add 09_UART/14

IMX6ULL/doc_pic/09_UART/14_编写虚拟UART驱动程序_实现uart_ops.md

@@ -0,0 +1,48 @@
+## 编写虚拟UART驱动程序\_实现uart_ops
+
+* 参考代码
+
+  ```shell
+  硬件相关：
+  drivers/tty/serial/imx.c
+  drivers/tty/serial/stm32-usart.c
+  
+  串口核心层：
+  drivers/tty/serial/serial_core.c
+  
+  TTY层:
+  drivers/tty/tty_io.c
+  ```
+
+  
+
+* 本节课程源码在GIT仓库里
+
+  ```shell
+  doc_and_source_for_drivers\IMX6ULL\source\09_UART
+  	05_virtual_uart_driver_uart_ops
+  doc_and_source_for_drivers\STM32MP157\source\A7\09_UART
+  	05_virtual_uart_driver_uart_ops
+  ```
+  
+  
+
+### 1. 虚拟UART的驱动组成
+
+![image-20210730142813809](pic/09_UART/39_uart_driver.png)
+
+
+
+### 2. 虚拟UART的数据流程
+
+![image-20210730150445225](pic/09_UART/40_virtual_uart.png)
+
+为了做实验，我们还要创建一个虚拟文件：/proc/virt_uart_buf
+
+* 要发数据给虚拟串口时，执行：echo "xxx" > /proc/virt_uart_buf
+* 要读取虚拟串口的数据时，执行：cat /proc/virt_uart_buf
+
+
+
+### 3. 编写uart_ops
+

IMX6ULL/source/09_UART/05_virtual_uart_driver_uart_ops/virtual_uart.c

@@ -0,0 +1,167 @@
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/platform_device.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/rational.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/irq.h>
+
+static struct uart_port	*virt_port;
+static unsigned char txbuf[1024];
+static int tx_buf_r = 0;
+static int tx_buf_w = 0;
+
+static struct uart_driver virt_uart_drv = {
+	.owner          = THIS_MODULE,
+	.driver_name    = "VIRT_UART",
+	.dev_name       = "ttyVIRT",
+	.major          = 0,
+	.minor          = 0,
+	.nr             = 1,
+};
+
+static unsigned int virt_tx_empty(struct uart_port *port)
+{
+	/* 因为要发送的数据瞬间存入buffer */
+	return 1;
+}
+
+
+/*
+ * interrupts disabled on entry
+ */
+static void virt_start_tx(struct uart_port *port)
+{
+	struct circ_buf *xmit = &port->state->xmit;
+
+	while (!uart_circ_empty(xmit) &&
+	       !uart_tx_stopped(port)) {
+		/* send xmit->buf[xmit->tail]
+		 * out the port here */
+
+		/* 把circ buffer中的数据全部存入txbuf */
+
+		txbuf[tx_buf_w++] =  xmit->buf[xmit->tail];
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+	}
+
+   if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+	   uart_write_wakeup(port);
+
+}
+
+static void
+virt_set_termios(struct uart_port *port, struct ktermios *termios,
+		   struct ktermios *old)
+{
+	return;
+}
+
+static const struct uart_ops virt_pops = {
+	.tx_empty	= virt_tx_empty,
+	//.set_mctrl	= imx_set_mctrl,
+	//.get_mctrl	= imx_get_mctrl,
+	//.stop_tx	= imx_stop_tx,
+	.start_tx	= virt_start_tx,
+	//.stop_rx	= imx_stop_rx,
+	//.enable_ms	= imx_enable_ms,
+	//.break_ctl	= imx_break_ctl,
+	//.startup	= imx_startup,
+	//.shutdown	= imx_shutdown,
+	//.flush_buffer	= imx_flush_buffer,
+	.set_termios	= virt_set_termios,
+	//.type		= imx_type,
+	//.config_port	= imx_config_port,
+	//.verify_port	= imx_verify_port,
+};
+
+
+static int virtual_uart_probe(struct platform_device *pdev)
+{	
+	int rxirq;
+	//uart_add_one_port(struct uart_driver * drv, struct uart_port * uport);
+
+	/* 从设备树获得硬件信息 */
+	rxirq = platform_get_irq(pdev, 0);
+	
+	/* 分配设置注册uart_port */
+	virt_port = devm_kzalloc(&pdev->dev, sizeof(*virt_port), GFP_KERNEL);
+
+	virt_port->dev = &pdev->dev;
+	virt_port->iotype = UPIO_MEM;
+	virt_port->irq = rxirq;
+	virt_port->fifosize = 32;
+	virt_port->ops = &virt_pops;
+	virt_port->flags = UPF_BOOT_AUTOCONF;
+	
+	return uart_add_one_port(&virt_uart_drv, virt_port);
+	
+}
+static int virtual_uart_remove(struct platform_device *pdev)
+{
+	
+	return 0;
+}
+
+
+
+static const struct of_device_id virtual_uart_of_match[] = {
+	{ .compatible = "100ask,virtual_uart", },
+	{ },
+};
+
+
+static struct platform_driver virtual_uart_driver = {
+	.probe		= virtual_uart_probe,
+	.remove		= virtual_uart_remove,
+	.driver		= {
+		.name	= "100ask_virtual_uart",
+		.of_match_table = of_match_ptr(virtual_uart_of_match),
+	}
+};
+
+
+/* 1. 入口函数 */
+static int __init virtual_uart_init(void)
+{	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	
+	int ret = uart_register_driver(&virt_uart_drv);
+
+	if (ret)
+		return ret;
+	
+	/* 1.1 注册一个platform_driver */
+	return platform_driver_register(&virtual_uart_driver);
+}
+
+
+/* 2. 出口函数 */
+static void __exit virtual_uart_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 2.1 反注册platform_driver */
+	platform_driver_unregister(&virtual_uart_driver);
+}
+
+module_init(virtual_uart_init);
+module_exit(virtual_uart_exit);
+
+MODULE_LICENSE("GPL");
+
+

