1 /* Copyright (C) 1999-2015 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by David Mosberger-Tang <davidm@hpl.hp.com>.
5 The GNU C Library is free software; you can redistribute it and/or
6 modify it under the terms of the GNU Lesser General Public
7 License as published by the Free Software Foundation; either
8 version 2.1 of the License, or (at your option) any later version.
10 The GNU C Library is distributed in the hope that it will be useful,
11 but WITHOUT ANY WARRANTY; without even the implied warranty of
12 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
13 Lesser General Public License for more details.
15 You should have received a copy of the GNU Lesser General Public
16 License along with the GNU C Library; if not, see
17 <http://www.gnu.org/licenses/>. */
19 /* I/O access is restricted to ISA port space (ports 0..65535).
20 Modern devices hopefully are sane enough not to put any performance
21 critical registers in i/o space.
23 On the first call to ioperm() or iopl(), the entire (E)ISA port
24 space is mapped into the virtual address space at address io.base.
25 mprotect() calls are then used to enable/disable access to ports.
26 Per 4KB page, there are 4 I/O ports. */
35 #include <sys/types.h>
38 #define MAX_PORT 0x10000
41 * Memory fence w/accept. This should never be used in code that is
44 #define __ia64_mf_a() __asm__ __volatile__ ("mf.a" ::: "memory")
48 unsigned long int base
;
49 unsigned long int page_mask
;
53 __inline__
unsigned long int
54 io_offset (unsigned long int port
)
56 return ((port
>> 2) << 12) | (port
& 0xfff);
60 _ioperm (unsigned long int from
, unsigned long int num
, int turn_on
)
62 unsigned long int base
;
64 /* this test isn't as silly as it may look like; consider overflows! */
65 if (from
>= MAX_PORT
|| from
+ num
> MAX_PORT
)
75 unsigned long phys_io_base
, len
;
78 io
.page_mask
= ~(__getpagesize() - 1);
80 /* get I/O base physical address from ar.k0 as per PRM: */
81 __asm__ ("mov %0=ar.k0" : "=r"(phys_io_base
));
83 /* The O_SYNC flag tells the /dev/mem driver to map the
85 fd
= __open ("/dev/mem", O_RDWR
| O_SYNC
);
89 len
= io_offset (MAX_PORT
);
90 /* see comment below */
91 base
= (unsigned long int) __mmap (0, len
, PROT_READ
| PROT_WRITE
, MAP_SHARED
,
95 if ((long) base
== -1)
104 return 0; /* never was turned on... */
107 /* We can't do mprotect because that would cause us to lose the
108 uncached flag that the /dev/mem driver turned on. A MAP_UNCACHED
109 flag seems so much cleaner...
111 See the history of this file for a version that tried mprotect. */
116 _iopl (unsigned int level
)
120 __set_errno (EINVAL
);
125 int retval
= _ioperm (0, MAX_PORT
, 1);
126 /* Match the documented error returns of the x86 version. */
127 if (retval
< 0 && errno
== EACCES
)
135 _inb (unsigned long int port
)
137 volatile unsigned char *addr
= (void *) io
.base
+ io_offset (port
);
146 _inw (unsigned long int port
)
148 volatile unsigned short *addr
= (void *) io
.base
+ io_offset (port
);
157 _inl (unsigned long int port
)
159 volatile unsigned int *addr
= (void *) io
.base
+ io_offset (port
);
168 _outb (unsigned char val
, unsigned long int port
)
170 volatile unsigned char *addr
= (void *) io
.base
+ io_offset (port
);
177 _outw (unsigned short val
, unsigned long int port
)
179 volatile unsigned short *addr
= (void *) io
.base
+ io_offset (port
);
186 _outl (unsigned int val
, unsigned long int port
)
188 volatile unsigned int *addr
= (void *) io
.base
+ io_offset (port
);
194 weak_alias (_ioperm
, ioperm
);
195 weak_alias (_iopl
, iopl
);
196 weak_alias (_inb
, inb
);
197 weak_alias (_inw
, inw
);
198 weak_alias (_inl
, inl
);
199 weak_alias (_outb
, outb
);
200 weak_alias (_outw
, outw
);
201 weak_alias (_outl
, outl
);