kernel: add pending bcm47xxpart support for failsafe TRX partition

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>

1 files changed, 108 insertions, 0 deletions

diff --git a/target/linux/generic/patches-4.4/141-0002-mtd-bcm47xxpart-support-layouts-with-multiple-TRX-pa.patch b/target/linux/generic/patches-4.4/141-0002-mtd-bcm47xxpart-support-layouts-with-multiple-TRX-pa.patch
new file mode 100644
index 0000000000..1065322fd8
--- /dev/null
+++ b/target/linux/generic/patches-4.4/141-0002-mtd-bcm47xxpart-support-layouts-with-multiple-TRX-pa.patch
@@ -0,0 +1,108 @@
+From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
+Subject: [PATCH 2/2] mtd: bcm47xxpart: support layouts with multiple TRX
+ partitions
+MIME-Version: 1.0
+Content-Type: text/plain; charset=UTF-8
+Content-Transfer-Encoding: 8bit
+
+Some devices may have an extra TRX partition used as failsafe one. If
+we detect such partition we should set a proper name for it and don't
+parse it.
+
+Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
+---
+ drivers/mtd/bcm47xxpart.c | 56 ++++++++++++++++++++++++++++++++++++++---------
+ 1 file changed, 46 insertions(+), 10 deletions(-)
+
+--- a/drivers/mtd/bcm47xxpart.c
++++ b/drivers/mtd/bcm47xxpart.c
+@@ -9,6 +9,7 @@
+  *
+  */
+ 
++#include <linux/bcm47xx_nvram.h>
+ #include <linux/module.h>
+ #include <linux/kernel.h>
+ #include <linux/slab.h>
+@@ -147,6 +148,30 @@ static int bcm47xxpart_parse_trx(struct
+ 	return curr_part;
+ }
+ 
++/**
++ * bcm47xxpart_bootpartition - gets index of TRX partition used by bootloader
++ *
++ * Some devices may have more than one TRX partition. In such case one of them
++ * is the main one and another a failsafe one. Bootloader may fallback to the
++ * failsafe firmware if it detects corruption of the main image.
++ *
++ * This function provides info about currently used TRX partition. It's the one
++ * containing kernel started by the bootloader.
++ */
++static int bcm47xxpart_bootpartition(void)
++{
++	char buf[4];
++	int bootpartition;
++
++	/* Check CFE environment variable */
++	if (bcm47xx_nvram_getenv("bootpartition", buf, sizeof(buf)) > 0) {
++		if (!kstrtoint(buf, 0, &bootpartition))
++			return bootpartition;
++	}
++
++	return 0;
++}
++
+ static int bcm47xxpart_parse(struct mtd_info *master,
+ 			     struct mtd_partition **pparts,
+ 			     struct mtd_part_parser_data *data)
+@@ -157,7 +182,8 @@ static int bcm47xxpart_parse(struct mtd_
+ 	size_t bytes_read;
+ 	uint32_t offset;
+ 	uint32_t blocksize = master->erasesize;
+-	int trx_part = -1;
++	int trx_parts[2]; /* Array with indexes of TRX partitions */
++	int trx_num = 0; /* Number of found TRX partitions */
+ 	int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
+ 	int err;
+ 
+@@ -246,7 +272,11 @@ static int bcm47xxpart_parse(struct mtd_
+ 		if (buf[0x000 / 4] == TRX_MAGIC) {
+ 			struct trx_header *trx;
+ 
+-			trx_part = curr_part;
++			if (trx_num >= ARRAY_SIZE(trx_parts))
++				pr_warn("No enough space to store another TRX found at 0x%X\n",
++					offset);
++			else
++				trx_parts[trx_num++] = curr_part;
+ 			bcm47xxpart_add_part(&parts[curr_part++], "firmware",
+ 					     offset, 0);
+ 
+@@ -332,14 +362,20 @@ static int bcm47xxpart_parse(struct mtd_
+ 	}
+ 
+ 	/* If there was TRX parse it now */
+-	if (trx_part >= 0) {
+-		int num_parts;
++	for (i = 0; i < trx_num; i++) {
++		struct mtd_partition *trx = &parts[trx_parts[i]];
+ 
+-		num_parts = bcm47xxpart_parse_trx(master, &parts[trx_part],
+-						  parts + curr_part,
+-						  BCM47XXPART_MAX_PARTS - curr_part);
+-		if (num_parts > 0)
+-			curr_part += num_parts;
++		if (i == bcm47xxpart_bootpartition()) {
++			int num_parts;
++
++			num_parts = bcm47xxpart_parse_trx(master, trx,
++							  parts + curr_part,
++							  BCM47XXPART_MAX_PARTS - curr_part);
++			if (num_parts > 0)
++				curr_part += num_parts;
++		} else {
++			trx->name = "failsafe";
++		}
+ 	}
+ 
+ 	*pparts = parts;