[PATCH v2] wifi: mt7601u: check multiple firmware paths

[Christian Hewitt]

The linux-firmware repo moved mt7601u.bin from its root folder to
the mediatek sub-folder some time ago, but the driver still tries
to load firmware from the old location. Users might have firmware
in either location so update the driver to check both.

Signed-off-by: Christian Hewitt <christianshewitt at gmail.com>
---
The firmware was moved in [0]. Changes were requested to a previous
patch [1] to accomodate backwards compatibility but there was no
follow-up from the original author. So here's my novice attempt at
the requested improvement.

Current kernel with firmware in /usr/lib/firmware/mediatek/mt7601u.bin:

Nov 07 12:43:13.398922 LibreELEC kernel: mt7601u 1-1.3:1.0: ASIC revision: 76010001 MAC revision: 76010500
Nov 07 12:43:13.402276 LibreELEC kernel: mt7601u 1-1.3:1.0: Direct firmware load for mt7601u.bin failed with error -2
Nov 07 12:43:13.405524 LibreELEC kernel: mt7601u 1-1.3:1.0: probe with driver mt7601u failed with error -2

And with the patch:

Nov 07 12:43:13.274633 LibreELEC kernel: mt7601u 1-1.3:1.0: ASIC revision: 76010001 MAC revision: 76010500
Nov 07 12:43:13.311200 LibreELEC kernel: mt7601u 1-1.3:1.0: Firmware Version: 0.1.00 Build: 7640 Build time: 201302052146____
Nov 07 12:43:13.704693 LibreELEC kernel: mt7601u 1-1.3:1.0: EEPROM ver:0c fae:00

[0] https://git.kernel.org/pub/scm/linux/kernel/git/firmware/linux-firmware.git/commit/?id=8451c2b1d529dc1a49328ac9235d3cf5bb8a8fcb
[1] https://patchwork.kernel.org/project/linux-wireless/patch/fefcbf36f13873ae0d97438a0156b87e7e1ae64e.1684191377.git.daniel@makrotopia.org/

Changes since v1:
- Reword patch description and comment to make the problem clearer
- Fix checkpatch warning for static const array declaration

 drivers/net/wireless/mediatek/mt7601u/mcu.c | 15 ++++++++++++++-
 drivers/net/wireless/mediatek/mt7601u/usb.h |  1 +
 2 files changed, 15 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt7601u/mcu.c b/drivers/net/wireless/mediatek/mt7601u/mcu.c
index 1b5cc271a9e1..bad6ca821400 100644
--- a/drivers/net/wireless/mediatek/mt7601u/mcu.c
+++ b/drivers/net/wireless/mediatek/mt7601u/mcu.c
@@ -403,12 +403,18 @@ mt7601u_upload_firmware(struct mt7601u_dev *dev, const struct mt76_fw *fw)
 	return ret;
 }
 
+static const char * const mt7601u_fw_paths[] = {
+	"mediatek/" MT7601U_FIRMWARE,
+	MT7601U_FIRMWARE,
+};
+
 static int mt7601u_load_firmware(struct mt7601u_dev *dev)
 {
 	const struct firmware *fw;
 	const struct mt76_fw_header *hdr;
 	int len, ret;
 	u32 val;
+	int i;
 
 	mt7601u_wr(dev, MT_USB_DMA_CFG, (MT_USB_DMA_CFG_RX_BULK_EN |
 					 MT_USB_DMA_CFG_TX_BULK_EN));
@@ -416,7 +422,14 @@ static int mt7601u_load_firmware(struct mt7601u_dev *dev)
 	if (firmware_running(dev))
 		return firmware_request_cache(dev->dev, MT7601U_FIRMWARE);
 
-	ret = request_firmware(&fw, MT7601U_FIRMWARE, dev->dev);
+	/* Try loading firmware from multiple locations */
+	fw = NULL;
+	for (i = 0; i < MT7601U_FIRMWARE_PATHS; i++) {
+		ret = request_firmware(&fw, mt7601u_fw_paths[i], dev->dev);
+		if (ret == 0)
+			break;
+	}
+
 	if (ret)
 		return ret;
 
diff --git a/drivers/net/wireless/mediatek/mt7601u/usb.h b/drivers/net/wireless/mediatek/mt7601u/usb.h
index 9fdf35970339..723025f84483 100644
--- a/drivers/net/wireless/mediatek/mt7601u/usb.h
+++ b/drivers/net/wireless/mediatek/mt7601u/usb.h
@@ -9,6 +9,7 @@
 #include "mt7601u.h"
 
 #define MT7601U_FIRMWARE	"mt7601u.bin"
+#define MT7601U_FIRMWARE_PATHS	ARRAY_SIZE(mt7601u_fw_paths)
 
 #define MT_VEND_REQ_MAX_RETRY	10
 #define MT_VEND_REQ_TOUT_MS	300
-- 
2.34.1