[U-Boot] [PATCH] fsl_esdhc: Do not clear interrupt status bits until data processed

[Dirk Behme <dirk.behme@de.bosch.com>]

On 11.06.2013 17:34, Andrew Gabbasov wrote:
> After waiting for the command completion event, the interrupt status
> bits, that occured to be set by that time, are cleared by writing them
> back. It is supposed, that it should be command related bits (command
> complete and may be command errors).
>
> However, in some cases the DMA already completes by that time before
> the full transaction completes. The corresponding DINT bit gets set
> and then cleared before even entering the loop, waiting for data part
> completion. That waiting loop never gets this bit set, causing the
> operation to hang. This is reported to happen, for example, for write
> operation of 1 sector to upper area (block #7400000) of SanDisk Ultra II
> 8GB card.
>
> The solution could be to explicitly clear only command related interrupt
> status bits. However, since subsequent processing does not rely on
> any command bits state, it could be easier just to remove clearing
> of any bits at that point, leaving them all until all data processing
> completes. After that the whole register will be cleared at once.
>
> Also, on occasion, interrupts masking moved to before writing the command,
> just for the case there should be no chance of interrupt between the first
> command and interrupts masking.
>
> Reported-by: Dirk Behme <dirk.behme@de.bosch.com>
> Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>

Acked-by: Dirk Behme <dirk.behme@de.bosch.com>

Thanks

Dirk

> ---
>   drivers/mmc/fsl_esdhc.c |    7 +++----
>   1 file changed, 3 insertions(+), 4 deletions(-)
>
> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
> index 861f4b9..b501b4d 100644
> --- a/drivers/mmc/fsl_esdhc.c
> +++ b/drivers/mmc/fsl_esdhc.c
> @@ -310,6 +310,9 @@ esdhc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, struct mmc_data *data)
>   	/* Figure out the transfer arguments */
>   	xfertyp = esdhc_xfertyp(cmd, data);
>
> +	/* Mask all irqs */
> +	esdhc_write32(&regs->irqsigen, 0);
> +
>   	/* Send the command */
>   	esdhc_write32(&regs->cmdarg, cmd->cmdarg);
>   #if defined(CONFIG_FSL_USDHC)
> @@ -320,15 +323,11 @@ esdhc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, struct mmc_data *data)
>   	esdhc_write32(&regs->xfertyp, xfertyp);
>   #endif
>
> -	/* Mask all irqs */
> -	esdhc_write32(&regs->irqsigen, 0);
> -
>   	/* Wait for the command to complete */
>   	while (!(esdhc_read32(&regs->irqstat) & (IRQSTAT_CC | IRQSTAT_CTOE)))
>   		;
>
>   	irqstat = esdhc_read32(&regs->irqstat);
> -	esdhc_write32(&regs->irqstat, irqstat);
>
>   	/* Reset CMD and DATA portions on error */
>   	if (irqstat & (CMD_ERR | IRQSTAT_CTOE)) {