[U-Boot] Issue about support spi-nand in u-boot

[Peter Pan 潘栋 (peterpandong)]

Hi Jagan

I looked through your code[1] about support Linux spi-nor framework in u-boot.
It is really great.

I'm working on spi-nand in u-boot now. And I met some issues. Maybe we
can have a discussion.
  1. Currently spi_flash struct is tied with spi nor, as spi nand is also
     a kind of spi flash. I think we should make spi_flash struct shareable.
  2. In Linux, we can use parameter .tx_nbits and .rx_nbits in spi_transfer
     struct to tell controller driver to use 1bit, 2bits or 4bits to transfer
     data. But I didn't find a way to do it in u-boot. Maybe we can add some
     transfer flags to do this.
  3. Should we use spi nand via "sf" command set or create another command set?

Any suggestion is appreciated.

Another question, do you have any schedule about when to merge spi-nor framework?

[1] http://git.denx.de/?p=u-boot/u-boot-spi.git;a=shortlog;h=refs/heads/spi-nor

Thanks
Peter Pan