devmem: new applet

diff --git a/include/applets.h b/include/applets.h
index e3f9294..d52f9f0 100644 (file)
--- a/include/applets.h
+++ b/include/applets.h
@@ -119,6 +119,7 @@ USE_DELUSER(APPLET(deluser, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_DEPMOD(APPLET(depmod, _BB_DIR_SBIN, _BB_SUID_NEVER))
 USE_MODPROBE_SMALL(APPLET_ODDNAME(depmod, modprobe, _BB_DIR_SBIN, _BB_SUID_NEVER, modprobe))
 USE_DEVFSD(APPLET(devfsd, _BB_DIR_SBIN, _BB_SUID_NEVER))
+USE_DEVMEM(APPLET(devmem, _BB_DIR_SBIN, _BB_SUID_NEVER))
 USE_DF(APPLET(df, _BB_DIR_BIN, _BB_SUID_NEVER))
 USE_APP_DHCPRELAY(APPLET(dhcprelay, _BB_DIR_USR_SBIN, _BB_SUID_NEVER))
 USE_DIFF(APPLET(diff, _BB_DIR_USR_BIN, _BB_SUID_NEVER))

diff --git a/include/usage.h b/include/usage.h
index 3c11013..dbef9f6 100644 (file)
--- a/include/usage.h
+++ b/include/usage.h
@@ -690,6 +690,15 @@
 #define depmod_trivial_usage NOUSAGE_STR
 #define depmod_full_usage ""
 
+#define devmem_trivial_usage \
+       "ADDRESS [WIDTH [VALUE]]"
+
+#define devmem_full_usage "\n\n" \
+       "Read/write from physical address\n" \
+     "\n       ADDRESS Address to act upon" \
+     "\n       WIDTH   Width (8/16/...)" \
+     "\n       VALUE   Data to be written" \
+
 #define devfsd_trivial_usage \
        "mntpnt [-v]" USE_DEVFSD_FG_NP("[-fg][-np]")
 #define devfsd_full_usage "\n\n" \

diff --git a/miscutils/Config.in b/miscutils/Config.in
index 074e6c4..f8b4575 100644 (file)
--- a/miscutils/Config.in
+++ b/miscutils/Config.in
@@ -196,6 +196,13 @@ config FEATURE_DEVFS
          /dev/loop0. If your /dev directory has normal names instead of
          devfs names, you don't want this.
 
+config DEVMEM
+       bool "devmem"
+       default n
+       help
+         devmem is a small program that reads and writes from physical
+         memory using /dev/mem.
+
 config EJECT
        bool "eject"
        default n

diff --git a/miscutils/Kbuild b/miscutils/Kbuild
index c12b12d..13791ef 100644 (file)
--- a/miscutils/Kbuild
+++ b/miscutils/Kbuild
@@ -13,6 +13,7 @@ lib-$(CONFIG_CROND)       += crond.o
 lib-$(CONFIG_CRONTAB)     += crontab.o
 lib-$(CONFIG_DC)          += dc.o
 lib-$(CONFIG_DEVFSD)      += devfsd.o
+lib-$(CONFIG_DEVMEM)      += devmem.o
 lib-$(CONFIG_EJECT)       += eject.o
 lib-$(CONFIG_FBSPLASH)    += fbsplash.o
 lib-$(CONFIG_HDPARM)      += hdparm.o

