深挖串口,UART驱动实现过程

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kernel/common/virtual_serial.c

@@ -194,7 +194,7 @@ ERROUT:
     set_errno(-ret);
     return VFS_ERROR;
 }
-
+/// 事件查询, UartHostPollEvent(Uart) --> Hi35xxPollEvent --> poll_wait
 STATIC INT32 SerialPoll(struct file *filep, poll_table *fds)
 {
     INT32 ret;
@@ -216,21 +216,69 @@ ERROUT:
     set_errno(-ret);
     return VFS_ERROR;
 }
-///串口实现VFS接口,以便支持按文件方式操作串口
-STATIC const struct file_operations_vfs g_serialDevOps = {
+/*! 
+串口实现VFS接口, 以hi35xx为例,列出底层路径
+调用读/写的过程如下,一直调到UART最底层驱动 
+	g_consoleDevOps(上级)
+		g_serialDevOps(本级)
+			g_uartDevFops
+				g_uartHostMethod
+					Pl011Read (读)
+						memcpy_s(buf,rxTransfer->data, ... )
+					g_pl011Uops (写)	
+						Pl011StartTx
+							UartPutsReg
+控制函数实现
+static int32_t UartDevIoctl(struct file *filep, int32_t cmd, unsigned long arg)
+{
+    int32_t ret = HDF_FAILURE;
+    struct UartHost *host = NULL;
+    if (filep == NULL || filep->f_vnode == NULL) {
+        return HDF_ERR_INVALID_PARAM;
+    }
+    struct drv_data *drv = (struct drv_data *)filep->f_vnode->data;
+    host = (struct UartHost *)drv->priv;
+
+    switch (cmd) {
+        case UART_CFG_BAUDRATE:
+            ret = UartHostSetBaud(host, arg);
+            break;
+        case UART_CFG_RD_BLOCK:
+            if (arg == UART_RD_BLOCK) {
+                ret = UartHostSetTransMode(host, UART_MODE_RD_BLOCK);
+            } else if (arg == UART_RD_NONBLOCK) {
+                ret = UartHostSetTransMode(host, UART_MODE_RD_NONBLOCK);
+            }
+            break;
+        case UART_CFG_ATTR:
+            ret = UartCfgAttr(host, arg);
+            break;
+        case TIOCGWINSZ:
+            /* Simply support ioctl(f->fd, TIOCGWINSZ, &wsz) system call, and the detailed design will be done later  * /
+            ret = LOS_OK;
+            break;
+        default:
+            HDF_LOGE("%s cmd %d not support", __func__, cmd);
+            ret = HDF_ERR_NOT_SUPPORT;
+            break;
+    }
+    return ret;
+}
+*/
+STATIC const struct file_operations_vfs g_serialDevOps = { 
     SerialOpen,  /* open */
     SerialClose, /* close */
     SerialRead,  /* read */
-    SerialWrite,
+    SerialWrite,	///< 写串口
     NULL,
-    SerialIoctl,
+    SerialIoctl,	///< 设置波特率,设置转换模式,各种配置 == 
     NULL,
 #ifndef CONFIG_DISABLE_POLL
     SerialPoll,
 #endif
     NULL,
 };
-//虚拟串口初始化,注册驱动程序 ,例如 : deviceName = "/dev/uartdev-0"
+/// 虚拟串口初始化,注册驱动程序 ,例如 : deviceName = "/dev/uartdev-0"
 INT32 virtual_serial_init(const CHAR *deviceName)
 {
     INT32 ret;
@@ -250,9 +298,9 @@ INT32 virtual_serial_init(const CHAR *deviceName)
         goto ERROUT;
     }
 	//接着是 vnode < -- > file 的绑定操作
-    (VOID)memset_s(&g_serialFilep, sizeof(struct file), 0, sizeof(struct file));
+    (VOID)memset_s(&g_serialFilep, sizeof(struct file), 0, sizeof(struct file));//文件的内核层表现file为fd背后的内容
     g_serialFilep.f_oflags = O_RDWR;//可读可写
-    g_serialFilep.f_vnode = vnode;	//
+    g_serialFilep.f_vnode = vnode;	//绑定索引节点
     g_serialFilep.ops = ((struct drv_data *)vnode->data)->ops;//这里代表 访问 /dev/serial 意味着是访问 /dev/uartdev-0
 	
     if (g_serialFilep.ops->open != NULL) {//用于检测是否有默认的驱动程序
@@ -264,7 +312,6 @@ INT32 virtual_serial_init(const CHAR *deviceName)
     }
     (VOID)register_driver(SERIAL, &g_serialDevOps, DEFFILEMODE, &g_serialFilep);//注册虚拟串口驱动程序
 	//g_serialFilep作为私有数据给了 (drv_data)data->priv = g_serialFilep
-	//
     VnodeDrop();
     return ENOERR;
 

kernel/include/los_base.h

@@ -139,19 +139,19 @@ extern VOID PrintExcInfo(const CHAR *fmt, ...);
 
