ubispl: add support for loading volumes by name

The motivation is to use the UBI atomic volume rename functionality to
allow double copy software updates on UBI. To that end the SPL is
configured to always load the same volume name (e.g. "u-boot"),
whereas a software updater always installs into the secondary volume
"u-boot_r". After successful installation, these two volume names are
switched.

This extension is protected by #ifdefs as it will somewhat slow down
loading of volumes by id. This is because the code needs to disable
the optimization of ignoring all volume ids which are not
to-be-loaded, since these can only be resolved after attaching.

This adds two vtbl related functions from Linux, which are taken from
the same kernel version as the current main U-Boot UBI code (Linux 4.2
64291f7db5bd8).

Signed-off-by: Hamish Guthrie <hamish.guthrie@kistler.com>
Signed-off-by: Markus Klotzbuecher <markus.klotzbuecher@kistler.com>
Reviewed-by: Heiko Schocher <hs@denx.de>
Cc: Kyungmin Park <kmpark@infradead.org>

2 files changed, 220 insertions, 2 deletions

diff --git a/drivers/mtd/ubispl/ubispl.c b/drivers/mtd/ubispl/ubispl.c
index eeb1cbe..3f3b9b4 100644
--- a/drivers/mtd/ubispl/ubispl.c
+++ b/drivers/mtd/ubispl/ubispl.c
@@ -45,6 +45,187 @@ static int ubi_io_is_bad(struct ubi_scan_info *ubi, int peb)
 	return peb >= ubi->peb_count || peb < 0;
 }
 
