Re: [PATCH 1/2] Bluetooth: Add quirk for reading BD_ADDR from fwnode property

From: Balakrishna Godavarthi
Date: Fri Oct 26 2018 - 01:01:52 EST

Hi Matthias,

I missed to add a point here.

On 2018-10-25 20:06, Balakrishna Godavarthi wrote:
On 2018-10-25 05:51, Matthias Kaehlcke wrote:
Add HCI_QUIRK_USE_BDADDR_PROPERTY to allow controllers to retrieve
the public Bluetooth address from the firmware node property
'local-bd-address'. If quirk is set and the property does not exist
or is invalid the controller is marked as unconfigured.

Signed-off-by: Matthias Kaehlcke <mka@xxxxxxxxxxxx>
---
hci_dev_get_bd_addr_from_property() currently assumes that the
firmware node with 'local-bd-address' is from hdev->dev.parent, not
sure if this universally true. However if it is true for existing
device that might use this interface we can assume this for now
(unless there is a clear solution now), and cross the bridge of
finding an alternative when we actually encounter the situation.
One option could be to look for the first parent that has a fwnode.
---
include/net/bluetooth/hci.h | 12 +++++++++++
net/bluetooth/hci_core.c | 42 +++++++++++++++++++++++++++++++++++++
net/bluetooth/mgmt.c | 6 ++++--
3 files changed, 58 insertions(+), 2 deletions(-)

diff --git a/include/net/bluetooth/hci.h b/include/net/bluetooth/hci.h
index cdd9f1fe7cfa..a5d748099752 100644
--- a/include/net/bluetooth/hci.h
+++ b/include/net/bluetooth/hci.h
@@ -158,6 +158,18 @@ enum {
*/
HCI_QUIRK_INVALID_BDADDR,

+ /* 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
+ * specified in the fwnode property 'local-bd-address'.
+ * If this property does not exist or is invalid controller
+ * configuration is required before this device can be used.
+ *
+ * This quirk can be set before hci_register_dev is called or
+ * during the hdev->setup vendor callback.
+ */
+ HCI_QUIRK_USE_BDADDR_PROPERTY,
+
/* 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_core.c b/net/bluetooth/hci_core.c
index 74b29c7d841c..97214262c4fb 100644
--- a/net/bluetooth/hci_core.c
+++ b/net/bluetooth/hci_core.c
@@ -30,6 +30,7 @@
#include <linux/rfkill.h>
#include <linux/debugfs.h>
#include <linux/crypto.h>
+#include <linux/property.h>
#include <asm/unaligned.h>

#include <net/bluetooth/bluetooth.h>
@@ -1355,9 +1356,40 @@ int hci_inquiry(void __user *arg)
return err;
}

+/**
+ * hci_dev_get_bd_addr_from_property - Get the Bluetooth Device Address
+ * (BD_ADDR) for a HCI device from
+ * a firmware node property.
+ * @hdev: The HCI device
+ *
+ * Search the firmware node for 'local-bd-address'.
+ *
+ * All-zero BD addresses are rejected, because those could be properties
+ * that exist in the firmware tables, but were not updated by the firmware. For
+ * example, the DTS could define 'local-bd-address', with zero BD addresses.
+ */
+static int hci_dev_get_bd_addr_from_property(struct hci_dev *hdev)
+{
+ struct fwnode_handle *fwnode = dev_fwnode(hdev->dev.parent);
+ bdaddr_t ba;
+ int ret;
+
+ ret = fwnode_property_read_u8_array(fwnode, "local-bd-address",
+ (u8 *)&ba, sizeof(ba));
+ if (ret < 0)
+ return ret;
+ if (!bacmp(&ba, BDADDR_ANY))
+ return -ENODATA;
+
+ hdev->public_addr = ba;
+
+ return 0;
+}
+
static int hci_dev_do_open(struct hci_dev *hdev)
{
int ret = 0;
+ bool bd_addr_set = false;

BT_DBG("%s %p", hdev->name, hdev);

@@ -1422,6 +1454,16 @@ static int hci_dev_do_open(struct hci_dev *hdev)
if (hdev->setup)
ret = hdev->setup(hdev);

+ if (test_bit(HCI_QUIRK_USE_BDADDR_PROPERTY, &hdev->quirks)) {
+ if (!hci_dev_get_bd_addr_from_property(hdev))
+ if (hdev->set_bdaddr &&
+ !hdev->set_bdaddr(hdev, &hdev->public_addr))
+ bd_addr_set = true;

Can we check the return status of hdev->setup() before calling hdev->set_bdaddr().
some vendors assign hdev->set_baddr helper before calling hdev->setup().
https://elixir.bootlin.com/linux/v4.19-rc8/source/drivers/bluetooth/btqcomsmd.c#L194
There will no use in calling hdev->set_baddr() if hdev->setup() fails.

+
+ if (!bd_addr_set)
+ hci_dev_set_flag(hdev, HCI_UNCONFIGURED);
+ }
+
/* The transport driver can set these quirks before
* creating the HCI device or in its setup callback.
*
diff --git a/net/bluetooth/mgmt.c b/net/bluetooth/mgmt.c
index 3bdc8f3ca259..3d9edb752403 100644
--- a/net/bluetooth/mgmt.c
+++ b/net/bluetooth/mgmt.c
@@ -551,7 +551,8 @@ static bool is_configured(struct hci_dev *hdev)
!hci_dev_test_flag(hdev, HCI_EXT_CONFIGURED))
return false;

- if (test_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks) &&
+ if ((test_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks) ||
+ test_bit(HCI_QUIRK_USE_BDADDR_PROPERTY, &hdev->quirks)) &&
!bacmp(&hdev->public_addr, BDADDR_ANY))
return false;

@@ -566,7 +567,8 @@ static __le32 get_missing_options(struct hci_dev *hdev)
!hci_dev_test_flag(hdev, HCI_EXT_CONFIGURED))
options |= MGMT_OPTION_EXTERNAL_CONFIG;

- if (test_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks) &&
+ if ((test_bit(HCI_QUIRK_INVALID_BDADDR, &hdev->quirks) ||
+ test_bit(HCI_QUIRK_USE_BDADDR_PROPERTY, &hdev->quirks)) &&
!bacmp(&hdev->public_addr, BDADDR_ANY))
options |= MGMT_OPTION_PUBLIC_ADDRESS;

Looks fine to me.

Reviewed-by: Balakrishna Godavarthi <bgodavar@xxxxxxxxxxxxxx>

--
Regards
Balakrishna.