Hi Robin,

On Wed, Apr 7, 2021 at 4:15 AM Robin Gong [off-list ref] wrote:

There is ecspi ERR009165 on i.mx6/7 soc family, which cause FIFO
transfer to be send twice in DMA mode. Please get more information from:
https://www.nxp.com/docs/en/errata/IMX6DQCE.pdf. The workaround is adding
new sdma ram script which works in XCH  mode as PIO inside sdma instead
of SMC mode, meanwhile, 'TX_THRESHOLD' should be 0. The issue should be
exist on all legacy i.mx6/7 soc family before i.mx6ul.
NXP fix this design issue from i.mx6ul, so newer chips including i.mx6ul/
6ull/6sll do not need this workaroud anymore. All other i.mx6/7/8 chips
still need this workaroud. This patch set add new 'fsl,imx6ul-ecspi'
for ecspi driver and 'ecspi_fixed' in sdma driver to choose if need errata
or not.
The first two reverted patches should be the same issue, though, it
seems 'fixed' by changing to other shp script. Hope Sean or Sascha could
have the chance to test this patch set if could fix their issues.
Besides, enable sdma support for i.mx8mm/8mq and fix ecspi1 not work
on i.mx8mm because the event id is zero.

PS:
   Please get sdma firmware from below linux-firmware and copy it to your
local rootfs /lib/firmware/imx/sdma.
https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/tree/imx/sdma

Without this series, SPI DMA does not work on i.MX8MM:

 [   41.315984] spi_master spi1: I/O Error in DMA RX

I applied your series and SPI DMA works now:

Reviewed-by: Fabio Estevam <festevam@gmail.com>

Thanks