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/syscalls.h>
13#include <asm/uaccess.h>
14#include "pci.h"
15
16SYSCALL_DEFINE5(pciconfig_read, unsigned long, bus, unsigned long, dfn,
17		unsigned long, off, unsigned long, len, void __user *, buf)
18{
19	struct pci_dev *dev;
20	u8 byte;
21	u16 word;
22	u32 dword;
23	long err;
24	long cfg_ret;
25
26	if (!capable(CAP_SYS_ADMIN))
27		return -EPERM;
28
29	err = -ENODEV;
30	dev = pci_get_bus_and_slot(bus, dfn);
31	if (!dev)
32		goto error;
33
34	switch (len) {
35	case 1:
36		cfg_ret = pci_user_read_config_byte(dev, off, &byte);
37		break;
38	case 2:
39		cfg_ret = pci_user_read_config_word(dev, off, &word);
40		break;
41	case 4:
42		cfg_ret = pci_user_read_config_dword(dev, off, &dword);
43		break;
44	default:
45		err = -EINVAL;
46		goto error;
47	}
48
49	err = -EIO;
50	if (cfg_ret != PCIBIOS_SUCCESSFUL)
51		goto error;
52
53	switch (len) {
54	case 1:
55		err = put_user(byte, (unsigned char __user *)buf);
56		break;
57	case 2:
58		err = put_user(word, (unsigned short __user *)buf);
59		break;
60	case 4:
61		err = put_user(dword, (unsigned int __user *)buf);
62		break;
63	}
64	pci_dev_put(dev);
65	return err;
66
67error:
68	/* ??? XFree86 doesn't even check the return value.  They
69	   just look for 0xffffffff in the output, since that's what
70	   they get instead of a machine check on x86.  */
71	switch (len) {
72	case 1:
73		put_user(-1, (unsigned char __user *)buf);
74		break;
75	case 2:
76		put_user(-1, (unsigned short __user *)buf);
77		break;
78	case 4:
79		put_user(-1, (unsigned int __user *)buf);
80		break;
81	}
82	pci_dev_put(dev);
83	return err;
84}
85
86SYSCALL_DEFINE5(pciconfig_write, unsigned long, bus, unsigned long, dfn,
87		unsigned long, off, unsigned long, len, void __user *, buf)
88{
89	struct pci_dev *dev;
90	u8 byte;
91	u16 word;
92	u32 dword;
93	int err = 0;
94
95	if (!capable(CAP_SYS_ADMIN))
96		return -EPERM;
97
98	dev = pci_get_bus_and_slot(bus, dfn);
99	if (!dev)
100		return -ENODEV;
101
102	switch (len) {
103	case 1:
104		err = get_user(byte, (u8 __user *)buf);
105		if (err)
106			break;
107		err = pci_user_write_config_byte(dev, off, byte);
108		if (err != PCIBIOS_SUCCESSFUL)
109			err = -EIO;
110		break;
111
112	case 2:
113		err = get_user(word, (u16 __user *)buf);
114		if (err)
115			break;
116		err = pci_user_write_config_word(dev, off, word);
117		if (err != PCIBIOS_SUCCESSFUL)
118			err = -EIO;
119		break;
120
121	case 4:
122		err = get_user(dword, (u32 __user *)buf);
123		if (err)
124			break;
125		err = pci_user_write_config_dword(dev, off, dword);
126		if (err != PCIBIOS_SUCCESSFUL)
127			err = -EIO;
128		break;
129
130	default:
131		err = -EINVAL;
132		break;
133	}
134	pci_dev_put(dev);
135	return err;
136}
137