diff --git a/miscutils/devmem.c b/miscutils/devmem.c
new file mode 100644 (file)
index 0000000..8b8edbe
--- /dev/null
+++ b/miscutils/devmem.c
@@ -0,0 +1,123 @@
+/*
+ * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ *  Copyright (C) 2000, Jan-Derk Bakker (J.D.Bakker@its.tudelft.nl)
+ *  Copyright (C) 2008, BusyBox Team. -solar 4/26/08
+ */
+
+#include "libbb.h"
+
+#define DEVMEM_MAP_SIZE 4096
+#define DEVMEM_MAP_MASK (off_t)(DEVMEM_MAP_SIZE - 1)
+
+int devmem_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
+int devmem_main(int argc UNUSED_PARAM, char **argv)
+{
+       void *map_base, *virt_addr;
+       uint64_t read_result;
+       uint64_t writeval = writeval; /* for compiler */
+       off_t target;
+       int fd;
+       int width = 8 * sizeof(int);
+
+       /* devmem ADDRESS [WIDTH [VALUE]] */
+
+       /* ADDRESS */
+       if (!argv[1])
+               bb_show_usage();
+       errno = 0;
+       target = bb_strtoull(argv[1], NULL, 0); /* allows hex, oct etc */
+
+       /* WIDTH */
+       if (argv[2]) {
+               if (isdigit(argv[2][0]) || argv[2][1])
+                       width = xatou(argv[2]);
+               else {
+                       static const char bhwl[] ALIGN1 = "bhwl";
+                       static const uint8_t sizes[] ALIGN1 = {
+                               8 * sizeof(char),
+                               8 * sizeof(short),
+                               8 * sizeof(int),
+                               8 * sizeof(long),
+                               0 /* bad */
+                       };
+                       width = strchrnul(bhwl, (argv[2][0] | 0x20)) - bhwl;
+                       width = sizes[width];
+               }
+               /* VALUE */
+               if (argv[3])
+                       writeval = bb_strtoull(argv[3], NULL, 0);
+       } else { /* argv[2] == NULL */
+               /* make argv[3] to be a valid thing to use */
+               argv--;
+       }
+       if (errno)
+               bb_show_usage(); /* bb_strtouXX failed */
+
+       fd = xopen("/dev/mem", argv[3] ? (O_RDWR | O_SYNC) : (O_RDONLY | O_SYNC));
+
+       map_base = mmap(NULL,
+                       DEVMEM_MAP_SIZE * 2 /* in case value spans page */,
+                       argv[3] ? (PROT_READ | PROT_WRITE) : PROT_READ,
+                       MAP_SHARED,
+                       fd,
+                       target & ~DEVMEM_MAP_MASK);
+       if (map_base == MAP_FAILED)
+               bb_perror_msg_and_die("mmap");
+
+//     printf("Memory mapped at address %p.\n", map_base);
+
+       virt_addr = (char*)map_base + (target & DEVMEM_MAP_MASK);
+
+       switch (width) {
+       case 8:
+               read_result = *(volatile uint8_t*)virt_addr;
+               break;
+       case 16:
+               read_result = *(volatile uint16_t*)virt_addr;
+               break;
+       case 32:
+               read_result = *(volatile uint32_t*)virt_addr;
+               break;
+       case 64:
+               read_result = *(volatile uint64_t*)virt_addr;
+               break;
+       default:
+               bb_error_msg_and_die("bad width");
+       }
+
+       printf("Value at address 0x%"OFF_FMT"X (%p): 0x%llX\n",
+                       target, virt_addr,
+                       (unsigned long long)read_result);
+
+       if (argv[3]) {
+               switch (width) {
+               case 8:
+                       *(volatile uint8_t*)virt_addr = writeval;
+                       read_result = *(volatile uint8_t*)virt_addr;
+                       break;
+               case 16:
+                       *(volatile uint16_t*)virt_addr = writeval;
+                       read_result = *(volatile uint16_t*)virt_addr;
+                       break;
+               case 32:
+                       *(volatile uint32_t*)virt_addr = writeval;
+                       read_result = *(volatile uint32_t*)virt_addr;
+                       break;
+               case 64:
+                       *(volatile uint64_t*)virt_addr = writeval;
+                       read_result = *(volatile uint64_t*)virt_addr;
+                       break;
+               }
+               printf("Written 0x%llX; readback 0x%llX\n",
+                               (unsigned long long)writeval,
+                               (unsigned long long)read_result);
+       }
+
+       if (ENABLE_FEATURE_CLEAN_UP) {
+               if (munmap(map_base, DEVMEM_MAP_SIZE) == -1)
+                       bb_perror_msg_and_die("munmap");
+               close(fd);
+       }
+
+       return EXIT_SUCCESS;
+}