stmhal: Fix USB MSC so that it unmounts correctly on Mac OS X.

Mac OS X sends a SCSI command to remove the medium when it unmounts a
drive.  If this command is not honoured, then OS X will automatically
remount the drive, making it impossible to eject.  This patch disables
the USB MSC when the right SCSI command is sent.

1 files changed, 25 insertions, 0 deletions

diff --git a/stmhal/usbd_msc_storage.c b/stmhal/usbd_msc_storage.c
index f3ecd023d..0225a2a23 100644
--- a/stmhal/usbd_msc_storage.c
+++ b/stmhal/usbd_msc_storage.c
@@ -35,6 +35,11 @@
 #include "diskio.h"
 #include "sdcard.h"
 
+// These are needed to support removal of the medium, so that the USB drive
+// can be unmounted, and won't be remounted automatically.
+static uint8_t flash_removed = 0;
+static uint8_t sdcard_removed = 0;
+
 /******************************************************************************/
 // Callback functions for when the internal flash is the mass storage device
 
@@ -83,6 +88,9 @@ int8_t FLASH_STORAGE_GetCapacity(uint8_t lun, uint32_t *block_num, uint16_t *blo
   * @retval Status
   */
 int8_t FLASH_STORAGE_IsReady(uint8_t lun) {
+    if (flash_removed) {
+        return -1;
+    }
     return 0;
 }
 
@@ -95,6 +103,12 @@ int8_t FLASH_STORAGE_IsWriteProtected(uint8_t lun) {
     return  0;
 }
 
+// Remove the lun
+int8_t FLASH_STORAGE_StopUnit(uint8_t lun) {
+    flash_removed = 1;
+    return 0;
+}
+
 /**
   * @brief  Read data from the medium
   * @param  lun : logical unit number
@@ -150,6 +164,7 @@ const USBD_StorageTypeDef USBD_FLASH_STORAGE_fops = {
     FLASH_STORAGE_GetCapacity,
     FLASH_STORAGE_IsReady,
     FLASH_STORAGE_IsWriteProtected,
+    FLASH_STORAGE_StopUnit,
     FLASH_STORAGE_Read,
     FLASH_STORAGE_Write,
     FLASH_STORAGE_GetMaxLun,
@@ -236,6 +251,9 @@ int8_t SDCARD_STORAGE_GetCapacity(uint8_t lun, uint32_t *block_num, uint16_t *bl
   * @retval Status
   */
 int8_t SDCARD_STORAGE_IsReady(uint8_t lun) {
+    if (sdcard_removed) {
+        return -1;
+    }
     /*
 #ifndef USE_STM3210C_EVAL  
   
@@ -271,6 +289,12 @@ int8_t SDCARD_STORAGE_IsWriteProtected(uint8_t lun) {
     return 0;
 }
 
+// Remove the lun
+int8_t SDCARD_STORAGE_StopUnit(uint8_t lun) {
+    sdcard_removed = 1;
+    return 0;
+}
+
 /**
   * @brief  Read data from the medium
   * @param  lun : logical unit number
@@ -315,6 +339,7 @@ const USBD_StorageTypeDef USBD_SDCARD_STORAGE_fops = {
     SDCARD_STORAGE_GetCapacity,
     SDCARD_STORAGE_IsReady,
     SDCARD_STORAGE_IsWriteProtected,
+    SDCARD_STORAGE_StopUnit,
     SDCARD_STORAGE_Read,
     SDCARD_STORAGE_Write,
     SDCARD_STORAGE_GetMaxLun,