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Diffstat (limited to 'libc/sysdeps/linux/arm/ioperm.c')
-rw-r--r--libc/sysdeps/linux/arm/ioperm.c246
1 files changed, 246 insertions, 0 deletions
diff --git a/libc/sysdeps/linux/arm/ioperm.c b/libc/sysdeps/linux/arm/ioperm.c
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index 000000000..74a6dc1dc
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+++ b/libc/sysdeps/linux/arm/ioperm.c
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+/* Copyright (C) 1998, 1999 Free Software Foundation, Inc.
+ This file is part of the GNU C Library.
+ Contributed by Phil Blundell, based on the Alpha version by
+ David Mosberger.
+
+ The GNU C Library is free software; you can redistribute it and/or
+ modify it under the terms of the GNU Lesser General Public
+ License as published by the Free Software Foundation; either
+ version 2.1 of the License, or (at your option) any later version.
+
+ The GNU C Library is distributed in the hope that it will be useful,
+ but WITHOUT ANY WARRANTY; without even the implied warranty of
+ MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
+ Lesser General Public License for more details.
+
+ You should have received a copy of the GNU Lesser General Public
+ License along with the GNU C Library; if not, write to the Free
+ Software Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA
+ 02111-1307 USA. */
+
+/* I/O port access on the ARM is something of a fiction. What we do is to
+ map an appropriate area of /dev/mem into user space so that a program
+ can blast away at the hardware in such a way as to generate I/O cycles
+ on the bus. To insulate user code from dependencies on particular
+ hardware we don't allow calls to inb() and friends to be inlined, but
+ force them to come through code in here every time. Performance-critical
+ registers tend to be memory mapped these days so this should be no big
+ problem. */
+
+/* Once upon a time this file used mprotect to enable and disable
+ access to particular areas of I/O space. Unfortunately the
+ mprotect syscall also has the side effect of enabling caching for
+ the area affected (this is a kernel limitation). So we now just
+ enable all the ports all of the time. */
+
+#include <errno.h>
+#include <fcntl.h>
+#include <stdio.h>
+#include <ctype.h>
+#include <stdlib.h>
+#include <string.h>
+#include <unistd.h>
+
+#include <sys/types.h>
+#include <sys/mman.h>
+
+#include <asm/page.h>
+#include <sys/sysctl.h>
+
+#define PATH_ARM_SYSTYPE "/etc/arm_systype"
+#define PATH_CPUINFO "/proc/cpuinfo"
+
+#define MAX_PORT 0x10000
+
+static struct {
+ unsigned long int base;
+ unsigned long int io_base;
+ unsigned int shift;
+ unsigned int initdone; /* since all the above could be 0 */
+} io;
+
+#define IO_BASE_FOOTBRIDGE 0x7c000000
+#define IO_SHIFT_FOOTBRIDGE 0
+
+static struct platform {
+ const char *name;
+ unsigned long int io_base;
+ unsigned int shift;
+} platform[] = {
+ /* All currently supported platforms are in fact the same. :-) */
+ {"Chalice-CATS", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
+ {"DEC-EBSA285", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
+ {"Corel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
+ {"Rebel-NetWinder", IO_BASE_FOOTBRIDGE, IO_SHIFT_FOOTBRIDGE},
+};
+
+#define IO_ADDR(port) (io.base + ((port) << io.shift))
+
+/*
+ * Initialize I/O system. There are several ways to get the information
+ * we need. Each is tried in turn until one succeeds.
+ *
+ * 1. Sysctl (CTL_BUS, BUS_ISA, ISA_*). This is the preferred method
+ * but not all kernels support it.
+ *
+ * 2. Read the value (not the contents) of symlink PATH_ARM_SYSTYPE.
+ * - If it matches one of the entries in the table above, use the
+ * corresponding values.
+ * - If it begins with a number, assume this is a previously
+ * unsupported system and the values encode, in order,
+ * "<io_base>,<port_shift>".
+ *
+ * 3. Lookup the "system type" field in /proc/cpuinfo. Again, if it
+ * matches an entry in the platform[] table, use the corresponding
+ * values.
