Message-ID: <5668A33E.4040405@simon.arlott.org.uk>
Date:	Wed, 9 Dec 2015 21:55:10 +0000
From:	Simon Arlott <simon@...e.lp0.eu>
To:	David Woodhouse <dwmw2@...radead.org>,
	Brian Norris <computersforpeace@...il.com>
Cc:	Linux Kernel Mailing List <linux-kernel@...r.kernel.org>,
	MTD Maling List <linux-mtd@...ts.infradead.org>,
	Florian Fainelli <f.fainelli@...il.com>,
	Jonas Gorski <jogo@...nwrt.org>,
	bcm-kernel-feedback-list <bcm-kernel-feedback-list@...adcom.com>
Subject: [PATCH linux-next] mtd: part: Add BCM962368 CFE partitioning support

Add partitioning support for BCM963268 boards with CFE bootloaders.
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:
[    1.904302] nand: device found, Manufacturer ID: 0xc2, Chip ID: 0xf1
[    1.911000] nand: Macronix NAND 128MiB 3,3V 8-bit
[    1.915855] nand: 128 MiB, SLC, erase size: 128 KiB, page size: 2048, OOB size: 64
[    1.923797] bcm6368_nand 10000200.nand: detected 128MiB total, 128KiB blocks, 2KiB pages, 16B OOB, 8-bit, Hamming ECC
[    1.936994] Bad block table found at page 65472, version 0x01
[    1.944121] Bad block table found at page 65408, version 0x01
[    1.951166] nand_read_bbt: bad block at 0x000007480000
[    1.990043] bcm963268part: rootfs1: CFE boot tag found at 0x20000 with version 6, board type 963168VX and sequence number 2
[    2.003060] bcm963268part: rootfs2: CFE boot tag found at 0x4000000 with version 6, board type 963168VX and sequence number 1
[    2.015159] bcm963268part: CFE bootline selected latest image rootfs1
[    2.022080] 6 bcm963268part partitions found on MTD device brcmnand.0
[    2.042659] Creating 6 MTD partitions on "brcmnand.0":
[    2.048025] 0x000000000000-0x000000020000 : "boot"
[    2.062134] 0x000000040000-0x000001120000 : "rootfs"
[    2.077632] 0x000007b00000-0x000007f00000 : "data"
[    2.091363] 0x000000020000-0x000003ac0000 : "rootfs1_update"
[    2.106228] 0x000004000000-0x000007ac0000 : "rootfs2_update"
[    2.121093] 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 verified by
reading from the boot partition which is assumed to be at offset 0
and the 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 or nvram partition number is used to select a rootfs.

Signed-off-by: Simon Arlott <simon@...e.lp0.eu>
---
I'm aware that this is not compatible with the mtd partition/device tree
reorganisation patches and will rework the patch when this is committed.

Should I try to put the "struct bcm963268_nvram" in a common header file
for all 63xx SoCs? It's hard to know if there is only one purpose for
each byte in the nvram across all SoCs or whether it would be a complex
type involving unions for different SoCs.

The partitioning needs to match what exists already for this board so
that it's practical to swap between an flash image released by the
manufacturer/distributor of the hardware, and a custom image based on
the latest vanilla kernel.

 drivers/mtd/Kconfig         |  21 +++
 drivers/mtd/Makefile        |   1 +
 drivers/mtd/bcm963268part.c | 373 ++++++++++++++++++++++++++++++++++++++++++++
 3 files changed, 395 insertions(+)
 create mode 100644 drivers/mtd/bcm963268part.c

diff --git a/drivers/mtd/Kconfig b/drivers/mtd/Kconfig
index 42cc953..63cb2db 100644
--- a/drivers/mtd/Kconfig
+++ b/drivers/mtd/Kconfig
@@ -148,6 +148,27 @@ config MTD_BCM63XX_PARTS
 	  This provides partions parsing for BCM63xx devices with CFE
 	  bootloaders.
 
