Add an optional byte-oriented write method to the MTD interface

ChangeLog

@@ -4653,3 +4653,6 @@
 	* configs/sim/mkroe-stm32f4:  Support for the MikroElektronika
 	  Mikromedia for STM32F4 development board (from Ken Petit, 2013-4-30).
 	* fs/smartfs:  Add Ken Pettits SMART FS (2013-4-30).
+	* include/nuttx/mtd.h and most MTD drivers:  Add support for
+	  (optional) method to perform byte oriented writes if so configured
+	  (2013-5-1)

Documentation/NuttxPortingGuide.html

@@ -3192,12 +3192,21 @@ extern void up_ledoff(int led);
     </ul>
     <p>
       Some devices may support byte oriented reads (optional).
-      Most MTD devices are inherently block oriented so byte-oriented writing is not supported.
+      Most MTD devices are inherently block oriented so byte-oriented accesses are not supported.
       It is recommended that low-level drivers not support read() if it requires buffering.
     </p>
     <ul>
      <p><code>ssize_t (*read)(FAR struct mtd_dev_s *dev, off_t offset, size_t nbytes, FAR uint8_t *buffer);</code></p>
     </ul>
+    <p>
+      Some devices may also support byte oriented writes (optional).
+      Most MTD devices are inherently block oriented so byte-oriented accesses are not supported.
+      It is recommended that low-level drivers not support read() if it requires buffering.
+      This interface is only available if <code>CONFIG_MTD_BYTE_WRITE</code> is defined.
+    </p>
+    <ul>
+     <p><code>ssize_t (*write)(FAR struct mtd_dev_s *dev, off_t offset, size_t nbytes, FAR const uint8_t *buffer);</code></p>
+    </ul>
     <p>
       Support other, less frequently used commands:
     </p>

drivers/mtd/Kconfig

@@ -3,6 +3,8 @@
 # see misc/tools/kconfig-language.txt.
 #
 
+comment "MTD Configuration"
+
 config MTD_PARTITION
 	bool "Support MTD partitions"
 	default n
@@ -24,6 +26,17 @@ config MTD_PARTITION
 		managing the sub-region of flash beginning at 'offset' (in blocks)
 		and of size 'nblocks' on the device specified by 'mtd'.
 
+config MTD_BYTE_WRITE
+	bool "Byte write"
+	default n
+	---help---
+		Some devices (such as the EON EN25F80) support writing an arbitrary
+		number of bytes to FLASH. This setting enables MTD interfaces to
+		support such writes.  The SMART file system can take advantage of
+		this option if it is enabled.
+
+comment "MTD Device Drivers"
+
 config RAMMTD
 	bool "RAM-based MTD driver"
 	default n
@@ -132,9 +145,9 @@ config MP25P_SUBSECTOR_ERASE
 	bool "Sub-Sector Erase"
 	default n
 	---help---
-		Some devices (the EON EN25F80) support a smaller erase block size (4K vs 64K).
+		Some devices (such as the EON EN25F80) support a smaller erase block
-		This option enables support for sub-sector erase.  The SMART file system can
+		size (4K vs 64K).  This option enables support for sub-sector erase.
-		take advantage of this option if it is enabled.
+		The SMART file system can take advantage of this option if it is enabled.
 
 config MP25P_BYTEWRITE
 	bool "Enable ByteWrite ioctl support"

drivers/mtd/at24xx.c

@@ -10,7 +10,7 @@
  *
  * Derived from drivers/mtd/m25px.c
  *
- *   Copyright (C) 2009-2011 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009-2011, 2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -365,7 +365,7 @@ static int at24c_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg)
         break;
 
       case MTDIOC_BULKERASE:
-        ret=at24c_eraseall(priv);
+        ret = at24c_eraseall(priv);
         break;
 
       case MTDIOC_XIPBASE:
@@ -413,6 +413,10 @@ FAR struct mtd_dev_s *at24c_initialize(FAR struct i2c_dev_s *dev)
       priv->pagesize   = AT24XX_PAGESIZE;
       priv->npages     = AT24XX_NPAGES;
 
+      /* NOTE since the pre-allocated device structure lies in .bss, any
+       * unsupported methods should have been nullified.
+       */
+
       priv->mtd.erase  = at24c_erase;
       priv->mtd.bread  = at24c_bread;
       priv->mtd.bwrite = at24c_bwrite;

drivers/mtd/at25.c

@@ -2,7 +2,7 @@
  * drivers/mtd/at25.c
  * Driver for SPI-based AT25DF321 (32Mbit) flash.
  *
- *   Copyright (C) 2009-2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2009-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *           Petteri Aimonen <jpa@nx.mail.kapsi.fi>
  *
@@ -664,10 +664,12 @@ FAR struct mtd_dev_s *at25_initialize(FAR struct spi_dev_s *dev)
    * to be extended to handle multiple FLASH parts on the same SPI bus.
    */
 
