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Commit | Line | Data |
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5085cb26 DB |
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 | ||
eb05bfe4 DB |
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 | |
5085cb26 DB |
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; | |
a9a55243 | 46 | while (len--) { |
5085cb26 DB |
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 | } |