IMX6ULL/source/09_UART/05_virtual_uart_driver_uart_ops/virtual_uart.dts

@@ -0,0 +1,13 @@
+
+
+/{
+	virtual_uart: virtual_uart_100ask {
+		compatible = "100ask,virtual_uart";
+		
+		interrupt-parent = <&intc>;
+		interrupts = <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>;
+		
+	};
+	
+	
+};

README.md

@@ -360,6 +360,12 @@ git clone https://e.coding.net/weidongshan/linux/doc_and_source_for_drivers.git
   12_UART驱动调试方法
   13_编写虚拟UART驱动程序_框架
   ```
+  
+* 2021.08.02 发布"UART子系统"
+
+  ```shell
+  14_编写虚拟UART驱动程序_实现uart_ops
+  ```
 
 ## 6. 联系方式
 

STM32MP157/doc_pic/09_UART/14_编写虚拟UART驱动程序_实现uart_ops.md

@@ -0,0 +1,48 @@
+## 编写虚拟UART驱动程序\_实现uart_ops
+
+* 参考代码
+
+  ```shell
+  硬件相关：
+  drivers/tty/serial/imx.c
+  drivers/tty/serial/stm32-usart.c
+  
+  串口核心层：
+  drivers/tty/serial/serial_core.c
+  
+  TTY层:
+  drivers/tty/tty_io.c
+  ```
+
+  
+
+* 本节课程源码在GIT仓库里
+
+  ```shell
+  doc_and_source_for_drivers\IMX6ULL\source\09_UART
+  	05_virtual_uart_driver_uart_ops
+  doc_and_source_for_drivers\STM32MP157\source\A7\09_UART
+  	05_virtual_uart_driver_uart_ops
+  ```
+  
+  
+
+### 1. 虚拟UART的驱动组成
+
+![image-20210730142813809](pic/09_UART/39_uart_driver.png)
+
+
+
+### 2. 虚拟UART的数据流程
+
+![image-20210730150445225](pic/09_UART/40_virtual_uart.png)
+
+为了做实验，我们还要创建一个虚拟文件：/proc/virt_uart_buf
+
+* 要发数据给虚拟串口时，执行：echo "xxx" > /proc/virt_uart_buf
+* 要读取虚拟串口的数据时，执行：cat /proc/virt_uart_buf
+
+
+
+### 3. 编写uart_ops
+

STM32MP157/source/A7/09_UART/05_virtual_uart_driver_uart_ops/virtual_uart.c

@@ -0,0 +1,167 @@
+#include <linux/module.h>
+#include <linux/ioport.h>
+#include <linux/init.h>
+#include <linux/console.h>
+#include <linux/sysrq.h>
+#include <linux/platform_device.h>
+#include <linux/tty.h>
+#include <linux/tty_flip.h>
+#include <linux/serial_core.h>
+#include <linux/serial.h>
+#include <linux/clk.h>
+#include <linux/delay.h>
+#include <linux/rational.h>
+#include <linux/reset.h>
+#include <linux/slab.h>
+#include <linux/of.h>
+#include <linux/of_device.h>
+#include <linux/io.h>
+#include <linux/dma-mapping.h>
+
+#include <asm/irq.h>
+
+static struct uart_port	*virt_port;
+static unsigned char txbuf[1024];
+static int tx_buf_r = 0;
+static int tx_buf_w = 0;
+
+static struct uart_driver virt_uart_drv = {
+	.owner          = THIS_MODULE,
+	.driver_name    = "VIRT_UART",
+	.dev_name       = "ttyVIRT",
+	.major          = 0,
+	.minor          = 0,
+	.nr             = 1,
+};
+
+static unsigned int virt_tx_empty(struct uart_port *port)
+{
+	/* 因为要发送的数据瞬间存入buffer */
+	return 1;
+}
+
+
+/*
+ * interrupts disabled on entry
+ */
+static void virt_start_tx(struct uart_port *port)
+{
+	struct circ_buf *xmit = &port->state->xmit;
+
+	while (!uart_circ_empty(xmit) &&
+	       !uart_tx_stopped(port)) {
+		/* send xmit->buf[xmit->tail]
+		 * out the port here */
+
