[PATCH v2 04/10] spi: spi-mem: Add driver for Aspeed SMC controllers

[Joel Stanley]

On Wed, 2 Mar 2022 at 17:31, Cédric Le Goater <clg at kaod.org> wrote:
>
> This SPI driver adds support for the Aspeed static memory controllers
> of the AST2600, AST2500 and AST2400 SoCs using the spi-mem interface.
>
>  * AST2600 Firmware SPI Memory Controller (FMC)
>    . BMC firmware
>    . 3 chip select pins (CE0 ~ CE2)
>    . Only supports SPI type flash memory
>    . different segment register interface
>    . single, dual and quad mode.
>
>  * AST2600 SPI Flash Controller (SPI1 and SPI2)
>    . host firmware
>    . 2 chip select pins (CE0 ~ CE1)
>    . different segment register interface
>    . single, dual and quad mode.
>
>  * AST2500 Firmware SPI Memory Controller (FMC)
>    . BMC firmware
>    . 3 chip select pins (CE0 ~ CE2)
>    . supports SPI type flash memory (CE0-CE1)
>    . CE2 can be of NOR type flash but this is not supported by the driver
>    . single, dual mode.
>
>  * AST2500 SPI Flash Controller (SPI1 and SPI2)
>    . host firmware
>    . 2 chip select pins (CE0 ~ CE1)
>    . single, dual mode.
>
>  * AST2400 New Static Memory Controller (also referred as FMC)
>    . BMC firmware
>    . New register set
>    . 5 chip select pins (CE0 ∼ CE4)
>    . supports NOR flash, NAND flash and SPI flash memory.
>    . single, dual and quad mode.
>
> Each controller has a memory range on which flash devices contents are
> mapped. Each device is assigned a window that can be changed at bootime
> with the Segment Address Registers.
>
> Each SPI flash device can then be accessed in two modes: Command and
> User. When in User mode, SPI transfers are initiated with accesses to
> the memory segment of a device. When in Command mode, memory
> operations on the memory segment of a device generate SPI commands
> automatically using a Control Register for the settings.
>
> This initial patch adds support for User mode. Command mode needs a little
> more work to check that the memory window on the AHB bus fits the device
> size. It will come later when support for direct mapping is added.
>
> Single and dual mode RX transfers are supported. Other types than SPI
> are not supported.
>
> Signed-off-by: Chin-Ting Kuo <chin-ting_kuo at aspeedtech.com>
> Signed-off-by: Cédric Le Goater <clg at kaod.org>

Reviewed-by: Joel Stanley <joel at jms.id.au>