From 18d2eeab8e4b12fd8c1083a760cf00e519a913f9 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?=C3=81lvaro=20Fern=C3=A1ndez=20Rojas?= <noltari@gmail.com>
Date: Tue, 2 Jun 2020 17:52:12 +0200
Subject: [PATCH] kernel: mtdsplit: support Broadcom WFI bootflags
MIME-Version: 1.0
Content-Type: text/plain; charset=UTF-8
Content-Transfer-Encoding: 8bit

When firmware is flashed, cferam.000 extension is renamed to the next number.
When booting, CFE scans the NAND and picks the partition with the highest
cferam extension and ignores the other one.

Signed-off-by: Álvaro Fernández Rojas <noltari@gmail.com>
---
 .../drivers/mtd/mtdsplit/mtdsplit_bcm_wfi.c   | 110 ++++++++++++++++++
 1 file changed, 110 insertions(+)

diff --git a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_bcm_wfi.c b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_bcm_wfi.c
index 7487567ed5..56bcff31c2 100644
--- a/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_bcm_wfi.c
+++ b/target/linux/generic/files/drivers/mtd/mtdsplit/mtdsplit_bcm_wfi.c
@@ -37,6 +37,10 @@
 
 #define UBI_MAGIC		0x55424923
 
+#define CFE_MAGIC_PFX		"cferam."
+#define CFE_MAGIC_PFX_LEN	(sizeof(CFE_MAGIC_PFX) - 1)
+#define CFE_MAGIC		"cferam.000"
+#define CFE_MAGIC_LEN		(sizeof(CFE_MAGIC) - 1)
 #define SERCOMM_MAGIC_PFX	"eRcOmM."
 #define SERCOMM_MAGIC_PFX_LEN	(sizeof(SERCOMM_MAGIC_PFX) - 1)
 #define SERCOMM_MAGIC		"eRcOmM.000"
@@ -250,6 +254,111 @@ static struct mtd_part_parser mtdsplit_bcm_wfi_parser = {
 	.type = MTD_PARSER_TYPE_FIRMWARE,
 };
 
+static int cferam_bootflag_value(const char *name, size_t name_len)
+{
+	int rc = -ENOENT;
+
+	if (name &&
+	    (name_len >= CFE_MAGIC_LEN) &&
+	    !memcmp(name, CFE_MAGIC_PFX, CFE_MAGIC_PFX_LEN)) {
+		rc = char_to_num(name[CFE_MAGIC_PFX_LEN + 0]) * 100;
+		rc += char_to_num(name[CFE_MAGIC_PFX_LEN + 1]) * 10;
+		rc += char_to_num(name[CFE_MAGIC_PFX_LEN + 2]) * 1;
+	}
+
+	return rc;
+}
+
+static int mtdsplit_parse_bcm_wfi_split(struct mtd_info *master,
+					const struct mtd_partition **pparts,
+					struct mtd_part_parser_data *data)
+{
+	loff_t cfe_off;
+	loff_t img1_off = 0;
+	loff_t img2_off = master->size / 2;
+	loff_t img1_size = (img2_off - img1_off);
+	loff_t img2_size = (master->size - img2_off);
+	loff_t active_off, inactive_off;
+	loff_t active_size, inactive_size;
+	uint8_t *buf;
+	char *cfe1_name = NULL, *cfe2_name = NULL;
+	size_t cfe1_size = 0, cfe2_size = 0;
+	int ret;
+	int bf1, bf2;
+
+	buf = kzalloc(master->erasesize, GFP_KERNEL);
+	if (!buf)
+		return -ENOMEM;
+
+	cfe_off = img1_off;
+	ret = jffs2_find_file(master, buf, CFERAM_NAME, CFERAM_NAME_LEN,
+			      &cfe_off, img1_size, &cfe1_name, &cfe1_size);
+
+	cfe_off = img2_off;
+	ret = jffs2_find_file(master, buf, CFERAM_NAME, CFERAM_NAME_LEN,
+			      &cfe_off, img2_size, &cfe2_name, &cfe2_size);
+
+	bf1 = cferam_bootflag_value(cfe1_name, cfe1_size);
+	if (bf1 >= 0)
+		printk("cferam: bootflag1=%d\n", bf1);
+
+	bf2 = cferam_bootflag_value(cfe2_name, cfe2_size);
+	if (bf2 >= 0)
+		printk("cferam: bootflag2=%d\n", bf2);
+
+	kfree(cfe1_name);
+	kfree(cfe2_name);
+
+	if (bf1 >= bf2) {
+		active_off = img1_off;
+		active_size = img1_size;
+		inactive_off = img2_off;
+		inactive_size = img2_size;
+	} else {
+		active_off = img2_off;
+		active_size = img2_size;
+		inactive_off = img1_off;
+		inactive_size = img1_size;
+	}
+
+	ret = parse_bcm_wfi(master, pparts, buf, active_off, active_size, true);
+
+	kfree(buf);
+
+	if (ret > 0) {
+		struct mtd_partition *parts;
+
+		parts = kzalloc((ret + 1) * sizeof(*parts), GFP_KERNEL);
+		if (!parts)
+			return -ENOMEM;
+
+		memcpy(parts, *pparts, ret * sizeof(*parts));
+		kfree(*pparts);
+
+		parts[ret].name = "img2";
+		parts[ret].offset = inactive_off;
+		parts[ret].size = inactive_size;
+		ret++;
+
+		*pparts = parts;
+	}
+
+	return ret;
+}
+
+static const struct of_device_id mtdsplit_bcm_wfi_split_of_match[] = {
+	{ .compatible = "brcm,wfi-split" },
+	{ },
+};
+
+static struct mtd_part_parser mtdsplit_bcm_wfi_split_parser = {
+	.owner = THIS_MODULE,
+	.name = "bcm-wfi-split-fw",
+	.of_match_table = mtdsplit_bcm_wfi_split_of_match,
+	.parse_fn = mtdsplit_parse_bcm_wfi_split,
+	.type = MTD_PARSER_TYPE_FIRMWARE,
+};
+
 static int sercomm_bootflag_value(struct mtd_info *mtd, uint8_t *buf)
 {
 	size_t retlen;
@@ -370,6 +479,7 @@ static struct mtd_part_parser mtdsplit_ser_wfi_parser = {
 static int __init mtdsplit_bcm_wfi_init(void)
 {
 	register_mtd_parser(&mtdsplit_bcm_wfi_parser);
+	register_mtd_parser(&mtdsplit_bcm_wfi_split_parser);
 	register_mtd_parser(&mtdsplit_ser_wfi_parser);
 
 	return 0;