Message-id: <561C6C5A.7090806@samsung.com>
Date:	Tue, 13 Oct 2015 11:28:42 +0900
From:	Jaehoon Chung <jh80.chung@...sung.com>
To:	Krzysztof Kozlowski <k.kozlowski@...sung.com>,
	Anand Moon <linux.amoon@...il.com>
Cc:	k.kozlowski.k@...il.com, Kukjin Kim <kgene@...nel.org>,
	Javier Martinez Canillas <javier@....samsung.com>,
	Lukasz Majewski <l.majewski@...sung.com>,
	devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
	"linux-samsung-soc@...r.kernel.org" 
	<linux-samsung-soc@...r.kernel.org>,
	Linux Kernel <linux-kernel@...r.kernel.org>
Subject: Re: [PATCH 3/3] ARM: dts: exynos5422-odroidxu3: Added UHS-I bus speed
 support

On 10/12/2015 10:16 PM, Krzysztof Kozlowski wrote:
> W dniu 12.10.2015 o 22:04, Jaehoon Chung pisze:
>> On 10/12/2015 09:42 PM, Krzysztof Kozlowski wrote:
>>> W dniu 12.10.2015 o 19:46, Anand Moon pisze:
>>>> Hi Krzysztof,
>>>>
>>>> On 12 October 2015 at 11:14, Krzysztof Kozlowski
>>>> <k.kozlowski@...sung.com> wrote:
>>>>> On 12.10.2015 00:46, Anand Moon wrote:
>>>>>> Added support for UHS-I bus speed 50MB/s (SDR50, DDR50) 104MB/s (SDR104)
>>>>>
>>>>> This description is not entirely correct. The MMC driver already
>>>>> supports these UHS speeds (you did not any code) so you rather enabled
>>>>> it (description of bindings says "is supported").
>>>>>
>>>>> You mentioned DDR50 but I don't see respective property below.
>>>> Looks like I missed it, I will add this in the next patch,
>>>>>
>>>>> How do you know that these modes are really supported? I don't know. Can
>>>>> you convince me?
>>>
>>> That part was not answered...
>>
>> In my experiment, it needs two requirements.
>> One is that Host controller supported UHS-I mode or others, other is SD-card.
>> In Anand's commit message, there is no information for this.
>>
>> And 50MB/s or 104MB/s is not real performance. (Just theoretical values)
>> It seems that can get those performances.
> 
> Right. But do you know if the host actually supports these?

Actually, it needs to check the User Manual for SoC.
If i can't check the User manual, i can't also know whether it supports or not.
Especially, there is no register that can be known which SD specification version at dw-mmc controller.

Well, if i miss something, let me know. I will also check more.

