Re: [PATCH] Bluetooth: hci_bcm: Configure SCO routing automatically

[Rob Herring <robh+dt@kernel.org>]

On Fri, Jun 8, 2018 at 10:20 AM,  <attitokes@gmail.com> wrote:
> From: Attila Tőkés <attitokes@gmail.com>
>
> Added support to automatically configure the SCO packet routing at the device setup. The SCO packets are used with the HSP / HFP profiles, but in some devices (ex. CYW43438) they are routed to a PCM output by default. This change allows sending the vendor specific HCI command to configure the SCO routing. The parameters of the command are loaded from the device tree.

Please wrap your commit msg.

>
> Signed-off-by: Attila Tőkés <attitokes@gmail.com>
> ---
>  .../bindings/net/broadcom-bluetooth.txt       |  7 ++

Please split bindings to separate patch.

>  drivers/bluetooth/hci_bcm.c                   | 72 +++++++++++++++++++
>  2 files changed, 79 insertions(+)
>
> diff --git a/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt b/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt
> index 4194ff7e..aea3a094 100644
> --- a/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt
> +++ b/Documentation/devicetree/bindings/net/broadcom-bluetooth.txt
> @@ -21,6 +21,12 @@ Optional properties:
>   - clocks: clock specifier if external clock provided to the controller
>   - clock-names: should be "extclk"
>
> + SCO routing parameters:
> + - sco-routing: 0-3 (PCM, Transport, Codec, I2S)
> + - pcm-interface-rate: 0-4 (128 Kbps - 2048 Kbps)
> + - pcm-frame-type: 0 (short), 1 (long)
> + - pcm-sync-mode: 0 (slave), 1 (master)
> + - pcm-clock-mode: 0 (slave), 1 (master)

Are these Broadcom specific? Properties need either vendor prefix or
to be documented in a common location. I think these look like the
latter.

However, this also looks incomplete to me. For example, which SoC
I2S/PCM port is BT audio connected to and how does it fit into the
existing audio related bindings? There's been work on HDMI audio
bindings which would be similar (except for the SCO over UART at
least).


>
>  Example:
>
> @@ -31,5 +37,6 @@ Example:
>         bluetooth {
>                 compatible = "brcm,bcm43438-bt";
>                 max-speed = <921600>;
> +               sco-routing = <1>; /* 1 = transport (UART) */
>         };
>  };
> diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
> index ddbd8c6a..0e729534 100644
> --- a/drivers/bluetooth/hci_bcm.c
> +++ b/drivers/bluetooth/hci_bcm.c
> @@ -83,6 +83,16 @@
>   * @hu: pointer to HCI UART controller struct,
>   *     used to disable flow control during runtime suspend and system sleep
>   * @is_suspended: whether flow control is currently disabled
> + *
> + *  SCO routing parameters:
> + *   used as the parameters for the bcm_set_pcm_int_params command
> + *     @sco_routing:
> + *      >= 255 (skip SCO routing configuration)
> + *      0-3 (PCM, Transport, Codec, I2S)
> + *     @pcm_interface_rate: 0-4 (128 Kbps - 2048 Kbps)
> + *     @pcm_frame_type: 0 (short), 1 (long)
> + *     @pcm_sync_mode: 0 (slave), 1 (master)
> + *     @pcm_clock_mode: 0 (slave), 1 (master)
>   */
>  struct bcm_device {
>         /* Must be the first member, hci_serdev.c expects this. */
> @@ -114,6 +124,13 @@ struct bcm_device {
>         struct hci_uart         *hu;
>         bool                    is_suspended;
>  #endif
> +
> +       /* SCO routing parameters */
> +       u8                      sco_routing;
> +       u8                      pcm_interface_rate;
> +       u8                      pcm_frame_type;
> +       u8                      pcm_sync_mode;
> +       u8                      pcm_clock_mode;
>  };
>
>  /* generic bcm uart resources */
> @@ -189,6 +206,40 @@ static int bcm_set_baudrate(struct hci_uart *hu, unsigned int speed)
>         return 0;
>  }
>
> +static int bcm_configure_sco_routing(struct hci_uart *hu, struct bcm_device *bcm_dev)
> +{
> +       struct hci_dev *hdev = hu->hdev;
> +       struct sk_buff *skb;
> +       struct bcm_set_pcm_int_params params;
> +
> +       if (bcm_dev->sco_routing >= 0xff) {
> +               /* SCO routing configuration should be skipped */
> +               return 0;
> +       }
> +
> +       bt_dev_dbg(hdev, "BCM: Configuring SCO routing (%d %d %d %d %d)",
> +                       bcm_dev->sco_routing, bcm_dev->pcm_interface_rate, bcm_dev->pcm_frame_type,
> +                       bcm_dev->pcm_sync_mode, bcm_dev->pcm_clock_mode);
> +
> +       params.routing = bcm_dev->sco_routing;
> +       params.rate = bcm_dev->pcm_interface_rate;
> +       params.frame_sync = bcm_dev->pcm_frame_type;
> +       params.sync_mode = bcm_dev->pcm_sync_mode;
> +       params.clock_mode = bcm_dev->pcm_clock_mode;
> +
> +       /* Send the SCO routing configuration command */
> +       skb = __hci_cmd_sync(hdev, 0xfc1c, sizeof(params), &params, HCI_CMD_TIMEOUT);
> +       if (IS_ERR(skb)) {
> +               int err = PTR_ERR(skb);
> +               bt_dev_err(hdev, "BCM: failed to configure SCO routing (%d)", err);
> +               return err;
> +       }
> +
> +       kfree_skb(skb);
> +
> +       return 0;
> +}
> +
>  /* bcm_device_exists should be protected by bcm_device_lock */
>  static bool bcm_device_exists(struct bcm_device *device)
>  {
> @@ -534,6 +585,9 @@ static int bcm_setup(struct hci_uart *hu)
>                         host_set_baudrate(hu, speed);
>         }
>
> +       /* Configure SCO routing if needed */
> +       bcm_configure_sco_routing(hu, bcm->dev);
> +
>  finalize:
>         release_firmware(fw);
>
> @@ -1004,9 +1058,21 @@ static int bcm_acpi_probe(struct bcm_device *dev)
>  }
>  #endif /* CONFIG_ACPI */
>
> +static void read_u8_device_property(struct device *device, const char *property, u8 *destination) {
> +       u32 temp;
> +       if (device_property_read_u32(device, property, &temp) == 0) {
> +               *destination = temp & 0xff;
> +       }
> +}
> +
>  static int bcm_of_probe(struct bcm_device *bdev)
>  {
>         device_property_read_u32(bdev->dev, "max-speed", &bdev->oper_speed);
> +       read_u8_device_property(bdev->dev, "sco-routing", &bdev->sco_routing);
> +       read_u8_device_property(bdev->dev, "pcm-interface-rate", &bdev->pcm_interface_rate);
> +       read_u8_device_property(bdev->dev, "pcm-frame-type", &bdev->pcm_frame_type);
> +       read_u8_device_property(bdev->dev, "pcm-sync-mode", &bdev->pcm_sync_mode);
> +       read_u8_device_property(bdev->dev, "pcm-clock-mode", &bdev->pcm_clock_mode);

These are actually broken because the DT properties are 32-bit.

Rob