[PATCH] Bluetooth: hci_bcm: Configure SCO routing automatically

From: attitokes
Date: Fri Jun 08 2018 - 12:21:12 EST

From: Attila TÅkÃs <attitokes@xxxxxxxxx>

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.

Signed-off-by: Attila TÅkÃs <attitokes@xxxxxxxxx>
---
.../bindings/net/broadcom-bluetooth.txt | 7 ++
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)

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);
return 0;
}

@@ -1022,6 +1088,9 @@ static int bcm_probe(struct platform_device *pdev)
dev->dev = &pdev->dev;
dev->irq = platform_get_irq(pdev, 0);

+ /* SCO routing configuration is disabled by default */
+ dev->sco_routing = 0xff;
+
if (has_acpi_companion(&pdev->dev)) {
ret = bcm_acpi_probe(dev);
if (ret)
@@ -1281,6 +1350,9 @@ static int bcm_serdev_probe(struct serdev_device *serdev)
bcmdev->serdev_hu.serdev = serdev;
serdev_device_set_drvdata(serdev, bcmdev);

+ /* SCO routing configuration is disabled by default */
+ bcmdev->sco_routing = 0xff;
+
if (has_acpi_companion(&serdev->dev))
err = bcm_acpi_probe(bcmdev);
else
--
2.17.0