[PATCH linux-next v4 11/11] mtd: bcm63xxpart: Add NAND partitioning support

[Simon Arlott <simon@fire.lp0.eu>]

Add partitioning support for BCM963xx boards with NAND flash.

The following partitions are defined:
  "boot":           CFE and nvram data
  "rootfs":         Currently selected rootfs
  "data":           Configuration data
  "rootfs1_update": Container for the whole flash area used
                    for the first rootfs to allow it to be
                    updated
  "rootfs2_update": Container for the whole flash area used
                    for the second rootfs to allow it to be
                    updated
  "rootfs_other":   The other (not currently selected) rootfs

Example:
[    2.157094] nand: device found, Manufacturer ID: 0xc2, Chip ID: 0xf1
[    2.163796] nand: Macronix NAND 128MiB 3,3V 8-bit
[    2.168648] nand: 128 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
[    2.176588] bcm6368_nand 10000200.nand: detected 128MiB total, 128KiB blocks, 2KiB pages, 16B OOB, 8-bit, Hamming ECC
[    2.189782] Bad block table found at page 65472, version 0x01
[    2.196910] Bad block table found at page 65408, version 0x01
[    2.204003] nand_read_bbt: bad block at 0x000007480000
[    2.225220] bcm63xxpart: rootfs1: CFE image tag found at 0x20000 with version 6, board type 963168VX
[    2.236188] bcm63xxpart: rootfs2: CFE image tag found at 0x4000000 with version 6, board type 963168VX
[    2.246165] bcm63xxpart: CFE bootline selected latest image rootfs1 (rootfs1_seq=2, rootfs2_seq=1)
[    2.255800] 6 bcm63xxpart partitions found on MTD device brcmnand.0
[    2.275360] Creating 6 MTD partitions on "brcmnand.0":
[    2.280804] 0x000000000000-0x000000020000 : "boot"
[    2.294609] 0x000000040000-0x000001120000 : "rootfs"
[    2.310078] 0x000007b00000-0x000007f00000 : "data"
[    2.324052] 0x000000020000-0x000003ac0000 : "rootfs1_update"
[    2.339190] 0x000004000000-0x000007ac0000 : "rootfs2_update"
[    2.354290] 0x000004020000-0x000005060000 : "rootfs_other"

The nvram contains the offset and size of the boot, rootfs1, rootfs2
and data partitions. The presence of CFE and nvram is already verified
by reading from the boot partition which is assumed to be at offset 0
and the NAND process aborts if the nvram read indicates that this is
not the case.

There is bcm_tag information at the start of each rootfs that is used
to determine which rootfs is newer and what its real offset/size is.

The CFE bootline is used to select a rootfs.

Signed-off-by: Simon Arlott <simon@fire.lp0.eu>
---
v4: Reorganised functions based on earlier new patches in the series,
    no real logic changes other than having to check for nvram->version
    >= 6 within the nand function instead of the nvram read function.

    Renamed "curpart" to "i" because it allows the partition layout
    lines to be under 80 characters.

v3: Use COMPILE_TEST.

    Ensure that strings read from flash are null terminated and validate
    bcm_tag integer values (this also moves reporting of rootfs sequence
    numbers to later on).

v2: Use external struct bcm963xx_nvram definition for bcm963268part.

    Removed support for the nand partition number field, it's not a
    standard Broadcom field (was added by MitraStar Technology Corp.).

 drivers/mtd/bcm63xxpart.c | 196 ++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 190 insertions(+), 6 deletions(-)

diff --git a/drivers/mtd/bcm63xxpart.c b/drivers/mtd/bcm63xxpart.c
index 26c38a1..4576b78 100644
--- a/drivers/mtd/bcm63xxpart.c
+++ b/drivers/mtd/bcm63xxpart.c
@@ -16,10 +16,9 @@
  * 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., 51 Franklin St, Fifth Floor, Boston, MA  02110-1301  USA
- *
+ * NAND flash layout derived from bcm963xx_4.12L.06B_consumer/bcmdrivers/opensource/char/board/bcm963xx/impl1/board.c,
+ *	bcm963xx_4.12L.06B_consumer/shared/opensource/include/bcm963xx/bcm_hwdefs.h:
+ * Copyright (c) 2002 Broadcom Corporation
  */
 
 #define pr_fmt(fmt) KBUILD_MODNAME ": " fmt
@@ -124,6 +123,25 @@ static int bcm63xx_read_image_tag(struct mtd_info *master, const char *name,
 	return 1;
 }
 
