A patch from Vincent Sanders to fix the arm implementation of

ioperm() and iopl()

1 files changed, 246 insertions, 0 deletions

diff --git a/libc/sysdeps/linux/arm/ioperm.c b/libc/sysdeps/linux/arm/ioperm.c
new file mode 100644
index 000000000..74a6dc1dc
--- /dev/null
+++ b/libc/sysdeps/linux/arm/ioperm.c
@@ -0,0 +1,246 @@
+/* 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)));
+}