On Sun, May 21, 2023 at 02:19:40PM +0200, Marek Behún wrote: > There seems to be a bug within the mv64xxx I2C controller, wherein the > status register may not necessarily contain valid value immediately > after the IFLG flag is set in the control register. > > My theory is that the controller: > - first sets the IFLG in control register > - then updates the status register > - then raises an interrupt > > This may sometime cause weird bugs when in atomic mode, since in this > mode we do not wait for an interrupt, but instead we poll the control > register for IFLG and read status register immediately after. > > I encountered -ENXIO from mv64xxx_i2c_fsm() due to this issue when using > this driver in atomic mode. > > Note that I've only seen this issue on Armada 385, I don't know whether > other SOCs with this controller are also affected. Also note that this > fix has been in U-Boot for over 4 years [1] without anybody complaining, > so it should not cause regressions. > > [1] https://source.denx.de/u-boot/u-boot/-/commit/d50e29662f78 > > Fixes: 544a8d75f3d6 ("i2c: mv64xxx: Add atomic_xfer method to driver") > Signed-off-by: Marek Behún <kabel@xxxxxxxxxx> Applied to for-current, thanks!
Attachment:
signature.asc
Description: PGP signature
