update SD card driver for auto initial.

bsp/stm32f10x/drivers/sdcard.c

@@ -221,7 +221,7 @@ SD_Error SD_PowerON(void)
     SDIO_CmdInitStructure.SDIO_Wait = SDIO_Wait_No;
     SDIO_CmdInitStructure.SDIO_CPSM = SDIO_CPSM_Enable;
 
-  for(i = 0;i < 74; i++)
+    for(i = 0; i < 74; i++)
     {
         SDIO_SendCommand(&SDIO_CmdInitStructure);
         errorstatus = CmdError();
@@ -3159,7 +3159,7 @@ static rt_err_t rt_sdcard_control(rt_device_t dev, rt_uint8_t cmd, void *args)
     return RT_EOK;
 }
 
-void rt_hw_sdcard_init()
+int rt_hw_sdcard_init(void)
 {
     /* SDIO POWER */
     GPIO_InitTypeDef GPIO_InitStructure;
@@ -3191,7 +3191,7 @@ void rt_hw_sdcard_init()
         if (sector == RT_NULL)
         {
             rt_kprintf("allocate partition sector buffer failed\n");
-			return;
+            return 0;
         }
         status = SD_ReadBlock(0, (uint32_t*)sector, 512);
         if (status == SD_OK)
@@ -3229,18 +3229,19 @@ void rt_hw_sdcard_init()
         rt_device_register(&sdcard_device, "sd0",
                            RT_DEVICE_FLAG_RDWR | RT_DEVICE_FLAG_REMOVABLE | RT_DEVICE_FLAG_STANDALONE);
 
-		return;
+        return 0;
     }
 
 __return:
     rt_kprintf("sdcard init failed\n");
     GPIO_SetBits(GPIOC,GPIO_Pin_6); /* SD card power down */
+
+    return 0;
 }
+INIT_DEVICE_EXPORT(rt_hw_sdcard_init);
 
 void SDIO_IRQHandler(void)
 {
-    extern int SD_ProcessIRQSrc(void);
-
     /* enter interrupt */
     rt_interrupt_enter();