fix: 解决OsMountRootfs失败问题

主干存在该问题，下一步同步主干.

挂载rootfs需要emmc驱动，emmc驱动还没有初始化好，内核就尝试挂载rootfs了，
现修改为通过一个事件同步，emmc驱动完成后写事件，内核读到这个事件再挂载rootfs

close: #I43WLG
Signed-off-by: wanghao-free <wanghao453@huawei.com>

fs/include/disk.h

@@ -700,6 +700,8 @@ INT32 los_alloc_diskid_byname(const CHAR *diskName);
  *
  */
 INT32 los_get_diskid_byname(const CHAR *diskName);
+INT32 DiskEventRead(void);
+INT32 DiskEventInit(void);
 
 #ifdef __cplusplus
 #if __cplusplus

fs/vfs/disk/disk.c

@@ -58,6 +58,10 @@ spinlock_t g_diskFatBlockSpinlock;
 
 UINT32 g_usbMode = 0;
 
+#ifdef LOSCFG_STORAGE_EMMC
+static struct tagEvent g_diskInitEvent;
+#endif
+
 #define MEM_ADDR_ALIGN_BYTE  64
 #define RWE_RW_RW            0755
 
@@ -1360,6 +1364,16 @@ INT32 los_disk_init(const CHAR *diskName, const struct block_operations *bops,
     } else {
         disk->type = OTHERS;
     }
+#ifdef LOSCFG_STORAGE_EMMC
+    ret = LOS_EventWrite(&g_diskInitEvent, 1);
+    if (ret < 0) {
+        PRINT_ERR("Disk initialization event write fail \n");
+        (void)unregister_blockdriver(diskName);
+        disk->disk_status = STAT_UNUSED;
+        return VFS_ERROR;
+    }
+#endif
+
     return ENOERR;
 
 DISK_BLKDRIVER_ERROR:
@@ -1370,6 +1384,24 @@ DISK_FIND_ERROR:
     return VFS_ERROR;
 }
 
+INT32 DiskEventInit(void)
+{
+#ifdef LOSCFG_STORAGE_EMMC
+    return LOS_EventInit(&g_diskInitEvent);
+#else
+    return LOS_OK;
+#endif
+}
+
+INT32 DiskEventRead(void)
+{
+#ifdef LOSCFG_STORAGE_EMMC
+    return LOS_EventRead(&g_diskInitEvent, 1, LOS_WAITMODE_OR, LOS_WAIT_FOREVER);
+#else
+    return LOS_OK;
+#endif
+}
+
 INT32 los_disk_deinit(INT32 diskID)
 {
     los_disk *disk = get_disk(diskID);

kernel/common/los_rootfs.c

@@ -246,6 +246,7 @@ STATIC INT32 GetArgs(CHAR **args)
     }
 
 #ifdef LOSCFG_STORAGE_EMMC
+    (void)DiskEventRead();
     g_emmcDisk = GetMmcDisk(EMMC);
     if (g_emmcDisk == NULL) {
         PRINT_ERR("Get EMMC disk failed!\n");