mtd: add support for MTDIOC_ERASESECTORS ioctl

Current driver supports MTDIOC_BULKERASE ioctl that erases the entire
device. The added ioctl MTDIOC_ERASESECTORS adds possibility to erase
just sectors defined by the user.

This is similar to MEMERASE call in Linux kernel.

Signed-off-by: Michal Lenc <michallenc@seznam.cz>

drivers/mtd/mtd_partition.c

@@ -469,6 +469,19 @@ static int part_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg)
         }
         break;
 
+      case MTDIOC_ERASESECTORS:
+        {
+          /* Erase sectors as defined in mtd_erase_s structure */
+
+          FAR struct mtd_erase_s *erase = (FAR struct mtd_erase_s *)arg;
+
+          ret = priv->parent->erase(priv->parent,
+                                    priv->firstblock / priv->blkpererase +
+                                    erase->startblock,
+                                    erase->nblocks);
+        }
+        break;
+
       default:
         {
           /* Pass any unhandled ioctl() calls to the underlying driver */

include/nuttx/mtd/mtd.h

@@ -74,6 +74,8 @@
 #define MTDIOC_ERASESTATE   _MTDIOC(0x000a) /* IN:  Pointer to uint8_t
                                              * OUT: Byte value that represents the
                                              *      erased state of the MTD cell */
+#define MTDIOC_ERASESECTORS _MTDIOC(0x000c) /* IN: Pointer to mtd_erase_s structure
+                                             * OUT: None */
 
 /* Macros to hide implementation */
 
@@ -139,6 +141,14 @@ struct mtd_byte_write_s
   const uint8_t *buffer;  /* Pointer to the data to write */
 };
 
+/* This structure describes a range of erase sectors to be erased. */
+
+struct mtd_erase_s
+{
+  uint32_t startblock;  /* First block to be erased */
+  uint32_t nblocks;     /* Number of blocks to be erased */
+};
+
 /* This structure defines the interface to a simple memory technology device.
  * It will likely need to be extended in the future to support more complex
  * devices.