Best Regards,
Jaehoon Chung

> 
>>
>>>
>>>>>
>>>>
>>>>>>
>>>>>> Signed-off-by: Anand Moon <linux.amoon@...il.com>
>>>>>>
>>>>>> ---
>>>>>> Changes based on git://git.kernel.org/pub/scm/linux/kernel/git/kgene/linux-samsung.git v4.4-next/dt-samsung branch
>>>>>>
>>>>>> Changes Fixed the UHS-I bus speed detedtion on cold boot.
>>>>>
>>>>> I don't get what is exactly fixed here. What was the error? What is the
>>>>> outcome of this fix? The log below is before or after?
>>>>>
>>>>> Best regards,
>>>>> Krzysztof
>>>>>
>>>>>>
>>>>>> [    2.439806] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot req 100000000Hz, actual 100000000HZ div = 0)
>>>>>> [    2.449729] mmc1: new ultra high speed SDR50 SDHC card at address aaaa
>>>>>> [    2.455984] mmcblk0: mmc1:aaaa SL32G 29.7 GiB
>>>>>> [    2.461743]  mmcblk0: p1 p2
>>>>>
>>>>>> ---
>>>>>>  arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi | 4 ++++
>>>>>>  1 file changed, 4 insertions(+)
>>>>>>
>>>>>> diff --git a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>>>>>> index 58c06d3..ba4a87b 100644
>>>>>> --- a/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>>>>>> +++ b/arch/arm/boot/dts/exynos5422-odroidxu3-common.dtsi
>>>>>> @@ -364,6 +364,10 @@
>>>>>>       pinctrl-0 = <&sd2_clk &sd2_cmd &sd2_cd &sd2_bus4>;
>>>>>>       bus-width = <4>;
>>>>>>       cap-sd-highspeed;
>>>>>> +     sd-uhs-sdr12;
>>>>>> +     sd-uhs-sdr25;
>>>>>> +     sd-uhs-sdr50;
>>>>>> +     sd-uhs-sdr104;
>>>>>>  };
>>>>>>
>>>>>>  &pinctrl_0 {
>>>>>>
>>>>>
>>>>
>>>> Changes were made to support Sandisk Ultra UHS-I class 10 card support.
>>>> OdroidXU3/XU4 board would not boot up using this card.
>>>>
>>>> Depending on the capability of the UHS-I card, the speed of the card
>>>> is selected.
>>>> I have just added the enhance capability feature to support them.
>>>
>>> So without these capabilities mentioned microSD card cannot be used? So
>>> I have a UHS-I card, that one exactly:
>>> http://www.samsung.com/us/support/owners/product/MB-MP32D/APC
>>>
>>> It works:
>>> [    2.628365] mmc_host mmc1: Bus speed (slot 0) = 50000000Hz (slot req
>>> 50000000Hz, actual 50000000HZ div = 0)
>>> [    2.693296] mmc1: new high speed SDHC card at address 0001
>>> [    2.703867] mmcblk0: mmc1:0001 00000 29.8 GiB
>>> [    2.708406]  mmcblk0: p1 p2
>>>
>>> This is just HS mode.
>>>
>>> In the same time isn't UHS-I backward compatible? Your report seems
>>> surprising.
>>
>> Right. it's not issue. just working as lower mode than its capability.
> 
> Anand's report mentions "board would not boot up" which seems quite
> drastic. :)
> 
> Thanks Jaehoon for help in reviewing this patch.
> 
> 
> Dear Anand,
> 
> Could you describe in more details observable issues, what is fixed or
> what feature is added?
> 
> Best regards,
> Krzysztof
> 
>>
>> Best Regards,
>> Jaehoon Chung
>>
>>>
>>> Best regards,
>>> Krzysztof
>>>
>>>>
>>>> On warm boot: i.e reboot of the board.
>>>> [    4.649073] mmc_host mmc1: Bus speed (slot 0) = 50000000Hz (slot
>>>> req 50000000Hz, actual 50000000HZ div = 0)
>>>> [    4.657555] mmc1: new high speed SDHC card at address aaaa
>>>> [    4.663787] mmcblk0: mmc1:aaaa SL32G 29.7 GiB
>>>> [    4.669206]  mmcblk0: p1 p2
>>>>
>>>> On cold boot:: ie: power on the board.
>>>>
>>>> [    4.630237] mmc_host mmc1: Bus speed (slot 0) = 100000000Hz (slot
>>>> req 100000000Hz, actual 100000000HZ div = 0)
>>>> [    4.639820] mmc1: new ultra high speed SDR50 SDHC card at address aaaa
>>>> [    4.646266] mmcblk0: mmc1:aaaa SL32G 29.7 GiB
>>>> [    4.650293] IRQ56 no longer affine to CPU7
>>>> [    4.650581] CPU7: shutdown
>>>> [    4.658293]  mmcblk0: p1 p2
>>>>
>>>> Note: Their is need to reset the PMIC
>>>> S2MPS11_REG_L13CTRL/S2MPS11_REG_L19CTRL registers
>>>>          to support this feature consistently on every reboot.
>>>>
>>>> -Anand Moon
>>>> --
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>>>>
>>>
>>>
>>
> 
> 

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