initial commit

3 files changed, 294 insertions, 0 deletions

diff --git a/.gitignore b/.gitignore
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+++ b/.gitignore
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+*.o
+*.a
+*.pyc
+*~
+*.swp
+.*
+*.tmp
+*.old
diff --git a/README b/README
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+
+                                _            _   _ 
+                          _   _(_) ___   ___| |_| |
+                         | | | | |/ _ \ / __| __| |
+                         | |_| | | (_) | (__| |_| |
+                          \__,_|_|\___/ \___|\__|_|
+ 
+
+trivial utility for manipulating simple Linux UIO devices ("Userspace I/O").
+eg, reading and writing bytes to memory mapped devices or monitoring
+interrupts.
+can list all devices and their mappings.
+little-endian by default.
+
+-------------------------------------------------------------------------------
+
+gcc uioctl.c -o uioctl
+
+-------------------------------------------------------------------------------
+
+./uioctl -h
+little-endian by default
+    -w  select word width (default: 4)
+    -s  size of mmap (default: base + length, rounded up to PAGE_SIZE)
+
+./uioctl /dev/uio0 0 -n 100 -w 1 -r 0
+./uioctl /dev/uio0 0x818 0
+./uioctl /dev/uio0 -m
+./uioctl -l
+
+also, secret trick:
+
+sudo ./uioctl /dev/mem 0x818 -n 5
+
+BUT WAIT?
+
+hexdump -C /dev/uio0 -s 0x
+
+-------------------------------------------------------------------------------
+
+UIO: user-space drivers (2007)
+https://lwn.net/Articles/232575/
+
+The Userspace I/O HOWTO (2006-2009)
+https://www.kernel.org/doc/htmldocs/uio-howto/
+
+Simple userland drivers for FPGA interfaces (eg, AXI)
+http://svenand.blogdrive.com/archive/150.html
+
+devmem2.c: Simple program to read/write from/to any location in memory
+http://sources.buildroot.net/devmem2.c
+
+pydevmem
+https://github.com/kylemanna/pydevmem
diff --git a/uioctl.c b/uioctl.c
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+/*
+ * uioctl.c: Userspace I/O manipulation utility
+ *
+ * Copyright (C) 2013, Bryan Newbold <bnewbold@leaflabs.com>
+ *
+ * ISC License: Permission to use, copy, modify, and/or distribute this
+ * software for any purpose with or without fee is hereby granted, provided
+ * that the above copyright notice and this permission notice appear in all
+ * copies. THE SOFTWARE IS PROVIDED "AS IS" AND THE AUTHOR DISCLAIMS ALL
+ * WARRANTIES WITH REGARD TO THIS SOFTWARE INCLUDING ALL IMPLIED WARRANTIES OF
+ * MERCHANTABILITY AND FITNESS. IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY
+ * SPECIAL, DIRECT, INDIRECT, OR CONSEQUENTIAL DAMAGES OR ANY DAMAGES
+ * WHATSOEVER RESULTING FROM LOSS OF USE, DATA OR PROFITS, WHETHER IN AN ACTION
+ * OF CONTRACT, NEGLIGENCE OR OTHER TORTIOUS ACTION, ARISING OUT OF OR IN
+ * CONNECTION WITH THE USE OR PERFORMANCE OF THIS SOFTWARE.
+ *
+ * Changelog:
+ *  2013-12-04: bnewbold: Initial version; missing width management, list mode
+ *
+ */
+
+#include <errno.h>
+#include <getopt.h>
+#include <inttypes.h>
+#include <stdio.h>
+#include <fcntl.h>
+#include <stdlib.h>
+#include <stdint.h>
+#include <unistd.h>
+#include <sys/mman.h>
+#include <sys/timeb.h>
+
+#define DEFAULT_WIDTH 4
+#define PROGRAM_NAME "uioctl"
+
+enum mode_type {
+    MODE_READ,
+    MODE_WRITE,
+    MODE_LIST,
+    MODE_MONITOR
+};
+
+static void usage(int exit_status) {
+    fprintf(exit_status == EXIT_SUCCESS ? stdout : stderr,
+        "Usage: %s [options] [-l] [/dev/uioX [-m] [<addr> [<value>]]]\n"
+        "\n"
+        "Functions:\n"
+        "  monitor (-m) the device for interrupts\n"
+        "  list (-l) all devices and their mappings\n"
+        "  read words from <addr>\n"
+        "  write <value> to <addr> (will zero-pad word width)\n"
+        "\n"
+        "Options:\n"
+        "  -r\tselect the device's memory region to map (default: 0)\n"
+        "  -w\tword size (in bytes; default: %d)\n"
+        "  -n\tnumber of words to read (in words; default: 1)\n"
+        "  -x\texit with success after the first interrupt (implies -m mode)\n"
+        ,
+        PROGRAM_NAME, DEFAULT_WIDTH);
+    exit(exit_status);
+}
+
+static void list_devices() {
+    // TODO:
+    // - try to list /sys/devices/uio*
+    // - for each in the above, print memory regions
+    fprintf(stderr, "listing not yet implemented\n");
+    exit(EXIT_FAILURE);
+}
+
+static void monitor(char *fpath, int forever) {
+    char buf[4];
+    int bytes;
+    int fd;
+    struct timeb tp;
+    char startval[] = {0,0,0,1};
+   
