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Diffstat (limited to 'libc/sysdeps/linux/arm/ioperm.c')
| -rw-r--r-- | libc/sysdeps/linux/arm/ioperm.c | 246 |
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))); +} |