[PATCH] wifi: mwifiex: fix freeze for 60 seconds caused by request_firmware

[Georgi Valkov <gvalkov@gmail.com>]

Fix regression in rgpower table loading, caused by using
request_firmware(): when the requested firmware does not exist, e.g.
nxp/rgpower_WW.bin does not exist on OpenWRT builds for WRT3200ACM,
request_firmware() falls back to firmware_fallback_sysfs(), which expects
the firmware to be provided by user space using SYSFS. No such utility is
provided in this configuration, so the entire system locks up for 60
seconds, until the request times out. During this time, no other log
messages are observed, and the device does not respond to commands over
UART.

The request_firmware() call is performed in the following context:
current->comm kworker/1:2  in_task 1  irqs_disabled 0  in_atomic 0

Fixed by using request_firmware_direct(). This prevents fallback to SYSFS,
and avoids delay. The rgpower table is optional. The driver falls back
to the device tree power table if the firmware is not present.

The error code is printed for debugging and returned to the caller,
which only cares for success or failure, so there are no side effects.

Fixes: 7b6f16a25806 ("wifi: mwifiex: add rgpower table loading support")
Signed-off-by: Georgi Valkov <gvalkov@gmail.com>
---
 drivers/net/wireless/marvell/mwifiex/sta_ioctl.c | 14 ++++++++------
 1 file changed, 8 insertions(+), 6 deletions(-)

diff --git a/drivers/net/wireless/marvell/mwifiex/sta_ioctl.c b/drivers/net/wireless/marvell/mwifiex/sta_ioctl.c
index a6550548d3b4..9460d5352b23 100644
--- a/drivers/net/wireless/marvell/mwifiex/sta_ioctl.c
+++ b/drivers/net/wireless/marvell/mwifiex/sta_ioctl.c
@@ -196,6 +196,7 @@ static int mwifiex_request_rgpower_table(struct mwifiex_private *priv)
 	struct mwifiex_adapter *adapter = priv->adapter;
 	char rgpower_table_name[30];
 	char country_code[3];
+	int ret;
 
 	strscpy(country_code, domain_info->country_code, sizeof(country_code));
 
@@ -214,16 +215,17 @@ static int mwifiex_request_rgpower_table(struct mwifiex_private *priv)
 		adapter->rgpower_data = NULL;
 	}
 
-	if ((request_firmware(&adapter->rgpower_data, rgpower_table_name,
-			      adapter->dev))) {
+	ret = request_firmware_direct(&adapter->rgpower_data, rgpower_table_name,
+				      adapter->dev);
+
+	if (ret) {
 		mwifiex_dbg(
 			adapter, INFO,
-			"info: %s: failed to request regulatory power table\n",
-			__func__);
-		return -EIO;
+			"info: %s: failed to request regulatory power table: %d\n",
+			__func__, ret);
 	}
 
-	return 0;
+	return ret;
 }
 
 static int mwifiex_dnld_rgpower_table(struct mwifiex_private *priv)
-- 
2.55.0