[PATCH 06/18] wifi: mt76: mt7925: add MT7927 power management, DBDC, and CNM fixes

[Javier Tia]

Three MT7927-specific fixes for WiFi functionality:

1. Disable runtime PM: Every CLR_OWN triggers the ROM to reinitialize
   WFDMA, destroying DMA ring configuration. Disable PM until the wake
   path properly handles MT7927.

2. Enable DBDC (dual-band): MT7927 firmware defaults to single-band
   (2.4GHz only). MT7925 firmware handles DBDC automatically, but
   MT7927 requires an explicit MCU_UNI_CMD(SET_DBDC_PARMS) with
   mbmc_en=1. Without this, 5GHz scan requests are silently discarded.

3. Force CNM capability: MT7927 firmware lacks the connac2 feature
   trailer, causing mt792x_get_mac80211_ops() to replace channel
   context operations with emulated stubs. This prevents ROC (remain
   on channel) before authentication, causing auth frames to be
   silently dropped. Force the CNM flag and restore mt7925_ops.

Tested-by: Marcin FM <marcin at lgic.pl>
Tested-by: Cristian-Florin Radoi <radoi.chris at gmail.com>
Tested-by: George Salukvadze <giosal90 at gmail.com>
Tested-by: Evgeny Kapusta <3193631 at gmail.com>
Tested-by: Samu Toljamo <samu.toljamo at gmail.com>
Tested-by: Ariel Rosenfeld <ariel.rosenfeld.750 at gmail.com>
Tested-by: Chapuis Dario <chapuisdario4 at gmail.com>
Tested-by: Thibaut François <tibo at humeurlibre.fr>
Tested-by: 张旭涵 <Loong.0x00 at gmail.com>
Signed-off-by: Javier Tia <floss at jetm.me>
---
 drivers/net/wireless/mediatek/mt76/mt7925/init.c | 17 ++++++++++++++++-
 drivers/net/wireless/mediatek/mt76/mt7925/pci.c  | 10 ++++++++++
 2 files changed, 26 insertions(+), 1 deletion(-)

diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/init.c b/drivers/net/wireless/mediatek/mt76/mt7925/init.c
index 3ce5d6fcc69d..1e9eadca3988 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/init.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/init.c
@@ -115,6 +115,18 @@ static int __mt7925_init_hardware(struct mt792x_dev *dev)
 	if (ret)
 		goto out;
 
+	/* MT7927: Enable DBDC (dual-band) mode. Without this, firmware
+	 * defaults to 2.4GHz only and ignores 5GHz scan requests.
+	 * MT7925 firmware handles DBDC automatically. */
+	if (is_mt7927(&dev->mt76)) {
+		ret = mt7925_mcu_set_dbdc(&dev->mphy, true);
+		if (ret) {
+			dev_warn(dev->mt76.dev,
+				 "MT7927 DBDC enable failed: %d\n", ret);
+			ret = 0;
+		}
+	}
+
 out:
 	return ret;
 }
@@ -230,7 +242,10 @@ int mt7925_register_device(struct mt792x_dev *dev)
 	dev->pm.idle_timeout = MT792x_PM_TIMEOUT;
 	dev->pm.stats.last_wake_event = jiffies;
 	dev->pm.stats.last_doze_event = jiffies;
-	if (!mt76_is_usb(&dev->mt76)) {
+	/* MT7927: disable power management. Every CLR_OWN triggers the
+	 * ROM to reinitialize WFDMA, destroying DMA ring configuration.
+	 * Keep the device awake until the PM wake path handles MT7927. */
+	if (!mt76_is_usb(&dev->mt76) && !is_mt7927(&dev->mt76)) {
 		dev->pm.enable_user = true;
 		dev->pm.enable = true;
 		dev->pm.ds_enable_user = true;
diff --git a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
index ca9ccfe9975c..dce9f30b68d7 100644
--- a/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
+++ b/drivers/net/wireless/mediatek/mt76/mt7925/pci.c
@@ -527,6 +527,16 @@ static int mt7925_pci_probe(struct pci_dev *pdev,
 		goto err_free_pci_vec;
 	}
 
+	/* MT7927 firmware lacks the connac2 feature trailer, so
+	 * mt792x_get_mac80211_ops() can't detect CNM support and
+	 * replaces chanctx/ROC/mgd_prepare_tx ops with stubs.
+	 * Force CNM and restore the original mt7925 ops. */
+	if ((pdev->device == 0x6639 || pdev->device == 0x7927) &&
+	    !(features & MT792x_FW_CAP_CNM)) {
+		features |= MT792x_FW_CAP_CNM;
+		memcpy(ops, &mt7925_ops, sizeof(*ops));
+	}
+
 	mdev = mt76_alloc_device(&pdev->dev, sizeof(*dev), ops, &drv_ops);
 	if (!mdev) {
 		ret = -ENOMEM;

-- 
2.53.0