diff options
Diffstat (limited to 'target/linux/generic')
| -rw-r--r-- | target/linux/generic/files/drivers/mtd/parsers/routerbootpart.c | 365 |
1 files changed, 365 insertions, 0 deletions
diff --git a/target/linux/generic/files/drivers/mtd/parsers/routerbootpart.c b/target/linux/generic/files/drivers/mtd/parsers/routerbootpart.c new file mode 100644 index 0000000000..e019094058 --- /dev/null +++ b/target/linux/generic/files/drivers/mtd/parsers/routerbootpart.c @@ -0,0 +1,365 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * Parser for MikroTik RouterBoot partitions. + * + * Copyright (C) 2020 Thibaut VARÈNE <hacks+kernel@slashdirt.org> + * + * This program is free software; you can redistribute it and/or modify it + * under the terms of the GNU General Public License version 2 as published + * by the Free Software Foundation. + * + * This parser builds from the "fixed-partitions" one (see ofpart.c), but it can + * handle dynamic partitions as found on routerboot devices. + * + * DTS nodes are defined as follows: + * For fixed partitions: + * node-name@unit-address { + * reg = <prop-encoded-array>; + * label = <string>; + * read-only; + * lock; + * }; + * + * reg property is mandatory; other properties are optional. + * reg format is <address length>. length can be 0 if the next partition is + * another fixed partition or a "well-known" partition as defined below: in that + * case the partition will extend up to the next one. + * + * For dynamic partitions: + * node-name { + * size = <prop-encoded-array>; + * label = <string>; + * read-only; + * lock; + * }; + * + * size property is normally mandatory. It can only be omitted (or set to 0) if: + * - the partition is a "well-known" one (as defined below), in which case + * the partition size will be automatically adjusted; or + * - the next partition is a fixed one or a "well-known" one, in which case + * the current partition will extend up to the next one. + * Other properties are optional. + * size format is <length>. + * By default dynamic partitions are appended after the preceding one, except + * for "well-known" ones which are automatically located on flash. + * + * Well-known partitions (matched via label or node-name): + * - "hard_config" + * - "soft_config" + * - "dtb_config" + * + * Note: this parser will happily register 0-sized partitions if misused. + * + * This parser requires the DTS to list partitions in ascending order as + * expected on the MTD device. + * + * Since only the "hard_config" and "soft_config" partitions are used in OpenWRT, + * a minimal working DTS could define only these two partitions dynamically (in + * the right order, usually hard_config then soft_config). + * + * Note: some mips RB devices encode the hard_config offset and length in two + * consecutive u32 located at offset 0x14 (for ramips) or 0x24 (for ath79) on + * the SPI NOR flash. Unfortunately this seems inconsistent across machines and + * does not apply to e.g. ipq-based ones, so we ignore that information. + * + * Note: To find well-known partitions, this parser will go through the entire + * top mtd partition parsed, _before_ the DTS nodes are processed. This works + * well in the current state of affairs, and is a simpler implementation than + * searching for known partitions in the "holes" left between fixed-partition, + * _after_ processing DTS nodes. + */ + +#include <linux/module.h> +#include <linux/slab.h> +#include <linux/mtd/mtd.h> +#include <linux/mtd/partitions.h> +#include <linux/of.h> +#include <linux/of_fdt.h> +#include <linux/libfdt_env.h> +#include <linux/string.h> + +#define