+		/* 把circ buffer中的数据全部存入txbuf */
+
+		txbuf[tx_buf_w++] =  xmit->buf[xmit->tail];
+		xmit->tail = (xmit->tail + 1) & (UART_XMIT_SIZE - 1);
+		port->icount.tx++;
+	}
+
+   if (uart_circ_chars_pending(xmit) < WAKEUP_CHARS)
+	   uart_write_wakeup(port);
+
+}
+
+static void
+virt_set_termios(struct uart_port *port, struct ktermios *termios,
+		   struct ktermios *old)
+{
+	return;
+}
+
+static const struct uart_ops virt_pops = {
+	.tx_empty	= virt_tx_empty,
+	//.set_mctrl	= imx_set_mctrl,
+	//.get_mctrl	= imx_get_mctrl,
+	//.stop_tx	= imx_stop_tx,
+	.start_tx	= virt_start_tx,
+	//.stop_rx	= imx_stop_rx,
+	//.enable_ms	= imx_enable_ms,
+	//.break_ctl	= imx_break_ctl,
+	//.startup	= imx_startup,
+	//.shutdown	= imx_shutdown,
+	//.flush_buffer	= imx_flush_buffer,
+	.set_termios	= virt_set_termios,
+	//.type		= imx_type,
+	//.config_port	= imx_config_port,
+	//.verify_port	= imx_verify_port,
+};
+
+
+static int virtual_uart_probe(struct platform_device *pdev)
+{	
+	int rxirq;
+	//uart_add_one_port(struct uart_driver * drv, struct uart_port * uport);
+
+	/* 从设备树获得硬件信息 */
+	rxirq = platform_get_irq(pdev, 0);
+	
+	/* 分配设置注册uart_port */
+	virt_port = devm_kzalloc(&pdev->dev, sizeof(*virt_port), GFP_KERNEL);
+
+	virt_port->dev = &pdev->dev;
+	virt_port->iotype = UPIO_MEM;
+	virt_port->irq = rxirq;
+	virt_port->fifosize = 32;
+	virt_port->ops = &virt_pops;
+	virt_port->flags = UPF_BOOT_AUTOCONF;
+	
+	return uart_add_one_port(&virt_uart_drv, virt_port);
+	
+}
+static int virtual_uart_remove(struct platform_device *pdev)
+{
+	
+	return 0;
+}
+
+
+
+static const struct of_device_id virtual_uart_of_match[] = {
+	{ .compatible = "100ask,virtual_uart", },
+	{ },
+};
+
+
+static struct platform_driver virtual_uart_driver = {
+	.probe		= virtual_uart_probe,
+	.remove		= virtual_uart_remove,
+	.driver		= {
+		.name	= "100ask_virtual_uart",
+		.of_match_table = of_match_ptr(virtual_uart_of_match),
+	}
+};
+
+
+/* 1. 入口函数 */
+static int __init virtual_uart_init(void)
+{	
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	
+	int ret = uart_register_driver(&virt_uart_drv);
+
+	if (ret)
+		return ret;
+	
+	/* 1.1 注册一个platform_driver */
+	return platform_driver_register(&virtual_uart_driver);
+}
+
+
+/* 2. 出口函数 */
+static void __exit virtual_uart_exit(void)
+{
+	printk("%s %s %d\n", __FILE__, __FUNCTION__, __LINE__);
+	/* 2.1 反注册platform_driver */
+	platform_driver_unregister(&virtual_uart_driver);
+}
+
+module_init(virtual_uart_init);
+module_exit(virtual_uart_exit);
+
+MODULE_LICENSE("GPL");
+
+

STM32MP157/source/A7/09_UART/05_virtual_uart_driver_uart_ops/virtual_uart.dts

@@ -0,0 +1,13 @@
+
+
+/{
+	virtual_uart: virtual_uart_100ask {
+		compatible = "100ask,virtual_uart";
+		
+		interrupt-parent = <&intc>;
+		interrupts = <GIC_SPI 99 IRQ_TYPE_LEVEL_HIGH>;
+		
+	};
+	
+	
+};