Merge pull request #4983 from geky/bd-trim-erase

bd: Tweaked block device API to fit SD cards and FTLs better

features/filesystem/bd/BlockDevice.h

@@ -91,7 +91,26 @@ public:
      *  @param size     Size to erase in bytes, must be a multiple of erase block size
      *  @return         0 on success, negative error code on failure
      */
-    virtual int erase(bd_addr_t addr, bd_size_t size) = 0;
+    virtual int erase(bd_addr_t addr, bd_size_t size)
+    {
+        return 0;
+    }
+
+    /** Mark blocks as no longer in use
+     *
+     *  This function provides a hint to the underlying block device that a region of blocks
+     *  is no longer in use and may be erased without side effects. Erase must still be called
+     *  before programming, but trimming allows flash-translation-layers to schedule erases when
+     *  the device is not busy.
+     *
+     *  @param addr     Address of block to mark as unused
+     *  @param size     Size to mark as unused in bytes, must be a multiple of erase block size
+     *  @return         0 on success, negative error code on failure
+     */
+    virtual int trim(bd_addr_t addr, bd_size_t size)
+    {
+        return 0;
+    }
 
     /** Get the size of a readable block
      *
@@ -111,7 +130,10 @@ public:
      *  @return         Size of a eraseable block in bytes
      *  @note Must be a multiple of the program size
      */
-    virtual bd_size_t get_erase_size() const = 0;
+    virtual bd_size_t get_erase_size() const
+    {
+        return get_program_size();
+    }
 
     /** Get the total size of the underlying device
      *

features/filesystem/fat/ChaN/ffconf.h

@@ -171,7 +171,7 @@
 /  disk_ioctl() function. */
 
 
-#define	_USE_TRIM	0
+#define	_USE_TRIM	1
 /* This option switches ATA-TRIM feature. (0:Disable or 1:Enable)
 /  To enable Trim feature, also CTRL_TRIM command should be implemented to the
 /  disk_ioctl() function. */

features/filesystem/fat/FATFileSystem.cpp

@@ -244,6 +244,15 @@ DRESULT disk_ioctl(BYTE pdrv, BYTE cmd, void *buff)
         case GET_BLOCK_SIZE:
             *((DWORD*)buff) = 1; // default when not known
             return RES_OK;
+        case CTRL_TRIM:
+            if (_ffs[pdrv] == NULL) {
+                return RES_NOTRDY;
+            } else {
+                DWORD *sectors = (DWORD*)buff;
+                DWORD ssize = disk_get_sector_size(pdrv);
+                int err = _ffs[pdrv]->trim(sectors[0]*ssize, (sectors[1]-sectors[0]+1)*ssize);
+                return err ? RES_PARERR : RES_OK;
+            }
     }
 
     return RES_PARERR;