-  priv = (FAR struct at25_dev_s *)kmalloc(sizeof(struct at25_dev_s));
+  priv = (FAR struct at25_dev_s *)kzalloc(sizeof(struct at25_dev_s));
   if (priv)
     {
-      /* Initialize the allocated structure */
+      /* Initialize the allocated structure (unsupported methods were
+       * nullified by kzalloc).
+       */
 
       priv->mtd.erase  = at25_erase;
       priv->mtd.bread  = at25_bread;

drivers/mtd/at45db.c

@@ -2,7 +2,7 @@
  * drivers/mtd/at45db.c
  * Driver for SPI-based AT45DB161D (16Mbit)
  *
- *   Copyright (C) 2010-2011 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2010-2011, 2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -827,10 +827,12 @@ FAR struct mtd_dev_s *at45db_initialize(FAR struct spi_dev_s *spi)
    * to be extended to handle multiple FLASH parts on the same SPI bus.
    */
 
-  priv = (FAR struct at45db_dev_s *)kmalloc(sizeof(struct at45db_dev_s));
+  priv = (FAR struct at45db_dev_s *)kzalloc(sizeof(struct at45db_dev_s));
   if (priv)
     {
-      /* Initialize the allocated structure */
+      /* Initialize the allocated structure. (unsupported methods were
+       * nullified by kzalloc).
+       */
 
       priv->mtd.erase  = at45db_erase;
       priv->mtd.bread  = at45db_bread;

drivers/mtd/m25px.c

@@ -995,10 +995,12 @@ FAR struct mtd_dev_s *m25p_initialize(FAR struct spi_dev_s *dev)
    * to be extended to handle multiple FLASH parts on the same SPI bus.
    */
 
-  priv = (FAR struct m25p_dev_s *)kmalloc(sizeof(struct m25p_dev_s));
+  priv = (FAR struct m25p_dev_s *)kzalloc(sizeof(struct m25p_dev_s));
   if (priv)
     {
-      /* Initialize the allocated structure */
+      /* Initialize the allocated structure. (unsupported methods were
+       * nullified by kzalloc).
+       */
 
       priv->mtd.erase  = m25p_erase;
       priv->mtd.bread  = m25p_bread;

drivers/mtd/mtd_partition.c

@@ -395,14 +395,16 @@ FAR struct mtd_dev_s *mtd_partition(FAR struct mtd_dev_s *mtd, off_t firstblock,
 
   /* Allocate a partition device structure */
 
-  part = (FAR struct mtd_partition_s *)malloc(sizeof(struct mtd_partition_s));
+  part = (FAR struct mtd_partition_s *)kzalloc(sizeof(struct mtd_partition_s));
   if (!part)
     {
       fdbg("ERROR: Failed to allocate memory for the partition device\n");
       return NULL;      
     }
 
-  /* Initialize the partition device structure */
+  /* Initialize the partition device structure. (unsupported methods were
+   * nullified by kzalloc).
+   */
 
   part->child.erase  = part_erase;
   part->child.bread  = part_bread;

drivers/mtd/rammtd.c

@@ -429,7 +429,7 @@ FAR struct mtd_dev_s *rammtd_initialize(FAR uint8_t *start, size_t size)
 
   /* Create an instance of the RAM MTD device state structure */
 
-  priv = (FAR struct ram_dev_s *)kmalloc(sizeof(struct ram_dev_s));
+  priv = (FAR struct ram_dev_s *)kzalloc(sizeof(struct ram_dev_s));
   if (!priv)
     {
       fdbg("Failed to allocate the RAM MTD state structure\n");
@@ -445,7 +445,9 @@ FAR struct mtd_dev_s *rammtd_initialize(FAR uint8_t *start, size_t size)
       return NULL;
     }
 
-  /* Perform initialization as necessary */
+  /* Perform initialization as necessary. (unsupported methods were
+   * nullified by kzalloc).
+   */
 
   priv->mtd.erase  = ram_erase;
   priv->mtd.bread  = ram_bread;

drivers/mtd/ramtron.c

@@ -660,10 +660,12 @@ FAR struct mtd_dev_s *ramtron_initialize(FAR struct spi_dev_s *dev)
    * to be extended to handle multiple FLASH parts on the same SPI bus.
    */
 
