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1 | /* |
2 | * The PCI Library -- Portable interface to pread() and pwrite() | |
3 | * | |
4 | * Copyright (c) 1997--2003 Martin Mares <mj@ucw.cz> | |
5 | * | |
6 | * Can be freely distributed and used under the terms of the GNU GPL. | |
7 | */ | |
8 | ||
9 | /* | |
10 | * We'd like to use pread/pwrite for configuration space accesses, but | |
11 | * unfortunately it isn't simple at all since all libc's until glibc 2.1 | |
12 | * don't define it. | |
13 | */ | |
14 | ||
15 | #if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ > 0 | |
16 | /* glibc 2.1 or newer -> pread/pwrite supported automatically */ | |
17 | ||
18 | #elif defined(i386) && defined(__GLIBC__) | |
19 | /* glibc 2.0 on i386 -> call syscalls directly */ | |
20 | #include <asm/unistd.h> | |
21 | #include <syscall-list.h> | |
22 | #ifndef SYS_pread | |
23 | #define SYS_pread 180 | |
24 | #endif | |
25 | static int pread(unsigned int fd, void *buf, size_t size, loff_t where) | |
26 | { return syscall(SYS_pread, fd, buf, size, where); } | |
27 | #ifndef SYS_pwrite | |
28 | #define SYS_pwrite 181 | |
29 | #endif | |
30 | static int pwrite(unsigned int fd, void *buf, size_t size, loff_t where) | |
31 | { return syscall(SYS_pwrite, fd, buf, size, where); } | |
32 | ||
11f7b31b MM |
33 | #else |
34 | /* In all other cases we use lseek/read/write instead to be safe */ | |
35 | #define make_rw_glue(op) \ | |
36 | static int do_##op(struct pci_dev *d, int fd, void *buf, size_t size, int where) \ | |
37 | { \ | |
38 | struct pci_access *a = d->access; \ | |
39 | int r; \ | |
40 | if (a->fd_pos != where && lseek(fd, where, SEEK_SET) < 0) \ | |
41 | return -1; \ | |
42 | r = op(fd, buf, size); \ | |
43 | if (r < 0) \ | |
44 | a->fd_pos = -1; \ | |
45 | else \ | |
46 | a->fd_pos = where + r; \ | |
47 | return r; \ | |
48 | } | |
49 | make_rw_glue(read) | |
50 | make_rw_glue(write) | |
489233b4 | 51 | #define PCI_HAVE_DO_READ |
11f7b31b MM |
52 | #endif |
53 | ||
489233b4 | 54 | #ifndef PCI_HAVE_DO_READ |
11f7b31b MM |
55 | #define do_read(d,f,b,l,p) pread(f,b,l,p) |
56 | #define do_write(d,f,b,l,p) pwrite(f,b,l,p) | |
57 | #endif |