+config MTD_BCM963268_PARTS
+	tristate "BCM963268 CFE partitioning support"
+	depends on BMIPS_GENERIC
+	select CRC32
+	help
+	  This provides partitions parsing for BCM963268 boards with CFE
+	  bootloaders. 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
+
+	  A decision is made regarding which of the two rootfs is to be
+	  used based on the nvram data.
+
 config MTD_BCM47XX_PARTS
 	tristate "BCM47XX partitioning support"
 	depends on BCM47XX || ARCH_BCM_5301X
diff --git a/drivers/mtd/Makefile b/drivers/mtd/Makefile
index 99bb9a1..f0f4140 100644
--- a/drivers/mtd/Makefile
+++ b/drivers/mtd/Makefile
@@ -12,6 +12,7 @@ obj-$(CONFIG_MTD_CMDLINE_PARTS) += cmdlinepart.o
 obj-$(CONFIG_MTD_AFS_PARTS)	+= afs.o
 obj-$(CONFIG_MTD_AR7_PARTS)	+= ar7part.o
 obj-$(CONFIG_MTD_BCM63XX_PARTS)	+= bcm63xxpart.o
+obj-$(CONFIG_MTD_BCM963268_PARTS) += bcm963268part.o
 obj-$(CONFIG_MTD_BCM47XX_PARTS)	+= bcm47xxpart.o
 
