1 /* Copyright (C) 1998, 1999 Free Software Foundation, Inc.
2 This file is part of the GNU C Library.
3 Contributed by Phil Blundell, based on the Alpha version by
6 The GNU C Library is free software; you can redistribute it and/or
7 modify it under the terms of the GNU Lesser General Public
8 License as published by the Free Software Foundation; either
9 version 2.1 of the License, or (at your option) any later version.
11 The GNU C Library is distributed in the hope that it will be useful,
12 but WITHOUT ANY WARRANTY; without even the implied warranty of
13 MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
14 Lesser General Public License for more details.
16 You should have received a copy of the GNU Lesser General Public
17 License along with the GNU C Library; if not, write to the Free
18 Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
21 /* I/O port access on the ARM is something of a fiction. What we do is to
22 map an appropriate area of /dev/mem into user space so that a program
23 can blast away at the hardware in such a way as to generate I/O cycles
24 on the bus. To insulate user code from dependencies on particular
25 hardware we don't allow calls to inb() and friends to be inlined, but
26 force them to come through code in here every time. Performance-critical
27 registers tend to be memory mapped these days so this should be no big
30 /* Once upon a time this file used mprotect to enable and disable
31 access to particular areas of I/O space. Unfortunately the
32 mprotect syscall also has the side effect of enabling caching for
33 the area affected (this is a kernel limitation). So we now just
34 enable all the ports all of the time. */
44 #include <sys/types.h>
48 #include <sys/sysctl.h>
50 libc_hidden_proto(readlink)
51 libc_hidden_proto(mmap)
52 libc_hidden_proto(sscanf)
53 libc_hidden_proto(fscanf)
54 libc_hidden_proto(fprintf)
55 libc_hidden_proto(fgets)
56 libc_hidden_proto(fopen)
57 libc_hidden_proto(fclose)
58 libc_hidden_proto(strcmp)
59 libc_hidden_proto(open)
60 libc_hidden_proto(close)
62 #include <linux/version.h>
64 #define PATH_ARM_SYSTYPE "/etc/arm_systype"
65 #define PATH_CPUINFO "/proc/cpuinfo"
67 #define MAX_PORT 0x10000
70 unsigned long int base;
71 unsigned long int io_base;
73 unsigned int initdone; /* since all the above could be 0 */
76 #define IO_BASE_FOOTBRIDGE 0x7c000000
77 #define IO_SHIFT_FOOTBRIDGE 0
79 static struct platform {
81 unsigned long int io_base;
84 /* All currently supported platforms are in fact the same. :-) */
85 {"Chalice-CATS", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
86 {"DEC-EBSA285", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
87 {"Corel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
88 {"Rebel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
91 #define IO_ADDR(port) (io.base + ((port) << io.shift))
94 * Initialize I/O system. There are several ways to get the information
95 * we need. Each is tried in turn until one succeeds.
97 * 1. Sysctl (CTL_BUS, BUS_ISA, ISA_*). This is the preferred method
98 * but not all kernels support it.
100 * 2. Read the value (not the contents) of symlink PATH_ARM_SYSTYPE.
101 * - If it matches one of the entries in the table above, use the
102 * corresponding values.
103 * - If it begins with a number, assume this is a previously
104 * unsupported system and the values encode, in order,
105 * "<io_base>,<port_shift>".
107 * 3. Lookup the "system type" field in /proc/cpuinfo. Again, if it
108 * matches an entry in the platform[] table, use the corresponding
111 * 4. BUS_ISA is changed to CTL_BUS_ISA (for kernel since 2.4.23).
120 #if LINUX_VERSION_CODE < 132119
121 static int iobase_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_BASE };
122 static int ioshift_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_SHIFT };
124 static int iobase_name[] = { CTL_BUS, CTL_BUS_ISA, BUS_ISA_PORT_BASE };
125 static int ioshift_name[] = { CTL_BUS, CTL_BUS_ISA, BUS_ISA_PORT_SHIFT };
128 size_t len = sizeof(io.base);
130 if (! sysctl (iobase_name, 3, &io.io_base, &len, NULL, 0)
131 && ! sysctl (ioshift_name, 3, &io.shift, &len, NULL, 0)) {
136 n = readlink (PATH_ARM_SYSTYPE, systype, sizeof (systype) - 1);
139 if (isdigit (systype[0])) {
140 if (sscanf (systype, "%li,%i", &io.io_base, &io.shift) == 2) {
144 /* else we're likely going to fail with the system match below */
150 fp = fopen (PATH_CPUINFO, "r");
153 while ((n = fscanf (fp, "Hardware\t: %256[^\n]\n", systype)) != EOF) {
157 fgets (systype, 256, fp);
162 /* this can happen if the format of /proc/cpuinfo changes... */
163 fprintf (stderr, "ioperm: Unable to determine system type.\n"
164 "\t(May need " PATH_ARM_SYSTYPE " symlink?)\n");
165 __set_errno (ENODEV);
170 /* translate systype name into i/o system: */
171 for (i = 0; i < sizeof (platform) / sizeof (platform[0]); ++i) {
172 if (strcmp (platform[i].name, systype) == 0) {
173 io.shift = platform[i].shift;
174 io.io_base = platform[i].io_base;
180 /* systype is not a known platform name... */
181 __set_errno (EINVAL);
185 int ioperm (unsigned long int from, unsigned long int num, int turn_on)
187 if (! io.initdone && init_iosys () < 0)
190 /* this test isn't as silly as it may look like; consider overflows! */
191 if (from >= MAX_PORT || from + num > MAX_PORT) {
192 __set_errno (EINVAL);
200 fd = open ("/dev/mem", O_RDWR);
204 io.base = (unsigned long int) mmap (0, MAX_PORT << io.shift,
205 PROT_READ | PROT_WRITE,
206 MAP_SHARED, fd, io.io_base);
208 if ((long) io.base == -1)
215 libc_hidden_proto(ioperm)
216 libc_hidden_def(ioperm)
220 outb(unsigned char b, unsigned long int port)
222 *((volatile unsigned char *)(IO_ADDR (port))) = b;
227 outw(unsigned short b, unsigned long int port)
229 *((volatile unsigned short *)(IO_ADDR (port))) = b;
234 outl(unsigned int b, unsigned long int port)
236 *((volatile unsigned long *)(IO_ADDR (port))) = b;
241 inb (unsigned long int port)
243 return *((volatile unsigned char *)(IO_ADDR (port)));
248 inw(unsigned long int port)
250 return *((volatile unsigned short *)(IO_ADDR (port)));
255 inl(unsigned long int port)
257 return *((volatile unsigned long *)(IO_ADDR (port)));