xref: /openbmc/linux/drivers/pnp/isapnp/proc.c (revision 6c33a6f4)
1 // SPDX-License-Identifier: GPL-2.0-or-later
2 /*
3  *  ISA Plug & Play support
4  *  Copyright (c) by Jaroslav Kysela <perex@perex.cz>
5  */
6 
7 #include <linux/module.h>
8 #include <linux/isapnp.h>
9 #include <linux/proc_fs.h>
10 #include <linux/init.h>
11 #include <linux/uaccess.h>
12 
13 extern struct pnp_protocol isapnp_protocol;
14 
15 static struct proc_dir_entry *isapnp_proc_bus_dir = NULL;
16 
17 static loff_t isapnp_proc_bus_lseek(struct file *file, loff_t off, int whence)
18 {
19 	return fixed_size_llseek(file, off, whence, 256);
20 }
21 
22 static ssize_t isapnp_proc_bus_read(struct file *file, char __user * buf,
23 				    size_t nbytes, loff_t * ppos)
24 {
25 	struct pnp_dev *dev = PDE_DATA(file_inode(file));
26 	int pos = *ppos;
27 	int cnt, size = 256;
28 
29 	if (pos >= size)
30 		return 0;
31 	if (nbytes >= size)
32 		nbytes = size;
33 	if (pos + nbytes > size)
34 		nbytes = size - pos;
35 	cnt = nbytes;
36 
37 	if (!access_ok(buf, cnt))
38 		return -EINVAL;
39 
40 	isapnp_cfg_begin(dev->card->number, dev->number);
41 	for (; pos < 256 && cnt > 0; pos++, buf++, cnt--) {
42 		unsigned char val;
43 		val = isapnp_read_byte(pos);
44 		__put_user(val, buf);
45 	}
46 	isapnp_cfg_end();
47 
48 	*ppos = pos;
49 	return nbytes;
50 }
51 
52 static const struct proc_ops isapnp_proc_bus_proc_ops = {
53 	.proc_lseek	= isapnp_proc_bus_lseek,
54 	.proc_read	= isapnp_proc_bus_read,
55 };
56 
57 static int isapnp_proc_attach_device(struct pnp_dev *dev)
58 {
59 	struct pnp_card *bus = dev->card;
60 	struct proc_dir_entry *de, *e;
61 	char name[16];
62 
63 	if (!(de = bus->procdir)) {
64 		sprintf(name, "%02x", bus->number);
65 		de = bus->procdir = proc_mkdir(name, isapnp_proc_bus_dir);
66 		if (!de)
67 			return -ENOMEM;
68 	}
69 	sprintf(name, "%02x", dev->number);
70 	e = dev->procent = proc_create_data(name, S_IFREG | S_IRUGO, de,
71 					    &isapnp_proc_bus_proc_ops, dev);
72 	if (!e)
73 		return -ENOMEM;
74 	proc_set_size(e, 256);
75 	return 0;
76 }
77 
78 int __init isapnp_proc_init(void)
79 {
80 	struct pnp_dev *dev;
81 
82 	isapnp_proc_bus_dir = proc_mkdir("bus/isapnp", NULL);
83 	protocol_for_each_dev(&isapnp_protocol, dev) {
84 		isapnp_proc_attach_device(dev);
85 	}
86 	return 0;
87 }
88