wifi: mt76: mt7915: add module param to select 5 GHz or 6 GHz on MT7916

Due to a limitation in available memory, the MT7916 firmware can only
handle either 5 GHz or 6 GHz at a time. It does not support runtime
switching without a full restart.

On older firmware, this accidentally worked to some degree due to missing
checks, but couldn't be supported properly, because it left the 6 GHz
channels uncalibrated.
Newer firmware refuses to start on either band if the passed EEPROM
data indicates support for both.

Deal with this limitation by using a module parameter to specify the
preferred band in case both are supported.

Fixes: b4d093e321bd ("mt76: mt7915: add 6 GHz support")
Cc: stable@vger.kernel.org
Signed-off-by: Shayne Chen <shayne.chen@mediatek.com>
Link: https://patch.msgid.link/20241010083816.51880-1-nbd@nbd.name
Signed-off-by: Felix Fietkau <nbd@nbd.name>

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/eeprom.c b/drivers/net/wireless/mediatek/mt76/mt7915/eeprom.c
index bfdbc15abaa9a733a9800b7402f0a27b4d4015d5..928e0b07a9bf18b22dd2b107d391d28930865c30 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7915/eeprom.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/eeprom.c
@@ -2,9 +2,14 @@
 /* Copyright (C) 2020 MediaTek Inc. */
 
 #include <linux/firmware.h>
+#include <linux/moduleparam.h>
 #include "mt7915.h"
 #include "eeprom.h"
 
+static bool enable_6ghz;
+module_param(enable_6ghz, bool, 0644);
+MODULE_PARM_DESC(enable_6ghz, "Enable 6 GHz instead of 5 GHz on hardware that supports both");
+
 static int mt7915_eeprom_load_precal(struct mt7915_dev *dev)
 {
        struct mt76_dev *mdev = &dev->mt76;
@@ -170,8 +175,20 @@ static void mt7915_eeprom_parse_band_config(struct mt7915_phy *phy)
                        phy->mt76->cap.has_6ghz = true;
                        return;
                case MT_EE_V2_BAND_SEL_5GHZ_6GHZ:
-                       phy->mt76->cap.has_5ghz = true;
-                       phy->mt76->cap.has_6ghz = true;
+                       if (enable_6ghz) {
+                               phy->mt76->cap.has_6ghz = true;
+                               u8p_replace_bits(&eeprom[MT_EE_WIFI_CONF + band],
+                                                MT_EE_V2_BAND_SEL_6GHZ,
+                                                MT_EE_WIFI_CONF0_BAND_SEL);
+                       } else {
+                               phy->mt76->cap.has_5ghz = true;
+                               u8p_replace_bits(&eeprom[MT_EE_WIFI_CONF + band],
+                                                MT_EE_V2_BAND_SEL_5GHZ,
+                                                MT_EE_WIFI_CONF0_BAND_SEL);
+                       }
+                       /* force to buffer mode */
+                       dev->flash_mode = true;
+
                        return;
                default:
                        phy->mt76->cap.has_2ghz = true;

diff --git a/drivers/net/wireless/mediatek/mt76/mt7915/init.c b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
index 6bef96e3d2a3d9543fcb716aacaefe81ac2b91b9..f82216d1bda087e35b565bd570cfd805df03c0b5 100644 (file)
--- a/drivers/net/wireless/mediatek/mt76/mt7915/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7915/init.c
@@ -1239,14 +1239,14 @@ int mt7915_register_device(struct mt7915_dev *dev)
        if (ret)
                goto unreg_dev;
 
-       ieee80211_queue_work(mt76_hw(dev), &dev->init_work);
-
        if (phy2) {
                ret = mt7915_register_ext_phy(dev, phy2);
                if (ret)
                        goto unreg_thermal;
        }
 
+       ieee80211_queue_work(mt76_hw(dev), &dev->init_work);
+
        dev->recovery.hw_init_done = true;
 
        ret = mt7915_init_debugfs(&dev->phy);