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5、6、7、8 bits数据位。支持1、1.5、2 bits停止位。支持奇【qí】校验和偶校验,不支持【chí】mark校验和space校验【yàn】。支持接【jiē】收FIFO和发【fā】送FIFO,一般为32字节或者64字节。支持最【zuì】高4M波【bō】特率【lǜ】,实际支持波【bō】特率需【xū】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串口通用驱动【dòng】,以下为主要驱动文【wén】件:
drivers/tty/serial/8250/8250_core.c # 8250串口驱动核心【xīn】
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驱动
drivers/tty/serial/8250/8250_port.c # 8250串【chuàn】口端口操作
drivers/tty/serial/8250/8250_early.c # 8250串口early console驱【qū】动【dòng】
SDK中提供的UART默认配【pèi】置已【yǐ】经使【shǐ】用了8250驱动我们就不需要修【xiū】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【jù】体哪个文件根【gēn】据对应开发板来决定【dìng】,通常【cháng】描述设【shè】备硬件配置在rkxxxx.dtsi中【zhōng】,比如【rú】在rk3588s.dtsi中:
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【wéi】控制台【tái】,使用【yòng】fiq_debugger流程。
在dts中fiq_debugger节【jiē】点【diǎn】配置如下。由【yóu】于fiq_debugger和普【pǔ】通串口【kǒu】互【hù】斥,在使能fiq_debugger节【jiē】点【diǎn】后必须禁用对应的普通串口uart节点。
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【xiū】改serial-id到不同UART,fiq_debugger设备也【yě】会注册【cè】成ttyFIQ0设备。 rockchip,irq-mode-enable:配置【zhì】为1使用irq中断【duàn】,配置【zhì】为0使用fiq中【zhōng】断。interrupts:配置的辅助中断,保【bǎo】持默【mò】认即可。pinctrl-0:使用的串口引脚rockchip,baudrate:波【bō】特率配置【zhì】普通【tōng】串口设【shè】备将【jiāng】会根据dts中的aliase来对串口进行【háng】编【biān】号,对【duì】应注册【cè】成ttySx设备。注册的节点【diǎn】为/dev/ttyS4,命名规则是通过dts中的aliases来的。
aliases {serial0 = &uart0;serial1 = &uart1;serial2 = &uart2;serial3 = &uart3;}
对应uart0注【zhù】册为ttyS0,uart0注册【cè】为ttyS1,如果需要把uart3注册成ttyS1,可以进行【háng】以【yǐ】下【xià】修改
serial1 = &uart3; serial3 = &uart1;
Rockchip UART打【dǎ】印通【tōng】常【cháng】包括DDR阶段、Miniloader阶段【duàn】、TF-A (Trusted Firmware-A)阶段、OP-TEE阶段、Uboot阶段和【hé】Kernel阶段,我们平时主要【yào】关注【zhù】的是uboot阶段【duàn】和【hé】kernel阶段的打印,在【zài】这两个阶段我们可以【yǐ】尝试关闭所【suǒ】有打印或切换所有打印到其他UART,RK平台默认的调试【shì】串口是【shì】uart2_m0这一组引脚,假如现在我将打印换【huàn】成其他【tā】串口,可【kě】以尝【cháng】试以下做法。
DDR Loader中【zhōng】关闭或切换打印,需【xū】要修【xiū】改DDR Loader中的【de】UART打印配置,修改文【wén】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【wéi】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】打印【yìn】,需【xū】要在menuconfig中,打开配【pèi】CONFIG_DISABLE_CONSOLE,保存到.config文件【jiàn】
Uboot中切换打【dǎ】印【yìn】,由传参机制决定,不需要进行额外修改。uboot解析传参【cān】机制相【xiàng】关代码在arch/arm/mach-rockchip/board.c的【de】board_init_f_init_serial()函【hán】数中。
去掉打印需要在【zài】menuconfig中,关闭【bì】配置CONFIG_SERIAL_8250_CONSOLE。
Device Drivers --->
Character devices --->
Serial drivers --->
[ ]Console on 8250/16550 and compatible serial port
在dts配置中找到类似以下【xià】内容,并去掉【diào】UART基【jī】地【dì】址和【hé】console相关配置参【cān】数
chosen: chosen {bootargs = "earlycon=uart8250,mmio32,0xfeb50000 console=ttyFIQ0 irqchip.gicv3_pseudo_nmi=0 root=PARTUUID=614e0000-0000 rw rootwait";};
将0xfeb50000 console=ttyFIQ0 去掉,然后【hòu】找到fiq-debugger节点,修改serial-id为0xffffffff,去掉UART引脚【jiǎo】复用相关配置。注意【yì】,需要【yào】保持fiqdebugger节【jiē】点使能,保持fiq-debugger流程系统才能【néng】正常启【qǐ】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";};
切换打印串口例如【rú】将Kernel打印从UART2切换到UART3,在dts配置【zhì】中找到【dào】类似【sì】以下内容,将UART基地址由UART2改为UART3.
bootargs = "earlycon=uart8250,mmio32,0xfe670000 console=ttyFIQ0";
0xfe670000是UART3基【jī】地址,然后找【zhǎo】到fiq-debugger节点,修改serial-id为【wéi】3,修改UART3引脚复用配置pinctrl-0 = <&uart3m0_xfer>。注意,同时需【xū】要将切换【huàn】为【wéi】打印串口的UART3作为普通串口的【de】节点【diǎn】禁用。
在开发板上跑一套应用【yòng】程序,可以发送【sòng】数据,可【kě】以接收数据,测试方【fāng】法【fǎ】可以短接【jiē】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]; // 存储读取【qǔ】的【de】数据【jù】 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【lǐ】读取错【cuò】误或设备关闭的情况【kuàng】 break; } } pthread_exit(NULL);}void *write_thread(void *arg) { int fd = *(int *)arg;char input[1024]; // 存储【chǔ】用户输入的【de】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【yòng】户输入 "q" 或 "Q",退出循环 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【rù】线程【chéng】 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【dú】取线【xiàn】程和写入线程结束 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