File: /usr/src/linux/drivers/pci/syscall.c
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/sched.h>
11 #include <linux/errno.h>
12 #include <linux/pci.h>
13 #include <linux/smp_lock.h>
14 #include <asm/uaccess.h>
15
16
17 asmlinkage long
18 sys_pciconfig_read(unsigned long bus, unsigned long dfn,
19 unsigned long off, unsigned long len, void *buf)
20 {
21 struct pci_dev *dev;
22 u8 byte;
23 u16 word;
24 u32 dword;
25 long err, cfg_ret;
26
27 err = -EPERM;
28 if (!capable(CAP_SYS_ADMIN))
29 goto error;
30
31 err = -ENODEV;
32 dev = pci_find_slot(bus, dfn);
33 if (!dev)
34 goto error;
35
36 lock_kernel();
37 switch (len) {
38 case 1:
39 cfg_ret = pci_read_config_byte(dev, off, &byte);
40 break;
41 case 2:
42 cfg_ret = pci_read_config_word(dev, off, &word);
43 break;
44 case 4:
45 cfg_ret = pci_read_config_dword(dev, off, &dword);
46 break;
47 default:
48 err = -EINVAL;
49 unlock_kernel();
50 goto error;
51 };
52 unlock_kernel();
53
54 err = -EIO;
55 if (cfg_ret != PCIBIOS_SUCCESSFUL)
56 goto error;
57
58 switch (len) {
59 case 1:
60 err = put_user(byte, (unsigned char *)buf);
61 break;
62 case 2:
63 err = put_user(word, (unsigned short *)buf);
64 break;
65 case 4:
66 err = put_user(dword, (unsigned int *)buf);
67 break;
68 };
69 return err;
70
71 error:
72 /* ??? XFree86 doesn't even check the return value. They
73 just look for 0xffffffff in the output, since that's what
74 they get instead of a machine check on x86. */
75 switch (len) {
76 case 1:
77 put_user(-1, (unsigned char *)buf);
78 break;
79 case 2:
80 put_user(-1, (unsigned short *)buf);
81 break;
82 case 4:
83 put_user(-1, (unsigned int *)buf);
84 break;
85 };
86 return err;
87 }
88
89 asmlinkage long
90 sys_pciconfig_write(unsigned long bus, unsigned long dfn,
91 unsigned long off, unsigned long len, void *buf)
92 {
93 struct pci_dev *dev;
94 u8 byte;
95 u16 word;
96 u32 dword;
97 int err = 0;
98
99 if (!capable(CAP_SYS_ADMIN))
100 return -EPERM;
101 if (!pcibios_present())
102 return -ENOSYS;
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 *)buf);
112 if (err)
113 break;
114 err = pci_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 *)buf);
121 if (err)
122 break;
123 err = pci_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 *)buf);
130 if (err)
131 break;
132 err = pci_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