-  priv = (FAR struct ramtron_dev_s *)kmalloc(sizeof(struct ramtron_dev_s));
+  priv = (FAR struct ramtron_dev_s *)kzalloc(sizeof(struct ramtron_dev_s));
   if (priv)
     {
-      /* Initialize the allocated structure */
+      /* Initialize the allocated structure. (unsupported methods were
+       * nullified by kzalloc).
+       */
 
       priv->mtd.erase  = ramtron_erase;
       priv->mtd.bread  = ramtron_bread;

drivers/mtd/skeleton.c

@@ -79,6 +79,10 @@ static ssize_t skel_bwrite(FAR struct mtd_dev_s *dev, off_t startblock, size_t n
                            FAR const uint8_t *buf);
 static ssize_t skel_read(FAR struct mtd_dev_s *dev, off_t offset, size_t nbytes,
                          FAR uint8_t *buffer);
+#ifdef CONFIG_MTD_BYTE_WRITE
+static ssize_t skel_write(FAR struct mtd_dev_s *dev, off_t offset, size_t nbytes,
+                          FAR const uint8_t *buffer);
+#endif
 static int skel_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg);
 
 /****************************************************************************
@@ -88,7 +92,15 @@ static int skel_ioctl(FAR struct mtd_dev_s *dev, int cmd, unsigned long arg);
 
 static struct skel_dev_s g_skeldev =
 {
-  { skel_erase, skel_rbead, skel_bwrite, skel_read, skel_ioctl },
+  { skel_erase,
+    skel_rbead,
+    skel_bwrite,
+    skel_read,
+#ifdef CONFIG_MTD_BYTE_WRITE
+    skel_write,
+#endif
+    skel_ioctl
+  },
   /* Initialization of any other implementation specific data goes here */
 };
 
@@ -202,6 +214,23 @@ static ssize_t skel_read(FAR struct mtd_dev_s *dev, off_t offset, size_t nbytes,
   return 0;
 }
 
+/****************************************************************************
+ * Name: skel_write
+ *
+ * Description:
+ *   Some FLASH parts have the ability to write an arbitrary number of
+ *   bytes to an arbitrary offset on the device.
+ *
+ ****************************************************************************/
+
+#ifdef CONFIG_MTD_BYTE_WRITE
+static ssize_t skel_write(FAR struct mtd_dev_s *dev, off_t offset, size_t nbytes,
+                          FAR const uint8_t *buffer)
+{
+  return -ENOSYS;
+}
+#endif
+
 /****************************************************************************
  * Name: skel_ioctl
  ****************************************************************************/

drivers/mtd/sst25.c

@@ -2,7 +2,7 @@
  * drivers/mtd/sst25.c
  * Driver for SPI-based SST25 FLASH.
  *
- *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2012-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -1195,7 +1195,9 @@ FAR struct mtd_dev_s *sst25_initialize(FAR struct spi_dev_s *dev)
   priv = (FAR struct sst25_dev_s *)kzalloc(sizeof(struct sst25_dev_s));
   if (priv)
     {
-      /* Initialize the allocated structure */
+      /* Initialize the allocated structure. (unsupported methods were
+       * nullified by kzalloc).
+       */
 
       priv->mtd.erase  = sst25_erase;
       priv->mtd.bread  = sst25_bread;

drivers/mtd/sst39vf.c

@@ -201,7 +201,10 @@ static struct sst39vf_dev_s g_sst39vf =
     sst39vf_bread,          /* bread method */
     sst39vf_bwrite,         /* bwrte method */
     sst39vf_read,           /* read method */
-    sst39vf_ioctl           /* write method */
+#ifdef CONFIG_MTD_BYTE_WRITE
+    NULL,                   /* write method */
+#endif
+    sst39vf_ioctl           /* ioctl method */
   },
   NULL                      /* Chip */
 };

drivers/mtd/w25.c

@@ -2,7 +2,7 @@
  * drivers/mtd/w25.c
  * Driver for SPI-based W25x16, x32, and x64 and W25q16, q32, q64, and q128 FLASH
  *
- *   Copyright (C) 2012 Gregory Nutt. All rights reserved.
+ *   Copyright (C) 2012-2013 Gregory Nutt. All rights reserved.
  *   Author: Gregory Nutt <gnutt@nuttx.org>
  *
  * Redistribution and use in source and binary forms, with or without
@@ -1124,7 +1124,9 @@ FAR struct mtd_dev_s *w25_initialize(FAR struct spi_dev_s *spi)
   priv = (FAR struct w25_dev_s *)kzalloc(sizeof(struct w25_dev_s));
   if (priv)
     {
-      /* Initialize the allocated structure */
+      /* Initialize the allocated structure (unsupported methods were
+       * nullified by kzalloc).
+       */
 