+static bool bcm63xx_boot_latest(struct bcm963xx_nvram *nvram)
+{
+	char *p;
+
+	STR_NULL_TERMINATE(nvram->bootline);
+
+	/* Find previous image parameter "p" */
+	if (!strncmp(nvram->bootline, "p=", 2))
+		p = nvram->bootline;
+	else
+		p = strstr(nvram->bootline, " p=");
+
+	if (p == NULL)
+		return true;
+
+	p += 2;
+	return *p != '0';
+}
+
 static int bcm63xx_parse_cfe_nor_partitions(struct mtd_info *master,
 	const struct mtd_partition **pparts, struct bcm963xx_nvram *nvram)
 {
@@ -283,6 +301,171 @@ out:
 	return nrparts;
 }
 
+static bool bcm63xx_parse_nand_image_tag(struct mtd_info *master,
+	const char *name, loff_t tag_offset, u64 *rootfs_offset,
+	u64 *rootfs_size, unsigned int *rootfs_sequence)
+{
+	struct bcm_tag *buf;
+	int ret;
+	bool rootfs_ok = false;
+
+	*rootfs_offset = 0;
+	*rootfs_size = 0;
+	*rootfs_sequence = 0;
+
+	buf = vmalloc(sizeof(struct bcm_tag));
+	if (!buf)
+		goto out;
+
+	ret = bcm63xx_read_image_tag(master, name, tag_offset, buf);
+	if (!ret) {
+		/* Get rootfs offset and size from tag data */
+		STR_NULL_TERMINATE(buf->flash_image_start);
+		if (kstrtou64(buf->flash_image_start, 10, rootfs_offset) ||
+				*rootfs_offset < BCM963XX_EXTENDED_SIZE) {
+			pr_err("%s: invalid rootfs offset: %*ph\n", name,
+				sizeof(buf->flash_image_start),
+				buf->flash_image_start);
+			goto out;
+		}
+
+		STR_NULL_TERMINATE(buf->root_length);
+		if (kstrtou64(buf->root_length, 10, rootfs_size) ||
+				rootfs_size == 0) {
+			pr_err("%s: invalid rootfs size: %*ph\n", name,
+				sizeof(buf->root_length), buf->root_length);
+			goto out;
+		}
+
+		/* Adjust for flash offset */
+		*rootfs_offset -= BCM963XX_EXTENDED_SIZE;
+
+		/* Remove bcm_tag data from length */
+		*rootfs_size -= *rootfs_offset - tag_offset;
+
+		/* Get image sequence number to determine which one is newer */
+		STR_NULL_TERMINATE(buf->image_sequence);
+		if (kstrtouint(buf->image_sequence, 10, rootfs_sequence)) {
+			pr_err("%s: invalid rootfs sequence: %*ph\n", name,
+				sizeof(buf->image_sequence),
+				buf->image_sequence);
+			goto out;
+		}
+
+		rootfs_ok = true;
+	}
+
+out:
+	vfree(buf);
+	return rootfs_ok;
+}
+
+static int bcm63xx_parse_cfe_nand_partitions(struct mtd_info *master,
+	const struct mtd_partition **pparts,
+	struct bcm963xx_nvram *nvram)
+{
+	int nrparts, i;
+	struct mtd_partition *parts;
+	u64 rootfs1_off, rootfs1_size;
+	unsigned int rootfs1_seq;
+	u64 rootfs2_off, rootfs2_size;
+	unsigned int rootfs2_seq;
+	bool rootfs1, rootfs2;
+	bool use_first;
+
+	if (nvram->version < 6) {
+		pr_warn("nvram version %u not supported\n", nvram->version);
+		return -EINVAL;
+	}
+
+	/* We've just read the nvram from offset 0,
+	 * so it must be located there.
+	 */
+	if (BCM963XX_NVRAM_NAND_PART_OFFSET(nvram, BOOT) != 0)
+		return -EINVAL;
+
+	/* Get the rootfs partition locations */
+	rootfs1 = bcm63xx_parse_nand_image_tag(master, "rootfs1",
+		BCM963XX_NVRAM_NAND_PART_OFFSET(nvram, ROOTFS_1),
+		&rootfs1_off, &rootfs1_size, &rootfs1_seq);
+	rootfs2 = bcm63xx_parse_nand_image_tag(master, "rootfs2",
