RockchipUART (Universal Asynchronous Receiver/Transmitter) 基于16550A串口标准,完整模块支持以下功能:
(资料图片仅供参考)
支持【chí】5、6、7、8 bits数据位。支持【chí】1、1.5、2 bits停止位。支持奇【qí】校【xiào】验【yàn】和偶校【xiào】验,不支【zhī】持【chí】mark校验和【hé】space校验【yàn】。支持接收FIFO和发送FIFO,一般为32字节或者64字节。支【zhī】持最高4M波特率,实际【jì】支持波特率【lǜ】需要芯片时钟分频策略配合。支持中断传输模式和DMA传输模式。 支持硬件自动流控,RTS+CTS。在Linuxkernel 中,使用8250串口通【tōng】用驱动,以【yǐ】下【xià】为主【zhǔ】要【yào】驱动文件:
drivers/tty/serial/8250/8250_core.c # 8250串【chuàn】口驱动核【hé】心
drivers/tty/serial/8250/8250_dw.c # Synopsis DesignWare 8250串口驱动
drivers/tty/serial/8250/8250_dma.c # 8250串口【kǒu】DMA驱【qū】动
drivers/tty/serial/8250/8250_port.c # 8250串口【kǒu】端【duān】口操作
drivers/tty/serial/8250/8250_early.c # 8250串口early console驱【qū】动
SDK中提供的【de】UART默【mò】认配置已经使用【yòng】了8250驱动【dòng】我们就不需要修改
串口功能的硬件上比较简单,这是只附上调试串口的原理图
rk平台的设备树修改路径都是在kernel\\arch\\arm64\\boot\\dts\\rockchip下面,具体【tǐ】哪个文件【jiàn】根据对应开发板来决定,通常描述设备硬件配【pèi】置在rkxxxx.dtsi中【zhōng】,比如【rú】在rk3588s.dtsi中【zhōng】:
uart2: serial@feb50000 {compatible = "rockchip,rk3588-uart", "snps,dw-apb-uart";reg = < 0x0 0xfeb50000 0x0 0x100 >;interrupts = < GIC_SPI 333 IRQ_TYPE_LEVEL_HIGH >;clocks = < &cru SCLK_UART2 >, < &cru PCLK_UART2 >;clock-names = "baudclk", "apb_pclk";reg-shift = < 2 >;reg-io-width = < 4 >;dmas = < &dmac0 10 >, < &dmac0 11 >;pinctrl-names = "default";pinctrl-0 = < &uart2m1_xfer >;status = "disabled";};
假入我们想使用w3开发板上40PIN上的uart7
我们在dts可以使用如下配置打开
&uart7 {status = "okay";pinctrl-names = "default";pinctrl-0 = < &uart7m1_xfer >;};
Rockchip UART作为控制【zhì】台,使用fiq_debugger流程。
在dts中fiq_debugger节【jiē】点配置如下。由于fiq_debugger和【hé】普【pǔ】通串【chuàn】口互斥,在使能fiq_debugger节点后必须禁用对【duì】应的普通串【chuàn】口uart节【jiē】点。
chosen: chosen {bootargs = "earlycon=uart8250,mmio32,0xfe660000 console=ttyFIQ0";};fiq-debugger {compatible = "rockchip,fiq-debugger";rockchip,serial-id = < 2 >;rockchip,wake-irq = < 0 >;/* If enable uart uses irq insteadof fiq */rockchip,irq-mode-enable = < 1 >;rockchip,baudrate = < 1500000 >; /* Only 115200 and 1500000 */interrupts = < GIC_SPI 252 IRQ_TYPE_LEVEL_LOW >;pinctrl-names = "default";pinctrl-0 = < &uart2m0_xfer >;status = "okay";};&uart2 {status = "disabled";};
