fw_env: fix writing environment for mtd devices

Signed-off-by: Oliver Metz <oliver@freetz.org>
Tested-by: Luka Perkov <luka@openwrt.org>

diff --git a/tools/env/fw_env.c b/tools/env/fw_env.c
index 65be5f3fb07e3d202c4f9b960c8dae81b1da0c5c..577ce2de4725249ba4989d02f78c57595d6f93c6 100644 (file)
--- a/tools/env/fw_env.c
+++ b/tools/env/fw_env.c
@@ -727,27 +727,39 @@ static int flash_write_buf (int dev, int fd, void *buf, size_t count,
                                   MEMGETBADBLOCK needs 64 bits */
        int rc;
 
-       blocklen = DEVESIZE (dev);
+       /*
+        * For mtd devices only offset and size of the environment do matter
+        */
+       if (mtd_type == MTD_ABSENT) {
+               blocklen = count;
+               top_of_range = offset + count;
+               erase_len = blocklen;
+               blockstart = offset;
+               block_seek = 0;
+               write_total = blocklen;
+       } else {
+               blocklen = DEVESIZE(dev);
 
-       top_of_range = ((DEVOFFSET(dev) / blocklen) +
-                                       ENVSECTORS (dev)) * blocklen;
+               top_of_range = ((DEVOFFSET(dev) / blocklen) +
+                                       ENVSECTORS(dev)) * blocklen;
 
-       erase_offset = (offset / blocklen) * blocklen;
+               erase_offset = (offset / blocklen) * blocklen;
 
-       /* Maximum area we may use */
-       erase_len = top_of_range - erase_offset;
+               /* Maximum area we may use */
+               erase_len = top_of_range - erase_offset;
 
-       blockstart = erase_offset;
-       /* Offset inside a block */
-       block_seek = offset - erase_offset;
+               blockstart = erase_offset;
+               /* Offset inside a block */
+               block_seek = offset - erase_offset;
 
-       /*
-        * Data size we actually have to write: from the start of the block
-        * to the start of the data, then count bytes of data, and to the
-        * end of the block
-        */
-       write_total = ((block_seek + count + blocklen - 1) /
-                                               blocklen) * blocklen;
+               /*
+                * Data size we actually write: from the start of the block
+                * to the start of the data, then count bytes of data, and
+                * to the end of the block
+                */
+               write_total = ((block_seek + count + blocklen - 1) /
+                                                       blocklen) * blocklen;
+       }
 
        /*
         * Support data anywhere within erase sectors: read out the complete
@@ -818,17 +830,18 @@ static int flash_write_buf (int dev, int fd, void *buf, size_t count,
                        continue;
                }
 
-               erase.start = blockstart;
-               ioctl (fd, MEMUNLOCK, &erase);
-               /* These do not need an explicit erase cycle */
-               if (mtd_type != MTD_ABSENT &&
-                   mtd_type != MTD_DATAFLASH)
-                       if (ioctl (fd, MEMERASE, &erase) != 0) {
-                               fprintf (stderr, "MTD erase error on %s: %s\n",
-                                        DEVNAME (dev),
-                                        strerror (errno));
-                               return -1;
-                       }
+               if (mtd_type != MTD_ABSENT) {
+                       erase.start = blockstart;
+                       ioctl(fd, MEMUNLOCK, &erase);
+                       /* These do not need an explicit erase cycle */
+                       if (mtd_type != MTD_DATAFLASH)
+                               if (ioctl(fd, MEMERASE, &erase) != 0) {
+                                       fprintf(stderr,
+                                               "MTD erase error on %s: %s\n",
+                                               DEVNAME(dev), strerror(errno));
+                                       return -1;
+                               }
+               }
 
                if (lseek (fd, blockstart, SEEK_SET) == -1) {
                        fprintf (stderr,
@@ -847,7 +860,8 @@ static int flash_write_buf (int dev, int fd, void *buf, size_t count,
                        return -1;
                }
 
-               ioctl (fd, MEMLOCK, &erase);
+               if (mtd_type != MTD_ABSENT)
+                       ioctl(fd, MEMLOCK, &erase);
 
                processed  += blocklen;
                block_seek = 0;