed_drv_type; /* fixed driver type for non-removable media */
>
> @@ -638,6 +639,11 @@ static inline int mmc_card_uhs(struct mmc_card *card)
> card->host->ios.timing <= MMC_TIMING_UHS_DDR50;
> }
>
> +static inline int mmc_card_is_sduc(struct mmc_host *host)
> +{
> + return host->caps2 & MMC_CAP2_SD_SDUC;
> +}
> +
> void mmc_retune_timer_stop(struct mmc_host *host);
>
> static inline void mmc_retune_needed(struct mmc_host *host)
> diff --git a/include/linux/mmc/sd.h b/include/linux/mmc/sd.h
> index 6727576a8755..865cc0ca8543 100644
> --- a/include/linux/mmc/sd.h
> +++ b/include/linux/mmc/sd.h
> @@ -36,6 +36,7 @@
> /* OCR bit definitions */
> #define SD_OCR_S18R (1 << 24) /* 1.8V switching request */
> #define SD_ROCR_S18A SD_OCR_S18R /* 1.8V switching accepted by card */
> +#define SD_OCR_2T (1 << 27) /* HO2T/CO2T - SDUC support */
> #define SD_OCR_XPC (1 << 28) /* SDXC power control */
> #define SD_OCR_CCS (1 << 30) /* Card Capacity Status */
>
> --
> 2.25.1
>
Kind regards
Uffe
