ath25: add back target support

Discussion on the mailing list reveals that this target has active
users. As we are finally able to upgrade this target to kernel 5.4,
add it back to master.

This reverts commit 7d29a5571403 ("ath25: drop target") and
immediately moves the relevant files to 5.4, without touching
the content.

Signed-off-by: Adrian Schmutzler <freifunk@adrianschmutzler.de>

1 files changed, 72 insertions, 0 deletions

diff --git a/target/linux/ath25/patches-5.4/142-redboot_various_erase_size_fix.patch b/target/linux/ath25/patches-5.4/142-redboot_various_erase_size_fix.patch
new file mode 100644
index 0000000000..ce039df9f1
--- /dev/null
+++ b/target/linux/ath25/patches-5.4/142-redboot_various_erase_size_fix.patch
@@ -0,0 +1,72 @@
+--- a/drivers/mtd/redboot.c
++++ b/drivers/mtd/redboot.c
+@@ -58,6 +58,22 @@ static inline int redboot_checksum(struc
+ 	return 1;
+ }
+ 
++static uint32_t mtd_get_offset_erasesize(struct mtd_info *mtd, uint64_t offset)
++{
++	struct mtd_erase_region_info *regions = mtd->eraseregions;
++	int i;
++
++	for (i = 0; i < mtd->numeraseregions; i++) {
++		if (regions[i].offset +
++		    regions[i].numblocks * regions[i].erasesize <= offset)
++			continue;
++
++		return regions[i].erasesize;
++	}
++
++	return mtd->erasesize;
++}
++
+ static int parse_redboot_partitions(struct mtd_info *master,
+ 				    const struct mtd_partition **pparts,
+ 				    struct mtd_part_parser_data *data)
+@@ -74,6 +90,7 @@ static int parse_redboot_partitions(stru
+ 	int namelen = 0;
+ 	int nulllen = 0;
+ 	int numslots;
++	int first_slot;
+ 	unsigned long offset;
+ #ifdef CONFIG_MTD_REDBOOT_PARTS_UNALLOCATED
+ 	static char nullstring[] = "unallocated";
+@@ -186,7 +203,10 @@ static int parse_redboot_partitions(stru
+ 		goto out;
+ 	}
+ 
+-	for (i = 0; i < numslots; i++) {
++	first_slot = (buf[i].flash_base & (master->erasesize - 1)) /
++		     sizeof(struct fis_image_desc);
++
++	for (i = first_slot; i < first_slot + numslots; i++) {
+ 		struct fis_list *new_fl, **prev;
+ 
+ 		if (buf[i].name[0] == 0xff) {
+@@ -262,12 +282,13 @@ static int parse_redboot_partitions(stru
+ 	}
+ #endif
+ 	for ( ; i<nrparts; i++) {
+-		if (max_offset < buf[i].flash_base + buf[i].size)
+-			max_offset = buf[i].flash_base + buf[i].size;
+ 		parts[i].size = fl->img->size;
+ 		parts[i].offset = fl->img->flash_base;
+ 		parts[i].name = names;
+ 
++		if (max_offset < parts[i].offset + parts[i].size)
++			max_offset = parts[i].offset + parts[i].size;
++
+ 		strcpy(names, fl->img->name);
+ #ifdef CONFIG_MTD_REDBOOT_PARTS_READONLY
+ 		if (!memcmp(names, "RedBoot", 8) ||
+@@ -297,7 +318,9 @@ static int parse_redboot_partitions(stru
+ 		fl = fl->next;
+ 		kfree(tmp_fl);
+ 	}
+-	if (master->size - max_offset >= master->erasesize) {
++
++	if (master->size - max_offset >=
++	    mtd_get_offset_erasesize(master, max_offset)) {
+ 		parts[nrparts].size = master->size - max_offset;
+ 		parts[nrparts].offset = max_offset;
+ 		parts[nrparts].name = names;