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From b522d7b0ebe3539340c2a6d46d787ae3d33bcb92 Mon Sep 17 00:00:00 2001
From: =?UTF-8?q?Rafa=C5=82=20Mi=C5=82ecki?= <rafal@milecki.pl>
Date: Tue, 10 Jan 2017 23:15:24 +0100
Subject: [PATCH] mtd: bcm47xxpart: move TRX parsing code to separated function
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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>
---
 drivers/mtd/bcm47xxpart.c | 121 ++++++++++++++++++++++++++++------------------
 1 file changed, 74 insertions(+), 47 deletions(-)

--- 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,
                             struct mtd_partition **pparts,
                             struct mtd_part_parser_data *data)
@@ -93,9 +154,7 @@ static int bcm47xxpart_parse(struct mtd_
        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_
 
                /* 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_
                                       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;