+		BCM963XX_NVRAM_NAND_PART_OFFSET(nvram, ROOTFS_2),
+		&rootfs2_off, &rootfs2_size, &rootfs2_seq);
+
+	/* Determine primary rootfs partition */
+	if (rootfs1 && rootfs2) {
+		bool use_latest = bcm63xx_boot_latest(nvram);
+
+		/* Compare sequence numbers */
+		if (use_latest)
+			use_first = rootfs1_seq > rootfs2_seq;
+		else
+			use_first = rootfs1_seq < rootfs2_seq;
+
+		pr_info("CFE bootline selected %s image rootfs%u (rootfs1_seq=%u, rootfs2_seq=%u)\n",
+			use_latest ? "latest" : "previous",
+			use_first ? 1 : 2,
+			rootfs1_seq, rootfs2_seq);
+	} else {
+		use_first = rootfs1;
+	}
+
+	/* Partitions:
+	 * 1 boot
+	 * 2 rootfs
+	 * 3 data
+	 * 4 rootfs1_update
+	 * 5 rootfs2_update
+	 * 6 rootfs_other
+	 */
+	nrparts = 6;
+	i = 0;
+
+	parts = kcalloc(nrparts, sizeof(*parts), GFP_KERNEL);
+	if (!parts)
+		return -ENOMEM;
+
+	parts[i].name = "boot";
+	parts[i].offset = BCM963XX_NVRAM_NAND_PART_OFFSET(nvram, BOOT);
+	parts[i].size = BCM963XX_NVRAM_NAND_PART_SIZE(nvram, BOOT);
+	i++;
+
+	/* Primary rootfs if either is available */
+	if (rootfs1 || rootfs2) {
+		parts[i].name = "rootfs";
+		parts[i].offset = use_first ? rootfs1_off : rootfs2_off;
+		parts[i].size = use_first ? rootfs1_size : rootfs2_size;
+		i++;
+	}
+
+	parts[i].name = "data";
+	parts[i].offset = BCM963XX_NVRAM_NAND_PART_OFFSET(nvram, DATA);
+	parts[i].size = BCM963XX_NVRAM_NAND_PART_SIZE(nvram, DATA);
+	i++;
+
+	/* Full rootfs partitions for updates */
+	parts[i].name = "rootfs1_update";
+	parts[i].offset = BCM963XX_NVRAM_NAND_PART_OFFSET(nvram, ROOTFS_1);
+	parts[i].size = BCM963XX_NVRAM_NAND_PART_SIZE(nvram, ROOTFS_1);
+	i++;
+
+	parts[i].name = "rootfs2_update";
+	parts[i].offset = BCM963XX_NVRAM_NAND_PART_OFFSET(nvram, ROOTFS_2);
+	parts[i].size = BCM963XX_NVRAM_NAND_PART_SIZE(nvram, ROOTFS_2);
+	i++;
+
+	/* Other rootfs if both are available */
+	if (rootfs1 && rootfs2) {
+		parts[i].name = "rootfs_other";
+		parts[i].offset = use_first ? rootfs2_off : rootfs1_off;
+		parts[i].size = use_first ? rootfs2_size : rootfs1_size;
+		i++;
+	}
+
+	*pparts = parts;
+	return nrparts;
+}
+
 static int bcm63xx_parse_cfe_partitions(struct mtd_info *master,
 					const struct mtd_partition **pparts,
 					struct mtd_part_parser_data *data)
@@ -304,7 +487,7 @@ static int bcm63xx_parse_cfe_partitions(struct mtd_info *master,
 	if (!mtd_type_is_nand(master))
 		ret = bcm63xx_parse_cfe_nor_partitions(master, pparts, nvram);
 	else
-		ret = -EINVAL;
+		ret = bcm63xx_parse_cfe_nand_partitions(master, pparts, nvram);
 
 out:
 	vfree(nvram);
@@ -321,5 +504,6 @@ MODULE_LICENSE("GPL");
 MODULE_AUTHOR("Daniel Dickinson <openwrt@cshore.neomailbox.net>");
 MODULE_AUTHOR("Florian Fainelli <florian@openwrt.org>");
 MODULE_AUTHOR("Mike Albon <malbon@openwrt.org>");
-MODULE_AUTHOR("Jonas Gorski <jonas.gorski@gmail.com");
+MODULE_AUTHOR("Jonas Gorski <jonas.gorski@gmail.com>");
+MODULE_AUTHOR("Simon Arlott");
 MODULE_DESCRIPTION("MTD partitioning for BCM63XX CFE bootloaders");
-- 
2.1.4

-- 
Simon Arlott