RK3288
Firefly-RK3288 开发板内置 5 路 UART，分别为 uart0，uart1，uart2，uart3，uart4。
uart0 为 uart_bt，用于蓝牙传输。
uart2 为 uart_dbg，用做调试串口。
uart 1、uart3、uart4 可做外部串口使用，开发板已将其引脚连接至 J10 处，其中 uart4 和 SPI0 引脚复用。
拥有 64 字节的 FIFO 收发缓冲区，支持 5 位、6 位、7 位、8 位数据收发和 DMA 操作。
DTS
调试串口就是将普通串口切换成了console来处理，rockchip调试串口的数据处理代码在arch/arm/mach-rockchip/rk_fiq_debugger.c中，其中dts默认参数如下：
arch/arm/boot/dts/rk3288-firefly.dtsi
fiq-debugger {
compatible = "rockchip,fiq-debugger";
interrupts = <GIC_SPI 155 IRQ_TYPE_LEVEL_HIGH>;
rockchip,serial-id = <2>;
rockchip,wake-irq = <0>;
rockchip,irq-mode-enable = <0>; /* If enable uart uses irq instead of fiq */
rockchip,baudrate = <115200>; /* Only 115200 and 1500000 */
pinctrl-names = "default";
pinctrl-0 = <&uart2_xfer>;
};
关闭调试串口只需要取消CONFIG_FIQ_DEBUGGER宏的配置
/proc/tty/drivers
serial /dev/ttyS 4 64-68 serial
rk3288:/ # cat /proc/tty/drivers
/dev/tty /dev/tty 5 0 system:/dev/tty
/dev/console /dev/console 5 1 system:console
/dev/ptmx /dev/ptmx 5 2 system
rfcomm /dev/rfcomm 216 0-255 serial
g_serial /dev/ttyGS 241 0-3 serial
usbserial /dev/ttyUSB 188 0-511 serial
acm /dev/ttyACM 166 0-255 serial
hso /dev/ttyHS 243 0-255 serial
serial /dev/ttyS 4 64-68 serial
pty_slave /dev/pts 136 0-1048575 pty:slave
pty_master /dev/ptm 128 0-1048575 pty:master
fiq-debugger /dev/ttyFIQ 254 0 serial
rk3288:/ # ls -al dev/tty*
crw-rw-rw- 1 root root 5, 0 2022-01-10 13:47 dev/tty
crw------- 1 root root 254, 0 2022-01-10 13:47 dev/ttyFIQ0
crw-rw---- 1 bluetooth net_bt_stack 4, 64 2022-01-10 13:47 dev/ttyS0
crwxrwxrwx 1 root root 4, 65 2022-01-10 13:47 dev/ttyS1
crwxrwxrwx 1 root root 4, 66 2022-01-10 13:47 dev/ttyS2
crwxrwxrwx 1 root root 4, 67 2022-01-10 13:47 dev/ttyS3
crwxrwxrwx 1 root root 4, 68 2022-01-10 13:47 dev/ttyS4
crw-rw---- 1 radio radio 188, 0 2022-01-10 13:47 dev/ttyUSB0
crw-rw---- 1 radio radio 188, 1 2022-01-10 14:36 dev/ttyUSB1
串口驱动代码(RK3288)
kernel/drivers/tty/tty_io.c
kernel/drivers/tty/serial/8250/8250_core.c
A33
主控有 5 路 uart 接口,5 路支持 4 线或者 2 线通讯(但十分不建议用 uart0 作为控制台以外的用途),实例中,有些路仅仅写出 2 路的配置形式,但实际使用时只要将其按照 4 路的格式补全,也能支持 4 线通讯
./vendor/softwinner/tools/pack/chips/sun8iw5p1/configs/default/env.cfg
console=ttyS0,115200
./vendor/softwinner/tools/pack/chips/sun8iw5p1/configs/dvk3/sys_config.fex
;----------------------------------------------------------------------------------
;[uart_para] boot debug port configuration
;uart_debug_port = uart port ID for boot debug
;----------------------------------------------------------------------------------
[uart_para]
uart_debug_port = 0
uart_debug_tx = port:PF02<3><1><default><default>
uart_debug_rx = port:PF04<3><1><default><default>
;--------------------------------------------------------------------------------
;blue tooth
;bt_used ---- blue tooth used (0- no used, 1- used)
;bt_uard_id ---- uart index
;--------------------------------------------------------------------------------
[bt_para]
bt_used = 1
bt_uart_id = 1
;----------------------------------------------------------------------------------
;uart configuration
;uart_used = uart x enable
;uart_type = 2:2 wire,4:4 wire,8:8 wire, full function
;----------------------------------------------------------------------------------
[uart0]
uart_used = 1
uart_port = 0
uart_type = 2
uart_tx = port:PF02<3><1><default><default>
uart_rx = port:PF04<3><1><default><default>
[uart1]
uart_used = 1
uart_type = 4
uart_tx = port:PG06<2><1><default><default>
uart_rx = port:PG07<2><1><default><default>
uart_rts = port:PG08<2><1><default><default>
uart_cts = port:PG09<2><1><default><default>
[uart2]
uart_used = 1
uart_type = 2
uart_tx = port:PB00<2><1><default><default>
uart_rx = port:PB01<2><1><default><default>
;uart_rts = port:PB02<2><1><default><default>
;uart_cts = port:PB03<2><1><default><default>
[uart3]
uart_used = 1
uart_type = 4
uart_tx = port:PH06<3><1><default><default>
uart_rx = port:PH07<3><1><default><default>
[uart4]
uart_used = 1
uart_port = 4
uart_type = 2
uart_tx = port:PA04<2><1><default><default>
uart_rx = port:PA05<2><1><default><default>
uart_rts = port:PA06<2><1><default><default>
uart_cts = port:PA07<2><1><default><default>
