[flashrom] particular spi flash controller

[Andriy Gapon]

On 01/12/2017 19:36, David Hendricks wrote:
> 
> 
> On Fri, Dec 1, 2017 at 12:11 AM, Andriy Gapon <avg at freebsd.org
> <mailto:avg at freebsd.org>> wrote:
> 
> 
>     Hello.
> 
>     I wonder if anyone here encountered an SPI flash controller (master) that has a
>     three register interface where the first register is used for control and status
>     bits, the second register is used for setting a flash address (if one is needed)
>     and the third is used for reading or writing the flash data.  A specific
>     operation is requested by writing an SPI opcode into the control register.
>     The interface seems to be rather simple, but I couldn't find any driver that
>     implements access to anything like that or any documentation that would describe
>     a similar interface.
> 
>     Does it sound familiar to anyone?
>     Could anyone give me some hints / pointers?
> 
> 
> Is this an interface that you've actually used before? It sounds too simplistic
> since at the very least you'd also need to set the number of bytes to transfer,
> the direction, and have some control over chip select.


Likely, those things are set in the control register, but I don't know the exact
meaning of the bits.  Also, some status bits are checked in the same register to
make sure that the operation is completed.
I can make some guesses, but I'd rather find documentation if possible.

Meanwhile, I also looked at Linux drivers and this one seems to be somewhat
similar but still different:
http://elixir.free-electrons.com/linux/latest/source/drivers/spi/spi-falcon.c
See SFCMD / SFADDR / SFDATA.

-- 
Andriy Gapon