RB_MAGIC_HARD (('H') | ('a' << 8) | ('r' << 16) | ('d' << 24)) +#define RB_MAGIC_SOFT (('S') | ('o' << 8) | ('f' << 16) | ('t' << 24)) +#define RB_BLOCK_SIZE 0x1000 + +struct routerboot_dynpart { + const char * const name; + const u32 magic; + int (* const size_fixup)(struct mtd_info *, struct routerboot_dynpart *); + size_t offset; + size_t size; + bool found; +}; + +static int routerboot_dtbsfixup(struct mtd_info *, struct routerboot_dynpart *); + +static struct routerboot_dynpart rb_dynparts[] = { + { + .name = "hard_config", + .magic = RB_MAGIC_HARD, // stored in CPU-endianness on flash + .size_fixup = NULL, + .offset = 0x0, + .size = RB_BLOCK_SIZE, + .found = false, + }, { + .name = "soft_config", + .magic = RB_MAGIC_SOFT, // stored in CPU-endianness on flash + .size_fixup = NULL, + .offset = 0x0, + .size = RB_BLOCK_SIZE, + .found = false, + }, { + .name = "dtb_config", + .magic = fdt32_to_cpu(OF_DT_HEADER), // stored BE on flash + .size_fixup = routerboot_dtbsfixup, + .offset = 0x0, + .size = 0x0, + .found = false, + } +}; + +static int routerboot_dtbsfixup(struct mtd_info *master, struct routerboot_dynpart *rbdpart) +{ + int err; + size_t bytes_read, psize; + struct { + fdt32_t magic; + fdt32_t totalsize; + fdt32_t off_dt_struct; + fdt32_t off_dt_strings; + fdt32_t off_mem_rsvmap; + fdt32_t version; + fdt32_t last_comp_version; + fdt32_t boot_cpuid_phys; + fdt32_t size_dt_strings; + fdt32_t size_dt_struct; + } fdt_header; + + err = mtd_read(master, rbdpart->offset, sizeof(fdt_header), + &bytes_read, (u8 *)&fdt_header); + if (err) + return err; + + if (bytes_read != sizeof(fdt_header)) + return -EIO; + + psize = fdt32_to_cpu(fdt_header.totalsize); + if (!psize) + return -EINVAL; + + rbdpart->size = psize; + return 0; +} + +static void routerboot_find_dynparts(struct mtd_info *master) +{ + size_t bytes_read, offset; + bool allfound; + int err, i; + u32 buf; + + /* + * Dynamic RouterBoot partitions offsets are aligned to RB_BLOCK_SIZE: + * read the whole partition at RB_BLOCK_SIZE intervals to find sigs. + * Skip partition content when possible. + */ + offset = 0; + while (offset < master->size) { + err = mtd_read(master, offset, sizeof(buf), &bytes_read, (u8 *)&buf); + if (err) { + pr_err("%s: mtd_read error while parsing (offset: 0x%X): %d\n", + master->name, offset, err); + continue; + } + + allfound = true; + + for (i = 0; i < ARRAY_SIZE(rb_dynparts); i++) { + if (rb_dynparts[i].found) + continue; + + allfound = false; + + if (rb_dynparts[i].magic == buf) { + rb_dynparts[i].offset = offset; + + if (rb_dynparts[i].size_fixup) { + err = rb_dynparts[i].size_fixup(master, &rb_dynparts[i]); + if (err) { + pr_err("%s: size fixup error while parsing \"%s\": %d\n", + master->name, rb_dynparts[i].name, err); + continue; + } + } + + rb_dynparts[i].found = true; + + /* + * move offset to skip the whole partition on + * next iteration if size > RB_BLOCK_SIZE. + */ + if (rb_dynparts[i].size > RB_BLOCK_SIZE) + offset += ALIGN_DOWN((rb_dynparts[i].size - RB_BLOCK_SIZE), RB_BLOCK_SIZE); + + break; + } + } + + offset += RB_BLOCK_SIZE; + + if (allfound) + break; + } +} + +static int routerboot_partitions_parse(struct mtd_info *master, + const struct mtd_partition **pparts, + struct mtd_part_parser_data *data) +{ + struct device_node *rbpart_node, *pp; + struct mtd_partition *parts; + const char *partname; + size_t master_ofs; + int np; + + /* Pull of_node from the master device node */ + rbpart_node = mtd_get_of_node(master); + if (!rbpart_node) + return 0; + + /* First count the subnodes */ + np = 0; + for_each_child_of_node(rbpart_node, pp) + np++; + + if (!np) + return 0; + + parts = kcalloc(np, sizeof(*parts), GFP_KERNEL); + if (!parts) + return -ENOMEM; + + /* Preemptively look for known parts in flash */ + routerboot_find_dynparts(master); + + np = 0; + master_ofs = 0; + for_each_child_of_node(rbpart_node, pp) { + const __be32 *reg, *sz; + size_t offset, size; + int i, len, a_cells, s_cells; + + partname = of_get_property(pp, "label", &len); + /* Allow deprecated use of "name" instead of "label" */ + if (!partname) + partname = of_get_property(pp, "name", &len); + /* Fallback to node name per spec if all else fails: partname is always set */ + if (!partname) + partname = pp->name; + parts[np].name = partname; + + reg = of_get_property(pp, "reg", &len); + if (reg) { + /* Fixed partition */ + a_cells = of_n_addr_cells(pp); + s_cells = of_n_size_cells(pp); + + if ((len / 4) != (a_cells + s_cells)) { + pr_debug("%s: routerboot partition %pOF (%pOF) error parsing reg property.\n", + master->name, pp, rbpart_node); + goto rbpart_fail; + } + + offset = of_read_number(reg, a_cells); + size = of_read_number(reg + a_cells, s_cells); + } else { + /* Dynamic partition */ + /* Default: part starts at current offset, 0 size */ + offset = master_ofs; + size = 0; + + /* Check if well-known partition */ + for (i = 0; i < ARRAY_SIZE(rb_dynparts); i++) { + if (!strcmp(partname, rb_dynparts[i].name) && rb_dynparts[i].found) { + offset = rb_dynparts[i].offset; + size = rb_dynparts[i].size; + break; + } + } + + /* Standalone 'size' property? Override size */ + sz = of_get_property(pp, "size", &len); + if (sz) { + s_cells = of_n_size_cells(pp); + if ((len / 4) != s_cells) { + pr_debug("%s: routerboot partition %pOF (%pOF) error parsing size property.\n", + master->name, pp, rbpart_node); + goto rbpart_fail; + } + + size = of_read_number(sz, s_cells); + } + } + + if (np > 0) { + /* Minor sanity check for overlaps */ + if (offset < (parts[np-1].offset + parts[np-1].size)) { + pr_err("%s: routerboot partition %pOF (%pOF) \"%s\" overlaps with previous partition \"%s\".\n", + master->name, pp, rbpart_node, + partname, parts[np-1].name); + goto rbpart_fail; + } + + /* Fixup end of previous partition if necessary */ + if (!parts[np-1].size) + parts[np-1].size = (offset - parts[np-1].offset); + } + + if ((offset + size) > master->size) { + pr_err("%s: routerboot partition %pOF (%pOF) \"%s\" extends past end of segment.\n", + master->name, pp, rbpart_node, partname); + goto rbpart_fail; + } + + parts[np].offset = offset; + parts[np].size = size; + parts[np].of_node = pp; + + if (of_get_property(pp, "read-only", &len)) + parts[np].mask_flags |= MTD_WRITEABLE; + + if (of_get_property(pp, "lock", &len)) + parts[np].mask_flags |= MTD_POWERUP_LOCK; + + /* Keep master offset aligned to RB_BLOCK_SIZE */ + master_ofs = ALIGN(offset + size, RB_BLOCK_SIZE); + np++; + } + + *pparts = parts; + return np; + +rbpart_fail: + pr_err("%s: error parsing routerboot partition %pOF (%pOF)\n", + master->name, pp, rbpart_node); + of_node_put(pp); + kfree(parts); + return -EINVAL; +} + +static const struct of_device_id parse_routerbootpart_match_table[] = { + { .compatible = "mikrotik,routerboot-partitions" }, + {}, +}; +MODULE_DEVICE_TABLE(of, parse_routerbootpart_match_table); + +static struct mtd_part_parser routerbootpart_parser = { + .parse_fn = routerboot_partitions_parse, + .name = "routerbootpart", + .of_match_table = parse_routerbootpart_match_table, +}; +module_mtd_part_parser(routerbootpart_parser); + +MODULE_LICENSE("GPL v2"); +MODULE_DESCRIPTION("MTD partitioning for RouterBoot"); +MODULE_AUTHOR("Thibaut VARENE"); |