1 Matching of PCMCIA devices to drivers is done using one or more of the
2 following 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
10 You should use the helpers in include/pcmcia/device_id.h for generating the
11 struct pcmcia_device_id[] entries which match devices to drivers.
12
13 If you want to match product ID strings, you also need to pass the crc32
14 hashes of the string to the macro, e.g. if you want to match the product ID
15 string 1, you need to use
16
17 PCMCIA_DEVICE_PROD_ID1("some_string", 0x(hash_of_some_string)),
18
19 If the hash is incorrect, the kernel will inform you about this in "dmesg"
20 upon module initialization, and tell you of the correct hash.
21
22 You 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
24 in the following form:
25 pcmcia:m0149cC1ABf06pfn00fn00pa725B842DpbF1EFEE84pc0877B627pd00000000
26
27 The hex value after "pa" is the hash of product ID string 1, after "pb" for
28 string 2 and so on.
29
30 Alternatively, you can use this small tool to determine the crc32 hash.
31 simply pass the string you want to evaluate as argument to this program,
32 e.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
42 unsigned int crc32(unsigned char const *p, unsigned int len)
43 {
44 int i;
45 unsigned int crc = 0;
46 while (len--) {
47 crc ^= *p++;
48 for (i = 0; i < 8; i++)
49 crc = (crc >> 1) ^ ((crc & 1) ? 0xedb88320 : 0);
50 }
51 return crc;
52 }
53
54 int 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 }
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