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

[Jagan Teki]

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.

Thanks,
Jagan,