Add recovery logic when we suspect that the system is re-ordering
MMIOs. Re-ordered MMIOs to the send mailbox can cause bogus tx
completions and hit BUG_ON() in the tx completion path.
tg3 already has logic to handle re-ordered MMIOs by flushing the MMIOs
that must be strictly ordered (such as the send mailbox). Determining
when to enable the flush is currently a manual process of adding known
chipsets to a list.
The new code replaces the BUG_ON() in the tx completion path with the
call to tg3_tx_recover(). It will set the TG3_FLAG_MBOX_WRITE_REORDER
flag and reset the chip later in the workqueue to recover and start
flushing MMIOs to the mailbox.
A message to report the problem will be printed. We will then decide
whether or not to add the host bridge to the list of chipsets that do
re-ordering.
We may add some additional code later to print the host bridge's ID so
that the user can report it more easily.
The assumption that re-ordering can only happen on x86 systems is also
removed.
Signed-off-by: Michael Chan <mchan@broadcom.com>
Signed-off-by: David S. Miller <davem@davemloft.net>
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