Commit bacfe09d authored by David Woodhouse's avatar David Woodhouse Committed by David Woodhouse
Browse files

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: default avatarDavid Woodhouse <dwmw2@infradead.org>
parent 88ecf814

include/linux/ihex.h

0 → 100644
+50 −0
Original line number Diff line number Diff line 
/*

 * 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 <linux/types.h>

#include <linux/firmware.h>



/* 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__ */

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