       priv->mtd.erase  = w25_erase;
       priv->mtd.bread  = w25_bread;

include/nuttx/mtd.h

@@ -52,11 +52,12 @@
 
 /* Macros to hide implementation */
 
-#define MTD_ERASE(d,s,n)   ((d)->erase  ? (d)->erase(d,s,n)    : (-ENOSYS))
+#define MTD_ERASE(d,s,n)   ((d)->erase   ? (d)->erase(d,s,n)    : (-ENOSYS))
-#define MTD_BREAD(d,s,n,b) ((d)->bread  ? (d)->bread(d,s,n,b)  : (-ENOSYS))
+#define MTD_BREAD(d,s,n,b) ((d)->bread   ? (d)->bread(d,s,n,b)  : (-ENOSYS))
-#define MTD_READ(d,s,n,b)  ((d)->read   ? (d)->read(d,s,n,b)   : (-ENOSYS))
+#define MTD_BWRITE(d,s,n,b)((d)->bwrite  ? (d)->bwrite(d,s,n,b) : (-ENOSYS))
-#define MTD_BWRITE(d,s,n,b)((d)->bwrite ? (d)->bwrite(d,s,n,b) : (-ENOSYS))
+#define MTD_READ(d,s,n,b)  ((d)->read    ? (d)->read(d,s,n,b)   : (-ENOSYS))
-#define MTD_IOCTL(d,c,a)   ((d)->ioctl  ? (d)->ioctl(d,c,a)    : (-ENOSYS))
+#define MTD_WRITE(d,s,n,b) ((d)->write   ? (d)->write(d,s,n,b)  : (-ENOSYS))
+#define MTD_IOCTL(d,c,a)   ((d)->ioctl   ? (d)->ioctl(d,c,a)    : (-ENOSYS))
 
 /* If any of the low-level device drivers declare they want sub-sector erase
  * support, then define MTD_SUBSECTOR_ERASE.
@@ -108,7 +109,12 @@ struct mtd_dev_s
 {
   /* The following methods operate on the MTD: */
 
-  /* Erase the specified erase blocks (units are erase blocks) */
+  /* Erase the specified erase blocks (units are erase blocks).  Semantic
+   * Clarification:  Here, we are not referring to the erase block according
+   * to the FLASH data sheet.  Rather, we are referring to the *smallest*
+   * eraseable part of the FLASH which may have a name like a page or sector
+   * or subsector.
+   */
 
   int (*erase)(FAR struct mtd_dev_s *dev, off_t startblock, size_t nblocks);
 
@@ -127,6 +133,10 @@ struct mtd_dev_s
 
   ssize_t (*read)(FAR struct mtd_dev_s *dev, off_t offset, size_t nbytes,
                   FAR uint8_t *buffer);
+#ifdef CONFIG_MTD_BYTE_WRITE
+  ssize_t (*write)(FAR struct mtd_dev_s *dev, off_t offset, size_t nbytes,
+                   FAR const uint8_t *buffer);
+#endif
 
   /* Support other, less frequently used commands:
    *  - MTDIOC_GEOMETRY:  Get MTD geometry

tools/mkconfig.c

@@ -208,6 +208,7 @@ int main(int argc, char **argv, char **envp)
   printf("# undef CONFIG_FS_FAT\n");
   printf("# undef CONFIG_FS_ROMFS\n");
   printf("# undef CONFIG_FS_NXFFS\n");
+  printf("# undef CONFIG_FS_SMARTFS\n");
   printf("# undef CONFIG_FS_BINFS\n");
   printf("# undef CONFIG_NFS\n");
   printf("#endif\n\n");
@@ -215,7 +216,8 @@ int main(int argc, char **argv, char **envp)
   printf("#undef CONFIG_FS_READABLE\n");
   printf("#undef CONFIG_FS_WRITABLE\n");
   printf("#if defined(CONFIG_FS_FAT) || defined(CONFIG_FS_ROMFS) || defined(CONFIG_USBMSC) || \\\n");
-  printf("    defined(CONFIG_FS_NXFFS) || defined(CONFIG_FS_BINFS) || defined(CONFIG_NFS)\n");
+  printf("    defined(CONFIG_FS_NXFFS) || defined(CONFIG_FS_SMARTFS) || defined(CONFIG_FS_BINFS) || \\\n");
+  printf("    defined(CONFIG_NFS)\n");
   printf("# define CONFIG_FS_READABLE 1\n");
   printf("#endif\n\n");
   printf("#if defined(CONFIG_FS_FAT) || defined(CONFIG_USBMSC) || defined(CONFIG_FS_NXFFS) || \\\n");