3 files changed, 35 insertions, 0 deletions

diff --git a/drivers/mtd/ubi/debug.c b/drivers/mtd/ubi/debug.c
index 54b0186915fb..4876977e52cb 100644
--- a/drivers/mtd/ubi/debug.c
+++ b/drivers/mtd/ubi/debug.c
@@ -196,4 +196,36 @@ void ubi_dbg_dump_mkvol_req(const struct ubi_mkvol_req *req)
         printk(KERN_DEBUG "\t1st 16 characters of name: %s\n", nm);
 }
 
+/**
+ * ubi_dbg_dump_flash - dump a region of flash.
+ * @ubi: UBI device description object
+ * @pnum: the physical eraseblock number to dump
+ * @offset: the starting offset within the physical eraseblock to dump
+ * @len: the length of the region to dump
+ */
+void ubi_dbg_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len)
+{
+        int err;
+        size_t read;
+        void *buf;
+        loff_t addr = (loff_t)pnum * ubi->peb_size + offset;
+
+        buf = vmalloc(len);
+        if (!buf)
+                return;
+        err = ubi->mtd->read(ubi->mtd, addr, len, &read, buf);
+        if (err && err != -EUCLEAN) {
+                ubi_err("error %d while reading %d bytes from PEB %d:%d, "
+                        "read %zd bytes", err, len, pnum, offset, read);
+                goto out;
+        }
+
+        dbg_msg("dumping %d bytes of data from PEB %d, offset %d",
+                len, pnum, offset);
+        print_hex_dump(KERN_DEBUG, "", DUMP_PREFIX_OFFSET, 32, 1, buf, len, 1);
+out:
+        vfree(buf);
+        return;
+}
+
 #endif /* CONFIG_MTD_UBI_DEBUG */
diff --git a/drivers/mtd/ubi/debug.h b/drivers/mtd/ubi/debug.h
index a4da7a09b949..f30bcb372c05 100644
--- a/drivers/mtd/ubi/debug.h
+++ b/drivers/mtd/ubi/debug.h
@@ -55,6 +55,7 @@ void ubi_dbg_dump_vtbl_record(const struct ubi_vtbl_record *r, int idx);
 void ubi_dbg_dump_sv(const struct ubi_scan_volume *sv);
 void ubi_dbg_dump_seb(const struct ubi_scan_leb *seb, int type);
 void ubi_dbg_dump_mkvol_req(const struct ubi_mkvol_req *req);
+void ubi_dbg_dump_flash(struct ubi_device *ubi, int pnum, int offset, int len);
 
 #ifdef CONFIG_MTD_UBI_DEBUG_MSG
 /* General debugging messages */
@@ -167,6 +168,7 @@ static inline int ubi_dbg_is_erase_failure(void)
 #define ubi_dbg_dump_sv(sv)              ({})
 #define ubi_dbg_dump_seb(seb, type)      ({})
 #define ubi_dbg_dump_mkvol_req(req)      ({})
+#define ubi_dbg_dump_flash(ubi, pnum, offset, len) ({})
 
 #define UBI_IO_DEBUG               0
 #define DBG_DISABLE_BGT            0
diff --git a/drivers/mtd/ubi/io.c b/drivers/mtd/ubi/io.c
index 4e7bcb215075..b693138fc519 100644
--- a/drivers/mtd/ubi/io.c
+++ b/drivers/mtd/ubi/io.c
@@ -269,6 +269,7 @@ int ubi_io_write(struct ubi_device *ubi, const void *buf, int pnum, int offset,
                 ubi_err("error %d while writing %d bytes to PEB %d:%d, written "
                         "%zd bytes", err, len, pnum, offset, written);
                 ubi_dbg_dump_stack();
+                ubi_dbg_dump_flash(ubi, pnum, offset, len);
         } else
                 ubi_assert(written == len);