mtd: bcm47xxpart: support layouts with multiple TRX partitions

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>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
index 10930257c14c1b5f303cd7d5ed14b8abba8c8fdb..d10fa6c8f074648e0a7ec5e05562e15f4695b849 100644 (file)
--- 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>
@@ -144,6 +145,30 @@ static int bcm47xxpart_parse_trx(struct mtd_info *master,
        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,
                             const struct mtd_partition **pparts,
                             struct mtd_part_parser_data *data)
@@ -154,7 +179,8 @@ static int bcm47xxpart_parse(struct mtd_info *master,
        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;
 
@@ -243,7 +269,11 @@ static int bcm47xxpart_parse(struct mtd_info *master,
                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);
 
@@ -329,14 +359,20 @@ static int bcm47xxpart_parse(struct mtd_info *master,
        }
 
        /* If there was TRX parse it now */
-       if (trx_part >= 0) {
-               int num_parts;
-
-               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;
+       for (i = 0; i < trx_num; i++) {
+               struct mtd_partition *trx = &parts[trx_parts[i]];
+
+               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;