[U-Boot] [PATCH v2 00/26] mmc: Add support for HS200 and UHS modes

[Marek Vasut]

On 10/18/2017 03:19 PM, Jean-Jacques Hiblot wrote:
> 
> 
> On 14/10/2017 16:51, Marek Vasut wrote:
>> On 10/02/2017 11:15 AM, Jean-Jacques Hiblot wrote:
>>>
>>> On 22/09/2017 16:42, Jaehoon Chung wrote:
>>>> Dear JJ,
>>>>
>>>> On 09/21/2017 11:29 PM, Jean-Jacques Hiblot wrote:
>>>>> This series brings support for HS200 and UHS modes to the mmc core.
>>>>> It has been tested with the hsmmc driver on several platforms (DRA7,
>>>>> AM57x, AM437x, beaglebone black, Atmel SAMA5D3 xplained). Some
>>>>> modifications
>>>>> are required in the host driver to take advantage of this (voltage
>>>>> switching,
>>>>> tuning). The changes to the host driver will be posted a another
>>>>> series as this
>>>>> one is already long enough.
>>>>>
>>>>> The series starts with a small refactoring of th sd/mmc startup. The
>>>>> first 5 commits
>>>>> are mostly moving code around with little or no functionnal change.
>>>>>
>>>>> Then the notion of "mode" is introduced. Until now, this information
>>>>> wasn't
>>>>> kept in struct mmc. Only the clock and a flag for ddr was kept. Later
>>>>> the mode
>>>>> information will be used to select the clock frequency, the ddr flag
>>>>> and the
>>>>> tuning procedure. It will be also be check against the host
>>>>> capabilities.
>>>>>
>>>>> Then comes the big refactoring job in:
>>>>> "mmc: refactor MMC startup to make it easier to support new modes" and
>>>>> "mmc: refactor SD startup to make it easier to support new modes"
>>>>> Since the number of modes is increasing, it makes sense to try them
>>>>> in a more
>>>>> organized way. those commits use a list of supported modes and
>>>>> iterate through
>>>>> them to find the best working one. It also allows to switch more
>>>>> easilly from
>>>>> one mode to another (switching from HS200 to DDR52 to access boot
>>>>> partitions for example)
>>>>>
>>>>> Then there are a couple of new callback added to:
>>>>> - send the initialization stream (74 clock cycles)
>>>>> - wait while the card is busy (used during UHS voltage switching).
>>>>> checking is
>>>>>     done on dat0.
>>>>> - select the IO voltage
>>>>>
>>>>> Then Power cycle is added. Without power cycle, if a UHS card fails
>>>>> to enumerate in
>>>>> UHS mode, it can't fall back to high speed mode and card enumeration
>>>>> will fail.
>>>>> Also in case of a reset (as opposed to a power on), it ensures that
>>>>> the SDCard
>>>>> is in clean state before re-doing the initialization.
>>>>>
>>>>> And finally the last commits add the support for HS200 and UHS.
>>>>>
>>>>> With this in place and the required changes in the HSMMC host driver
>>>>> (including
>>>>> DMA), we observe significant improvements in the performances on a
>>>>> DRA72 evm:
>>>>> eMMC HS200: 124 MB/s
>>>>> eMMC DDR52: 78 MB/s
>>>>> sd   SDR104: 71 MB/s
>>>>> sd   SDR50: 44 MB/s
>>>> I have one question.
>>>>
>>>> Did you test about accessing Boot partition of eMMC?
>>>> As i know, boot partition doesn't support the HS200 mode.
>>>>
>>>> When i checked your patches, there is no the function of mode changing
>>>> for accessing boot partition.
>>>> If i missed it, let me know, plz.
>>> Yes I did test the boot partitions. HS200 is not used in this case.
>>> The key function is mmc_boot_part_access_chk(). It checks if the current
>>> mode is supported by the partition. If not, it'll reselect a new mode.
>> Is anything new happening on the HS200 front ?
> I've been busy lately but I'll send the v3  in a few days that adresses
> all the comments done by Jaheoon and Simon.

Awesome, thanks !

If you have a tree with those patches applied somewhere, that'd be nice
as I'm working on adding HS200/SDR104 support into the uniphier-sd driver.

Also, any plan for HS400 ? :-)

-- 
Best regards,
Marek Vasut