+#ifdef CONFIG_SPL_UBI_LOAD_BY_VOLNAME
+
+/**
+ * ubi_dump_vtbl_record - dump a &struct ubi_vtbl_record object.
+ * @r: the object to dump
+ * @idx: volume table index
+ */
+void ubi_dump_vtbl_record(const struct ubi_vtbl_record *r, int idx)
+{
+	int name_len = be16_to_cpu(r->name_len);
+
+	ubi_dbg("Volume table record %d dump: size: %d",
+		idx, sizeof(struct ubi_vtbl_record));
+	ubi_dbg("\treserved_pebs   %d", be32_to_cpu(r->reserved_pebs));
+	ubi_dbg("\talignment       %d", be32_to_cpu(r->alignment));
+	ubi_dbg("\tdata_pad        %d", be32_to_cpu(r->data_pad));
+	ubi_dbg("\tvol_type        %d", (int)r->vol_type);
+	ubi_dbg("\tupd_marker      %d", (int)r->upd_marker);
+	ubi_dbg("\tname_len        %d", name_len);
+
+	if (r->name[0] == '\0') {
+		ubi_dbg("\tname            NULL");
+		return;
+	}
+
+	if (name_len <= UBI_VOL_NAME_MAX &&
+	    strnlen(&r->name[0], name_len + 1) == name_len) {
+		ubi_dbg("\tname            %s", &r->name[0]);
+	} else {
+		ubi_dbg("\t1st 5 characters of name: %c%c%c%c%c",
+			r->name[0], r->name[1], r->name[2], r->name[3],
+			r->name[4]);
+	}
+	ubi_dbg("\tcrc             %#08x", be32_to_cpu(r->crc));
+}
+
+/* Empty volume table record */
+static struct ubi_vtbl_record empty_vtbl_record;
+
+/**
+ * vtbl_check - check if volume table is not corrupted and sensible.
+ * @ubi: UBI device description object
+ * @vtbl: volume table
+ *
+ * This function returns zero if @vtbl is all right, %1 if CRC is incorrect,
+ * and %-EINVAL if it contains inconsistent data.
+ */
+static int vtbl_check(struct ubi_scan_info *ubi,
+		      struct ubi_vtbl_record *vtbl)
+{
+	int i, n, reserved_pebs, alignment, data_pad, vol_type, name_len;
+	int upd_marker, err;
+	uint32_t crc;
+	const char *name;
+
+	for (i = 0; i < UBI_SPL_VOL_IDS; i++) {
+		reserved_pebs = be32_to_cpu(vtbl[i].reserved_pebs);
+		alignment = be32_to_cpu(vtbl[i].alignment);
+		data_pad = be32_to_cpu(vtbl[i].data_pad);
+		upd_marker = vtbl[i].upd_marker;
+		vol_type = vtbl[i].vol_type;
+		name_len = be16_to_cpu(vtbl[i].name_len);
+		name = &vtbl[i].name[0];
+
+		crc = crc32(UBI_CRC32_INIT, &vtbl[i], UBI_VTBL_RECORD_SIZE_CRC);
+		if (be32_to_cpu(vtbl[i].crc) != crc) {
+			ubi_err("bad CRC at record %u: %#08x, not %#08x",
+				i, crc, be32_to_cpu(vtbl[i].crc));
+			ubi_dump_vtbl_record(&vtbl[i], i);
+			return 1;
+		}
+
+		if (reserved_pebs == 0) {
+			if (memcmp(&vtbl[i], &empty_vtbl_record,
+				   UBI_VTBL_RECORD_SIZE)) {
+				err = 2;
+				goto bad;
+			}
+			continue;
+		}
+
+		if (reserved_pebs < 0 || alignment < 0 || data_pad < 0 ||
+		    name_len < 0) {
+			err = 3;
+			goto bad;
+		}
+
+		if (alignment > ubi->leb_size || alignment == 0) {
+			err = 4;
+			goto bad;
+		}
+
+		n = alignment & (CONFIG_SPL_UBI_VID_OFFSET - 1);
+		if (alignment != 1 && n) {
+			err = 5;
+			goto bad;
+		}
+
+		n = ubi->leb_size % alignment;
+		if (data_pad != n) {
+			ubi_err("bad data_pad, has to be %d", n);
+			err = 6;
+			goto bad;
+		}
+
+		if (vol_type != UBI_VID_DYNAMIC && vol_type != UBI_VID_STATIC) {
+			err = 7;
+			goto bad;
+		}
+
+		if (upd_marker != 0 && upd_marker != 1) {
+			err = 8;
+			goto bad;
+		}
+
+		if (name_len > UBI_VOL_NAME_MAX) {
+			err = 10;
+			goto bad;
+		}
+
+		if (name[0] == '\0') {
+			err = 11;
+			goto bad;
+		}
+
+		if (name_len != strnlen(name, name_len + 1)) {
+			err = 12;
+			goto bad;
+		}
+
+		ubi_dump_vtbl_record(&vtbl[i], i);
+	}
+
+	/* Checks that all names are unique */
+	for (i = 0; i < UBI_SPL_VOL_IDS - 1; i++) {
+		for (n = i + 1; n < UBI_SPL_VOL_IDS; n++) {
+			int len1 = be16_to_cpu(vtbl[i].name_len);
+			int len2 = be16_to_cpu(vtbl[n].name_len);
+
+			if (len1 > 0 && len1 == len2 &&
+			    !strncmp(vtbl[i].name, vtbl[n].name, len1)) {
+				ubi_err("volumes %d and %d have the same name \"%s\"",
+					i, n, vtbl[i].name);
+				ubi_dump_vtbl_record(&vtbl[i], i);
+				ubi_dump_vtbl_record(&vtbl[n], n);
+				return -EINVAL;
+			}
+		}
+	}
+
+	return 0;
+
+bad:
+	ubi_err("volume table check failed: record %d, error %d", i, err);
+	ubi_dump_vtbl_record(&vtbl[i], i);
+	return -EINVAL;
+}
+
+static int ubi_read_volume_table(struct ubi_scan_info *ubi, u32 pnum)
+{
+	int err = -EINVAL;
+
+	empty_vtbl_record.crc = cpu_to_be32(0xf116c36b);
+
+	err = ubi_io_read(ubi, &ubi->vtbl, pnum, ubi->leb_start,
+			  sizeof(struct ubi_vtbl_record) * UBI_SPL_VOL_IDS);
+	if (err && err != UBI_IO_BITFLIPS) {
+		ubi_err("unable to read volume table");
+		goto out;
+	}
+
+	if (!vtbl_check(ubi, ubi->vtbl)) {
+		ubi->vtbl_valid = 1;
+		err = 0;
+	}
+out:
+	return err;
+}
+
+#endif /* CONFIG_SPL_UBI_LOAD_BY_VOLNAME */
+
 static int ubi_io_read_vid_hdr(struct ubi_scan_info *ubi, int pnum,
 			       struct ubi_vid_hdr *vh, int unused)
 {
@@ -210,14 +391,23 @@ static int ubi_scan_vid_hdr(struct ubi_scan_info *ubi, struct ubi_vid_hdr *vh,
 	if (vol_id == UBI_FM_SB_VOLUME_ID)
 		return ubi->fm_enabled ? UBI_FASTMAP_ANCHOR : 0;
 
