a9a55243d4
Fix example hash generator in Documentation. Signed-off-by: Dominik Brodowski <linux@dominikbrodowski.net> Signed-off-by: Andrew Morton <akpm@osdl.org> Signed-off-by: Linus Torvalds <torvalds@osdl.org>
65 lines
1.9 KiB
Plaintext
65 lines
1.9 KiB
Plaintext
Matching of PCMCIA devices to drivers is done using one or more of the
|
|
following criteria:
|
|
|
|
- manufactor ID
|
|
- card ID
|
|
- product ID strings _and_ hashes of these strings
|
|
- function ID
|
|
- device function (actual and pseudo)
|
|
|
|
You should use the helpers in include/pcmcia/device_id.h for generating the
|
|
struct pcmcia_device_id[] entries which match devices to drivers.
|
|
|
|
If you want to match product ID strings, you also need to pass the crc32
|
|
hashes of the string to the macro, e.g. if you want to match the product ID
|
|
string 1, you need to use
|
|
|
|
PCMCIA_DEVICE_PROD_ID1("some_string", 0x(hash_of_some_string)),
|
|
|
|
If the hash is incorrect, the kernel will inform you about this in "dmesg"
|
|
upon module initialization, and tell you of the correct hash.
|
|
|
|
You can determine the hash of the product ID strings by running
|
|
"pcmcia-modalias %n.%m" [%n being replaced with the socket number and %m being
|
|
replaced with the device function] from pcmciautils. It generates a string
|
|
in the following form:
|
|
pcmcia:m0149cC1ABf06pfn00fn00pa725B842DpbF1EFEE84pc0877B627pd00000000
|
|
|
|
The hex value after "pa" is the hash of product ID string 1, after "pb" for
|
|
string 2 and so on.
|
|
|
|
Alternatively, you can use this small tool to determine the crc32 hash.
|
|
simply pass the string you want to evaluate as argument to this program,
|
|
e.g.
|
|
$ ./crc32hash "Dual Speed"
|
|
|
|
-------------------------------------------------------------------------
|
|
/* crc32hash.c - derived from linux/lib/crc32.c, GNU GPL v2 */
|
|
#include <string.h>
|
|
#include <stdio.h>
|
|
#include <ctype.h>
|
|
#include <stdlib.h>
|
|
|
|
unsigned int crc32(unsigned char const *p, unsigned int len)
|
|
{
|
|
int i;
|
|
unsigned int crc = 0;
|
|
while (len--) {
|
|
crc ^= *p++;
|
|
for (i = 0; i < 8; i++)
|
|
crc = (crc >> 1) ^ ((crc & 1) ? 0xedb88320 : 0);
|
|
}
|
|
return crc;
|
|
}
|
|
|
|
int main(int argc, char **argv) {
|
|
unsigned int result;
|
|
if (argc != 2) {
|
|
printf("no string passed as argument\n");
|
|
return -1;
|
|
}
|
|
result = crc32(argv[1], strlen(argv[1]));
|
|
printf("0x%x\n", result);
|
|
return 0;
|
|
}
|