blob: 3351c0355143d8be4e00d89798e20108d7650375 [file] [log] [blame]
Dominik Brodowski5085cb22005-06-27 16:28:45 -07001Matching of PCMCIA devices to drivers is done using one or more of the
2following criteria:
3
4- manufactor ID
5- card ID
6- product ID strings _and_ hashes of these strings
7- function ID
8- device function (actual and pseudo)
9
10You should use the helpers in include/pcmcia/device_id.h for generating the
11struct pcmcia_device_id[] entries which match devices to drivers.
12
13If you want to match product ID strings, you also need to pass the crc32
14hashes of the string to the macro, e.g. if you want to match the product ID
15string 1, you need to use
16
17PCMCIA_DEVICE_PROD_ID1("some_string", 0x(hash_of_some_string)),
18
19If the hash is incorrect, the kernel will inform you about this in "dmesg"
20upon module initialization, and tell you of the correct hash.
21
Dominik Brodowskieb05bfe2005-06-30 02:58:47 -070022You can determine the hash of the product ID strings by catting the file
23"modalias" in the sysfs directory of the PCMCIA device. It generates a string
Dominik Brodowski5085cb22005-06-27 16:28:45 -070024in the following form:
25pcmcia:m0149cC1ABf06pfn00fn00pa725B842DpbF1EFEE84pc0877B627pd00000000
26
27The hex value after "pa" is the hash of product ID string 1, after "pb" for
28string 2 and so on.
29
30Alternatively, you can use this small tool to determine the crc32 hash.
31simply pass the string you want to evaluate as argument to this program,
32e.g.
33$ ./crc32hash "Dual Speed"
34
35-------------------------------------------------------------------------
36/* crc32hash.c - derived from linux/lib/crc32.c, GNU GPL v2 */
37#include <string.h>
38#include <stdio.h>
39#include <ctype.h>
40#include <stdlib.h>
41
42unsigned int crc32(unsigned char const *p, unsigned int len)
43{
44 int i;
45 unsigned int crc = 0;
Jara9a55242005-06-27 16:28:58 -070046 while (len--) {
Dominik Brodowski5085cb22005-06-27 16:28:45 -070047 crc ^= *p++;
48 for (i = 0; i < 8; i++)
49 crc = (crc >> 1) ^ ((crc & 1) ? 0xedb88320 : 0);
50 }
51 return crc;
52}
53
54int main(int argc, char **argv) {
55 unsigned int result;
56 if (argc != 2) {
57 printf("no string passed as argument\n");
58 return -1;
59 }
60 result = crc32(argv[1], strlen(argv[1]));
61 printf("0x%x\n", result);
62 return 0;
63}