+ */
+
+static int
+init_iosys (void)
+{
+ char systype[256];
+ int i, n;
+ static int iobase_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_BASE };
+ static int ioshift_name[] = { CTL_BUS, BUS_ISA, BUS_ISA_PORT_SHIFT };
+ size_t len = sizeof(io.base);
+
+ if (! sysctl (iobase_name, 3, &io.io_base, &len, NULL, 0)
+ && ! sysctl (ioshift_name, 3, &io.shift, &len, NULL, 0)) {
+ io.initdone = 1;
+ return 0;
+ }
+
+ n = readlink (PATH_ARM_SYSTYPE, systype, sizeof (systype) - 1);
+ if (n > 0) {
+ systype[n] = '\0';
+ if (isdigit (systype[0])) {
+ if (sscanf (systype, "%li,%i", &io.io_base, &io.shift) == 2) {
+ io.initdone = 1;
+ return 0;
+ }
+ /* else we're likely going to fail with the system match below */
+ }
+ }
+ else {
+ FILE * fp;
+
+ fp = fopen (PATH_CPUINFO, "r");
+ if (! fp)
+ return -1;
+ while ((n = fscanf (fp, "Hardware\t: %256[^\n]\n", systype)) != EOF) {
+ if (n == 1)
+ break;
+ else
+ fgets (systype, 256, fp);
+ }
+ fclose (fp);
+
+ if (n == EOF) {
+ /* this can happen if the format of /proc/cpuinfo changes... */
+ fprintf (stderr, "ioperm: Unable to determine system type.\n"
+ "\t(May need " PATH_ARM_SYSTYPE " symlink?)\n");
+ __set_errno (ENODEV);
+ return -1;
+ }
+ }
+
+ /* translate systype name into i/o system: */
+ for (i = 0; i < sizeof (platform) / sizeof (platform[0]); ++i) {
+ if (strcmp (platform[i].name, systype) == 0) {
+ io.shift = platform[i].shift;
+ io.io_base = platform[i].io_base;
+ io.initdone = 1;
+ return 0;
+ }
+ }
+
+ /* systype is not a known platform name... */
+ __set_errno (EINVAL);
+ return -1;
+}
+
+int ioperm (unsigned long int from, unsigned long int num, int turn_on)
+{
+ if (! io.initdone && init_iosys () < 0)
+ return -1;
+
+ /* this test isn't as silly as it may look like; consider overflows! */
+ if (from >= MAX_PORT || from + num > MAX_PORT) {
+ __set_errno (EINVAL);
+ return -1;
+ }
+
+ if (turn_on) {
+ if (! io.base) {
+ int fd;
+
+ fd = open ("/dev/mem", O_RDWR);
+ if (fd < 0)
+ return -1;
+
+ io.base = (unsigned long int) mmap (0, MAX_PORT << io.shift,
+ PROT_READ | PROT_WRITE,
+ MAP_SHARED, fd, io.io_base);
+ close (fd);
+ if ((long) io.base == -1)
+ return -1;
+ }
+ }
+
+ return 0;
+}
+
+
+int iopl (unsigned int level)
+{
+ if (level > 3) {
+ __set_errno (EINVAL);
+ return -1;
+ }
+ if (level) {
+ return ioperm (0, MAX_PORT, 1);
+ }
+ return 0;
+}
+
+
+void
+outb(unsigned char b, unsigned long int port)
+{
+ *((volatile unsigned char *)(IO_ADDR (port))) = b;
+}
+
+
+void
+outw(unsigned short b, unsigned long int port)
+{
+ *((volatile unsigned short *)(IO_ADDR (port))) = b;
+}
+
+
+void
+outl(unsigned int b, unsigned long int port)
+{
+ *((volatile unsigned long *)(IO_ADDR (port))) = b;
+}
+
+
+unsigned int
+inb (unsigned long int port)
+{
+ return *((volatile unsigned char *)(IO_ADDR (port)));
+}
+
+
+unsigned int
+inw(unsigned long int port)
+{
+ return *((volatile unsigned short *)(IO_ADDR (port)));
+}
+
+
+unsigned int
+inl(unsigned long int port)
+{
+ return *((volatile unsigned long *)(IO_ADDR (port)));
+}