mtd: bcm47xxpart: move TRX parsing code to separated function

This change simplifies main parsing loop logic a bit. In future it may
be useful for moving TRX support to separated module / parser (if we
implement support for them at some point).
Finally parsing TRX at the end puts us in a better position as we have
better flash layout knowledge. It may be useful e.g. if it appears there
is more than 1 TRX partition.

Signed-off-by: Rafał Miłecki <rafal@milecki.pl>
Acked-by: Marek Vasut <marek.vasut@gmail.com>
Signed-off-by: Brian Norris <computersforpeace@gmail.com>

1 files changed, 74 insertions, 47 deletions

diff --git a/drivers/mtd/bcm47xxpart.c b/drivers/mtd/bcm47xxpart.c
index 283ff7e17a0f..10930257c14c 100644
--- a/drivers/mtd/bcm47xxpart.c
+++ b/drivers/mtd/bcm47xxpart.c
@@ -83,6 +83,67 @@ out_default:
         return "rootfs";
 }
 
+static int bcm47xxpart_parse_trx(struct mtd_info *master,
+                                 struct mtd_partition *trx,
+                                 struct mtd_partition *parts,
+                                 size_t parts_len)
+{
+        struct trx_header header;
+        size_t bytes_read;
+        int curr_part = 0;
+        int i, err;
+
+        if (parts_len < 3) {
+                pr_warn("No enough space to add TRX partitions!\n");
+                return -ENOMEM;
+        }
+
+        err = mtd_read(master, trx->offset, sizeof(header), &bytes_read,
+                       (uint8_t *)&header);
+        if (err && !mtd_is_bitflip(err)) {
+                pr_err("mtd_read error while reading TRX header: %d\n", err);
+                return err;
+        }
+
+        i = 0;
+
+        /* We have LZMA loader if offset[2] points to sth */
+        if (header.offset[2]) {
+                bcm47xxpart_add_part(&parts[curr_part++], "loader",
+                                     trx->offset + header.offset[i], 0);
+                i++;
+        }
+
+        if (header.offset[i]) {
+                bcm47xxpart_add_part(&parts[curr_part++], "linux",
+                                     trx->offset + header.offset[i], 0);
+                i++;
+        }
+
+        if (header.offset[i]) {
+                size_t offset = trx->offset + header.offset[i];
+                const char *name = bcm47xxpart_trx_data_part_name(master,
+                                                                  offset);
+
+                bcm47xxpart_add_part(&parts[curr_part++], name, offset, 0);
+                i++;
+        }
+
+        /*
+         * Assume that every partition ends at the beginning of the one it is
+         * followed by.
+         */
+        for (i = 0; i < curr_part; i++) {
+                u64 next_part_offset = (i < curr_part - 1) ?
+                                        parts[i + 1].offset :
+                                        trx->offset + trx->size;
+
+                parts[i].size = next_part_offset - parts[i].offset;
+        }
+
+        return curr_part;
+}
+
 static int bcm47xxpart_parse(struct mtd_info *master,
                              const struct mtd_partition **pparts,
                              struct mtd_part_parser_data *data)
@@ -93,9 +154,7 @@ static int bcm47xxpart_parse(struct mtd_info *master,
         size_t bytes_read;
         uint32_t offset;
         uint32_t blocksize = master->erasesize;
-        struct trx_header *trx;
         int trx_part = -1;
-        int last_trx_part = -1;
         int possible_nvram_sizes[] = { 0x8000, 0xF000, 0x10000, };
         int err;
 
@@ -182,54 +241,14 @@ static int bcm47xxpart_parse(struct mtd_info *master,
 
                 /* TRX */
                 if (buf[0x000 / 4] == TRX_MAGIC) {
-                        if (BCM47XXPART_MAX_PARTS - curr_part < 4) {
-                                pr_warn("Not enough partitions left to register trx, scanning stopped!\n");
-                                break;
-                        }
-
-                        trx = (struct trx_header *)buf;
+                        struct trx_header *trx;
 
                         trx_part = curr_part;
                         bcm47xxpart_add_part(&parts[curr_part++], "firmware",
                                              offset, 0);
 
-                        i = 0;
-                        /* We have LZMA loader if offset[2] points to sth */
-                        if (trx->offset[2]) {
-                                bcm47xxpart_add_part(&parts[curr_part++],
-                                                     "loader",
-                                                     offset + trx->offset[i],
-                                                     0);
-                                i++;
-                        }
-
-                        if (trx->offset[i]) {
-                                bcm47xxpart_add_part(&parts[curr_part++],
-                                                     "linux",
-                                                     offset + trx->offset[i],
-                                                     0);
-                                i++;
-                        }
-
-                        /*
-                         * Pure rootfs size is known and can be calculated as:
-                         * trx->length - trx->offset[i]. We don't fill it as
-                         * we want to have jffs2 (overlay) in the same mtd.
-                         */
-                        if (trx->offset[i]) {
-                                const char *name;
-
-                                name = bcm47xxpart_trx_data_part_name(master, offset + trx->offset[i]);
-                                bcm47xxpart_add_part(&parts[curr_part++],
-                                                     name,
-                                                     offset + trx->offset[i],
-                                                     0);
-                                i++;
-                        }
-
-                        last_trx_part = curr_part - 1;
-
                         /* Jump to the end of TRX */
+                        trx = (struct trx_header *)buf;
                         offset = roundup(offset + trx->length, blocksize);
                         /* Next loop iteration will increase the offset */
                         offset -= blocksize;
@@ -307,9 +326,17 @@ static int bcm47xxpart_parse(struct mtd_info *master,
                                        parts[i + 1].offset : master->size;
 
                 parts[i].size = next_part_offset - parts[i].offset;
-                if (i == last_trx_part && trx_part >= 0)
-                        parts[trx_part].size = next_part_offset -
-                                               parts[trx_part].offset;
+        }
+
+        /* 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;
         }
 
         *pparts = parts;