Re: [PATCH v5 0/6] mtd: spi-nor: parse SFDP tables to setup (Q)SPI memories

[Marek Vasut <marek.vasut@gmail.com>]

On 03/29/2017 06:45 PM, Cyrille Pitchen wrote:
> Hi all,
> 
> Le 23/03/2017 à 00:33, Cyrille Pitchen a écrit :
>> Hi all,
>>
>> based on git-hub/spi-nor and likely applicable on linux-next within the
>> next few days.
>>
>>
>> This new series of patchs aims to upgrade to spi-nor framework. We need to
>> take into account latest SPI memories which cannot be handled correctly by
>> the current implementation.
>>
>> For instance, SPI NOR memories like Spansion S25FS512S or Macronix
>> MX25U4035 support only the Fast Read 1-4-4 (EBh) command but not the
>> Fast Read 1-1-4 (6Bh) command. However the current spi-nor framework
>> supports only Fast Read 1-1-4 (6Bh).
>>
>> Also the Spansion S25FS512S memory (and others) may use a non-uniform
>> sector erase map, whereas the spi-nor framework assumes that a single
>> sector erase size and opcode can be used anywhere inside the data array.
>> This assumption is no longer valid.
>>
>> Then parsing SFDP tables is an attempt to solve many of those issues by
>> discovering dynamically most of the parameters and settings of the SPI NOR
>> memory:
>> - the flash size
>> - the page size for Page Program commands
>> - the supported Fast Read commands with the associated opcodes and number
>>   of mode/wait-state (dummy) cycles.
>> - the supported Sector/Block Erase commands with the associated opcodes
>>   and sizes.
>> - the erase sector map (for non-uniform memory).
>>
>>
>> Besides, most QSPI controllers from the different vendors are capable to
>> support the SPI 1-2-2 and 1-4-4 protocols but the spi-nor framework was
>> not ready to use them. This series also fixes this issue and computes the
>> best match between the hardware capabilies of both the SPI memory and the
>> SPI controler (master) to select the right opcodes and dummy cycles for
>> Fast Read and Page Program operations.
>>
>> The new 'struct spi_nor_hwcaps' uses a bitmask to describe all the
>> supported hardware capabilies and makes the difference between Fast Read
>> and Page Program operations and also between the different SPI protocols
>> (SPI 1-1-2 vs SPI 1-2-2 or SPI 1-1-4 vs SPI 1-4-4).
>>
>>
>> IMHO, the first 3 patches of this series are ready to be merged into the
>> github/spi-nor tree. Marek, do you agree with that?
> 
> Marek, if you have no comment on them, I will merge patches 1, 2, 3 in
> the spi-nor tree within the next few days. Hence, people like Cédric
> waiting for the series to merged could base their work on these patches.

Hm well, you could've at least poked me about this, I was so snowed
under that I didn't have any chance to take a look :(

-- 
Best regards,
Marek Vasut