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pp bootloader: speed up loading of the OF in the mi4 format

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This change replaces an odd way to increment tea key in a function responsible
for finding the proper key (it doesn't have to be done in a for loop, it's just
adding a 32bit number to a 128bit number). It reduces the time needed to find
the key practically to zero and it gives in the best case 2 seconds of overall
speedup in loading the OF.

Change-Id: I0632526c3dfeb4d0603e77239f298a89076b630b
Reviewed-on: http://gerrit.rockbox.org/230
Tested-by: Szymon Dziok <b0hoon@o2.pl>
Reviewed-by: Thomas Martitz <kugel@rockbox.org>
Reviewed-by: Szymon Dziok <b0hoon@o2.pl>
This commit is contained in:
Szymon Dziok 2012-05-04 22:28:26 +02:00
parent e359202aa1
commit ba3b6ceb4b
1 changed files with 13 additions and 20 deletions
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33
bootloader/main-pp.c
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@ -170,7 +170,7 @@ struct tea_key tea_keytable[] = {
{ "c200_106", { 0xa913d139, 0xf842f398, 0x3e03f1a6, 0x060ee012 } }, { "c200_106", { 0xa913d139, 0xf842f398, 0x3e03f1a6, 0x060ee012 } },
{ "view", { 0x70e19bda, 0x0c69ea7d, 0x2b8b1ad1, 0xe9767ced } }, { "view", { 0x70e19bda, 0x0c69ea7d, 0x2b8b1ad1, 0xe9767ced } },
{ "sa9200", { 0x33ea0236, 0x9247bdc5, 0xdfaedf9f, 0xd67c9d30 } }, { "sa9200", { 0x33ea0236, 0x9247bdc5, 0xdfaedf9f, 0xd67c9d30 } },
{ "hdd1630", { 0x04543ced, 0xcebfdbad, 0xf7477872, 0x0d12342e } }, { "hdd1630/hdd63x0", { 0x04543ced, 0xcebfdbad, 0xf7477872, 0x0d12342e } },
{ "vibe500", { 0xe3a66156, 0x77c6b67a, 0xe821dca5, 0xca8ca37c } }, { "vibe500", { 0xe3a66156, 0x77c6b67a, 0xe821dca5, 0xca8ca37c } },
}; };
@ -247,19 +247,19 @@ static int tea_find_key(struct mi4header_t *mi4header, int fd)
{ {
unsigned int i; unsigned int i;
int rc; int rc;
unsigned int j;
uint32_t key[4]; uint32_t key[4];
uint32_t keyinc;
unsigned char magic_enc[8]; unsigned char magic_enc[8];
int key_found = -1; int key_found = -1;
unsigned int magic_location = mi4header->length-4; unsigned int magic_location = mi4header->length-4;
int unaligned = 0; int unaligned = 0;
if ( (magic_location % 8) != 0 ) if ( (magic_location % 8) != 0 )
{ {
unaligned = 1; unaligned = 1;
magic_location -= 4; magic_location -= 4;
} }
/* Load encrypted magic 0xaa55aa55 to check key */ /* Load encrypted magic 0xaa55aa55 to check key */
lseek(fd, MI4_HEADER_SIZE + magic_location, SEEK_SET); lseek(fd, MI4_HEADER_SIZE + magic_location, SEEK_SET);
rc = read(fd, magic_enc, 8); rc = read(fd, magic_enc, 8);
@ -273,30 +273,23 @@ static int tea_find_key(struct mi4header_t *mi4header, int fd)
key[1] = tea_keytable[i].key[1]; key[1] = tea_keytable[i].key[1];
key[2] = tea_keytable[i].key[2]; key[2] = tea_keytable[i].key[2];
key[3] = tea_keytable[i].key[3]; key[3] = tea_keytable[i].key[3];
/* Now increment the key */ /* Now increment the key */
for(j=0; j<((magic_location-mi4header->plaintext)/8); j++){ keyinc = (magic_location-mi4header->plaintext)/8;
key[0]++; if ((key[0]+keyinc) < key[0]) key[1]++;
if (key[0]==0) { key[0] += keyinc;
key[1]++; if (key[1]==0) key[2]++;
if (key[1]==0) { if (key[2]==0) key[3]++;
key[2]++;
if (key[2]==0) {
key[3]++;
}
}
}
}
if (tea_test_key(magic_enc,key,unaligned)) if (tea_test_key(magic_enc,key,unaligned))
{ {
key_found = i; key_found = i;
printf("%s...found", tea_keytable[i].name); printf("%s...found", tea_keytable[i].name);
} else { } else {
/* printf("%s...failed", tea_keytable[i].name); */ /* printf("%s...failed", tea_keytable[i].name); */
} }
} }
return key_found; return key_found;
} }