[U-Boot] [PATCH] dm: mmc: socfpga: call dwmci_probe()

[Jaehoon Chung]

Dear Patrick,

On 03/09/2018 03:51 PM, Patrick Brünn wrote:
>> From: Patrick Brünn
>> Sent: Donnerstag, 8. März 2018 06:39
>>> From: Jaehoon Chung [mailto:jh80.chung at samsung.com]
>>> Sent: Donnerstag, 8. März 2018 04:57
>>> On 03/08/2018 12:12 PM, Marek Vasut wrote:
>>>> On 03/08/2018 03:17 AM, Jaehoon Chung wrote:
>>>>> On 03/06/2018 05:07 PM, linux-kernel-dev at beckhoff.com wrote:
>>>>>> From: Patrick Bruenn <p.bruenn at beckhoff.com>
>>>>>>
>>>>>> On a socfpga_cyclone5 based board the SD card, was never powered
>> up.
>>> For
>>>>>> other dw_mmc based SoCs dwmci_probe() is called in the platform
>>> specific
>>>>>> probe(). It seems this call is missing for socfpga_dw_mmc.
>>>>>>
>>>>>> With this change DWMCI_PWREN is set by dmwci_init().
>>>>>>
>>>>>> Signed-off-by: Patrick Bruenn <p.bruenn at beckhoff.com>
>>>>>
>>>>> Reviewed-by: Jaehoon Chung <jh80.chung at samsung.com>
>>>>>
>>>>> Will apply this patch before releasing v2018.03.
>>>>> (I have a problem about accessing git.denx.de. After fixing my problem,
>>> will resend email about applying.)
>>>>
>>>> DWMMC works on SoCFPGA for me (tested on rc4), so I don't understand
>>> what this patch is trying to fix. I'd prefer if you did not hastily apply this.
>>>
>>> It's my misunderstanding. When i checked more. I think that Marek is right.
>>> Thanks Marek for pointing out.
>>>
>> Okay, but do you have any hint what I am doing wrong? My board (cx8100 not
>> mainline, yet) is based on socfpga_cyclone5. And on my board "
>> dwmci_writel(host, DWMCI_PWREN, 1);" is never called, because
>> dwmci_init() is never called.
>> As far as I can see with CONFIG_DM_MMC enabled dwmci_init() should be
>> called by dwmci_probe().
>>
>> exynos  and rockchip do call dwmci_probe() within
>> exynos/rockchip_dwmmc_probe().
>> but socfpga_dwmmc_probe() is missing this call. So I looked deeper but found
>> no place for socfpga platform to call dwmci_probe() or dwmci_init().
>> What am I missing?
>>
> I got an idea, what might be the difference between my board and your boards.
> I suspect you use U-BOOT SPL without CONFIG_DM_MMC set, so
> dwmci_init() is called indirectly by mmc_start_init().

Right, it's difference with CONFIG_DM_MMC. I had checked this.

> Now, when your main U-Boot (with CONFIG_DM_MMC) is launched,
> everything is already configured and it isn't necessary to call dwmci_init() again.
> On my board the Altera MPL is used (and I can't replace it).  Which seems to
> disable DWMCI_PWREN before launching U-Boot.
> If my assumption is correct, I still think it is a U-Boot bug to assume code like in
> dwmci_init() was already run before U-Boot gets in control.
> Besides exynos/rockchip_dw_mmc don't have this precondition requirement.
> 
> Please take your time to look deeper into this issue, before deciding anything.
> I don't think we need to rush this into the next release, as normal mainline
> boards are "accidently" not affected.

Sure. I will check this patch. Before applying this, will check more carefully. 
I agreed about Marek's opinion "did not hastily apply this."
And i think that your approach also is right.

Best Regards,
Jaehoon Chung

> 
> Thanks and regards,
> Patrick
> 
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