2 * The PCI Library -- Portable interface to pread() and pwrite()
4 * Copyright (c) 1997--2003 Martin Mares <mj@ucw.cz>
6 * Can be freely distributed and used under the terms of the GNU GPL v2+
8 * SPDX-License-Identifier: GPL-2.0-or-later
12 * We'd like to use pread/pwrite for configuration space accesses, but
13 * unfortunately it isn't simple at all since all libc's until glibc 2.1
17 #if defined(__GLIBC__) && __GLIBC__ == 2 && __GLIBC_MINOR__ > 0
18 /* glibc 2.1 or newer -> pread/pwrite supported automatically */
20 #elif defined(i386) && defined(__GLIBC__)
21 /* glibc 2.0 on i386 -> call syscalls directly */
22 #include <asm/unistd.h>
23 #include <syscall-list.h>
27 static int pread(unsigned int fd, void *buf, size_t size, loff_t where)
28 { return syscall(SYS_pread, fd, buf, size, where); }
30 #define SYS_pwrite 181
32 static int pwrite(unsigned int fd, void *buf, size_t size, loff_t where)
33 { return syscall(SYS_pwrite, fd, buf, size, where); }
36 /* In all other cases we use lseek/read/write instead to be safe */
37 #define make_rw_glue(op) \
38 static int do_##op(struct pci_dev *d, int fd, void *buf, size_t size, int where) \
40 struct pci_access *a = d->access; \
42 if (a->fd_pos != where && lseek(fd, where, SEEK_SET) < 0) \
44 r = op(fd, buf, size); \
48 a->fd_pos = where + r; \
53 #define PCI_HAVE_DO_READ
56 #ifndef PCI_HAVE_DO_READ
57 #define do_read(d,f,b,l,p) pread(f,b,l,p)
58 #define do_write(d,f,b,l,p) pwrite(f,b,l,p)