 # 'Users' - code which presents functionality to userspace.
diff --git a/drivers/mtd/bcm963268part.c b/drivers/mtd/bcm963268part.c
new file mode 100644
index 0000000..a86de15
--- /dev/null
+++ b/drivers/mtd/bcm963268part.c
@@ -0,0 +1,373 @@
+/*
+ * BCM963268 CFE image tag parser
+ * Copyright 2015 Simon Arlott
+ *
+ * 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.
+ *
+ * Derived from drivers/mtd/bcm63xxpart.c:
+ * Copyright © 2006-2008  Florian Fainelli <florian@...nwrt.org>
+ *			  Mike Albon <malbon@...nwrt.org>
+ * Copyright © 2009-2010  Daniel Dickinson <openwrt@...ore.neomailbox.net>
+ * Copyright © 2011-2013  Jonas Gorski <jonas.gorski@...il.com>
+ *
+ * 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
+
+#include <linux/crc32.h>
+#include <linux/if_ether.h>
+#include <linux/module.h>
+#include <linux/kernel.h>
+#include <linux/sizes.h>
+#include <linux/slab.h>
+#include <linux/vmalloc.h>
+#include <linux/mtd/mtd.h>
+#include <linux/mtd/partitions.h>
+
+#include <asm/mach-bcm63xx/bcm963xx_tag.h>
+
+/* Extended flash address, needs to be subtracted from bcm_tag flash offsets */
+#define BCM63XX_EXTENDED_SIZE		0xBFC00000
+
+#define BCM63XX_CFE_MAGIC_OFFSET	0x4e0
+#define BCM963XX_CFE_VERSION_OFFSET	0x570
+#define BCM963XX_NVRAM_OFFSET		0x580
+
+enum bcm963268_nvram_part {
+	PART_BOOT = 0,
+	PART_ROOTFS_1,
+	PART_ROOTFS_2,
+	PART_DATA,
+	PART_BBT,
+	NR_PARTS
+};
+
+/*
+ * nvram structure
+ */
+struct bcm963268_nvram {
+	u32	version;
+	char	bootline[256];
+	u8	name[16];
+	u32	main_tp_number;
+	u32	psi_size;
+	u32	mac_addr_count;
+	u8	mac_addr_base[ETH_ALEN];
+	u8	reserved1[2];
+	u32	checksum_old;
+	u8	reserved2[292];
+	u32	part_offset[NR_PARTS];
+	u32	part_size[NR_PARTS];
+	u8	reserved3[254];
+	char	partition_number;
+	u8	reserved4[133];
+	u32	checksum_high;
+} __packed;
+
+static int bcm963268_detect_cfe(struct mtd_info *master)
+{
+	char buf[9];
+	int ret;
+	size_t retlen;
+
+	ret = mtd_read(master, BCM963XX_CFE_VERSION_OFFSET, 5, &retlen,
+		       (void *)buf);
+	buf[retlen] = 0;
+
+	if (ret < 0)
+		return ret;
+
+	if (strncmp("cfe-v", buf, 5) == 0)
+		return 0;
+
+	return -EINVAL;
+}
+
+static int bcm963268_read_nvram(struct mtd_info *master,
+	struct bcm963268_nvram *nvram)
+{
+	unsigned int check_len;
+	u32 crc, expected_crc;
+	size_t retlen;
+	int ret;
+
+	/* extract nvram data */
+	ret = mtd_read(master, BCM963XX_NVRAM_OFFSET, sizeof(*nvram), &retlen,
+		       (void *)nvram);
+
+	if (ret < 0)
+		return ret;
+
+	if (nvram->version < 6) {
+		pr_warn("nvram version %d not supported\n", nvram->version);
+		return -EINVAL;
+	}
+
+	/* check checksum before using data */
+	check_len = sizeof(*nvram);
+	expected_crc = nvram->checksum_high;
+	nvram->checksum_high = 0;
+
+	crc = crc32_le(~0, (u8 *)nvram, check_len);
+
+	if (crc != expected_crc)
+		pr_warn("nvram checksum failed, contents may be invalid (expected %08x, got %08x)\n",
+			expected_crc, crc);
+
+	return 0;
+}
+
+static bool bcm963268_boot_latest(struct bcm963268_nvram *nvram)
+{
+	char *p;
+
+	/* Ensure bootline is null terminated */
+	nvram->bootline[sizeof(nvram->bootline) - 1] = 0;
+
+	/* 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;
+	if (*p == '\0')
+		return true;
+
+	return *p != '0';
+}
+
+static bool bcm963268_parse_rootfs_tag(struct mtd_info *master,
+	const char *name, loff_t rootfs_part, u64 *rootfs_offset,
+	u64 *rootfs_size, unsigned int *rootfs_sequence)
+{
+	struct bcm_tag *buf;
+	int ret;
+	size_t retlen;
+	u32 computed_crc;
+	bool rootfs_ok = false;
+
+	*rootfs_offset = 0;
+	*rootfs_size = 0;
+	*rootfs_sequence = 0;
+
+	buf = vmalloc(sizeof(struct bcm_tag));
+	if (!buf)
+		goto out;
+
+	ret = mtd_read(master, rootfs_part, sizeof(*buf), &retlen, (void *)buf);
+	if (ret < 0)
+		goto out;
+
+	if (retlen != sizeof(*buf))
+		goto out;
+
+	computed_crc = crc32_le(IMAGETAG_CRC_START, (u8 *)buf,
+				offsetof(struct bcm_tag, header_crc));
+	if (computed_crc == buf->header_crc) {
+		char *board_id = &buf->board_id[0];
+		char *tag_version = &buf->tag_version[0];
+
+		/* Get rootfs offset and size from tag data */
+		kstrtou64(buf->flash_image_start, 10, rootfs_offset);
+		kstrtou64(buf->root_length, 10, rootfs_size);
+		kstrtouint(buf->dual_image, 10, rootfs_sequence);
+
+		pr_info("%s: CFE boot tag found at 0x%llx with version %s, board type %s and sequence number %u\n",
+			name, rootfs_part, tag_version, board_id,
