From bacfe09dd7545467965e8d8f1eab20bc62dce00d Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Fri, 30 May 2008 13:57:27 +0300 Subject: ihex.h: binary representation of ihex records Some devices need their firmware as a set of {address, len, data...} records in some specific order rather than a simple blob. The normal way of doing this kind of thing is 'ihex', which is a text format and not entirely suitable for use in the kernel. This provides a binary representation which is very similar, but much more compact -- and a helper routine to skip to the next record, because the alignment constraints mean that everybody will screw it up for themselves otherwise. Also a helper function which can verify that a 'struct firmware' contains a valid set of ihex records, and that following them won't run off the end of the loaded data. Signed-off-by: David Woodhouse --- include/linux/ihex.h | 50 ++++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 50 insertions(+) create mode 100644 include/linux/ihex.h (limited to 'include/linux/ihex.h') diff --git a/include/linux/ihex.h b/include/linux/ihex.h new file mode 100644 index 00000000000..df89edd890a --- /dev/null +++ b/include/linux/ihex.h @@ -0,0 +1,50 @@ +/* + * Compact binary representation of ihex records. Some devices need their + * firmware loaded in strange orders rather than a single big blob, but + * actually parsing ihex-as-text within the kernel seems silly. Thus,... + */ + +#ifndef __LINUX_IHEX_H__ +#define __LINUX_IHEX_H__ + +#include +#include + +/* Intel HEX files actually limit the length to 256 bytes, but we have + drivers which would benefit from using separate records which are + longer than that, so we extend to 16 bits of length */ +struct ihex_binrec { + __be32 addr; + __be16 len; + uint8_t data[0]; +} __attribute__((aligned(4))); + +/* Find the next record, taking into account the 4-byte alignment */ +static inline const struct ihex_binrec * +ihex_next_binrec(const struct ihex_binrec *rec) +{ + int next = ((be16_to_cpu(rec->len) + 5) & ~3) - 2; + rec = (void *)&rec->data[next]; + + return be16_to_cpu(rec->len) ? rec : NULL; +} + +/* Check that ihex_next_binrec() won't take us off the end of the image... */ +static inline int ihex_validate_fw(const struct firmware *fw) +{ + const struct ihex_binrec *rec; + size_t ofs = 0; + + while (ofs <= fw->size - sizeof(*rec)) { + rec = (void *)&fw->data[ofs]; + + /* Zero length marks end of records */ + if (!be16_to_cpu(rec->len)) + return 0; + + /* Point to next record... */ + ofs += (sizeof(*rec) + be16_to_cpu(rec->len) + 3) & ~3; + } + return -EINVAL; +} +#endif /* __LINUX_IHEX_H__ */ -- cgit v1.2.3-70-g09d2 From f1485f3deb89e6ae10c4d34662ec9e692855ab5d Mon Sep 17 00:00:00 2001 From: David Woodhouse Date: Sat, 31 May 2008 15:20:37 +0300 Subject: ihex: request_ihex_firmware() function to load and validate firmware Provide a helper to load the file and validate it in one call, to simplify error handling in the drivers which are going to use it. Signed-off-by: David Woodhouse --- include/linux/ihex.h | 24 ++++++++++++++++++++++++ 1 file changed, 24 insertions(+) (limited to 'include/linux/ihex.h') diff --git a/include/linux/ihex.h b/include/linux/ihex.h index df89edd890a..2baace2788a 100644 --- a/include/linux/ihex.h +++ b/include/linux/ihex.h @@ -9,6 +9,7 @@ #include #include +#include /* Intel HEX files actually limit the length to 256 bytes, but we have drivers which would benefit from using separate records which are @@ -47,4 +48,27 @@ static inline int ihex_validate_fw(const struct firmware *fw) } return -EINVAL; } + +/* Request firmware and validate it so that we can trust we won't + * run off the end while reading records... */ +static inline int request_ihex_firmware(const struct firmware **fw, + const char *fw_name, + struct device *dev) +{ + const struct firmware *lfw; + int ret; + + ret = request_firmware(&lfw, fw_name, dev); + if (ret) + return ret; + ret = ihex_validate_fw(lfw); + if (ret) { + dev_err(dev, "Firmware \"%s\" not valid IHEX records\n", + fw_name); + release_firmware(lfw); + return ret; + } + *fw = lfw; + return 0; +} #endif /* __LINUX_IHEX_H__ */ -- cgit v1.2.3-70-g09d2