Re: [PATCH v2] mtd: rawnand: denali: add more delays before latching incoming data

[Ralph Siemsen]

On Tue, Mar 17, 2020 at 04:18:21PM +0900, Masahiro Yamada wrote:
> Marek Vasut reported this driver in the latest kernel does not work
> on his SOCFPGA board. (The on-board NAND chip is mode 5)

In a bit of an ironic twist, this change seems to cause a regression for 
me. I'm also using a Cyclone V SoC system, similar but not the same as 
the SOCFPGA eval board. The NAND device in my case is S34ML04G2.

It worked fine in 4.9, 4.19 and 5.4 kernels. However after upgrading to 
5.10 the NAND driver fails with "timeout while waiting for irq 0x4", 
just as was reported back in 2018:
https://lore.kernel.org/linux-mtd/737ejrj81y.fsf@xxxxxxxxxxxxxx/

Reverting commit 5756f2e8dad46eba6e2d3e530243b8eff4dd5a42 restores the 
behaviour in my case, but that would presumably break the SOCFPGA board.

Any thoughts on how we could make it work for everybody?

Ralph