[PATCH v9 08/10] Bluetooth: hci_sync: Add NVMEM-backed BD address retrieval

[Loic Poulain]

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 <bartosz.golaszewski@xxxxxxxxxxxxxxxx>
Reviewed-by: Piotr Kwapulinski <piotr.kwapulinski@xxxxxxxxx>
Signed-off-by: Loic Poulain <loic.poulain@xxxxxxxxxxxxxxxx>
---
 include/net/bluetooth/hci.h | 18 ++++++++++++++++++
 net/bluetooth/hci_sync.c    | 41 ++++++++++++++++++++++++++++++++++++++++-
 net/bluetooth/mgmt.c        |  6 ++++--
 3 files changed, 62 insertions(+), 3 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index 38186a245f14dbd2a26cbc331e7f1b3e72f1a607..145ab94e51482f903f4c9133d8c97561ac1c1e00 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -161,6 +161,24 @@ 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 3be8c3581c6caadeeea56e14e09d4123deb4ec03..c0ed7fb14d19bd79429a6892ec1c7cc89bc7ab3a 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>
@@ -3593,6 +3594,39 @@ 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).
+ *
+ * Return: 0 on success, or a negative error code on failure.
+ */
+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
@@ -5072,12 +5106,17 @@ 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);
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index d23ca1dd089365fe4606600c68475dceb561e5ee..42b6866f96a4c81850d98041b34b7fcb0f9d0e47 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -614,7 +614,8 @@ static bool is_configured(struct hci_dev *hdev)
 		return false;
 
 	if ((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)) &&
 	    !bacmp(&hdev->public_addr, BDADDR_ANY))
 		return false;
 
@@ -630,7 +631,8 @@ static __le32 get_missing_options(struct hci_dev *hdev)
 		options |= MGMT_OPTION_EXTERNAL_CONFIG;
 
 	if ((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)) &&
 	    !bacmp(&hdev->public_addr, BDADDR_ANY))
 		options |= MGMT_OPTION_PUBLIC_ADDRESS;
 

-- 
2.34.1