T113上uart转485功能实现
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如下是T113在linux下实现uart转485，patch可以参考附件，dts的配置如下：
uart1: uart@05000400 { status = "okay"; uart1_type = <2>; uart1_rs485=<1>; uart1_485fl=<0>; uart1_485oe=<&pio PG 1 1 0xffffffff 0xffffffff 0>; };patch如下：
diff --git a/arch/arm/boot/dts/sun8iw20p1.dtsi b/arch/arm/boot/dts/sun8iw20p1.dtsi index 6e51b72..4d3fb29 100644 --- a/arch/arm/boot/dts/sun8iw20p1.dtsi +++ b/arch/arm/boot/dts/sun8iw20p1.dtsi @@ -613,8 +613,11 @@ clock-names = "uart1"; resets = <&ccu RST_BUS_UART1>; uart1_port = <1>; - uart1_type = <4>; + uart1_type = <2>; status = "okay"; + uart1_rs485=<1>; + uart1_485fl=<0>; + uart1_485oe=<&pio PG 1 1 0xffffffff 0xffffffff 0>; }; uart2: uart@2500800 { diff --git a/drivers/tty/serial/sunxi-uart.c b/drivers/tty/serial/sunxi-uart.c index 395b1bd..f013ad2 100644 --- a/drivers/tty/serial/sunxi-uart.c +++ b/drivers/tty/serial/sunxi-uart.c @@ -43,6 +43,10 @@ #include <linux/of.h> #include <linux/of_irq.h> #include <linux/of_address.h> + +#include <linux/delay.h> +#include <uapi/linux/sched/types.h> +#include <linux/of_gpio.h> #include "sunxi-uart.h" #if defined(CONFIG_SERIAL_SUNXI_CONSOLE) && defined(CONFIG_MAGIC_SYSRQ) @@ -191,6 +195,28 @@ static inline void sw_uart_disable_ier_thri(struct uart_port *port) } } + +/********************************************************************/ +/* cet,liudachuan: rs485 delayed rts release control, not used now */ +# if 0 +static enum hrtimer_restart uart_set_rs485(struct hrtimer *u_timer) +{ + struct sw_uart_port *sw_uport = container_of(u_timer, struct sw_uart_port, uart_timer); + if(sw_uport == NULL) + { + SERIAL_DBG("faile to get sw_uport\n", __func__); + return HRTIMER_NORESTART; + } + + if(sw_uport->rs485_en){ + gpio_direction_output(sw_uport->rs485oe_io.gpio, sw_uport->rs485_fl); + } + + return HRTIMER_NORESTART; +} +#endif +/***********************************************************************************/ + static unsigned int sw_uart_handle_rx(struct sw_uart_port *sw_uport, unsigned int lsr) { unsigned char ch = 0; @@ -272,23 +298,66 @@ static unsigned int sw_uart_handle_rx(struct sw_uart_port *sw_uport, unsigned in return lsr; } + + +/******************************************************************************/ +/* cet,liudachuan: add sw-rs485 support */ +#define BITS_PER_SERIAL_BYTE 10 +#define NANOSECOND_PER_USECONDS 1000 +#define USECONDS_PER_SECOND 1000000 +static void sw_uart_rs485_cal_tout(struct uart_port *port, unsigned int lcr) +{ + struct sw_uart_port *sw_uport = UART_TO_SPORT(port); + unsigned int bits_per_byte; + if (lcr & SUNXI_UART_LCR_PARITY) /*有奇偶的时候，byte=start+8+parity=10*/ + bits_per_byte = 10; + else /*无奇偶的时候，byte=start+8=9*/ + bits_per_byte = 9; + + if (sw_uport->baud != 0) { + sw_uport->tout = + (bits_per_byte * USECONDS_PER_SECOND) / (sw_uport->baud) * NANOSECOND_PER_USECONDS; + } + else { + sw_uport->tout = 0; + } +} + static void sw_uart_stop_tx(struct uart_port *port) { -#if IS_ENABLED(CONFIG_SERIAL_SUNXI_DMA) struct sw_uart_port *sw_uport = UART_TO_SPORT(port); + +#if IS_ENABLED(CONFIG_SERIAL_SUNXI_DMA) struct sw_uart_dma *uart_dma = sw_uport->dma; if (uart_dma->use_dma & TX_DMA) sw_uart_stop_dma_tx(sw_uport); #endif sw_uart_disable_ier_thri(port); + /* cet,liudachuan: delay 1 byte transmit time then turn off rs485 tx-en */ + if (sw_uport->rs485_en) { + // hrtimer_start(&sw_uport->uart_timer, sw_uport->tout, HRTIMER_MODE_REL); + unsigned char lsr = 0; + while ((lsr & SUNXI_UART_LSR_BOTH_EMPTY) != SUNXI_UART_LSR_BOTH_EMPTY) { + // cpu_relax(); + udelay(10); + lsr = serial_in(port, SUNXI_UART_LSR); + }; + gpio_direction_output(sw_uport->rs485oe_io.gpio, sw_uport->rs485_fl); + } } static void sw_uart_start_tx(struct uart_port *port) { -#if IS_ENABLED(CONFIG_SERIAL_SUNXI_DMA) struct sw_uart_port *sw_uport = UART_TO_SPORT(port); + /* cet,liudachuan: rs485 rts = 1 */ + // serial_out(port, sw_uport->mcr & (~SUNXI_UART_MCR_RTS), SUNXI_UART_MCR); + if(sw_uport->rs485_en){ + // udelay(20); + gpio_direction_output(sw_uport->rs485oe_io.gpio, !sw_uport->rs485_fl); + } +#if IS_ENABLED(CONFIG_SERIAL_SUNXI_DMA) if (!((sw_uport->dma->use_dma & TX_DMA) && sw_uport->dma->tx_dma_used)) #endif sw_uart_enable_ier_thri(port); @@ -342,8 +411,14 @@ static void sw_uart_handle_tx(struct sw_uart_port *sw_uport) uart_write_wakeup(&sw_uport->port); spin_lock(&sw_uport->port.lock); } - if (uart_circ_empty(xmit)) - sw_uart_stop_tx(&sw_uport->port); + + /* cet,liudachuan: add sw-rs485 support */ + // if (uart_circ_empty(xmit)) + // sw_uart_stop_tx(&sw_uport->port); + if (!sw_uport->rs485_en) { + if (uart_circ_empty(xmit)) + sw_uart_stop_tx(&sw_uport->port); + } } static unsigned int sw_uart_modem_status(struct sw_uart_port *sw_uport) @@ -354,7 +429,7 @@ static unsigned int sw_uart_modem_status(struct sw_uart_port *sw_uport) sw_uport->msr_saved_flags = 0; if (status & SUNXI_UART_MSR_ANY_DELTA && sw_uport->ier & SUNXI_UART_IER_MSI && - sw_uport->port.state != NULL) { + sw_uport->port.state != NULL) { if (status & SUNXI_UART_MSR_TERI) sw_uport->port.icount.rng++; if (status & SUNXI_UART_MSR_DDSR) @@ -724,6 +799,25 @@ static enum hrtimer_restart sw_uart_report_dma_rx(struct hrtimer *rx_hrtimer) #endif + + +/** + * 串口中断实测14-135us,数据发完后gic_handle_irq两次进入中断，第二次才真正进入串口中断，导致整个延迟变大 + * 通过提高中断线程优先级为4以上，可以解决，时间缩短到(-5-35us),这里优先级设置为1 + * cet,ljt 2021.10 +*/ +static inline void sw_uart_irq_set_pri(struct sw_uart_port *sw_uport) +{ + struct sched_param param = { .sched_priority = MAX_USER_RT_PRIO - 2 }; + if (sw_uport->irq_pri_promoted) + return; + if (sched_setscheduler(current, SCHED_FIFO, ¶m) < 0) + { + SERIAL_MSG("sched_setscheduler set error\n"); + } + sw_uport->irq_pri_promoted = 1; +} + static irqreturn_t sw_uart_irq(int