+#ifdef CONFIG_SPL_UBI_LOAD_BY_VOLNAME
+	/* If this is a UBI volume table, read it and return */
+	if (vol_id == UBI_LAYOUT_VOLUME_ID && !ubi->vtbl_valid) {
+		res = ubi_read_volume_table(ubi, pnum);
+		return res;
+	}
+#endif
+
 	/* We only care about static volumes with an id < UBI_SPL_VOL_IDS */
 	if (vol_id >= UBI_SPL_VOL_IDS || vh->vol_type != UBI_VID_STATIC)
 		return 0;
 
+#ifndef CONFIG_SPL_UBI_LOAD_BY_VOLNAME
 	/* We are only interested in the volumes to load */
 	if (!test_bit(vol_id, ubi->toload))
 		return 0;
-
+#endif
 	lnum = be32_to_cpu(vh->lnum);
 	return ubi_add_peb_to_vol(ubi, vh, vol_id, pnum, lnum);
 }
@@ -232,13 +422,14 @@ static int assign_aeb_to_av(struct ubi_scan_info *ubi, u32 pnum, u32 lnum,
 
 	ubi->fastmap_pebs++;
 
+#ifndef CONFIG_SPL_UBI_LOAD_BY_VOLNAME
 	if (vol_id >= UBI_SPL_VOL_IDS || vol_type != UBI_STATIC_VOLUME)
 		return 0;
 
 	/* We are only interested in the volumes to load */
 	if (!test_bit(vol_id, ubi->toload))
 		return 0;
-
+#endif
 	vh = ubi->blockinfo + pnum;
 
 	return ubi_scan_vid_hdr(ubi, vh, pnum);
@@ -892,6 +1083,10 @@ retry:
 	ubi->peb_count = info->peb_count;
 	ubi->peb_offset = info->peb_offset;
 
+#ifdef CONFIG_SPL_UBI_LOAD_BY_VOLNAME
+	ubi->vtbl_valid = 0;
+#endif
+
 	fsize = info->peb_size * info->peb_count;
 	ubi->fsize_mb = fsize >> 20;
 
@@ -910,7 +1105,23 @@ retry:
 	for (i = 0; i < nrvols; i++) {
 		struct ubispl_load *lv = lvols + i;
 
+#ifdef CONFIG_SPL_UBI_LOAD_BY_VOLNAME
+		if (lv->vol_id == -1) {
+			for (int j = 0; j < UBI_SPL_VOL_IDS; j++) {
+				int len = be16_to_cpu(ubi->vtbl[j].name_len);
+
+				if (strncmp(lv->name,
+					    ubi->vtbl[j].name,
+					    len) == 0) {
+					lv->vol_id = j;
+					break;
+				}
+			}
+		}
+		ubi_msg("Loading VolName %s (VolId #%d)", lv->name, lv->vol_id);
+#else
 		ubi_msg("Loading VolId #%d", lv->vol_id);
+#endif
 		res = ipl_load(ubi, lv->vol_id, lv->load_addr);
 		if (res < 0) {
 			if (fastmap) {
diff --git a/drivers/mtd/ubispl/ubispl.h b/drivers/mtd/ubispl/ubispl.h
index 9e40b46..bcc376c 100644
--- a/drivers/mtd/ubispl/ubispl.h
+++ b/drivers/mtd/ubispl/ubispl.h
@@ -77,6 +77,8 @@ struct ubi_vol_info {
  * @blockinfo:		The vid headers of the scanned blocks
  * @volinfo:		The volume information of the interesting (toload)
  *			volumes
+ * @vtbl_corrupted:	Flag to indicate status of volume table
+ * @vtbl:		Volume table
  *
  * @fm_buf:		The large fastmap attach buffer
  */
@@ -112,6 +114,11 @@ struct ubi_scan_info {
 	struct ubi_vol_info		volinfo[UBI_SPL_VOL_IDS];
 	struct ubi_vid_hdr		blockinfo[CONFIG_SPL_UBI_MAX_PEBS];
 
+#ifdef CONFIG_SPL_UBI_LOAD_BY_VOLNAME
+	/* Volume table */
+	int                             vtbl_valid;
+	struct ubi_vtbl_record          vtbl[UBI_SPL_VOL_IDS];
+#endif
 	/* The large buffer for the fastmap */
 	uint8_t				fm_buf[UBI_FM_BUF_SIZE];
 };