[U-Boot] [BUG] 0001-mmc-fix-the-wrong-disabling-clock.patch

[Jaehoon Chung]

On 01/29/2018 10:41 AM, Heinrich Schuchardt wrote:
> On 01/29/2018 02:34 AM, Jaehoon Chung wrote:
>> On 01/29/2018 09:33 AM, Heinrich Schuchardt wrote:
>>> On 01/26/2018 07:58 AM, Jaehoon Chung wrote:
>>>> Hi Heinrich,
>>>>
>>>> On 01/26/2018 12:28 PM, Jaehoon Chung wrote:
>>>>> Hi,
>>>>>
>>>>> On 01/26/2018 04:37 AM, Heinrich Schuchardt wrote:
>>>>>> With git master HEAD the Odroid C2 hangs after the command line countdown.
>>>>>>
>>>>>> Bisecting teaches that this is the patch causing the problem:
>>>>>>
>>>>>> 9546eb92cb648a8bba0aa9d5930ac751e6e5b9a4
>>>>>> mmc: fix the wrong disabling clock
>>>>>
>>>>> When you search for commit with bisecting, this commit might be occurred a problem.
>>>>> So i have sent the patches a below patches.
>>>>>
>>>>> I don't have odroid-c2 board. so it's difficult to find what happen to your board.
>>>>> Could you share the log message?
>>>>>
>>>>> Almost all boards are working fine. and those patches make sense.
>>>>>
>>>>> If revert these patches, too many boards can't use MMC card.
>>>>>
>>>>>>
>>>>>> Please, revert the patch.
>>>>>
>>>>> Well, my opinion is first step that we try to find what is main problem about odriod-c2 or others..
>>>>> Not only revert the patch. Also i will try to solve your issue.
>>>>
>>>> I didn't have Odroid-C2 board, i can't test anything. Could you test with below code?
>>>>
>>>> diff --git a/drivers/mmc/meson_gx_mmc.c b/drivers/mmc/meson_gx_mmc.c
>>>> index 3cd934634d..c17efd25c6 100644
>>>> --- a/drivers/mmc/meson_gx_mmc.c
>>>> +++ b/drivers/mmc/meson_gx_mmc.c
>>>> @@ -35,6 +35,9 @@ static void meson_mmc_config_clock(struct mmc *mmc)
>>>>         uint32_t meson_mmc_clk = 0;
>>>>         unsigned int clk, clk_src, clk_div;
>>>>  
>>>> +       if (mmc->clock == 0)
>>>> +               return 0;
>>>
>>> You should not return 0 from a void function.
>>>
>>> So, please, write
>>>
>>> 	if (!mmc->clock)
>>> 		return;
>>
>> Just for checking your problem.
>> I didn't have odroid-c2, so i don't know whether it's working fine or not.
>> Is it working fine?
>>
>>>
>>>> +
>>>>         /* 1GHz / CLK_MAX_DIV = 15,9 MHz */
>>>>         if (mmc->clock > 16000000) {
>>>>                 clk = SD_EMMC_CLKSRC_DIV2;
>>>>
>>>
>>> Current git HEAD plus this change allows reading from MMC.
>>>
>>> I added a print command and found that the functions is called twice
>>> with a non-zero value:
>>>
>>> MMC:
>>> meson_mmc_config_clock: mmc->clock: 380953
>>> meson_mmc_config_clock: mmc->clock: 380953
>>> mmc at 72000: 0, mmc at 74000: 1
>>>
>>> But quite a lot of changes have been merged since my first mail, so I am
>>> not sure which change is relevant.
>>
>> twice called?
> 
> There is are two mmcs:
> mmc at 72000: 0, mmc at 74000: 1
> 
> Maybe that is why.
> 
> In my opinion, meson_gx_mmc is calling mmc_set_clock() in
> meson_mmc_probe() at probing time.
>> And after that, mmc_set_clock() is calling at initial time in mmc.c.
>> So it should be called twice..this is just my thinking.
>>
>> I want to know that odroid-c2 is working fine or not.?
> 
> With current git master + your patch it is running fine.
> Looking at the debug output I doubt that checking for division by zero
> is making a difference here.

My patch means the below thing?

>>>> +       if (mmc->clock == 0)
>>>> +               return 0;
>>>
>>> You should not return 0 from a void function.
>>>
>>> So, please, write
>>>
>>> 	if (!mmc->clock)
>>> 		return;

Best Regards,
Jaehoon Chung

> 
> But the git master has changed since my first mail in this thread.
> 
> Best regards
> 
> Heinrich
> 
> 
>>
>> Best Regards,
>> Jaehoon Chung
>>
>>>
>>> Best regards
>>>
>>> Heinrich
>>>
>>>> Best Regards,
>>>> Jaehoon Chung
>>>>
>>>>>
>>>>> Best Regards,
>>>>> Jaehoon Chung
>>>>>
>>>>>>
>>>>>> I could not find the patch in
>>>>>> https://lists.denx.de/pipermail/u-boot/2018-January/date.html
>>>>>>
>>>>>> http://patchwork.ozlabs.org/patch/864607/
>>>>>> seems to be related but does not solve the issue.
>>>>>>
>>>>>> Best regards
>>>>>>
>>>>>> Heinrich
>>>>>>
>>>>>>
>>>>>>
>>>>>
>>>>> _______________________________________________
>>>>> U-Boot mailing list
>>>>> U-Boot at lists.denx.de
>>>>> https://lists.denx.de/listinfo/u-boot
>>>>>
>>>>
>>>>
>>>
>>>
>>>
>>>
>>
>>
> 
> 
> 
>