UBI: Unsorted Block Images

[cascardo/linux.git] / drivers / mtd / ubi / misc.c

diff --git a/drivers/mtd/ubi/misc.c b/drivers/mtd/ubi/misc.c
new file mode 100644 (file)
index 0000000..38d4e67
--- /dev/null
+++ b/drivers/mtd/ubi/misc.c
@@ -0,0 +1,105 @@
+/*
+ * Copyright (c) International Business Machines Corp., 2006
+ *
+ * This program is free software; you can redistribute it and/or modify
+ * it under the terms of the GNU General Public License as published by
+ * the Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program is distributed in the hope that it will be useful,
+ * but WITHOUT ANY WARRANTY; without even the implied warranty of
+ * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See
+ * the GNU General Public License for more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program; if not, write to the Free Software
+ * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA 02111-1307 USA
+ *
+ * Author: Artem Bityutskiy (Битюцкий Артём)
+ */
+
+/* Here we keep miscellaneous functions which are used all over the UBI code */
+
+#include "ubi.h"
+
+/**
+ * calc_data_len - calculate how much real data is stored in a buffer.
+ * @ubi: UBI device description object
+ * @buf: a buffer with the contents of the physical eraseblock
+ * @length: the buffer length
+ *
+ * This function calculates how much "real data" is stored in @buf and returnes
+ * the length. Continuous 0xFF bytes at the end of the buffer are not
+ * considered as "real data".
+ */
+int ubi_calc_data_len(const struct ubi_device *ubi, const void *buf,
+                     int length)
+{
+       int i;
+
+       ubi_assert(length % ubi->min_io_size == 0);
+
+       for (i = length - 1; i >= 0; i--)
+               if (((const uint8_t *)buf)[i] != 0xFF)
+                       break;
+
+       /* The resulting length must be aligned to the minimum flash I/O size */
+       length = ALIGN(i + 1, ubi->min_io_size);
+       return length;
+}
+
+/**
+ * ubi_check_volume - check the contents of a static volume.
+ * @ubi: UBI device description object
+ * @vol_id: ID of the volume to check
+ *
+ * This function checks if static volume @vol_id is corrupted by fully reading
+ * it and checking data CRC. This function returns %0 if the volume is not
+ * corrupted, %1 if it is corrupted and a negative error code in case of
+ * failure. Dynamic volumes are not checked and zero is returned immediately.
+ */
+int ubi_check_volume(struct ubi_device *ubi, int vol_id)
+{
+       void *buf;
+       int err = 0, i;
+       struct ubi_volume *vol = ubi->volumes[vol_id];
+
+       if (vol->vol_type != UBI_STATIC_VOLUME)
+               return 0;
+
+       buf = kmalloc(vol->usable_leb_size, GFP_KERNEL);
+       if (!buf)
+               return -ENOMEM;
+
+       for (i = 0; i < vol->used_ebs; i++) {
+               int size;
+
+               if (i == vol->used_ebs - 1)
+                       size = vol->last_eb_bytes;
+               else
+                       size = vol->usable_leb_size;
+
+               err = ubi_eba_read_leb(ubi, vol_id, i, buf, 0, size, 1);
+               if (err) {
+                       if (err == -EBADMSG)
+                               err = 1;
+                       break;
+               }
+       }
+
+       kfree(buf);
+       return err;
+}
+
+/**
+ * ubi_calculate_rsvd_pool - calculate how many PEBs must be reserved for bad
+ * eraseblock handling.
+ * @ubi: UBI device description object
+ */
+void ubi_calculate_reserved(struct ubi_device *ubi)
+{
+       ubi->beb_rsvd_level = ubi->good_peb_count/100;
+       ubi->beb_rsvd_level *= CONFIG_MTD_UBI_BEB_RESERVE;
+       if (ubi->beb_rsvd_level < MIN_RESEVED_PEBS)
+               ubi->beb_rsvd_level = MIN_RESEVED_PEBS;
+}