[U-Boot] [PATCH] mmc: sdhci: Fixed timeout for sdhci_send_command()

[Steve Rae <srae@broadcom.com>]

Tested-by: Steve Rae <srae@broadcom.com>

(does resolve the issue on our board!)

On 14-06-27 02:37 AM, Pantelis Antoniou wrote:
> Hi Eli,
>
> On Jun 12, 2014, at 12:41 PM, Eli Billauer wrote:
>
>> The current wait loop just reads the status 10000 times, which makes the
>> actual timeout period platform-dependent. The udelay() call within the loop
>> makes the new timeout ~100 ms.
>>
>> Signed-off-by: Eli Billauer <eli.billauer@gmail.com>
>> ---
>> drivers/mmc/sdhci.c |    1 +
>> 1 files changed, 1 insertions(+), 0 deletions(-)
>>
>> diff --git a/drivers/mmc/sdhci.c b/drivers/mmc/sdhci.c
>> index 3125d13..80f3a91 100644
>> --- a/drivers/mmc/sdhci.c
>> +++ b/drivers/mmc/sdhci.c
>> @@ -226,6 +226,7 @@ int sdhci_send_command(struct mmc *mmc, struct mmc_cmd *cmd,
>> 			break;
>> 		if (--retry == 0)
>> 			break;
>> +		udelay(10);
>> 	} while ((stat & mask) != mask);
>>
>> 	if (retry == 0) {
>> --
>> 1.7.2.3
>
> Looking at the linux sources is no good, cause linux is interrupt driven.
> This delay is used because the driver is not interrupt driven, so you have
> to wait until the interrupt indication is delivered.
>
> The only reference to interrupt latency I found is related to tuning and is
> set to 50ms which I supposed is very pessimistic.
> I think a timeout of 100ms would be fine.
>
> Regards
>
> -- Pantelis
>
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