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

[Jagan Teki]

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.

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.
>>
>