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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 <dwmw2@infradead.org>
50 lines
1.4 KiB
C
50 lines
1.4 KiB
C
/*
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* Compact binary representation of ihex records. Some devices need their
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* firmware loaded in strange orders rather than a single big blob, but
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* actually parsing ihex-as-text within the kernel seems silly. Thus,...
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*/
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#ifndef __LINUX_IHEX_H__
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#define __LINUX_IHEX_H__
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#include <linux/types.h>
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#include <linux/firmware.h>
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/* Intel HEX files actually limit the length to 256 bytes, but we have
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drivers which would benefit from using separate records which are
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longer than that, so we extend to 16 bits of length */
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struct ihex_binrec {
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__be32 addr;
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__be16 len;
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uint8_t data[0];
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} __attribute__((aligned(4)));
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/* Find the next record, taking into account the 4-byte alignment */
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static inline const struct ihex_binrec *
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ihex_next_binrec(const struct ihex_binrec *rec)
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{
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int next = ((be16_to_cpu(rec->len) + 5) & ~3) - 2;
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rec = (void *)&rec->data[next];
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return be16_to_cpu(rec->len) ? rec : NULL;
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}
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/* Check that ihex_next_binrec() won't take us off the end of the image... */
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static inline int ihex_validate_fw(const struct firmware *fw)
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{
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const struct ihex_binrec *rec;
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size_t ofs = 0;
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while (ofs <= fw->size - sizeof(*rec)) {
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rec = (void *)&fw->data[ofs];
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/* Zero length marks end of records */
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if (!be16_to_cpu(rec->len))
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return 0;
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/* Point to next record... */
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ofs += (sizeof(*rec) + be16_to_cpu(rec->len) + 3) & ~3;
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}
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return -EINVAL;
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}
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#endif /* __LINUX_IHEX_H__ */
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