[PATCH v10 12/27] mtd: spi-nor-core: Rework hwcaps selection

[Bin Meng]

Hi Pratyush,

On Sat, Jun 26, 2021 at 3:20 AM Pratyush Yadav <p.yadav at ti.com> wrote:
>
> The spi-mem layer provides a spi_mem_supports_op() function to check
> whether a specific operation is supported by the controller or not.
> This is much more accurate than the hwcaps selection logic based on
> SPI_{RX,TX}_ flags.
>
> Rework the hwcaps selection logic to use spi_mem_supports_op().
>
> To make sure the build doesn't break for boards not using CONFIG_DM_SPI,
> add a simple SPI_{RX,TX}_ based hwcaps selection logic in spi-mem-nodm
> similar to spi_mem_default_supports_op(). This change is only
> compile-tested.
>
> To avoid SPL size problems on the x530 board, the old hwcaps selection
> is still kept around. Leaving the code in-place was getting difficult to
> read and understand, so the code is restructured to have it all in one
> isolated function. As a result of this, the parameter hwcaps to
> spi_nor_setup() is no longer needed. Remove it.
>
> Based on the Linux commit c76f5089796a (mtd: spi-nor: Rework hwcaps
> selection for the spi-mem case, 2019-08-06)
>
> Signed-off-by: Pratyush Yadav <p.yadav at ti.com>
> ---
>  drivers/mtd/spi/Kconfig        |   9 ++
>  drivers/mtd/spi/spi-nor-core.c | 244 ++++++++++++++++++++++++++-------
>  drivers/spi/spi-mem-nodm.c     |  62 +++++++++
>  include/linux/mtd/spi-nor.h    |  17 ++-
>  4 files changed, 280 insertions(+), 52 deletions(-)
>
> diff --git a/drivers/mtd/spi/Kconfig b/drivers/mtd/spi/Kconfig
> index f8db8e5213..a701167dcc 100644
> --- a/drivers/mtd/spi/Kconfig
> +++ b/drivers/mtd/spi/Kconfig
> @@ -88,6 +88,15 @@ config SPI_FLASH_SFDP_SUPPORT
>          SPI NOR flashes using Serial Flash Discoverable Parameters (SFDP)
>          tables as per JESD216 standard.
>
> +config SPI_FLASH_SMART_HWCAPS
> +       bool "Smart hardware capability detection based on SPI MEM supports_op() hook"
> +       default y

This commit unfortunately breaks ICH SPI driver working with SPI
flashes on Intel boards.

Switching off this option makes it work again.

I think this is due to that ICH SPI driver has set the flags
SPI_RX_SLOW | SPI_TX_BYTE but these 2 flags are not handled in the new
codes.
Any quick ideas on how to fix this?

> +       help
> +        Enable support for smart hardware capability detection based on SPI
> +        MEM supports_op() hook that lets controllers express whether they
> +        can support a type of operation in a much more refined way compared
> +        to using flags like SPI_RX_DUAL, SPI_TX_QUAD, etc.
> +

[snip]

Regards,
Bin