 /**
  * @ingroup los_base
- * Get a UINT8 value from addr.
+ * Get a UINT8 value from addr.| 从地址上获取8位值
  */
 #define GET_UINT8(addr)                             ({ UINT8 r = *((volatile UINT8 *)((UINTPTR)(addr))); DSB; r; })
 
 /**
  * @ingroup los_base
- * Get a UINT16 value from addr.
+ * Get a UINT16 value from addr.| 从地址上获取16位值
  */
 #define GET_UINT16(addr)                            ({ UINT16 r = *((volatile UINT16 *)((UINTPTR)(addr))); DSB; r; })
 
 /**
  * @ingroup los_base
- * Get a UINT32 value from addr.
+ * Get a UINT32 value from addr. | 从地址上获取32位值
  */
 #define GET_UINT32(addr)                            ({ UINT32 r = *((volatile UINT32 *)((UINTPTR)(addr))); DSB; r; })
 

net/telnet/src/telnet_loop.c

@@ -418,14 +418,14 @@ STATIC VOID *TelnetClientLoop(VOID *arg)
 
     (VOID)prctl(PR_SET_NAME, "TelnetClientLoop", 0, 0, 0);
     TelnetLock();
-    if (TelnetClientPrepare(clientFd) != 0) {
+    if (TelnetClientPrepare(clientFd) != 0) {//做好准备工作
         TelnetUnlock();
         (VOID)close(clientFd);
         return NULL;
     }
     TelnetUnlock();
 
-    while (1) {
+    while (1) {//死循环接受远程输入的数据
         pollFd.fd = clientFd;
         pollFd.events = POLLIN | POLLRDHUP;//监听读数据和挂起事件
         pollFd.revents = 0;
@@ -479,14 +479,14 @@ STATIC VOID *TelnetClientLoop(VOID *arg)
         }
 
         if ((UINT16)pollFd.revents & POLLIN) {//数据事件
-            nRead = read(clientFd, buf, sizeof(buf));//读外面过来的数据
+            nRead = read(clientFd, buf, sizeof(buf));//读远程终端过来的数据
             if (nRead <= 0) {
                 /* telnet client shutdown */
                 break;
             }
             cmdBuf = ReadFilter(buf, (UINT32)nRead, &len);//对数据过滤
             if (len > 0) {
-                (VOID)TelnetTx((CHAR *)cmdBuf, len);
+                (VOID)TelnetTx((CHAR *)cmdBuf, len);//从数据加工处理
             }
         }
     }

shell/full/include/shell.h

@@ -130,17 +130,17 @@ extern "C" {
 #define QUOTES_STATUS_OPEN(qu)  ((qu) == TRUE)
 /*! shell 控制块 */
 typedef struct {
-    UINT32   consoleID;	        ///< 控制台ID
-    UINT32   shellTaskHandle;	///< shell服务端任务
-    UINT32   shellEntryHandle;	///< shell客户端任务
+    UINT32   consoleID;	        ///< 控制台ID,shell必须捆绑一个控制台(串口或远程登录),以便接收输入和发送执行结果信息
+    UINT32   shellTaskHandle;	///< shell服务端任务(负责解析和执行来自客户端的信息)
+    UINT32   shellEntryHandle;	///< shell客户端任务(负责接受来自串口或远程登录的信息)
     VOID     *cmdKeyLink;		///< 待处理的shell命令链表
-    VOID     *cmdHistoryKeyLink; ///< 已处理的历史记录链表,去重,10个
-    VOID     *cmdMaskKeyLink;	///< 主要用于方向键上下遍历历史命令
+    VOID     *cmdHistoryKeyLink; ///< 已处理的命令历史记录链表,去重,10个
+    VOID     *cmdMaskKeyLink;	///< 主要用于方向键上下遍历命令历史
     UINT32   shellBufOffset;	///< buf偏移量
     UINT32   shellKeyType;	    ///< 按键类型
     EVENT_CB_S shellEvent;	    ///< 事件类型触发
     pthread_mutex_t keyMutex;	///< 按键互斥量
-    pthread_mutex_t historyMutex;	    ///< 历史记录互斥量
+    pthread_mutex_t historyMutex;	    ///< 命令历史记录互斥量
     CHAR     shellBuf[SHOW_MAX_LEN];	///< shell命令buf,接受键盘的输入,需要对输入字符解析.
     CHAR     shellWorkingDirectory[PATH_MAX]; ///< shell的工作目录
 } ShellCB;

zzz/git/push.sh

 git add -A
-git commit -m  ' 对虚拟串口,USB,UART实现注释
+git commit -m  ' 深挖串口,UART驱动实现过程
     百万汉字注解 + 百篇博客分析 => 挖透鸿蒙内核源码
     鸿蒙研究站 | http://weharmonyos.com (国内) 
               | https://weharmony.github.io (国外)