+			*rootfs_sequence);
+
+		/* Adjust for flash offset */
+		*rootfs_offset -= BCM63XX_EXTENDED_SIZE;
+
+		/* Remove bcm_tag data from length */
+		*rootfs_size -= *rootfs_offset - rootfs_part;
+
+		rootfs_ok = true;
+	} else {
+		pr_warn("%s: CFE boot tag at 0x%llx CRC invalid (expected %08x, actual %08x)\n",
+			name, rootfs_part, buf->header_crc, computed_crc);
+		goto out;
+	}
+
+out:
+	vfree(buf);
+	return rootfs_ok;
+}
+
+static int bcm963268_parse_cfe_partitions(struct mtd_info *master,
+					struct mtd_partition **pparts,
+					struct mtd_part_parser_data *data)
+{
+	int nrparts, curpart;
+	struct bcm963268_nvram *nvram = NULL;
+	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;
+	int ret;
+
+	if (bcm963268_detect_cfe(master)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	nvram = vmalloc(sizeof(*nvram));
+	if (!nvram) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	if (bcm963268_read_nvram(master, nvram)) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* We've just read the nvram from offset 0,
+	 * so it must be located there.
+	 */
+	if (nvram->part_offset[PART_BOOT] != 0) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Get the rootfs partition locations */
+	rootfs1 = bcm963268_parse_rootfs_tag(master, "rootfs1",
+		nvram->part_offset[PART_ROOTFS_1] * SZ_1K,
+		&rootfs1_off, &rootfs1_size, &rootfs1_seq);
+	rootfs2 = bcm963268_parse_rootfs_tag(master, "rootfs2",
+		nvram->part_offset[PART_ROOTFS_2] * SZ_1K,
+		&rootfs2_off, &rootfs2_size, &rootfs2_seq);
+	if (!rootfs1 && !rootfs2) {
+		ret = -EINVAL;
+		goto out;
+	}
+
+	/* Determine primary rootfs partition */
+	if (rootfs1 && rootfs2) {
+		if (nvram->partition_number == '0') {
+			use_first = true;
+			pr_info("NVRAM partition number selected rootfs1\n");
+		} else if (nvram->partition_number == '1') {
+			use_first = false;
+			pr_info("NVRAM partition number selected rootfs2\n");
+		} else {
+			bool use_latest = bcm963268_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\n",
+				use_latest ? "latest" : "previous",
+				use_first ? 1 : 2);
+		}
+	} else {
+		use_first = rootfs1;
+	}
+
+	/* Partitions:
+	 * 1 boot
+	 * 2 rootfs
+	 * 3 data
+	 * 4 rootfs1_update
+	 * 5 rootfs2_update
+	 * 6 rootfs_other
+	 */
+	nrparts = 6;
+	curpart = 0;
+
+	parts = kcalloc(nrparts, sizeof(*parts), GFP_KERNEL);
+	if (!parts) {
+		ret = -ENOMEM;
+		goto out;
+	}
+
+	parts[curpart].name = "boot";
+	parts[curpart].offset = nvram->part_offset[PART_BOOT] * SZ_1K;
+	parts[curpart].size = nvram->part_size[PART_BOOT] * SZ_1K;
+	curpart++;
+
+	parts[curpart].name = "rootfs";
+	parts[curpart].offset = use_first ? rootfs1_off : rootfs2_off;
+	parts[curpart].size = use_first ? rootfs1_size : rootfs2_size;
+	curpart++;
+
+	parts[curpart].name = "data";
+	parts[curpart].offset = nvram->part_offset[PART_DATA] * SZ_1K;
+	parts[curpart].size = nvram->part_size[PART_DATA] * SZ_1K;
+	curpart++;
+
+	/* Full rootfs partitions for updates */
+	parts[curpart].name = "rootfs1_update";
+	parts[curpart].offset = nvram->part_offset[PART_ROOTFS_1] * SZ_1K;
+	parts[curpart].size = nvram->part_size[PART_ROOTFS_1] * SZ_1K;
+	curpart++;
+
+	parts[curpart].name = "rootfs2_update";
+	parts[curpart].offset = nvram->part_offset[PART_ROOTFS_2] * SZ_1K;
+	parts[curpart].size = nvram->part_size[PART_ROOTFS_2] * SZ_1K;
+	curpart++;
+
+	/* Other rootfs if both are available */
+	if (rootfs1 && rootfs2) {
+		parts[curpart].name = "rootfs_other";
+		parts[curpart].offset = use_first ? rootfs2_off : rootfs1_off;
+		parts[curpart].size = use_first ? rootfs2_size : rootfs1_size;
+		curpart++;
+	}
+
+	*pparts = parts;
+	ret = 0;
+
+out:
+	vfree(nvram);
+
+	if (ret < 0)
+		return ret;
+
+	return nrparts;
+};
+
+static struct mtd_part_parser bcm963268_cfe_parser = {
+	.owner = THIS_MODULE,
+	.parse_fn = bcm963268_parse_cfe_partitions,
+	.name = "bcm963268part",
+};
+
+static int __init bcm963268_cfe_parser_init(void)
+{
+	register_mtd_parser(&bcm963268_cfe_parser);
+	return 0;
+}
+
+static void __exit bcm963268_cfe_parser_exit(void)
+{
+	deregister_mtd_parser(&bcm963268_cfe_parser);
+}
+
+module_init(bcm963268_cfe_parser_init);
+module_exit(bcm963268_cfe_parser_exit);
+
+MODULE_LICENSE("GPL");
+MODULE_AUTHOR("Simon Arlott");
+MODULE_DESCRIPTION("MTD partitioning for BCM963268 CFE bootloaders");
-- 
2.1.4

-- 
Simon Arlott
--
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