+    printf("Waiting for interrupts on %s\n", fpath);
+    fd = open(fpath, O_RDWR);
+    if (fd < 1) {
+        perror("uioctl");
+        fprintf(stderr, "Couldn't open UIO device file: %s\n", fpath);
+        exit(EXIT_FAILURE);
+    }
+    do {
+        bytes = pwrite(fd, &startval, 4, 0);
+        if (bytes != 4) {
+            perror("uioctl");
+            fprintf(stderr, "Problem clearing device file\n");
+            exit(EXIT_FAILURE);
+        }
+        //lseek(fd, 0, SEEK_SET);
+        bytes = pread(fd, buf, 4, 0);
+        ftime(&tp);
+        if (bytes != 4) {
+            perror("uioctl");
+            fprintf(stderr, "Problem reading from device file\n");
+            exit(EXIT_FAILURE);
+        }
+        printf("[%ld.%03d] interrupt: %d\n", tp.time, tp.millitm,
+            (buf[3] * 16777216 + buf[2] * 65536 + buf[1] * 256 + buf[0]));
+    } while (forever);
+    close(fd);
+    exit(EXIT_SUCCESS);
+}
+
+int main(int argc, char *argv[]) {
+    int c;
+    int fd;
+    enum mode_type mode = MODE_READ;
+    char *fpath;
+    void *ptr;
+    int map_size, value, addr;
+    int region = 0;
+    int count = 1;
+    int width = DEFAULT_WIDTH;
+    int forever = 1;
+
+    while((c = getopt(argc, argv, "hlmxr:n:w:")) != -1) {
+        errno = 0;
+        switch(c) {
+        case 'h':
+            usage(EXIT_SUCCESS);
+        case 'l':
+            list_devices();
+        case 'm':
+            mode = MODE_MONITOR;
+            break;
+        case 'x':
+            mode = MODE_MONITOR;
+            forever = 0;
+            break;
+        case 'r':
+            region = strtoul(optarg, NULL, 0);
+            if (errno) {
+                perror("uioctl");
+                exit(EXIT_FAILURE);
+            }
+            if (region != 0) {
+                fprintf(stderr, "region != 0 not yet implemented\n");
+                exit(EXIT_FAILURE);
+            }
+            break;
+        case 'n':
+            count = strtoul(optarg, NULL, 0);
+            if (errno) {
+                perror("uioctl");
+                exit(EXIT_FAILURE);
+            }
+            break;
+        case 'w':
+            width = strtoul(optarg, NULL, 0);
+            if (errno) {
+                perror("uioctl");
+                exit(EXIT_FAILURE);
+            }
+            if (width != 4) {
+                fprintf(stderr, "width != 4 not yet implemented\n");
+                exit(EXIT_FAILURE);
+            }
+            break;
+        default:
+            fprintf(stderr, "Unexpected argument; try -h\n");
+            exit(EXIT_FAILURE);
+        }
+    }
+
+    if (mode == MODE_MONITOR) {
+        if ((argc - optind) != 1) {
+            fprintf(stderr, "Wrong number of arguments; try -h\n");
+            exit(EXIT_FAILURE);
+        }
+        fpath = argv[optind];
+        monitor(fpath, forever);
+    }
+    if (mode == MODE_READ) {
+        if ((argc - optind) == 2) {
+            fpath = argv[optind++];
+            errno = 0;
+            addr = strtoul(argv[optind++], NULL, 0);
+            if (errno) {
+                perror("uioctl");
+                exit(EXIT_FAILURE);
+            }
+            //printf("addr: 0x%08x\n", addr);
+        } else
+        if ((argc - optind) == 3) {
+            mode = MODE_WRITE;
+            fpath = argv[optind++];
+            errno = 0;
+            addr = strtoul(argv[optind++], NULL, 0);
+            value = strtoul(argv[optind++], NULL, 0);
+            if (errno) {
+                perror("uioctl");
+                exit(EXIT_FAILURE);
+            }
+            //printf("addr: 0x%08x\n", addr);
+            //printf("value: 0x%08x\n", value);
+        } else {
+            fprintf(stderr, "Wrong number of arguments; try -h\n");
+            exit(EXIT_FAILURE);
+        }
+    }
+
+    map_size = count * width;
+
+    fd = open(fpath, O_RDWR|O_SYNC);
+    if (fd < 1) {
+        perror("uioctl");
+        fprintf(stderr, "Couldn't open UIO device file: %s\n", fpath);
+        return EXIT_FAILURE;
+    }
+    ptr = mmap(NULL, map_size, PROT_READ|PROT_WRITE, MAP_SHARED, fd, 0);
+
+    /* TODO: do the things... */
+    /* value = *((unsigned *) (ptr + offset); */
+    if (mode == MODE_READ) {
+        for (; count > 0; count--) {
+            value = *((unsigned *) (ptr + addr));
+            printf("0x%08x\t%08x\n", addr, value);
+            addr += width;
+        }
+    } else {
+        *((unsigned *)(ptr + addr)) = value;
+    }
+
+    /* clean up */
+    munmap(ptr, map_size);
+    close(fd);
+
+    return EXIT_SUCCESS;
+}