-----Original Message-----
From: Michal Simek <redacted>
Sent: Tuesday, August 24, 2021 12:29 PM
To: Marek Vasut <marex@denx.de>; linux-i2c@vger.kernel.org; Raviteja
Narayanam [off-list ref]
Cc: Michal Simek <redacted>; Shubhrajyoti Datta
[off-list ref]; Wolfram Sang [off-list ref]
Subject: Re: [PATCH v2 0/6] i2c: xiic: Fix broken locking

+ravi

On 8/23/21 11:41 PM, Marek Vasut wrote:

quoted

Booting ZynqMP with XIIC I2C driver shows multitude of race conditions
in the XIIC driver. This is because locking is completely missing from
the driver, and there are odd corner cases where the hardware behaves
strangely.

Most of these races could be triggered easily when booting on SMP
machines, like the ZynqMP which has up to 4 cores. It is sufficient
for the interrupt handler to run on another core than xiic_start_xfer
and the driver fails completely.

This does not add support for long transfers, this only fixes the
driver to be usable at all instead of being completely broken.

The V2 fixes a few remaining details which cropped up in deployment
over the last year or so, so I believe the result should be reasonably
well tested.

Thanks a lot for the patches, Marek. 
I have tested these on our boards and they are working fine. 

I will rebase my patch series on top of this and send after rc1. 

quoted

Marek Vasut (6):
  i2c: xiic: Fix broken locking on tx_msg
  i2c: xiic: Drop broken interrupt handler
  i2c: xiic: Defer xiic_wakeup() and __xiic_start_xfer() in
    xiic_process()
  i2c: xiic: Switch from waitqueue to completion
  i2c: xiic: Only ever transfer single message
  i2c: xiic: Fix RX IRQ busy check

 drivers/i2c/busses/i2c-xiic.c | 161
+++++++++++++++-------------------
 1 file changed, 69 insertions(+), 92 deletions(-)

Cc: Michal Simek <redacted>
Cc: Shubhrajyoti Datta <redacted>
Cc: Wolfram Sang <wsa@kernel.org>