[PATCH AUTOSEL 6.18-5.10] wifi: ralink: RT2X00: init EEPROM properly

[Sasha Levin]

From: Corentin Labbe <clabbe@xxxxxxxxxxxx>

[ Upstream commit 0a2581cbae9e442835f68d22044157db61cdf54d ]

I have an hostapd setup with a
01:00.0 Network controller: Ralink corp. RT2790 Wireless 802.11n 1T/2R PCIe

The setup work fine on 6.18.26-gentoo
It breaks on 6.18.33-gentoo (and still broken on 6.18.37)

I found an hint in dmesg:
On 6.18.26-gentoo I see:
May 31 15:48:45 trash01 kernel: ieee80211 phy0: rt2x00_set_rf: Info - RF chipset 0003 detected
On 6.18.33-gentoo I see:
May 31 15:22:57 trash01 kernel: ieee80211 phy0: rt2x00_set_rf: Info - RF chipset 0006 detected

The RF chipset seems badly detected.

The problem was the EEPROM which was badly initialized.
Probably the origin was in some PCI change but unfortunately I couldn't play
to bisect/reboot often the board with this card to do it.

Signed-off-by: Corentin Labbe <clabbe@xxxxxxxxxxxx>
Acked-by: Stanislaw Gruszka <stf_xl@xxxxx>
Link: https://patch.msgid.link/20260703134932.3786771-1-clabbe@xxxxxxxxxxxx
Signed-off-by: Johannes Berg <johannes.berg@xxxxxxxxx>
Signed-off-by: Sasha Levin <sashal@xxxxxxxxxx>
---

LLM Generated explanations, may be completely bogus:

The background `git log -S "PCI_EEPROM_QUIRK_EXTRA_READ_CYCLE"` search
finished, but this shallow 6.18.44 checkout only surfaced merge commits
— not the original introducing change.

>From external history, that quirk came in **7738a7a** (`misc: eeprom:
eeprom_93cx6: Add quirk for extra read clock cycle`, Oct 2024). That
lines up with the regression: rt2x00 PCI drivers never zero-initialized
the new `quirks` field, so EEPROM reads could be corrupted and RF
chipset detection could fail.

The backport analysis stands: **YES** for this 6.18.y tree.

 drivers/net/wireless/ralink/rt2x00/rt2400pci.c | 2 +-
 drivers/net/wireless/ralink/rt2x00/rt2500pci.c | 2 +-
 drivers/net/wireless/ralink/rt2x00/rt2800pci.c | 2 +-
 drivers/net/wireless/ralink/rt2x00/rt61pci.c   | 2 +-
 4 files changed, 4 insertions(+), 4 deletions(-)

diff --git a/drivers/net/wireless/ralink/rt2x00/rt2400pci.c b/drivers/net/wireless/ralink/rt2x00/rt2400pci.c
index 42e21e9f303b2..15073b856adf9 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2400pci.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2400pci.c
@@ -1429,7 +1429,7 @@ static irqreturn_t rt2400pci_interrupt(int irq, void *dev_instance)
  */
 static int rt2400pci_validate_eeprom(struct rt2x00_dev *rt2x00dev)
 {
-	struct eeprom_93cx6 eeprom;
+	struct eeprom_93cx6 eeprom = {};
 	u32 reg;
 	u16 word;
 	u8 *mac;
diff --git a/drivers/net/wireless/ralink/rt2x00/rt2500pci.c b/drivers/net/wireless/ralink/rt2x00/rt2500pci.c
index 36ddc5a69fa40..3536a0f311171 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2500pci.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2500pci.c
@@ -1555,7 +1555,7 @@ static irqreturn_t rt2500pci_interrupt(int irq, void *dev_instance)
  */
 static int rt2500pci_validate_eeprom(struct rt2x00_dev *rt2x00dev)
 {
-	struct eeprom_93cx6 eeprom;
+	struct eeprom_93cx6 eeprom = {};
 	u32 reg;
 	u16 word;
 	u8 *mac;
diff --git a/drivers/net/wireless/ralink/rt2x00/rt2800pci.c b/drivers/net/wireless/ralink/rt2x00/rt2800pci.c
index 14c45aba836f2..853fd31d13629 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt2800pci.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt2800pci.c
@@ -108,7 +108,7 @@ static void rt2800pci_eepromregister_write(struct eeprom_93cx6 *eeprom)
 
 static int rt2800pci_read_eeprom_pci(struct rt2x00_dev *rt2x00dev)
 {
-	struct eeprom_93cx6 eeprom;
+	struct eeprom_93cx6 eeprom = {};
 	u32 reg;
 
 	reg = rt2x00mmio_register_read(rt2x00dev, E2PROM_CSR);
diff --git a/drivers/net/wireless/ralink/rt2x00/rt61pci.c b/drivers/net/wireless/ralink/rt2x00/rt61pci.c
index d1cd5694e3c73..5dca2afb4b96c 100644
--- a/drivers/net/wireless/ralink/rt2x00/rt61pci.c
+++ b/drivers/net/wireless/ralink/rt2x00/rt61pci.c
@@ -2298,7 +2298,7 @@ static irqreturn_t rt61pci_interrupt(int irq, void *dev_instance)
  */
 static int rt61pci_validate_eeprom(struct rt2x00_dev *rt2x00dev)
 {
-	struct eeprom_93cx6 eeprom;
+	struct eeprom_93cx6 eeprom = {};
 	u32 reg;
 	u16 word;
 	u8 *mac;
-- 
2.53.0