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// SPDX-License-Identifier: GPL-2.0-or-later
/*
* drivers/mtd/scpart.c: Sercomm Partition Parser
*
* Copyright (C) 2018 NOGUCHI Hiroshi
* Copyright (C) 2022 Mikhail Zhilkin
*/
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/partitions.h>
#include <linux/module.h>
#define MOD_NAME "scpart"
#ifdef pr_fmt
#undef pr_fmt
#endif
#define pr_fmt(fmt) MOD_NAME ": " fmt
#define ID_ALREADY_FOUND 0xffffffffUL
#define MAP_OFFS_IN_BLK 0x800
#define MAP_MIRROR_NUM 2
static const char sc_part_magic[] = {
'S', 'C', 'F', 'L', 'M', 'A', 'P', 'O', 'K', '\0',
};
#define PART_MAGIC_LEN sizeof(sc_part_magic)
/* assumes that all fields are set by CPU native endian */
struct sc_part_desc {
uint32_t part_id;
uint32_t part_offs;
uint32_t part_bytes;
};
static uint32_t scpart_desc_is_valid(struct sc_part_desc *pdesc)
{
return ((pdesc->part_id != 0xffffffffUL) &&
(pdesc->part_offs != 0xffffffffUL) &&
(pdesc->part_bytes != 0xffffffffUL));
}
static int scpart_scan_partmap(struct mtd_info *master, loff_t partmap_offs,
struct sc_part_desc **ppdesc)
{
int cnt = 0;
int res = 0;
int res2;
uint32_t offs;
size_t retlen;
struct sc_part_desc *pdesc = NULL;
struct sc_part_desc *tmpdesc;
uint8_t *buf;
buf = kzalloc(master->erasesize, GFP_KERNEL);
if (!buf) {
res = -ENOMEM;
goto out;
}
res2 = mtd_read(master, partmap_offs, master->erasesize, &retlen, buf);
if (res2 || retlen != master->erasesize) {
res = -EIO;
goto free;
}
for (offs = MAP_OFFS_IN_BLK;
offs < master->erasesize - sizeof(*tmpdesc);
offs += sizeof(*tmpdesc)) {
tmpdesc = (struct sc_part_desc *)&buf[offs];
if (!scpart_desc_is_valid(tmpdesc))
break;
cnt++;
}
if (cnt > 0) {
int bytes = cnt * sizeof(*pdesc);
pdesc = kcalloc(cnt, sizeof(*pdesc), GFP_KERNEL);
if (!pdesc) {
res = -ENOMEM;
goto free;
}
memcpy(pdesc, &(buf[MAP_OFFS_IN_BLK]), bytes);
*ppdesc = pdesc;
res = cnt;
}
free:
kfree(buf);
out:
return res;
}
static int scpart_find_partmap(struct mtd_info *master,
struct sc_part_desc **ppdesc)
{
int magic_found = 0;
int res = 0;
int res2;
loff_t offs = 0;
size_t retlen;
uint8_t rdbuf[PART_MAGIC_LEN];
while ((magic_found < MAP_MIRROR_NUM) &&
(offs < master->size) &&
!mtd_block_isbad(master, offs)) {
res2 = mtd_read(master, offs, PART_MAGIC_LEN, &retlen, rdbuf);
if (res2 || retlen != PART_MAGIC_LEN) {
res = -EIO;
goto out;
}
if (!memcmp(rdbuf, sc_part_magic, PART_MAGIC_LEN)) {
pr_debug("Signature found at 0x%llx\n", offs);
magic_found++;
res = scpart_scan_partmap(master, offs, ppdesc);
if (res > 0)
goto out;
}
offs += master->erasesize;
}
out:
if (res > 0)
pr_info("Valid 'SC PART MAP' (%d partitions) found at 0x%llx\n", res, offs);
else
pr_info("No valid 'SC PART MAP' was found\n");
return res;
}
static int scpart_parse(struct mtd_info *master,
const struct mtd_partition **pparts,
struct mtd_part_parser_data *data)
{
const char *partname;
int n;
int nr_scparts;
int nr_parts = 0;
int res = 0;
struct sc_part_desc *scpart_map = NULL;
struct mtd_partition *parts = NULL;
struct device_node *mtd_node;
struct device_node *ofpart_node;
struct device_node *pp;
mtd_node = mtd_get_of_node(master);
if (!mtd_node) {
res = -ENOENT;
goto out;
}
ofpart_node = of_get_child_by_name(mtd_node, "partitions");
if (!ofpart_node) {
pr_info("%s: 'partitions' subnode not found on %pOF.\n",
master->name, mtd_node);
res = -ENOENT;
goto out;
}
nr_scparts = scpart_find_partmap(master, &scpart_map);
if (nr_scparts <= 0) {
pr_info("No any partitions was found in 'SC PART MAP'.\n");
res = -ENOENT;
goto free;
}
parts = kcalloc(of_get_child_count(ofpart_node), sizeof(*parts),
GFP_KERNEL);
if (!parts) {
res = -ENOMEM;
goto free;
}
for_each_child_of_node(ofpart_node, pp) {
u32 scpart_id;
if (of_property_read_u32(pp, "sercomm,scpart-id", &scpart_id))
continue;
for (n = 0 ; n < nr_scparts ; n++)
if ((scpart_map[n].part_id != ID_ALREADY_FOUND) &&
(scpart_id == scpart_map[n].part_id))
break;
if (n >= nr_scparts)
/* not match */
continue;
/* add the partition found in OF into MTD partition array */
parts[nr_parts].offset = scpart_map[n].part_offs;
parts[nr_parts].size = scpart_map[n].part_bytes;
parts[nr_parts].of_node = pp;
if (!of_property_read_string(pp, "label", &partname))
parts[nr_parts].name = partname;
if (of_property_read_bool(pp, "read-only"))
parts[nr_parts].mask_flags |= MTD_WRITEABLE;
if (of_property_read_bool(pp, "lock"))
parts[nr_parts].mask_flags |= MTD_POWERUP_LOCK;
/* mark as 'done' */
scpart_map[n].part_id = ID_ALREADY_FOUND;
nr_parts++;
}
if (nr_parts > 0) {
*pparts = parts;
res = nr_parts;
} else
pr_info("No partition in OF matches partition ID with 'SC PART MAP'.\n");
of_node_put(pp);
free:
of_node_put(ofpart_node);
kfree(scpart_map);
if (res <= 0)
kfree(parts);
out:
return res;
}
static const struct of_device_id scpart_parser_of_match_table[] = {
{ .compatible = "sercomm,sc-partitions" },
{},
};
MODULE_DEVICE_TABLE(of, scpart_parser_of_match_table);
static struct mtd_part_parser scpart_parser = {
.parse_fn = scpart_parse,
.name = "scpart",
.of_match_table = scpart_parser_of_match_table,
};
module_mtd_part_parser(scpart_parser);
/* mtd parsers will request the module by parser name */
MODULE_ALIAS("scpart");
MODULE_LICENSE("GPL");
MODULE_AUTHOR("NOGUCHI Hiroshi <drvlabo@gmail.com>");
MODULE_AUTHOR("Mikhail Zhilkin <csharper2005@gmail.com>");
MODULE_DESCRIPTION("Sercomm partition parser");
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