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1// SPDX-License-Identifier: GPL-2.0
2/*
3 * Linux kernel module helpers.
4 */
5
6#include <linux/of.h>
7#include <linux/module.h>
8#include <linux/slab.h>
9#include <linux/string.h>
10
11ssize_t of_modalias(const struct device_node *np, char *str, ssize_t len)
12{
13 const char *compat;
14 char *c;
15 struct property *p;
16 ssize_t csize;
17 ssize_t tsize;
18
19 /*
20 * Prevent a kernel oops in vsnprintf() -- it only allows passing a
21 * NULL ptr when the length is also 0. Also filter out the negative
22 * lengths...
23 */
24 if ((len > 0 && !str) || len < 0)
25 return -EINVAL;
26
27 /* Name & Type */
28 /* %p eats all alphanum characters, so %c must be used here */
29 csize = snprintf(buf: str, size: len, fmt: "of:N%pOFn%c%s", np, 'T',
30 of_node_get_device_type(np));
31 tsize = csize;
32 if (csize >= len)
33 csize = len > 0 ? len - 1 : 0;
34 len -= csize;
35 str += csize;
36
37 of_property_for_each_string(np, "compatible", p, compat) {
38 csize = snprintf(buf: str, size: len, fmt: "C%s", compat);
39 tsize += csize;
40 if (csize >= len)
41 continue;
42 for (c = str; c; ) {
43 c = strchr(c, ' ');
44 if (c)
45 *c++ = '_';
46 }
47 len -= csize;
48 str += csize;
49 }
50
51 return tsize;
52}
53
54int of_request_module(const struct device_node *np)
55{
56 char *str;
57 ssize_t size;
58 int ret;
59
60 if (!np)
61 return -ENODEV;
62
63 size = of_modalias(np, NULL, len: 0);
64 if (size < 0)
65 return size;
66
67 /* Reserve an additional byte for the trailing '\0' */
68 size++;
69
70 str = kmalloc(size, GFP_KERNEL);
71 if (!str)
72 return -ENOMEM;
73
74 of_modalias(np, str, len: size);
75 str[size - 1] = '\0';
76 ret = request_module(str);
77 kfree(objp: str);
78
79 return ret;
80}
81EXPORT_SYMBOL_GPL(of_request_module);
82

source code of linux/drivers/of/module.c