// SPDX-License-Identifier: GPL-2.0-or-later
/*======================================================================
drivers/mtd/afs.c: ARM Flash Layout/Partitioning
Copyright © 2000 ARM Limited
Copyright (C) 2019 Linus Walleij
This is access code for flashes using ARM's flash partitioning
standards.
======================================================================*/
#include <linux/module.h>
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/slab.h>
#include <linux/string.h>
#include <linux/init.h>
#include <linux/mtd/mtd.h>
#include <linux/mtd/map.h>
#include <linux/mtd/partitions.h>
#define AFSV1_FOOTER_MAGIC 0xA0FFFF9F
#define AFSV2_FOOTER_MAGIC1 0x464C5348 /* "FLSH" */
#define AFSV2_FOOTER_MAGIC2 0x464F4F54 /* "FOOT" */
struct footer_v1 {
u32 image_info_base; /* Address of first word of ImageFooter */
u32 image_start; /* Start of area reserved by this footer */
u32 signature; /* 'Magic' number proves it's a footer */
u32 type; /* Area type: ARM Image, SIB, customer */
u32 checksum; /* Just this structure */
};
struct image_info_v1 {
u32 bootFlags; /* Boot flags, compression etc. */
u32 imageNumber; /* Unique number, selects for boot etc. */
u32 loadAddress; /* Address program should be loaded to */
u32 length; /* Actual size of image */
u32 address; /* Image is executed from here */
char name[16]; /* Null terminated */
u32 headerBase; /* Flash Address of any stripped header */
u32 header_length; /* Length of header in memory */
u32 headerType; /* AIF, RLF, s-record etc. */
u32 checksum; /* Image checksum (inc. this struct) */
};
static u32 word_sum(void *words, int num)
{
u32 *p = words;
u32 sum = 0;
while (num--)
sum += *p++;
return sum;
}
static u32 word_sum_v2(u32 *p, u32 num)
{
u32 sum = 0;
int i;
for (i = 0; i < num; i++) {
u32 val;
val = p[i];
if (val > ~sum)
sum++;
sum += val;
}
return ~sum;
}
static bool afs_is_v1(struct mtd_info *mtd, u_int off)
{
/* The magic is 12 bytes from the end of the erase block */
u_int ptr = off + mtd->erasesize - 12;
u32 magic;
size_t sz;
int ret;
ret = mtd_read(mtd, ptr, 4, &sz, (u_char *)&magic);
if (ret < 0) {
printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
ptr, ret);
return false;
}
if (ret >= 0 && sz != 4)
return false;
return (magic == AFSV1_FOOTER_MAGIC);
}
static bool afs_is_v2(struct mtd_info *mtd, u_int off)
{
/* The magic is the 8 last bytes of the erase block */
u_int ptr = off + mtd->erasesize - 8;
u32 foot[2];
size_t sz;
int ret;
ret = mtd_read(mtd, ptr, 8, &sz, (u_char *)foot);
if (ret < 0) {
printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
ptr, ret);
return false;
}
if (ret >= 0 && sz != 8)
return false;
return (foot[0] == AFSV2_FOOTER_MAGIC1 &&
foot[1] == AFSV2_FOOTER_MAGIC2);
}
static int afs_parse_v1_partition(struct mtd_info *mtd,
u_int off, struct mtd_partition *part)
{
struct footer_v1 fs;
struct image_info_v1 iis;
u_int mask;
/*
* Static checks cannot see that we bail out if we have an error
* reading the footer.
*/
u_int iis_ptr;
u_int img_ptr;
u_int ptr;
size_t sz;
int ret;
int i;
/*
* This is the address mask; we use this to mask off out of
* range address bits.
*/
mask = mtd->size - 1;
ptr = off + mtd->erasesize - sizeof(fs);
ret = mtd_read(mtd, ptr, sizeof(fs), &sz, (u_char *)&fs);
if (ret >= 0 && sz != sizeof(fs))
ret = -EINVAL;
if (ret < 0) {
printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
ptr, ret);
return ret;
}
/*
* Check the checksum.
*/
if (word_sum(&fs, sizeof(fs) / sizeof(u32)) != 0xffffffff)
return -EINVAL;
/*
* Hide the SIB (System Information Block)
*/
if (fs.type == 2)
return 0;
iis_ptr = fs.image_info_base & mask;
img_ptr = fs.image_start & mask;
/*
* Check the image info base. This can not
* be located after the footer structure.
*/
if (iis_ptr >= ptr)
return 0;
/*
* Check the start of this image. The image
* data can not be located after this block.
*/
if (img_ptr > off)
return 0;
/* Read the image info block */
memset(&iis, 0, sizeof(iis));
ret = mtd_read(mtd, iis_ptr, sizeof(iis), &sz, (u_char *)&iis);
if (ret < 0) {
printk(KERN_ERR "AFS: mtd read failed at 0x%x: %d\n",
iis_ptr, ret);
return -EINVAL;
}
if (sz != sizeof(iis))
return -EINVAL;
/*
* Validate the name - it must be NUL terminated.
