i2c: cadence: Handle transfer_size rollover

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Under certain conditions, Cadence's I2C controller's transfer_size
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@ni.com>
Reviewed-by: Shubhrajyoti Datta <shubhrajyoti.datta@xilinx.com>
Reviewed-by: Michal Simek <michal.simek@xilinx.com> # in a seperate mail
Signed-off-by: Wolfram Sang <wsa@the-dreams.de>

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Alex Williams 2019-01-31 13:39:57 -08:00 • committed by Wolfram Sang

parent f53938d2c7

commit bbf967b223

1 changed files with 13 additions and 5 deletions

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18

drivers/i2c/busses/i2c-cadence.c

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