rockchip,serial-id:使用的UART编号。修改serial-id到【dào】不同UART,fiq_debugger设备也会注【zhù】册成ttyFIQ0设备。 rockchip,irq-mode-enable:配置为1使用【yòng】irq中断,配置为0使用fiq中断。interrupts:配置的【de】辅【fǔ】助中断【duàn】,保持【chí】默认【rèn】即可。pinctrl-0:使【shǐ】用的串口引脚rockchip,baudrate:波特率配置【zhì】普通【tōng】串口设备将【jiāng】会根【gēn】据dts中【zhōng】的aliase来对串口进行编号【hào】,对应【yīng】注册成ttySx设备。注【zhù】册的节点【diǎn】为/dev/ttyS4,命【mìng】名规则是通过dts中的aliases来的。
aliases {serial0 = &uart0;serial1 = &uart1;serial2 = &uart2;serial3 = &uart3;}
对应【yīng】uart0注册为ttyS0,uart0注册为【wéi】ttyS1,如果需要把uart3注册成ttyS1,可【kě】以进行【háng】以下修改
serial1 = &uart3; serial3 = &uart1;
Rockchip UART打印【yìn】通常包括DDR阶段、Miniloader阶段、TF-A (Trusted Firmware-A)阶【jiē】段、OP-TEE阶段【duàn】、Uboot阶段【duàn】和Kernel阶段,我【wǒ】们平时主要关注的是uboot阶段和kernel阶段的打印,在【zài】这两个【gè】阶【jiē】段我【wǒ】们可以尝试【shì】关闭所有打印或【huò】切换所有打印到其【qí】他UART,RK平台默认的调试串口是uart2_m0这一组引脚,假如现【xiàn】在我【wǒ】将打印换成其他串【chuàn】口,可以【yǐ】尝试以下【xià】做【zuò】法【fǎ】。
DDR Loader中关闭【bì】或【huò】切换打印,需【xū】要修改DDR Loader中【zhōng】的【de】UART打印【yìn】配置,修改文件rkbin/tools/ddrbin_param.txt中的以下参数:
uart id= # UART控制器【qì】id,配置为0xf为关闭打印
uart iomux= # 复用的IOMUX引脚 uart
baudrate= # 115200 or 1500000
修改完成后,使用以下命令重新生成ddr.bin固件。
./ddrbin_tool ddrbin_param.txt rk3588_ddr_lp4_2112MHz_lp5_2736MHz_v1.09.bin
Uboot中关闭【bì】打【dǎ】印,需要【yào】在menuconfig中【zhōng】,打开配CONFIG_DISABLE_CONSOLE,保存到.config文件
Uboot中切换打印,由传参【cān】机制【zhì】决定,不需要进行额外【wài】修改。uboot解【jiě】析传参机制【zhì】相【xiàng】关代码【mǎ】在arch/arm/mach-rockchip/board.c的board_init_f_init_serial()函数中。
去掉打【dǎ】印需要在menuconfig中,关闭配置【zhì】CONFIG_SERIAL_8250_CONSOLE。
Device Drivers --->
Character devices --->
Serial drivers --->
[ ]Console on 8250/16550 and compatible serial port
在dts配置中找【zhǎo】到【dào】类似以【yǐ】下内容【róng】,并去掉UART基地址和【hé】console相关配置参数
chosen: chosen {bootargs = "earlycon=uart8250,mmio32,0xfeb50000 console=ttyFIQ0 irqchip.gicv3_pseudo_nmi=0 root=PARTUUID=614e0000-0000 rw rootwait";};
将【jiāng】0xfeb50000 console=ttyFIQ0 去掉,然【rán】后找到fiq-debugger节点,修改serial-id为【wéi】0xffffffff,去掉【diào】UART引【yǐn】脚复用【yòng】相关配置。注意,需要保持【chí】fiqdebugger节点使能,保持fiq-debugger流程系统才能正常启动
fiq_debugger: fiq-debugger {compatible = "rockchip,fiq-debugger";rockchip,serial-id = < 0xffffffff >;rockchip,wake-irq = < 0 >;/* If enable uart uses irq instead of fiq */rockchip,irq-mode-enable = < 1 >;rockchip,baudrate = < 1500000 >; /* Only 115200 and 1500000 */interrupts = < GIC_SPI 423 IRQ_TYPE_LEVEL_LOW >;status = "okay";};
切换打印串口【kǒu】例【lì】如将Kernel打印【yìn】从UART2切换到【dào】UART3,在【zài】dts配置中找到类似以下内容,将UART基【jī】地【dì】址【zhǐ】由UART2改为UART3.
