Bluetooth: hci_uart: Add support for Amlogic HCI UART

Add a new HCI protocol HCI_UART_AML for the Amlogic Bluetooth
controller. It works on the standard H4 protocol via a 4-wire UART
interface, with baud rates up to 4 Mbps.

The controller supports two types of commands: the TCI commands and the
vendor command. The former is for initial setup including setting baud
rates, downloading fw, starting chip and etc, while the latter is for
dumping firmware versions and setting public address after firmware
updates and normal startup.

It was verified on board of T602 (S905X4 + W265S2).

dmesg:
..
[    5.313450] Bluetooth: HCI UART protocol AML registered
[    6.506052] Bluetooth: hci0: fw_version: date = 42.28, number = 0xb2fd
...
Co-developed-by: Ye He <ye.he@amlogic.com>
Signed-off-by: Ye He <ye.he@amlogic.com>
Signed-off-by: Yang Li <yang.li@amlogic.com>
Signed-off-by: Luiz Augusto von Dentz <luiz.von.dentz@intel.com>

drivers/bluetooth/Kconfig

@@ -274,6 +274,18 @@ config BT_HCIUART_MRVL
 
 	  Say Y here to compile support for HCI MRVL protocol.
 
+config BT_HCIUART_AML
+	bool "Amlogic protocol support"
+	depends on BT_HCIUART
+	depends on BT_HCIUART_SERDEV
+	select BT_HCIUART_H4
+	select FW_LOADER
+	help
+	  The Amlogic protocol support enables Bluetooth HCI over serial
+	  port interface for Amlogic Bluetooth controllers.
+
+	  Say Y here to compile support for HCI AML protocol.
+
 config BT_HCIBCM203X
 	tristate "HCI BCM203x USB driver"
 	depends on USB

drivers/bluetooth/Makefile

@@ -51,4 +51,5 @@ hci_uart-$(CONFIG_BT_HCIUART_BCM)	+= hci_bcm.o
 hci_uart-$(CONFIG_BT_HCIUART_QCA)	+= hci_qca.o
 hci_uart-$(CONFIG_BT_HCIUART_AG6XX)	+= hci_ag6xx.o
 hci_uart-$(CONFIG_BT_HCIUART_MRVL)	+= hci_mrvl.o
+hci_uart-$(CONFIG_BT_HCIUART_AML)	+= hci_aml.o
 hci_uart-objs				:= $(hci_uart-y)

drivers/bluetooth/hci_ldisc.c

@@ -870,7 +870,9 @@ static int __init hci_uart_init(void)
 #ifdef CONFIG_BT_HCIUART_MRVL
 	mrvl_init();
 #endif
-
+#ifdef CONFIG_BT_HCIUART_AML
+	aml_init();
+#endif
 	return 0;
 }
 
@@ -906,7 +908,9 @@ static void __exit hci_uart_exit(void)
 #ifdef CONFIG_BT_HCIUART_MRVL
 	mrvl_deinit();
 #endif
-
+#ifdef CONFIG_BT_HCIUART_AML
+	aml_deinit();
+#endif
 	tty_unregister_ldisc(&hci_uart_ldisc);
 }
 

drivers/bluetooth/hci_uart.h

@@ -20,7 +20,7 @@
 #define HCIUARTGETFLAGS		_IOR('U', 204, int)
 
 /* UART protocols */
-#define HCI_UART_MAX_PROTO	12
+#define HCI_UART_MAX_PROTO	13
 
 #define HCI_UART_H4	0
 #define HCI_UART_BCSP	1
@@ -34,6 +34,7 @@
 #define HCI_UART_AG6XX	9
 #define HCI_UART_NOKIA	10
 #define HCI_UART_MRVL	11
+#define HCI_UART_AML	12
 
 #define HCI_UART_RAW_DEVICE	0
 #define HCI_UART_RESET_ON_INIT	1
@@ -209,3 +210,8 @@ int ag6xx_deinit(void);
 int mrvl_init(void);
 int mrvl_deinit(void);
 #endif
+
+#ifdef CONFIG_BT_HCIUART_AML
+int aml_init(void);
+int aml_deinit(void);
+#endif