On Thu, May 19, 2016 at 1:47 AM, Chaotian Jing
<chaotian.jing@xxxxxxxxxxxx> wrote:
> Per JEDEC spec, it is not recommended to use CMD13 to get card status
> after speed mode switch. below are two reason about this:
> 1. CMD13 cannot be guaranteed due to the asynchronous operation.
> Therefore it is not recommended to use CMD13 to check busy completion
> of the timing change indication.
> 2. After switch to HS200, CMD13 will get response of 0x800, and even the
> busy signal gets de-asserted, the response of CMD13 is aslo 0x800.
>
> Signed-off-by: Chaotian Jing <chaotian.jing@xxxxxxxxxxxx>
> ---
> drivers/mmc/core/mmc.c | 112 ++++++++++++++++++++-----------------------------
> 1 file changed, 45 insertions(+), 67 deletions(-)
>
> diff --git a/drivers/mmc/core/mmc.c b/drivers/mmc/core/mmc.c
[..]
> @@ -1274,20 +1254,18 @@ static int mmc_select_hs200(struct mmc_card *card)
> err = __mmc_switch(card, EXT_CSD_CMD_SET_NORMAL,
> EXT_CSD_HS_TIMING, val,
> card->ext_csd.generic_cmd6_time,
> - true, send_status, true);
> + true, false, true);
> if (err)
> goto err;
> old_timing = host->ios.timing;
> mmc_set_timing(host, MMC_TIMING_MMC_HS200);
> - if (!send_status) {
> - err = mmc_switch_status(card);
> - /*
> - * mmc_select_timing() assumes timing has not changed if
> - * it is a switch error.
> - */
> - if (err == -EBADMSG)
> - mmc_set_timing(host, old_timing);
> - }
> + err = mmc_switch_status(card);
> + /*
> + * mmc_select_timing() assumes timing has not changed if
> + * it is a switch error.
> + */
> + if (err == -EBADMSG)
> + mmc_set_timing(host, old_timing);
Sorry for not spotting this earlier, but with the move of the call of
mmc_switch_status() to after mmc_set_timing() we get following error
with sdhci-msm:
mmc0: mmc_select_hs200 failed, error -110
mmc0: error -110 whilst initialising MMC card
mmc0: Reset 0x1 never completed.
sdhci: =========== REGISTER DUMP (mmc0)===========
sdhci: Sys addr: 0x00000000 | Version: 0x00002e02
sdhci: Blk size: 0x00004000 | Blk cnt: 0x00000000
sdhci: Argument: 0x00000000 | Trn mode: 0x00000000
sdhci: Present: 0x01f80000 | Host ctl: 0x00000000
sdhci: Power: 0x00000000 | Blk gap: 0x00000000
sdhci: Wake-up: 0x00000000 | Clock: 0x00000003
sdhci: Timeout: 0x00000000 | Int stat: 0x00000000
sdhci: Int enab: 0x00000000 | Sig enab: 0x00000000
sdhci: AC12 err: 0x00000000 | Slot int: 0x00000000
sdhci: Caps: 0x322dc8b2 | Caps_1: 0x00008007
sdhci: Cmd: 0x00000000 | Max curr: 0x00000000
sdhci: Host ctl2: 0x00000000
sdhci: ADMA Err: 0x00000000 | ADMA Ptr: 0x0000000000000000
sdhci: ===========================================
But I if I understand the commit correctly this is the intention of
the patch (not the error, but the move).
Regards,
Bjorn
> }
> err:
> if (err)
> --
> 1.8.1.1.dirty
>
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