bootargs = "earlycon=uart8250,mmio32,0xfe670000 console=ttyFIQ0";
0xfe670000是UART3基地【dì】址,然后找到fiq-debugger节点【diǎn】,修改serial-id为3,修改UART3引脚复用【yòng】配置pinctrl-0 = <&uart3m0_xfer>。注【zhù】意【yì】,同时需要将切换为打印串口的UART3作【zuò】为【wéi】普通串口的节点禁用【yòng】。
在开发板上跑【pǎo】一套【tào】应用程序【xù】,可以【yǐ】发送数据,可以接收【shōu】数据,测【cè】试方法可【kě】以短接TX_RX
#include < stdio.h >#include < stdlib.h >#include < errno.h >#include < unistd.h >#include < fcntl.h >#include < string.h >#include < termio.h >#include < time.h >#include < pthread.h >int read_data(int fd, void *buf, int len);int write_data(int fd, void *buf, int len);int setup_port(int fd, int baud, int databits, int parity, int stopbits);void print_usage(char *program_name);pthread_mutex_t mutex = PTHREAD_MUTEX_INITIALIZER;pthread_cond_t data_ready = PTHREAD_COND_INITIALIZER;int data_available = 0;void *read_thread(void *arg) { int fd = *(int *)arg; char buffer[1024]; // 存【cún】储【chǔ】读取【qǔ】的数据 while (1) { int bytes_read = read_data(fd, buffer, sizeof(buffer)); if (bytes_read > 0) { printf("Read Thread: Read %d bytes: %s\\n", bytes_read, buffer); } else { // 处理读取错误或设备关闭【bì】的情况 break; } } pthread_exit(NULL);}void *write_thread(void *arg) { int fd = *(int *)arg;char input[1024]; // 存储用户输【shū】入的数据 while (1) { printf("Enter data to write (or "q" to quit): "); fgets(input, sizeof(input), stdin); if (strcmp(input, "q\\n") == 0 || strcmp(input, "Q\\n") == 0) { // 用户【hù】输入 "q" 或 "Q",退出【chū】循环 break; } int len = strlen(input); int bytes_written = write_data(fd, input, len); if (bytes_written > 0) { printf("Write Thread: Wrote %d bytes: %s\\n", bytes_written, input); } } pthread_exit(NULL);}int main(int argc, char *argv[]) //./a.out /dev/ttyS4 115200 8 0 1{ int fd; int baud; int len; int count; int i; int databits; int stopbits; int parity; if (argc != 6) { print_usage(argv[0]); return 1; } baud = atoi(argv[2]); if ((baud < 0) || (baud > 921600)) { fprintf(stderr, "Invalid baudrate!\\n"); return 1; } databits = atoi(argv[3]); if ((databits < 5) || (databits > 8)) { fprintf(stderr, "Invalid databits!\\n"); return 1; } parity = atoi(argv[4]); if ((parity < 0) || (parity > 2)) { fprintf(stderr, "Invalid parity!\\n"); return 1; } stopbits = atoi(argv[5]); if ((stopbits < 1) || (stopbits > 2)) { fprintf(stderr, "Invalid stopbits!\\n"); return 1; } fd = open(argv[1], O_RDWR, 0); if (fd < 0) { fprintf(stderr, "open < %s > error %s\\n", argv[1], strerror(errno)); return 1; } if (setup_port(fd, baud, databits, parity, stopbits)) { fprintf(stderr, "setup_port error %s\\n", strerror(errno)); close(fd); return 1; }pthread_t read_tid, write_tid; int ret; // 创建读取线【xiàn】程 ret = pthread_create(&read_tid, NULL, read_thread, &fd); if (ret != 0) { fprintf(stderr, "Failed to create read thread\\n"); return 1; } // 创建写入线程 ret = pthread_create(&write_tid, NULL, write_thread, &fd); if (ret != 0) { fprintf(stderr, "Failed to create write