-----Original Message-----
From: Loic Poulain <loic.poulain@oss.qualcomm.com> 
Sent: Monday, June 29, 2026 10:55 AM
To: Ulf Hansson <ulfh@kernel.org>; Rob Herring <robh@kernel.org>; Krzysztof Kozlowski <krzk+dt@kernel.org>; Conor Dooley <conor+dt@kernel.org>; Bjorn Andersson <andersson@kernel.org>; Konrad Dybcio <konradybcio@kernel.org>; Jens Axboe <axboe@kernel.dk>; Johannes Berg <johannes@sipsolutions.net>; Jeff Johnson <jjohnson@kernel.org>; Bartosz Golaszewski <brgl@kernel.org>; Marcel Holtmann <marcel@holtmann.org>; Luiz Augusto von Dentz <luiz.dentz@gmail.com>; Balakrishna Godavarthi <redacted>; Rocky Liao <redacted>; David S. Miller <davem@davemloft.net>; Eric Dumazet <edumazet@google.com>; Jakub Kicinski <kuba@kernel.org>; Paolo Abeni <pabeni@redhat.com>; Simon Horman <horms@kernel.org>; Srinivas Kandagatla <srini@kernel.org>; Andrew Lunn <andrew@lunn.ch>; Heiner Kallweit <hkallweit1@gmail.com>; Russell King <linux@armlinux.org.uk>; Saravana Kannan <saravanak@kernel.org>; Christian Marangi <ansuelsmth@gmail.com>
Cc: linux-mmc@vger.kernel.org; devicetree@vger.kernel.org; linux-kernel@vger.kernel.org; linux-arm-msm@vger.kernel.org; linux-block@vger.kernel.org; linux-wireless@vger.kernel.org; ath10k@lists.infradead.org; linux-bluetooth@vger.kernel.org; netdev@vger.kernel.org; daniel@makrotopia.org; Loic Poulain <loic.poulain@oss.qualcomm.com>; Bartosz Golaszewski <redacted>
Subject: [PATCH v6 7/9] Bluetooth: hci_sync: Add NVMEM-backed BD address retrieval

Some devices store the Bluetooth BD address in non-volatile memory, which can be accessed through the NVMEM framework.
Similar to Ethernet or WiFi MAC addresses, add support for reading the BD address from a 'local-bd-address' NVMEM cell.

As with the device-tree provided BD address, add a quirk to indicate whether a device or platform should attempt to read the address from NVMEM when no valid in-chip address is present.
Also add a quirk to indicate if the address is stored in big-endian byte order.

Reviewed-by: Bartosz Golaszewski <redacted>
Signed-off-by: Loic Poulain <loic.poulain@oss.qualcomm.com>
---
include/net/bluetooth/hci.h | 18 ++++++++++++++++++
net/bluetooth/hci_sync.c    | 39 ++++++++++++++++++++++++++++++++++++++-
2 files changed, 56 insertions(+), 1 deletion(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h index 572b1c620c5d653a1fe10b26c1b0ba33e8f4968f..7686466d1109253b0d75edeb5f6a99fb98ce4cc6 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h

@@ -164,6 +164,24 @@ enum {

	 */
	HCI_QUIRK_BDADDR_PROPERTY_BROKEN,

+	/* When this quirk is set, the public Bluetooth address
+	 * initially reported by HCI Read BD Address command
+	 * is considered invalid. The public BD Address can be
+	 * retrieved via a 'local-bd-address' NVMEM cell.
+	 *
+	 * This quirk can be set before hci_register_dev is called or
+	 * during the hdev->setup vendor callback.
+	 */
+	HCI_QUIRK_USE_BDADDR_NVMEM,
+
+	/* When this quirk is set, the Bluetooth Device Address provided by
+	 * the 'local-bd-address' NVMEM is stored in big-endian order.
+	 *
+	 * This quirk can be set before hci_register_dev is called or
+	 * during the hdev->setup vendor callback.
+	 */
+	HCI_QUIRK_BDADDR_NVMEM_BE,
+
	/* When this quirk is set, the duplicate filtering during
	 * scanning is based on Bluetooth devices addresses. To allow
	 * RSSI based updates, restart scanning if needed.

diff --git a/net/bluetooth/hci_sync.c b/net/bluetooth/hci_sync.c index fd3aacdea512a37c22b9a2be90c89ddca4b4d99f..589ccdfa26c1281d6eb979370523fff0d7920302 100644
--- a/net/bluetooth/hci_sync.c
+++ b/net/bluetooth/hci_sync.c

@@ -7,6 +7,7 @@
 */

#include <linux/property.h>
+#include <linux/of_net.h>

#include <net/bluetooth/bluetooth.h>
#include <net/bluetooth/hci_core.h>

@@ -3588,6 +3589,37 @@ int hci_powered_update_sync(struct hci_dev *hdev)

	return 0;
}

+/**
+ * hci_dev_get_bd_addr_from_nvmem - Get the Bluetooth Device Address
+ *				    (BD_ADDR) for a HCI device from
+ *				    an NVMEM cell.
+ * @hdev:	The HCI device
+ *
+ * Search for 'local-bd-address' NVMEM cell in the device firmware node.
+ *
+ * All-zero BD addresses are rejected (unprovisioned).

+ */
+static int hci_dev_get_bd_addr_from_nvmem(struct hci_dev *hdev) {
+	struct device_node *np = dev_of_node(hdev->dev.parent);
+	u8 ba[sizeof(bdaddr_t)];
+	int err;
+
+	if (!np)
+		return -ENODEV;
+
+	err = of_get_nvmem_eui48(np, "local-bd-address", ba);
+	if (err)
+		return err;
+
+	if (hci_test_quirk(hdev, HCI_QUIRK_BDADDR_NVMEM_BE))
+		baswap(&hdev->public_addr, (bdaddr_t *)ba);
+	else
+		bacpy(&hdev->public_addr, (bdaddr_t *)ba);
+
+	return 0;
+}
+
/**
 * hci_dev_get_bd_addr_from_property - Get the Bluetooth Device Address
 *				       (BD_ADDR) for a HCI device from

@@ -5042,12 +5074,17 @@ static int hci_dev_setup_sync(struct hci_dev *hdev)

	 * its setup callback.
	 */
	invalid_bdaddr = hci_test_quirk(hdev, HCI_QUIRK_INVALID_BDADDR) ||
-			 hci_test_quirk(hdev, HCI_QUIRK_USE_BDADDR_PROPERTY);
+			 hci_test_quirk(hdev, HCI_QUIRK_USE_BDADDR_PROPERTY) ||
+			 hci_test_quirk(hdev, HCI_QUIRK_USE_BDADDR_NVMEM);
	if (!ret) {
		if (hci_test_quirk(hdev, HCI_QUIRK_USE_BDADDR_PROPERTY) &&
		    !bacmp(&hdev->public_addr, BDADDR_ANY))
			hci_dev_get_bd_addr_from_property(hdev);

+		if (hci_test_quirk(hdev, HCI_QUIRK_USE_BDADDR_NVMEM) &&
+		    !bacmp(&hdev->public_addr, BDADDR_ANY))
+			hci_dev_get_bd_addr_from_nvmem(hdev);
+
		if (invalid_bdaddr && bacmp(&hdev->public_addr, BDADDR_ANY) &&
		    hdev->set_bdaddr) {
			ret = hdev->set_bdaddr(hdev, &hdev->public_addr);

--
2.34.1