Re: Query| USE of MTD_CFI_ADV_OPTIONS for SPI-NOR/serial-NOR flash for BE-kernel on arm64

Re: Query| USE of MTD_CFI_ADV_OPTIONS for SPI-NOR/serial-NOR flash for BE-kernel on arm64

[Boris Brezillon]

Hi Ashish,

On Tue, 4 Sep 2018 11:21:11 +0000
Ashish Kumar <ashish.kumar@nxp.com> wrote:

> Hi all,
> 
> I may sound very naïve, but I do not have other options to look for.
> What I was trying to achieve was "running BE-kernel on arm64, with the SPI-NOR controller(fsl_qspi) configured for AHB and IP buffer in BE mode. It works to an extent but not all is working correctly.

Could you detail what is working and what is not?

> 
> I was grep-ing through /driver/mtd/ and include/linux/mtd to look for these advance option(MTD_CFI_ADV_OPTIONS) to be used for SPI-NOR interface, is there a way this(MTD_CFI_BE_BYTE_SWAP) can be achieved for SPI-NOR flash?
> 
> Is anyone working on this, or similar thing?

That's not the proper fix. If you want you driver to work in
big-endian, fix the driver.

Regards,

Boris

Query| USE of MTD_CFI_ADV_OPTIONS for SPI-NOR/serial-NOR flash for BE-kernel on arm64

[Ashish Kumar]

Hi all,

I may sound very naïve, but I do not have other options to look for.
What I was trying to achieve was "running BE-kernel on arm64, with the SPI-NOR controller(fsl_qspi) configured for AHB and IP buffer in BE mode. It works to an extent but not all is working correctly.

I was grep-ing through /driver/mtd/ and include/linux/mtd to look for these advance option(MTD_CFI_ADV_OPTIONS) to be used for SPI-NOR interface, is there a way this(MTD_CFI_BE_BYTE_SWAP) can be achieved for SPI-NOR flash?

Is anyone working on this, or similar thing?

config MTD_CFI_ADV_OPTIONS
        bool "Flash chip driver advanced configuration options"
        depends on MTD_GEN_PROBE
        help
          If you need to specify a specific endianness for access to flash
          chips, or if you wish to reduce the size of the kernel by including
          support for only specific arrangements of flash chips, say 'Y'. This
          option does not directly affect the code, but will enable other
          configuration options which allow you to do so.

          If unsure, say 'N'.

choice
        prompt "Flash cmd/query data swapping"
        depends on MTD_CFI_ADV_OPTIONS
        default MTD_CFI_NOSWAP
        ---help---
          This option defines the way in which the CPU attempts to arrange
          data bits when writing the 'magic' commands to the chips. Saying
          'NO', which is the default when CONFIG_MTD_CFI_ADV_OPTIONS isn't
          enabled, means that the CPU will not do any swapping; the chips
          are expected to be wired to the CPU in 'host-endian' form.
          Specific arrangements are possible with the BIG_ENDIAN_BYTE and
          LITTLE_ENDIAN_BYTE, if the bytes are reversed.

config MTD_CFI_NOSWAP
        bool "NO"

config MTD_CFI_BE_BYTE_SWAP
        bool "BIG_ENDIAN_BYTE"

config MTD_CFI_LE_BYTE_SWAP
        bool "LITTLE_ENDIAN_BYTE"

endchoice\

Regards
Ashish