irq, void *dev_id) { struct uart_port *port = dev_id; @@ -731,6 +825,9 @@ static irqreturn_t sw_uart_irq(int irq, void *dev_id) unsigned int iir = 0, lsr = 0; unsigned long flags; + /* if we hasn't promote the irq priority, set priority to 97 */ + //sw_uart_irq_set_pri(sw_uport); + spin_lock_irqsave(&port->lock, flags); iir = serial_in(port, SUNXI_UART_IIR) & SUNXI_UART_IIR_IID_MASK; @@ -1072,7 +1169,7 @@ static void sw_uart_flush_buffer(struct uart_port *port) } static void sw_uart_set_termios(struct uart_port *port, struct ktermios *termios, - struct ktermios *old) + struct ktermios *old) { struct sw_uart_port *sw_uport = UART_TO_SPORT(port); unsigned long flags; @@ -1119,6 +1216,12 @@ static void sw_uart_set_termios(struct uart_port *port, struct ktermios *termios dlh = quot >> 8; SERIAL_DBG("set baudrate %d, quot %d\n", baud, quot); + /* cet,liudachuan: add sw rs485 support */ + sw_uport->baud = baud; + if (sw_uport->rs485_en) { + sw_uart_rs485_cal_tout(port, lcr); + } + spin_lock_irqsave(&port->lock, flags); uart_update_timeout(port, termios->c_cflag, baud); @@ -1379,7 +1482,7 @@ static int sw_uart_ioctl(struct uart_port *port, unsigned int cmd, } static void sw_uart_pm(struct uart_port *port, unsigned int state, - unsigned int oldstate) + unsigned int oldstate) { #if IS_ENABLED(CONFIG_EVB_PLATFORM) int ret; @@ -1727,7 +1830,7 @@ static void sw_console_putchar(struct uart_port *port, int c) } static void sw_console_write(struct console *co, const char *s, - unsigned int count) + unsigned int count) { struct uart_port *port = NULL; struct sw_uart_port *sw_uport; @@ -1909,6 +2012,9 @@ static int sw_uart_probe(struct platform_device *pdev) char uart_para[16] = {0}; const char *uart_string; int ret = -1; + int rs485_en = 0; //2020.09.24 2¨??? ¨?¨a?¨?RS485???? + int rs485_fl = 0; + struct device_node *apk_np = of_find_node_by_name(NULL, "auto_print"); const char *apk_sta = NULL; #if IS_ENABLED(CONFIG_SERIAL_SUNXI_DMA) @@ -2052,6 +2158,45 @@ static int sw_uart_probe(struct platform_device *pdev) else sw_uport->card_print = false; + /* cet,liudachuan: add sw-rs485 support */ + /************ Modify by wangshunfan @2021.01.11 for this part *************/ + /* Get rs485 enable flag */ + snprintf(uart_para, sizeof(uart_para), "uart%d_rs485", pdev->id); + ret = of_property_read_u32(np, uart_para, &rs485_en); + if (ret) { + SERIAL_MSG("error to get uart%d_rs485\n", pdev->id); + rs485_en = 0; + } + sw_uport->rs485_en = rs485_en; + + //SERIAL_DBG("caid rs485_en = %d port = %d", rs485_en, pdev->id); + if (sw_uport->rs485_en) { + snprintf(uart_para, sizeof(uart_para), "uart%d_485fl", pdev->id); + ret = of_property_read_u32(np, uart_para, &rs485_fl); + if (ret) { + SERIAL_MSG("error to get tuart%d_rs485\n", pdev->id); + rs485_fl = 0; + } + sw_uport->rs485_fl = rs485_fl; + + /* Get rs485 enable control pin, request and init