Hi , Apologies for teh late reply, Somehow replied only to Alex. On Fri, Feb 15, 2019 at 8:59 PM Alex Williams <alex.williams@xxxxxxxxx> wrote: > > On Fri, Feb 15, 2019 at 2:53 AM Shubhrajyoti Datta > <shubhrajyoti.datta@xxxxxxxxx> wrote: > > > > HI Alex, > > > > Thanks for the patch. > > > > On Fri, Feb 1, 2019 at 4:22 AM <alex.williams@xxxxxxxxx> wrote: > > > > > > From: Alex Williams <alex.williams@xxxxxx> > > > > > > Under certain conditions, Cadence's I2C controller's transfer_size > > > > Any help in reproducing the conditions would be appreciated > > > > > > > register will roll over and generate invalid read transactions. Before > > > this change, the ISR relied solely on the RXDV bit to determine when to > > > write more data to the user's buffer. The invalid read data would cause > > > overruns, smashing stacks and worse. > > > > > > This change stops the buffer writes to the requested boundary and > > > reports the error. The controller will be reset so normal transactions > > > may resume. > > > > > > Signed-off-by: Alex Williams <alex.williams@xxxxxx> > > > One possible related errata is here: > https://www.xilinx.com/support/answers/61664.html > > In our case, we only needed to hammer on i2c to reproduce in a few > minutes, with a script like this: > while true > do date > cat /sys/class/gpio/gpio882/direction > /dev/null > cat /sys/class/gpio/gpio883/direction > /dev/null > cat /sys/class/gpio/gpio884/direction > /dev/null > cat /sys/class/gpio/gpio885/direction > /dev/null > cat /sys/class/gpio/gpio886/direction > /dev/null > cat /sys/class/gpio/gpio887/direction > /dev/null > cat /sys/class/gpio/gpio888/direction > /dev/null > cat /sys/class/gpio/gpio889/direction > /dev/null > cat /sys/class/gpio/gpio890/direction > /dev/null > cat /sys/class/gpio/gpio891/direction > /dev/null > cat /sys/class/gpio/gpio892/direction > /dev/null > > cat /sys/class/gpio/gpio894/direction > /dev/null > cat /sys/class/gpio/gpio895/direction > /dev/null > cat /sys/class/gpio/gpio896/direction > /dev/null > cat /sys/class/gpio/gpio897/direction > /dev/null > cat /sys/class/gpio/gpio898/direction > /dev/null > cat /sys/class/gpio/gpio899/direction > /dev/null > cat /sys/class/gpio/gpio900/direction > /dev/null > cat /sys/class/gpio/gpio901/direction > /dev/null > cat /sys/class/gpio/gpio902/direction > /dev/null > cat /sys/class/gpio/gpio903/direction > /dev/null > cat /sys/class/gpio/gpio904/direction > /dev/null > cat /sys/class/gpio/gpio905/direction > /dev/null > done > > In normal usage, we have code that sets up a number of i2c GPIO > expanders and pokes them for values as it initializes devices. > Occasionally, the transfer size register will roll over, and the ISR > will cause memory corruption, since it doesn't stop writing at the > requested boundary. Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@xxxxxxxxxx>
