On 30 November 2016 at 10:20, Adrian Hunter <adrian.hunter@xxxxxxxxx> wrote:
> Clearing the tuning bits should reset the tuning circuit. However there is
> more to do. Reset the command and data lines for good measure, and then
> for eMMC ensure the card is not still trying to process a tuning command by
> sending a stop command.
>
> Note the JEDEC eMMC specification says the stop command (CMD12) can be used
> to stop a tuning command (CMD21) whereas the SD specification is silent on
> the subject with respect to the SD tuning command (CMD19). Considering that
> CMD12 is not a valid SDIO command, the stop command is sent only when the
> tuning command is CMD21 i.e. for eMMC. That addresses cases seen so far
> which have been on eMMC.
>
> Note that this replaces the commit fe5fb2e3b58f ("mmc: sdhci: Reset cmd and
> data circuits after tuning failure") which is being reverted for v4.9+.
>
> Signed-off-by: Adrian Hunter <adrian.hunter@xxxxxxxxx>
> Tested-by: Dan O'Donovan <dan@xxxxxxxxxx>
> Cc: stable@xxxxxxxxxxxxxxx
> ---
> drivers/mmc/host/sdhci.c | 20 ++++++++++++++++++++
> 1 file changed, 20 insertions(+)
>
> diff --git a/drivers/mmc/host/sdhci.c b/drivers/mmc/host/sdhci.c
> index e761fe2aa99e..1d72a51287d4 100644
> --- a/drivers/mmc/host/sdhci.c
> +++ b/drivers/mmc/host/sdhci.c
> @@ -2095,7 +2095,27 @@ static int sdhci_execute_tuning(struct mmc_host *mmc, u32 opcode)
> ctrl &= ~SDHCI_CTRL_EXEC_TUNING;
> sdhci_writew(host, ctrl, SDHCI_HOST_CONTROL2);
>
> + sdhci_do_reset(host, SDHCI_RESET_CMD);
> + sdhci_do_reset(host, SDHCI_RESET_DATA);
> +
> err = -EIO;
> +
> + if (cmd.opcode != MMC_SEND_TUNING_BLOCK_HS200)
> + goto out;
> +
> + sdhci_writel(host, host->ier, SDHCI_INT_ENABLE);
> + sdhci_writel(host, host->ier, SDHCI_SIGNAL_ENABLE);
> +
> + spin_unlock_irqrestore(&host->lock, flags);
> +
> + memset(&cmd, 0, sizeof(cmd));
> + cmd.opcode = MMC_STOP_TRANSMISSION;
> + cmd.flags = MMC_RSP_SPI_R1B | MMC_RSP_R1B | MMC_CMD_AC;
> + cmd.busy_timeout = 50;
> + mmc_wait_for_cmd(mmc, &cmd, 0);
No, please don't add more hacks to send commands internally from sdhci.
Maybe even before you start fix the problems for tuning, perhaps you
try to clean up the current code when sending CMD21/19 in
sdhci_execute_tuning()?
Moreover, according to the change log above, it seems like a generic
thing to send CMD12 to abort tuning. In such case, we could either
make the core deal with it in the error path - or we could implement a
"mmc_abort_tuning()" function, host drivers may call when needed.
> +
> + spin_lock_irqsave(&host->lock, flags);
> +
> goto out;
> }
>
> --
> 1.9.1
>
Kind regards
Uffe
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