gpio */ + snprintf(uart_para, sizeof(uart_para), "uart%d_485oe", pdev->id); + sw_uport->rs485oe_io.gpio = of_get_named_gpio_flags(np, uart_para, 0, + (enum of_gpio_flags *)(&(sw_uport->rs485oe_io))); + if (gpio_is_valid(sw_uport->rs485oe_io.gpio)){ + gpio_request(sw_uport->rs485oe_io.gpio, NULL); + gpio_direction_output(sw_uport->rs485oe_io.gpio, sw_uport->rs485_fl); + } + + /* Init hrtimer for rs485 and set timeout callback function */ + // hrtimer_init(&sw_uport->uart_timer, CLOCK_MONOTONIC, HRTIMER_MODE_REL); + // sw_uport->uart_timer.function = uart_set_rs485; + + sw_uport->irq_pri_promoted = 0; + SERIAL_MSG("uart%d rs485 enabled\n", pdev->id); + } + /**************** end of modify by wangshunfan for this part ****************/ + pdata->used = 1; port->iotype = UPIO_MEM; port->type = PORT_SUNXI; @@ -2129,7 +2274,14 @@ static int sw_uart_remove(struct platform_device *pdev) struct sw_uart_port *sw_uport = platform_get_drvdata(pdev); SERIAL_DBG("release uart%d port\n", sw_uport->id); -#if IS_ENABLED(CONFIG_SERIAL_SUNXI_DMA) + + /* cet,liudachuan: add sw-rs485 support */ + if (sw_uport->rs485_en) { + gpio_free(sw_uport->rs485oe_io.gpio); /* free gpio of rs485 */ + // hrtimer_cancel(&sw_uport->uart_timer); /* canel hrtimer */ + } + +#ifdef CONFIG_SERIAL_SUNXI_DMA sw_uart_release_dma_tx(sw_uport); sw_uart_release_dma_rx(sw_uport); #endif diff --git a/drivers/tty/serial/sunxi-uart.h b/drivers/tty/serial/sunxi-uart.h index 565acbf..ab096d6 100644 --- a/drivers/tty/serial/sunxi-uart.h +++ b/drivers/tty/serial/sunxi-uart.h @@ -22,6 +22,8 @@ #include <linux/dmaengine.h> #include <linux/reset.h> //include <linux/serial_core.h> +#include <linux/ktime.h> +#include <linux/sunxi-gpio.h> /* SUNXI UART PORT definition*/ #define PORT_MAX_USED PORT_LINFLEXUART /* see include/uapi/linux/serial_core.h */ @@ -106,6 +108,16 @@ struct sw_uart_port { struct serial_rs485 rs485conf; bool card_print; bool throttled; + + /* cet,liudachuan: add rs485 support(not hardware's rs485) */ + struct gpio_config rs485oe_io; + unsigned int rs485_en; + unsigned int rs485_fl; + struct hrtimer uart_timer; + unsigned int baud; + int irq_pri_promoted; + /* Added by wangshunfan @2021.01.11 for hrtimer timeout */ + ktime_t tout; }; /* register offset define */ @@ -191,6 +203,8 @@ struct sw_uart_port { #define SUNXI_UART_LSR_OE (BIT(1)) #define SUNXI_UART_LSR_DR (BIT(0)) #define SUNXI_UART_LSR_BRK_ERROR_BITS 0x1E /* BI, FE, PE, OE bits */ +/* cet,liudachuan: add BOTH_EMPTY macro */ +#define SUNXI_UART_LSR_BOTH_EMPTY (SUNXI_UART_LSR_TEMT | SUNXI_UART_LSR_THRE) /* Modem Status Register */ #define SUNXI_UART_MSR_DCD (BIT(7)) #define SUNXI_UART_MSR_RI (BIT(6)) -
@zznzzn
感谢楼主分享。不过我没有看出来为什么要这么修改， 用UART自带的RTS控制MAX485的EN引脚不可以吗？
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@whycan 帖子上有30ms的时延 这个有点太长了，有点坑。
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