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, see
18 <http://www.gnu.org/licenses/>. */
20 /* I/O port access on the ARM is something of a fiction. What we do is to
21 map an appropriate area of /dev/mem into user space so that a program
22 can blast away at the hardware in such a way as to generate I/O cycles
23 on the bus. To insulate user code from dependencies on particular
24 hardware we don't allow calls to inb() and friends to be inlined, but
25 force them to come through code in here every time. Performance-critical
26 registers tend to be memory mapped these days so this should be no big
29 /* Once upon a time this file used mprotect to enable and disable
30 access to particular areas of I/O space. Unfortunately the
31 mprotect syscall also has the side effect of enabling caching for
32 the area affected (this is a kernel limitation). So we now just
33 enable all the ports all of the time. */
37 #include <sys/sysctl.h>
45 #include <linux/version.h>
47 #define PATH_ARM_SYSTYPE "/etc/arm_systype"
48 #define PATH_CPUINFO "/proc/cpuinfo"
50 #define MAX_PORT 0x10000
53 unsigned long int base;
54 unsigned long int io_base;
56 unsigned int initdone; /* since all the above could be 0 */
59 #define IO_BASE_FOOTBRIDGE 0x7c000000
60 #define IO_SHIFT_FOOTBRIDGE 0
62 static struct platform {
64 unsigned long int io_base;
67 /* All currently supported platforms are in fact the same. :-) */
68 {"Chalice-CATS", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
69 {"DEC-EBSA285", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
70 {"Corel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
71 {"Rebel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
74 #define IO_ADDR(port) (io.base + ((port) << io.shift))
77 * Initialize I/O system. There are several ways to get the information
78 * we need. Each is tried in turn until one succeeds.
80 * 1. Sysctl (CTL_BUS, BUS_ISA, ISA_*). This is the preferred method
81 * but not all kernels support it.
83 * 2. Read the value (not the contents) of symlink PATH_ARM_SYSTYPE.
84 * - If it matches one of the entries in the table above, use the
85 * corresponding values.
86 * - If it begins with a number, assume this is a previously
87 * unsupported system and the values encode, in order,
88 * "<io_base>,<port_shift>".
90 * 3. Lookup the "system type" field in /proc/cpuinfo. Again, if it
91 * matches an entry in the platform[] table, use the corresponding
94 * 4. BUS_ISA is changed to CTL_BUS_ISA (for kernel since 2.4.23).
103 #if LINUX_VERSION_CODE < 132119
104 static int iobase_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_BASE };
105 static int ioshift_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_SHIFT };
107 static int iobase_name[] = { CTL_BUS, CTL_BUS_ISA, BUS_ISA_PORT_BASE };
108 static int ioshift_name[] = { CTL_BUS, CTL_BUS_ISA, BUS_ISA_PORT_SHIFT };
111 size_t len = sizeof(io.base);
113 if (! sysctl (iobase_name, 3, &io.io_base, &len, NULL, 0)
114 && ! sysctl (ioshift_name, 3, &io.shift, &len, NULL, 0)) {
119 n = readlink (PATH_ARM_SYSTYPE, systype, sizeof (systype) - 1);
122 if (isdigit (systype[0])) {
123 if (sscanf (systype, "%li,%i", &io.io_base, &io.shift) == 2) {
127 /* else we're likely going to fail with the system match below */
133 fp = fopen (PATH_CPUINFO, "r");
136 while ((n = fscanf (fp, "Hardware\t: %256[^\n]\n", systype)) != EOF) {
140 fgets (systype, 256, fp);
145 /* this can happen if the format of /proc/cpuinfo changes... */
146 fprintf (stderr, "ioperm: Unable to determine system type.\n"
147 "\t(May need " PATH_ARM_SYSTYPE " symlink?)\n");
148 __set_errno (ENODEV);
153 /* translate systype name into i/o system: */
154 for (i = 0; i < sizeof (platform) / sizeof (platform[0]); ++i) {
155 if (strcmp (platform[i].name, systype) == 0) {
156 io.shift = platform[i].shift;
157 io.io_base = platform[i].io_base;
163 /* systype is not a known platform name... */
164 __set_errno (EINVAL);
168 int ioperm (unsigned long int from, unsigned long int num, int turn_on)
170 if (! io.initdone && init_iosys () < 0)
173 /* this test isn't as silly as it may look like; consider overflows! */
174 if (from >= MAX_PORT || from + num > MAX_PORT) {
175 __set_errno (EINVAL);
183 fd = open (_PATH_MEM, O_RDWR);
187 io.base = (unsigned long int) mmap (0, MAX_PORT << io.shift,
188 PROT_READ | PROT_WRITE,
189 MAP_SHARED, fd, io.io_base);
191 if ((long) io.base == -1)
198 libc_hidden_def(ioperm)
202 outb(unsigned char b, unsigned long int port)
204 *((__volatile__ unsigned char *)(IO_ADDR (port))) = b;
209 outw(unsigned short b, unsigned long int port)
211 *((__volatile__ unsigned short *)(IO_ADDR (port))) = b;
216 outl(unsigned long b, unsigned long int port)
218 *((__volatile__ unsigned long *)(IO_ADDR (port))) = b;
223 inb (unsigned long int port)
225 return *((__volatile__ unsigned char *)(IO_ADDR (port)));
230 inw(unsigned long int port)
232 return *((__volatile__ unsigned short *)(IO_ADDR (port)));
237 inl(unsigned long int port)
239 return *((__volatile__ unsigned long *)(IO_ADDR (port)));