linux-kernel - [PATCH] Bluetooth: btrtl: Avoid loading the config file on security chips

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Message-ID: <20251105063736.456618-1-max.chou@realtek.com>
Date: Wed, 5 Nov 2025 14:37:36 +0800
From: Max Chou <max.chou@...ltek.com>
To: Marcel Holtmann <marcel@...tmann.org>,
        Luiz Augusto von Dentz
	<luiz.dentz@...il.com>,
        <linux-bluetooth@...r.kernel.org>, <linux-kernel@...r.kernel.org>
CC: Hilda Wu <hildawu@...ltek.com>, alex_lu <alex_lu@...lsil.com.cn>,
        <niall_ni@...lsil.com.cn>, KidmanLee <kidman@...ltek.com>,
        Max Chou
	<max.chou@...ltek.com>
Subject: [PATCH] Bluetooth: btrtl: Avoid loading the config file on security chips

For chips with security enabled, it's only possible to load firmware
with a valid signature pattern.

- Example log for a security chip.

Bluetooth: hci0: RTL: examining hci_ver=0c hci_rev=000a
  lmp_ver=0c lmp_subver=8922
Bluetooth: hci0: RTL: rom_version status=0 version=1
Bluetooth: hci0: RTL: loading rtl_bt/rtl8922au_fw.bin
Bluetooth: hci0: RTL: cfg_sz 0, total sz 71301
Bluetooth: hci0: RTL: fw version 0x41c0c905

- Example log for a normal chip.

Bluetooth: hci0: RTL: examining hci_ver=0c hci_rev=000a
  lmp_ver=0c lmp_subver=8922
Bluetooth: hci0: RTL: rom_version status=0 version=1
Bluetooth: hci0: RTL: loading rtl_bt/rtl8922au_fw.bin
Bluetooth: hci0: RTL: loading rtl_bt/rtl8922au_config.bin
Bluetooth: hci0: RTL: cfg_sz 6, total sz 71307
Bluetooth: hci0: RTL: fw version 0x41c0c905

Tested-by: Hilda Wu <hildawu@...ltek.com>
Signed-off-by: Nial Ni <niall_ni@...lsil.com.cn>
Signed-off-by: Max Chou <max.chou@...ltek.com>
---
 drivers/bluetooth/btrtl.c | 24 +++++++++++++-----------
 1 file changed, 13 insertions(+), 11 deletions(-)

diff --git a/drivers/bluetooth/btrtl.c b/drivers/bluetooth/btrtl.c
index 8290932b8f7b..f6fccc6fdf22 100644
--- a/drivers/bluetooth/btrtl.c
+++ b/drivers/bluetooth/btrtl.c
@@ -50,7 +50,7 @@
 
 #define	RTL_CHIP_SUBVER (&(struct rtl_vendor_cmd) {{0x10, 0x38, 0x04, 0x28, 0x80}})
 #define	RTL_CHIP_REV    (&(struct rtl_vendor_cmd) {{0x10, 0x3A, 0x04, 0x28, 0x80}})
-#define	RTL_SEC_PROJ    (&(struct rtl_vendor_cmd) {{0x10, 0xA4, 0x0D, 0x00, 0xb0}})
+#define	RTL_SEC_PROJ    (&(struct rtl_vendor_cmd) {{0x10, 0xA4, 0xAD, 0x00, 0xb0}})
 
 #define RTL_PATCH_SNIPPETS		0x01
 #define RTL_PATCH_DUMMY_HEADER		0x02
@@ -544,7 +544,6 @@ static int rtlbt_parse_firmware_v2(struct hci_dev *hdev,
 {
 	struct rtl_epatch_header_v2 *hdr;
 	int rc;
-	u8 reg_val[2];
 	u8 key_id;
 	u32 num_sections;
 	struct rtl_section *section;
@@ -559,14 +558,7 @@ static int rtlbt_parse_firmware_v2(struct hci_dev *hdev,
 		.len  = btrtl_dev->fw_len - 7, /* Cut the tail */
 	};
 
-	rc = btrtl_vendor_read_reg16(hdev, RTL_SEC_PROJ, reg_val);
-	if (rc < 0)
-		return -EIO;
-	key_id = reg_val[0];
-
-	rtl_dev_dbg(hdev, "%s: key id %u", __func__, key_id);
-
-	btrtl_dev->key_id = key_id;
+	key_id = btrtl_dev->key_id;
 
 	hdr = rtl_iov_pull_data(&iov, sizeof(*hdr));
 	if (!hdr)
@@ -1081,6 +1073,8 @@ struct btrtl_device_info *btrtl_initialize(struct hci_dev *hdev,
 	u16 hci_rev, lmp_subver;
 	u8 hci_ver, lmp_ver, chip_type = 0;
 	int ret;
+	int rc;
+	u8 key_id;
 	u8 reg_val[2];
 
 	btrtl_dev = kzalloc(sizeof(*btrtl_dev), GFP_KERNEL);
@@ -1191,6 +1185,14 @@ struct btrtl_device_info *btrtl_initialize(struct hci_dev *hdev,
 		goto err_free;
 	}
 
+	rc = btrtl_vendor_read_reg16(hdev, RTL_SEC_PROJ, reg_val);
+	if (rc < 0)
+		goto err_free;
+
+	key_id = reg_val[0];
+	btrtl_dev->key_id = key_id;
+	rtl_dev_dbg(hdev, "%s: key id %u", __func__, key_id);
+
 	btrtl_dev->fw_len = -EIO;
 	if (lmp_subver == RTL_ROM_LMP_8852A && hci_rev == 0x000c) {
 		snprintf(fw_name, sizeof(fw_name), "%s_v2.bin",
@@ -1213,7 +1215,7 @@ struct btrtl_device_info *btrtl_initialize(struct hci_dev *hdev,
 		goto err_free;
 	}
 
-	if (btrtl_dev->ic_info->cfg_name) {
+	if (btrtl_dev->ic_info->cfg_name && !btrtl_dev->key_id) {
 		if (postfix) {
 			snprintf(cfg_name, sizeof(cfg_name), "%s-%s.bin",
 				 btrtl_dev->ic_info->cfg_name, postfix);
-- 
2.43.0