[PATH RESEND v2 00/10] tty: xuartps: Fix lock ups

From: Soren Brinkmann
Date: Thu Nov 19 2015 - 15:15:58 EST


Hi,

I guess this series got probably lost during the merge window. Hence, I
resend the patches.

This is v2, hopefully without any build issues. The changes are the same
as before, just the warning reported by kbuild test robot about unused
variables have been fixed. And, I added one more patch with some
cleanup/refactoring.

I recently found my system locking up under some conditions. I dug
through the code a bit and the result is this collections of various
changes. Some of it may not be required and has just been created out of
half-baked theories and re-reading the documentation. The actual failing
scenarios seem to be:
- RX IRQ conditions are handled while the receiver is disabled, leaving
the driver in an infinite loop
- console_put_char seems to be interrupted by uart_shutdown disabling
the transmitter while/just before printing

I.e. overall I tried to serialize all operations using the port lock to
avoid such interaction.

Thanks,
SÃren

SÃren Brinkmann (10):
tty: xuartps: Beautify read-modify writes
tty: xuartps: Use spinlock to serialize HW access
tty: xuartps: Always enable transmitter in start_tx
tty: xuartps: Clear interrupt status register in shutdown
tty: xuartps: Improve startup function
tty: xuartps: Keep lock for whole ISR
tty: xuartps: Acquire port lock for shutdown
tty: xuartps: Move RX path into helper function
tty: xuartps: Only handle RX IRQs when RX is enabled
tty: xuartps: Cleanup: Reformat if-else

drivers/tty/serial/xilinx_uartps.c | 247 ++++++++++++++++++++-----------------
1 file changed, 136 insertions(+), 111 deletions(-)

--
2.6.3.3.g9bb996a

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