Re: [PATCH] eeprom: at25: convert to spi-mem API

[Sverdlin, Alexander]

Hi Christophe,

On Mon, 2025-11-03 at 17:33 +0100, Christophe Leroy wrote:
> > Replace the RAW SPI accesses with spi-mem API. The latter will fall back to
> > RAW SPI accesses if spi-mem callbacks are not implemented by a controller
> > driver.
> 
> With this patch (kernel v6.17.1) our powerpc boards are totally 
> unstable, we get multiple random Oops due to bad memory accesses.
> 
> With this commit reverted the board is stable again.
> 
> The SPI driver is:
> 
> CONFIG_SPI=y
> CONFIG_SPI_MASTER=y
> CONFIG_SPI_MEM=y
> CONFIG_SPI_FSL_LIB=y
> CONFIG_SPI_FSL_CPM=y
> CONFIG_SPI_FSL_SPI=y
> 
> How can we further investigate the issue ?

could you share these "random Oops"?

Looks like spi-fsl-spi doesn't support spi-mem interface (similar to spi-fsl-lpspi
we use the patch with), so spi-mem falls back to the regular SPI. From this standpoint
it's not that much different from the situation before patch.

But let's look into the splats.

-- 
Alexander Sverdlin
Siemens AG
www.siemens.com