[U-Boot] [v2, 4/5] mmc: add workaround for eSDHC erratum A009620

[Jaehoon Chung]

On 08/02/2016 06:20 PM, Yangbo Lu wrote:
> Erratum Title:
> Data timeout error not getting set in case of command with busy
> response (R1b) as well as for busy period after last write block
> transfer.
> 
> Description:
> In the event that a busy timeout occurs for a command with a busy
> response (e.g. R1b response) as well as busy period after the last
> write block, the eSDHC does not set the IRQSTAT[DTOE] bit or the
> IRQSTAT[TC]. Therefore, the current command transfer is never completed.
> 
> Workaround:
> Workaround for CMD with busy:
> Don't set the XFRTYP[RSP]=2'b11 for commands with busy response and
> poll the busy status of the card from the PRSSTAT[DLSL]
> 
> Workaround for busy period after last write block:
> 1. After the command completion interrupt (IRQSTAT[CC]), wait for
>    de-assertion of PRSTAT[WTA].
> 2. Once PRSTAT[WTA] is de-asserted, start the software timer and poll
>    the busy signal (DAT0) using PRSTAT[DLSL[0]].
> 3. Wait for DAT0 signal to go high (which indicate transfer complete)
>    or software timer expiry (which indicate data timeout error).
> 4. Issue soft reset for data (SYSCTL[RSTD]).
> 5. In case of data timeout error (detected in step 3) perform the
>    error recovery.
> 
> The workaround for CMD with busy has already been applied in eSDHC
> driver. This patch is to add workaround for the 2nd issue.

This workaround is used the CONFIG_SYS_FSL_ERRATUM_ESDHC_A009620?..
Then if this config is disabled..how is it handling?

> 
> Signed-off-by: Yangbo Lu <yangbo.lu at nxp.com>
> ---
> Changes for v2:
> 	- Split original patch into config part and mmc part
> ---
>  drivers/mmc/fsl_esdhc.c | 26 ++++++++++++++++++++++++++
>  include/fsl_esdhc.h     |  1 +
>  2 files changed, 27 insertions(+)
> 
> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
> index 80bc177..99cadae 100644
> --- a/drivers/mmc/fsl_esdhc.c
> +++ b/drivers/mmc/fsl_esdhc.c
> @@ -482,6 +482,32 @@ esdhc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, struct mmc_data *data)
>  #ifdef CONFIG_SYS_FSL_ESDHC_USE_PIO
>  		esdhc_pio_read_write(mmc, data);
>  #else
> +#ifdef CONFIG_SYS_FSL_ERRATUM_ESDHC_A009620
> +		int timeout = 5000;
> +		if (data->flags & MMC_DATA_WRITE) {
> +			while (esdhc_read32(&regs->prsstat) & PRSSTAT_WTA)
> +				;

I don't want to have the potential infinite loop.

Best Regards,
Jaehoon Chung

> +
> +			/* Poll on DATA0 line for 500 ms */
> +			while (!(esdhc_read32(&regs->prsstat) & PRSSTAT_DAT0)) {
> +				udelay(100);
> +				timeout--;
> +				if (timeout <= 0) {
> +					err = TIMEOUT;
> +					break;
> +				}
> +			}
> +			if (!err) {
> +				esdhc_write32(&regs->sysctl,
> +					      esdhc_read32(&regs->sysctl) |
> +					      SYSCTL_RSTD);
> +				while ((esdhc_read32(&regs->sysctl) &
> +					SYSCTL_RSTD))
> +					;
> +			}
> +			goto out;
> +		}
> +#endif
>  		do {
>  			irqstat = esdhc_read32(&regs->irqstat);
>  
> diff --git a/include/fsl_esdhc.h b/include/fsl_esdhc.h
> index c6f4666..3f146f7 100644
> --- a/include/fsl_esdhc.h
> +++ b/include/fsl_esdhc.h
> @@ -97,6 +97,7 @@
>  #define PRSSTAT_CINS		(0x00010000)
>  #define PRSSTAT_BREN		(0x00000800)
>  #define PRSSTAT_BWEN		(0x00000400)
> +#define PRSSTAT_WTA		(0x00000100)
>  #define PRSSTAT_SDSTB		(0X00000008)
>  #define PRSSTAT_DLA		(0x00000004)
>  #define PRSSTAT_CICHB		(0x00000002)
>