*/
for (i = 0; i < sizeof(iis.name); i++)
if (iis.name[i] == '\0')
break;
if (i > sizeof(iis.name))
return -EINVAL;
part->name = kstrdup(iis.name, GFP_KERNEL);
if (!part->name)
return -ENOMEM;
part->size = (iis.length + mtd->erasesize - 1) & ~(mtd->erasesize - 1);
part->offset = img_ptr;
part->mask_flags = 0;
printk(" mtd: at 0x%08x, %5lluKiB, %8u, %s\n",
img_ptr, part->size / 1024,
iis.imageNumber, part->name);
return 0;
}
static int afs_parse_v2_partition(struct mtd_info *mtd,
u_int off, struct mtd_partition *part)
{
u_int ptr;
u32 footer[12];
u32 imginfo[36];
char *name;
u32 version;
u32 entrypoint;
u32 attributes;
u32 region_count;
u32 block_start;
u32 block_end;
u32 crc;
size_t sz;
int ret;
int i;
int pad = 0;
pr_debug("Parsing v2 partition @%08x-%08x\n",
off, off + mtd->erasesize);
/* First read the footer */
ptr = off + mtd->erasesize - sizeof(footer);
ret = mtd_read(mtd, ptr, sizeof(footer), &sz, (u_char *)footer);
if ((ret < 0) || (ret >= 0 && sz != sizeof(footer))) {
pr_err("AFS: mtd read failed at 0x%x: %d\n",
ptr, ret);
return -EIO;
}
name = (char *) &footer[0];
version = footer[9];
ptr = off + mtd->erasesize - sizeof(footer) - footer[8];
pr_debug("found image \"%s\", version %08x, info @%08x\n",
name, version, ptr);
/* Then read the image information */
ret = mtd_read(mtd, ptr, sizeof(imginfo), &sz, (u_char *)imginfo);
if ((ret < 0) || (ret >= 0 && sz != sizeof(imginfo))) {
pr_err("AFS: mtd read failed at 0x%x: %d\n",
ptr, ret);
return -EIO;
}
/* 32bit platforms have 4 bytes padding */
crc = word_sum_v2(&imginfo[1], 34);
if (!crc) {
pr_debug("Padding 1 word (4 bytes)\n");
pad = 1;
} else {
/* 64bit platforms have 8 bytes padding */
crc = word_sum_v2(&imginfo[2], 34);
if (!crc) {
pr_debug("Padding 2 words (8 bytes)\n");
pad = 2;
}
}
if (crc) {
pr_err("AFS: bad checksum on v2 image info: %08x\n", crc);
return -EINVAL;
}
entrypoint = imginfo[pad];
attributes = imginfo[pad+1];
region_count = imginfo[pad+2];
block_start = imginfo[20];
block_end = imginfo[21];
pr_debug("image entry=%08x, attr=%08x, regions=%08x, "
"bs=%08x, be=%08x\n",
entrypoint, attributes, region_count,
block_start, block_end);
for (i = 0; i < region_count; i++) {
u32 region_load_addr = imginfo[pad + 3 + i*4];
u32 region_size = imginfo[pad + 4 + i*4];
u32 region_offset = imginfo[pad + 5 + i*4];
u32 region_start;
u32 region_end;
pr_debug(" region %d: address: %08x, size: %08x, "
"offset: %08x\n",
i,
region_load_addr,
region_size,
region_offset);
region_start = off + region_offset;
region_end = region_start + region_size;
/* Align partition to end of erase block */
region_end += (mtd->erasesize - 1);
region_end &= ~(mtd->erasesize -1);
pr_debug(" partition start = %08x, partition end = %08x\n",
region_start, region_end);
/* Create one partition per region */
part->name = kstrdup(name, GFP_KERNEL);
if (!part->name)
return -ENOMEM;
part->offset = region_start;
part->size = region_end - region_start;
part->mask_flags = 0;
}
return 0;
}
static int parse_afs_partitions(struct mtd_info *mtd,
const struct mtd_partition **pparts,
struct mtd_part_parser_data *data)
{
struct mtd_partition *parts;
u_int off, sz;
int ret = 0;
int i;
/* Count the partitions by looping over all erase blocks */
for (i = off = sz = 0; off < mtd->size; off += mtd->erasesize) {
if (afs_is_v1(mtd, off)) {
sz += sizeof(struct mtd_partition);
i += 1;
}
if (afs_is_v2(mtd, off)) {
sz += sizeof(struct mtd_partition);
i += 1;
}
}
if (!i)
return 0;
parts = kzalloc(sz, GFP_KERNEL);
if (!parts)
return -ENOMEM;
/*
* Identify the partitions
*/
for (i = off = 0; off < mtd->size; off += mtd->erasesize) {
if (afs_is_v1(mtd, off)) {
ret = afs_parse_v1_partition(mtd, off, &parts[i]);
if (ret)
goto out_free_parts;
i++;
}
if (afs_is_v2(mtd, off)) {
ret = afs_parse_v2_partition(mtd, off, &parts[i]);
if (ret)
goto out_free_parts;
i++;
}
}
*pparts = parts;
return i;
out_free_parts:
while (--i >= 0)
kfree(parts[i].name);
kfree(parts);
*pparts = NULL;
return ret;
}
static const struct of_device_id mtd_parser_afs_of_match_table[] = {
{ .compatible = "arm,arm-firmware-suite" },
{},
};
MODULE_DEVICE_TABLE(of, mtd_parser_afs_of_match_table);
static struct mtd_part_parser afs_parser = {
.parse_fn = parse_afs_partitions,
.name = "afs",
.of_match_table = mtd_parser_afs_of_match_table,
};
module_mtd_part_parser(afs_parser);
MODULE_AUTHOR("ARM Ltd");
MODULE_DESCRIPTION("ARM Firmware Suite partition parser");
MODULE_LICENSE("GPL");
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