From: Kelvin Cao kelvin.cao@microchip.com
[ Upstream commit 526180408b815aa7b96fd48bd23cdd33ef04e38e ]
After submitting a Firmware Download MRPC command, Switchtec firmware will delay Management EP BAR MemRd TLP responses by more than 10ms. This is a firmware limitation. Delayed MemRd completions are a problem for systems with a low Completion Timeout (CTO).
The current driver checks the MRPC status immediately after submitting an MRPC command, which results in a delayed MemRd completion that may cause a Completion Timeout.
Remove the immediate status check and rely on the check after receiving an interrupt or timing out.
This is only a software workaround to the READ issue and a proper fix of this should be done in firmware.
Fixes: 080b47def5e5 ("MicroSemi Switchtec management interface driver") Signed-off-by: Kelvin Cao kelvin.cao@microchip.com Signed-off-by: Wesley Sheng wesley.sheng@microchip.com Signed-off-by: Bjorn Helgaas bhelgaas@google.com Reviewed-by: Logan Gunthorpe logang@deltatee.com Signed-off-by: Sasha Levin sashal@kernel.org --- drivers/pci/switch/switchtec.c | 4 ---- 1 file changed, 4 deletions(-)
diff --git a/drivers/pci/switch/switchtec.c b/drivers/pci/switch/switchtec.c index 5aaa4ce04ec3..ceb7ab3ba3d0 100644 --- a/drivers/pci/switch/switchtec.c +++ b/drivers/pci/switch/switchtec.c @@ -134,10 +134,6 @@ static void mrpc_cmd_submit(struct switchtec_dev *stdev) stuser->data, stuser->data_len); iowrite32(stuser->cmd, &stdev->mmio_mrpc->cmd);
- stuser->status = ioread32(&stdev->mmio_mrpc->status); - if (stuser->status != SWITCHTEC_MRPC_STATUS_INPROGRESS) - mrpc_complete_cmd(stdev); - schedule_delayed_work(&stdev->mrpc_timeout, msecs_to_jiffies(500)); }