From 526180408b815aa7b96fd48bd23cdd33ef04e38e Mon Sep 17 00:00:00 2001
From: Kelvin Cao <kelvin.cao@microchip.com>
Date: Mon, 10 Dec 2018 17:12:20 +0800
Subject: [PATCH] switchtec: Remove immediate status check after submitting MRPC command
Git-commit: 526180408b815aa7b96fd48bd23cdd33ef04e38e
Patch-mainline: v5.0-rc1
References: bsc#1051510
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>
Acked-by: Takashi Iwai <tiwai@suse.de>
---
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 54a8b30dda38..d2bca2dd9889 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));
}
--
2.16.4