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

From: Balakrishna Godavarthi <[email-masked]>
Date: Thu, 25 Oct 2018 20:06:39 +0530

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 <[email-masked]>
> ---
> 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;
> +
> +			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 <[email-masked]>
-- 
Regards
Balakrishna.