1/*
2 *	pci_syscall.c
3 *
4 * For architectures where we want to allow direct access
5 * to the PCI config stuff - it would probably be preferable
6 * on PCs too, but there people just do it by hand with the
7 * magic northbridge registers..
8 */
9
10#include <linux/errno.h>
11#include <linux/pci.h>
12#include <linux/smp_lock.h>
13#include <linux/syscalls.h>
14#include <asm/uaccess.h>
15#include "pci.h"
16
17asmlinkage long
18sys_pciconfig_read(unsigned long bus, unsigned long dfn,
19		   unsigned long off, unsigned long len,
20		   void __user *buf)
21{
22	struct pci_dev *dev;
23	u8 byte;
24	u16 word;
25	u32 dword;
26	long err, cfg_ret;
27
28	err = -EPERM;
29	if (!capable(CAP_SYS_ADMIN))
30		goto error;
31
32	err = -ENODEV;
33	dev = pci_find_slot(bus, dfn);
34	if (!dev)
35		goto error;
36
37	lock_kernel();
38	switch (len) {
39	case 1:
40		cfg_ret = pci_user_read_config_byte(dev, off, &byte);
41		break;
42	case 2:
43		cfg_ret = pci_user_read_config_word(dev, off, &word);
44		break;
45	case 4:
46		cfg_ret = pci_user_read_config_dword(dev, off, &dword);
47		break;
48	default:
49		err = -EINVAL;
50		unlock_kernel();
51		goto error;
52	};
53	unlock_kernel();
54
55	err = -EIO;
56	if (cfg_ret != PCIBIOS_SUCCESSFUL)
57		goto error;
58
59	switch (len) {
60	case 1:
61		err = put_user(byte, (unsigned char __user *)buf);
62		break;
63	case 2:
64		err = put_user(word, (unsigned short __user *)buf);
65		break;
66	case 4:
67		err = put_user(dword, (unsigned int __user *)buf);
68		break;
69	};
70	return err;
71
72error:
73	/* ??? XFree86 doesn't even check the return value.  They
74	   just look for 0xffffffff in the output, since that's what
75	   they get instead of a machine check on x86.  */
76	switch (len) {
77	case 1:
78		put_user(-1, (unsigned char __user *)buf);
79		break;
80	case 2:
81		put_user(-1, (unsigned short __user *)buf);
82		break;
83	case 4:
84		put_user(-1, (unsigned int __user *)buf);
85		break;
86	};
87	return err;
88}
89
90asmlinkage long
91sys_pciconfig_write(unsigned long bus, unsigned long dfn,
92		    unsigned long off, unsigned long len,
93		    void __user *buf)
94{
95	struct pci_dev *dev;
96	u8 byte;
97	u16 word;
98	u32 dword;
99	int err = 0;
100
101	if (!capable(CAP_SYS_ADMIN))
102		return -EPERM;
103
104	dev = pci_find_slot(bus, dfn);
105	if (!dev)
106		return -ENODEV;
107
108	lock_kernel();
109	switch(len) {
110	case 1:
111		err = get_user(byte, (u8 __user *)buf);
112		if (err)
113			break;
114		err = pci_user_write_config_byte(dev, off, byte);
115		if (err != PCIBIOS_SUCCESSFUL)
116			err = -EIO;
117		break;
118
119	case 2:
120		err = get_user(word, (u16 __user *)buf);
121		if (err)
122			break;
123		err = pci_user_write_config_word(dev, off, word);
124		if (err != PCIBIOS_SUCCESSFUL)
125			err = -EIO;
126		break;
127
128	case 4:
129		err = get_user(dword, (u32 __user *)buf);
130		if (err)
131			break;
132		err = pci_user_write_config_dword(dev, off, dword);
133		if (err != PCIBIOS_SUCCESSFUL)
134			err = -EIO;
135		break;
136
137	default:
138		err = -EINVAL;
139		break;
140	};
141	unlock_kernel();
142
143	return err;
144}
145