[PATCH 0/7] spi-nor: Add parallel and stacked memories support

[Michal Simek]

On 12/6/23 13:24, Jagan Teki wrote:
> On Fri, Aug 18, 2023 at 9:51 AM Ashok Reddy Soma
> <ashok.reddy.soma at amd.com> wrote:
>>
>> This series adds support for Xilinx qspi parallel and stacked memeories.
>>
>> In parallel mode, the current implementation assumes that a maximum of
>> two flashes are connected. The QSPI controller splits the data evenly
>> between both the flashes so, both the flashes that are connected in
>> parallel mode should be identical.
>> During each operation SPI-NOR sets 0th bit for CS0 & 1st bit for CS1 in
>> nor->flags.
>>
>> In stacked mode the current implementation assumes that a maximum of two
>> flashes are connected and both the flashes are of same make but can
>> differ in sizes. So, except the sizes all other flash parameters of both
>> the flashes are identical
>>
>> Spi-nor will pass on the appropriate flash select flag to low level
>> driver, and it will select pass all the data to that particular flash.
>>
>> Write operation in parallel mode are performed in page size * 2 chunks as
>> each write operation results in writing both the flashes. For doubling
>> the address space each operation is performed at addr/2 flash offset,
>> where addr is the address specified by the user.
>>
>> Similarly for read and erase operations it will read from both flashes,
>> so size and offset are divided by 2 and send to flash.
>>
>>
>>
>> Ashok Reddy Soma (7):
>>    dm: core: support reading a single indexed u64 value
>>    mtd: spi-nor: Add parallel and stacked memories support
>>    mtd: spi-nor: Add parallel memories support for read_sr and read_fsr
>>    mtd: spi-nor: Add parallel and stacked memories support in read_bar
>>      and write_bar
>>    spi: spi-uclass: Read chipselect and restrict capabilities
>>    spi: zynqmp_gqspi: Add parallel memories support in GQSPI driver
>>    spi: zynq_qspi: Add parallel memories support in QSPI driver
> 
> This set is a bit hard to go. We need to Sync the Linux SPI-NOR tree
> and let Linux approve the parallel and stacked otherwise it is very
> difficult to maintain.

Linux thread is here and it is pretty close to be merged.
https://lore.kernel.org/all/20231125092137.2948-1-amit.kumar-mahapatra@amd.com/

DT binding is already approved but have no clue how big effort is to synchronize 
it. When was it synchronized last time?

Thanks,
Michal