[PATCH v8] Bluetooth: hci_uart: Add bcm_set_baudrate()

[Frederic Danis <frederic.danis@xxxxxxxxxxxxxxx>]

Add vendor specific command to change controller device speed.

Signed-off-by: Frederic Danis <frederic.danis@xxxxxxxxxxxxxxx>
---
 drivers/bluetooth/btbcm.h   |  5 ++++
 drivers/bluetooth/hci_bcm.c | 58 +++++++++++++++++++++++++++++++++++++++++++++
 2 files changed, 63 insertions(+)

diff --git a/drivers/bluetooth/btbcm.h b/drivers/bluetooth/btbcm.h
index f405f84..e1770d8 100644
--- a/drivers/bluetooth/btbcm.h
+++ b/drivers/bluetooth/btbcm.h
@@ -21,6 +21,11 @@
  *
  */
 
+struct bcm_set_speed {
+	__le16   zero;
+	__le32   speed;
+} __packed;
+
 #if IS_ENABLED(CONFIG_BT_BCM)
 
 int btbcm_check_bdaddr(struct hci_dev *hdev);
diff --git a/drivers/bluetooth/hci_bcm.c b/drivers/bluetooth/hci_bcm.c
index 0704522..2a064a5 100644
--- a/drivers/bluetooth/hci_bcm.c
+++ b/drivers/bluetooth/hci_bcm.c
@@ -25,6 +25,7 @@
 #include <linux/errno.h>
 #include <linux/skbuff.h>
 #include <linux/firmware.h>
+#include <linux/tty.h>
 
 #include <net/bluetooth/bluetooth.h>
 #include <net/bluetooth/hci_core.h>
@@ -32,11 +33,59 @@
 #include "btbcm.h"
 #include "hci_uart.h"
 
+#define BCM43XX_CLOCK_48 1
+#define BCM43XX_CLOCK_24 2
+
 struct bcm_data {
 	struct sk_buff *rx_skb;
 	struct sk_buff_head txq;
 };
 
+static int bcm_set_baudrate(struct hci_uart *hu, unsigned int speed)
+{
+	struct hci_dev *hdev = hu->hdev;
+	struct sk_buff *skb;
+	struct bcm_set_speed param;
+
+	if (speed > 3000000) {
+		u8 clock = BCM43XX_CLOCK_48;
+
+		BT_DBG("%s: Set Controller clock (%d)", hdev->name, clock);
+
+		/* This Broadcom specific command changes the UART's controller
+		 * clock for baud rate > 3000000.
+		 */
+		skb = __hci_cmd_sync(hdev, 0xfc45, 1, &clock, HCI_INIT_TIMEOUT);
+		if (IS_ERR(skb)) {
+			BT_ERR("%s: BCM: failed to write update clock command"
+			       " (%ld)", hdev->name, PTR_ERR(skb));
+			return PTR_ERR(skb);
+		}
+
+		kfree_skb(skb);
+	}
+
+	BT_DBG("%s: Set Controller UART speed to %d bit/s", hdev->name, speed);
+
+	param.zero = cpu_to_le16(0);
+	param.speed = cpu_to_le32(speed);
+
+	/* This Broadcom specific command changes the UART's controller baud
+	 * rate.
+	 */
+	skb = __hci_cmd_sync(hdev, 0xfc18, sizeof(param), &param,
+			     HCI_INIT_TIMEOUT);
+	if (IS_ERR(skb)) {
+		BT_ERR("%s: BCM: failed to write update baudrate command (%ld)",
+		       hdev->name, PTR_ERR(skb));
+		return PTR_ERR(skb);
+	}
+
+	kfree_skb(skb);
+
+	return 0;
+}
+
 static int bcm_open(struct hci_uart *hu)
 {
 	struct bcm_data *bcm;
@@ -107,6 +156,12 @@ static int bcm_setup(struct hci_uart *hu)
 	if (hu->proto->init_speed)
 		hci_uart_set_baudrate(hu, hu->proto->init_speed);
 
+	if (hu->proto->oper_speed) {
+		err = bcm_set_baudrate(hu, hu->proto->oper_speed);
+		if (!err)
+			hci_uart_set_baudrate(hu, hu->proto->oper_speed);
+	}
+
 finalize:
 	release_firmware(fw);
 
@@ -162,10 +217,13 @@ static struct sk_buff *bcm_dequeue(struct hci_uart *hu)
 static const struct hci_uart_proto bcm_proto = {
 	.id		= HCI_UART_BCM,
 	.name		= "BCM",
+	.init_speed	= 115200,
+	.oper_speed	= 4000000,
 	.open		= bcm_open,
 	.close		= bcm_close,
 	.flush		= bcm_flush,
 	.setup		= bcm_setup,
+	.set_baudrate	= bcm_set_baudrate,
 	.recv		= bcm_recv,
 	.enqueue	= bcm_enqueue,
 	.dequeue	= bcm_dequeue,
-- 
1.9.1

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