[U-Boot] [PATCH] MMC: DWMMC: Fix FIFO_DEPTH calculation

[Rajeshwari Birje]

Hi Jagan,

Please find my comments below.
On Fri, May 24, 2013 at 10:31 AM, Jagan Teki <jagannadh.teki at gmail.com> wrote:
> On Fri, May 24, 2013 at 7:12 AM, Jaehoon Chung <jh80.chung at samsung.com> wrote:
>> On 05/24/2013 03:27 AM, Jagan Teki wrote:
>>> On Thu, May 23, 2013 at 6:45 PM, Rajeshwari Shinde
>>> <rajeshwari.s at samsung.com> wrote:
>>>> Current DWMMC driver used to give FIFO underrun/overrun error every 3rd time
>>>> for mmc rescan command.
>>>> In current code FIFO_DEPTH is getting calculated after reading the FIFOTH
>>>> register and extracting the RX_WMARK bits from it i.e (RX_WMARK = FIFO_DEPTH/2 -1).
>>>> Instead of storing the correct value, we were recalculating the FIFO_DEPT each
>>>> time which is not correct.
>>>>
>>>> Signed-off-by: Hatim Ali <hatim.rv at samsung.com>
>>>> Signed-off-by: Rajeshwari Shinde <rajeshwari.s at samsung.com>
>>>> ---
>>>>  drivers/mmc/dw_mmc.c |    6 ++++--
>>>>  1 files changed, 4 insertions(+), 2 deletions(-)
>>>>
>>>> diff --git a/drivers/mmc/dw_mmc.c b/drivers/mmc/dw_mmc.c
>>>> index 4070d4e..be590a4 100644
>>>> --- a/drivers/mmc/dw_mmc.c
>>>> +++ b/drivers/mmc/dw_mmc.c
>>>> @@ -332,11 +332,13 @@ static int dwmci_init(struct mmc *mmc)
>>>>         dwmci_writel(host, DWMCI_BMOD, 1);
>>>>
>>>>         fifo_size = dwmci_readl(host, DWMCI_FIFOTH);
>>>> -       if (host->fifoth_val)
>>>> +       if (host->fifoth_val) {
>>>
>>> What is the inital value for host->fifoth_val, for the first time call.?
>> It should be set into board-specific file(dw-mmc_exynos.c) or others.
>
> I am unable to find dw-mmc_exynos.c on the master, and also I haven't
> see fifoth_val used other than dw_mmc.c
> Could you please help me out.
dw-mmc_exynos.c is merged in mmc tree. Yes  FIFO_DEPTH is set only in dw_mmc.c
>
> Thanks,
> Jagan.
>
>>
>> Best Regards,
>> Jaehoon Chung
>>>
>>>>                 fifoth_val = host->fifoth_val;
>>>> -       else
>>>> +       } else {
>>>>                 fifoth_val = MSIZE(0x2) | RX_WMARK(fifo_size/2 -1) |
>>>>                         TX_WMARK(fifo_size/2);
>>>> +               host->fifoth_val = fifoth_val;
>>>> +       }
>>>>         dwmci_writel(host, DWMCI_FIFOTH, fifoth_val);
>>>>
>>>>         dwmci_writel(host, DWMCI_CLKENA, 0);
>>>> --
>>>> 1.7.4.4
>>>>
>>>
>>> Thanks,
>>> Jagan.
>>>
>>
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-- 
Regards,
Rajeshwari Shinde