| 1 | /* SPDX-License-Identifier: GPL-2.0 */ |
| 2 | /* |
| 3 | * Compact binary representation of ihex records. Some devices need their |
| 4 | * firmware loaded in strange orders rather than a single big blob, but |
| 5 | * actually parsing ihex-as-text within the kernel seems silly. Thus,... |
| 6 | */ |
| 7 | |
| 8 | #ifndef __LINUX_IHEX_H__ |
| 9 | #define __LINUX_IHEX_H__ |
| 10 | |
| 11 | #include <linux/types.h> |
| 12 | #include <linux/firmware.h> |
| 13 | #include <linux/device.h> |
| 14 | |
| 15 | /* Intel HEX files actually limit the length to 256 bytes, but we have |
| 16 | drivers which would benefit from using separate records which are |
| 17 | longer than that, so we extend to 16 bits of length */ |
| 18 | struct ihex_binrec { |
| 19 | __be32 addr; |
| 20 | __be16 len; |
| 21 | uint8_t data[]; |
| 22 | } __attribute__((packed)); |
| 23 | |
| 24 | static inline uint16_t ihex_binrec_size(const struct ihex_binrec *p) |
| 25 | { |
| 26 | return be16_to_cpu(p->len) + sizeof(*p); |
| 27 | } |
| 28 | |
| 29 | /* Find the next record, taking into account the 4-byte alignment */ |
| 30 | static inline const struct ihex_binrec * |
| 31 | __ihex_next_binrec(const struct ihex_binrec *rec) |
| 32 | { |
| 33 | const void *p = rec; |
| 34 | |
| 35 | return p + ALIGN(ihex_binrec_size(rec), 4); |
| 36 | } |
| 37 | |
| 38 | static inline const struct ihex_binrec * |
| 39 | ihex_next_binrec(const struct ihex_binrec *rec) |
| 40 | { |
| 41 | rec = __ihex_next_binrec(rec); |
| 42 | |
| 43 | return be16_to_cpu(rec->len) ? rec : NULL; |
| 44 | } |
| 45 | |
| 46 | /* Check that ihex_next_binrec() won't take us off the end of the image... */ |
| 47 | static inline int ihex_validate_fw(const struct firmware *fw) |
| 48 | { |
| 49 | const struct ihex_binrec *end, *rec; |
| 50 | |
| 51 | rec = (const void *)fw->data; |
| 52 | end = (const void *)&fw->data[fw->size - sizeof(*end)]; |
| 53 | |
| 54 | for (; rec <= end; rec = __ihex_next_binrec(rec)) { |
| 55 | /* Zero length marks end of records */ |
| 56 | if (rec == end && !be16_to_cpu(rec->len)) |
| 57 | return 0; |
| 58 | } |
| 59 | return -EINVAL; |
| 60 | } |
| 61 | |
| 62 | /* Request firmware and validate it so that we can trust we won't |
| 63 | * run off the end while reading records... */ |
| 64 | static inline int request_ihex_firmware(const struct firmware **fw, |
| 65 | const char *fw_name, |
| 66 | struct device *dev) |
| 67 | { |
| 68 | const struct firmware *lfw; |
| 69 | int ret; |
| 70 | |
| 71 | ret = request_firmware(&lfw, fw_name, dev); |
| 72 | if (ret) |
| 73 | return ret; |
| 74 | ret = ihex_validate_fw(lfw); |
| 75 | if (ret) { |
| 76 | dev_err(dev, "Firmware \"%s\" not valid IHEX records\n", |
| 77 | fw_name); |
| 78 | release_firmware(lfw); |
| 79 | return ret; |
| 80 | } |
| 81 | *fw = lfw; |
| 82 | return 0; |
| 83 | } |
| 84 | #endif /* __LINUX_IHEX_H__ */ |