[U-Boot] [Patch] fsl_esdhc: Fix DMA transfer completion waiting loop

Dirk Behme
2013-06-11T08:16:43Z

On 10.06.2013 16:51, Gabbasov, Andrew wrote:
> Hi Dirk,
> ________________________________________
>> From: Behme, Dirk - Bosch
>> Sent: Monday, June 10, 2013 16:06
>> To: Gabbasov, Andrew
>> Cc: u-boot at lists.denx.de; Stefano Babic; Fleming Andy-AFLEMING
>> Subject: Re: [U-Boot] [Patch] fsl_esdhc: Fix DMA transfer completion waiting loop
>>
>> On 08.04.2013 11:06, Andrew Gabbasov wrote:
>>> Rework the waiting for transfer completion loop condition
>>> to continue waiting until both Transfer Complete and DMA End
>>> interrupts occur. Checking of DLA bit in Present State register
>>> looks not needed in addition to interrupts status checking,
>>> so it can be removed from the condition. Also, DMA Error
>>> condition is added to the list of data errors, checked in the loop.
>>>
>>> Signed-off-by: Andrew Gabbasov <andrew_gabbasov@mentor.com>
>>> ---
>>> drivers/mmc/fsl_esdhc.c | 3 +--
>>> include/fsl_esdhc.h | 4 +++-
>>> 2 files changed, 4 insertions(+), 3 deletions(-)
>>>
>>> diff --git a/drivers/mmc/fsl_esdhc.c b/drivers/mmc/fsl_esdhc.c
>>> index 54b5363..814bba4 100644
>>> --- a/drivers/mmc/fsl_esdhc.c
>>> +++ b/drivers/mmc/fsl_esdhc.c
>>> @@ -400,8 +400,7 @@ esdhc_send_cmd(struct mmc *mmc, struct mmc_cmd *cmd, struct mmc_data *data)
>>>
>>> if (irqstat & DATA_ERR)
>>> return COMM_ERR;
>>> - } while (!(irqstat & IRQSTAT_TC) &&
>>> - (esdhc_read32(&regs->prsstat) & PRSSTAT_DLA));
>>> + } while ((irqstat & DATA_COMPLETE) != DATA_COMPLETE);
>>> #endif
>>> }
>>>
>>> diff --git a/include/fsl_esdhc.h b/include/fsl_esdhc.h
>>> index 47d2fe4..ea0880b 100644
>>> --- a/include/fsl_esdhc.h
>>> +++ b/include/fsl_esdhc.h
>>> @@ -63,7 +63,9 @@
>>> #define IRQSTAT_CC (0x00000001)
>>>
>>> #define CMD_ERR (IRQSTAT_CIE | IRQSTAT_CEBE | IRQSTAT_CCE)
>>> -#define DATA_ERR (IRQSTAT_DEBE | IRQSTAT_DCE | IRQSTAT_DTOE)
>>> +#define DATA_ERR (IRQSTAT_DEBE | IRQSTAT_DCE | IRQSTAT_DTOE | \
>>> + IRQSTAT_DMAE)
>>> +#define DATA_COMPLETE (IRQSTAT_TC | IRQSTAT_DINT)
>>>
>>> #define IRQSTATEN 0x0002e034
>>> #define IRQSTATEN_DMAE (0x10000000)
>>
>> I haven't tested this myself, but I got the following issue report
>> regarding this patch:
>>
>> Using a SANDISK ULTRA II 8GB card (or alternatively Transcend 16GB or
>> 32GB cards) and trying an mmc write [1] into the upper area of the 8GB
>> card makes the write hang in 9 of 10 cases. Sometimes even more.
>> Reverting this patch make these writes work again.
>>
>> mmc read does work fine, though. Even newer SANDISK Extreme III or
>> several micro SD cards are working fine.
>>
>> Any idea?
>>
>> Best regards
>>
>> Dirk
>
> So far the only idea that comes into my mind is that DMA for some reason completes
> its part of work too early so that the corresponding interrupt status bit appears and
> has already been cleared even before entering this loop.
>
> I will be trying to reproduce the issue.
>
> Meanwhile, is it possible to ask the reporter (who obviously can reproduce it)
> to try to add the debug print from the diff below and show what it prints when
> the write command hangs and when it succeeds?
>
> Thanks.
>
> Best regards,
> Andrew
>
> diff -u fsl_esdhc.c.orig fsl_esdhc.c
> --- fsl_esdhc.c.orig 2013-05-30 03:48:26.000000000 -0500
> +++ fsl_esdhc.c 2013-06-10 09:38:30.071905119 -0500
> @@ -329,6 +329,7 @@
>
> irqstat = esdhc_read32(&regs->irqstat);
> esdhc_write32(&regs->irqstat, irqstat);
> + printf("fsl_esdhc: irqstat = 0x%08x\n", irqstat);
>
> /* Reset CMD and DATA portions on error */
> if (irqstat & (CMD_ERR | IRQSTAT_CTOE)) {

1. Sandisk 8GB Ultra 2 class 4 SDHC

[ 23.967081] MMC write: dev # 0, block # 7400000, count 1 ...
fsl_esdhc: irqstat = 0x00000001
[ 23.977473] fsl_esdhc: irqstat = 0x00000009
=> hang

With "fsl_esdhc: Fix DMA transfer completion waiting loop" reverted:
[ 41.769231] MMC write: dev # 0, block # 7400000, count 1 ...
fsl_esdhc: irqstat = 0x00000001
[ 41.779622] fsl_esdhc: irqstat = 0x00000009
[ 41.798490] fsl_esdhc: irqstat = 0x00000001
[ 41.802593] 1 blocks write: OK
=> work

2. Sandisk 16GB Extreme class 10 (30MB/s)

[ 45.871140] MMC write: dev # 0, block # 7400000, count 1 ...
fsl_esdhc: irqstat = 0x00000001
[ 45.881528] fsl_esdhc: irqstat = 0x00000001
[ 46.054409] fsl_esdhc: irqstat = 0x00000001
[ 46.058513] 1 blocks write: OK
=> work

With "fsl_esdhc: Fix DMA transfer completion waiting loop" reverted:
[ 17.901514] MMC write: dev # 0, block # 7400000, count 1 ...
fsl_esdhc: irqstat = 0x00000001
[ 17.911901] fsl_esdhc: irqstat = 0x00000001
[ 18.081153] fsl_esdhc: irqstat = 0x00000001
[ 18.085256] 1 blocks write: OK
=> work

Best regards

Dirk