thread\\n"); return 1; } // 等待读取【qǔ】线程【chéng】和写【xiě】入线【xiàn】程结束 pthread_join(read_tid, NULL); pthread_join(write_tid, NULL); close(fd); return 0;}static int baudflag_arr[] = { B921600, B460800, B230400, B115200, B57600, B38400, B19200, B9600, B4800, B2400, B1800, B1200, B600, B300, B150, B110, B75, B50};static int speed_arr[] = { 921600, 460800, 230400, 115200, 57600, 38400, 19200, 9600, 4800, 2400, 1800, 1200, 600, 300, 150, 110, 75, 50};int speed_to_flag(int speed){ int i; for (i = 0; i < sizeof(speed_arr)/sizeof(int); i++) { if (speed == speed_arr[i]) { return baudflag_arr[i]; } } fprintf(stderr, "Unsupported baudrate, use 9600 instead!\\n"); return B9600;}static struct termio oterm_attr;int setup_port(int fd, int baud, int databits, int parity, int stopbits){ struct termio term_attr; if (ioctl(fd, TCGETA, &term_attr) < 0) { return -1; } memcpy(&oterm_attr, &term_attr, sizeof(struct termio)); term_attr.c_iflag &= ~(INLCR | IGNCR | ICRNL | ISTRIP); term_attr.c_oflag &= ~(OPOST | ONLCR | OCRNL); term_attr.c_lflag &= ~(ISIG | ECHO | ICANON | NOFLSH); term_attr.c_cflag &= ~CBAUD; term_attr.c_cflag |= CREAD | speed_to_flag(baud); term_attr.c_cflag &= ~(CSIZE); switch (databits) { case 5: term_attr.c_cflag |= CS5; break; case 6: term_attr.c_cflag |= CS6; break; case 7: term_attr.c_cflag |= CS7; break; case 8: default: term_attr.c_cflag |= CS8; break; } switch (parity) { case 1: term_attr.c_cflag |= (PARENB | PARODD); break; case 2: term_attr.c_cflag |= PARENB; term_attr.c_cflag &= ~(PARODD); break; case 0: default: term_attr.c_cflag &= ~(PARENB); break; } switch (stopbits) { case 2: term_attr.c_cflag |= CSTOPB; break; case 1: default: term_attr.c_cflag &= ~CSTOPB; break; } term_attr.c_cc[VMIN] = 1; term_attr.c_cc[VTIME] = 0; if (ioctl(fd, TCSETAW, &term_attr) < 0) { return -1; } if (ioctl(fd, TCFLSH, 2) < 0) { return -1; } return 0;} int read_data(int fd, void *buf, int len){ int count; int ret; ret = 0; count = 0; //while (len > 0) { ret = read(fd, (char*)buf + count, len); if (ret < 1) { fprintf(stderr, "Read error %s\\n", strerror(errno)); //break; } count += ret; len = len - ret; //} *((char*)buf + count) = 0; return count;} int write_data(int fd, void *buf, int len){ int count; int ret; ret = 0; count = 0; while (len > 0) { ret = write(fd, (char*)buf + count, len); if (ret < 1) { fprintf(stderr, "Write error %s\\n", strerror(errno)); break; } count += ret; len = len - ret; } return count;}void print_usage(char *program_name){ fprintf(stderr, "*************************************\\n" " A Simple Serial Port Test Utility\\n" "*************************************\\n\\n" "Usage:\\n %s < device > < baud > < databits > < parity > < stopbits > \\n" " databits: 5, 6, 7, 8\\n" " parity: 0(None), 1(Odd), 2(Even)\\n" " stopbits: 1, 2\\n" "Example:\\n %s /dev/ttyS4 115200 8 0 1\\n\\n", program_name, program_name );}
运行效果如下:
审核编辑:汤梓红