devmem: new applet
diff --git a/include/applets.h b/include/applets.h
index e3f9294..d52f9f0 100644
--- a/include/applets.h
+++ b/include/applets.h
@@ -119,6 +119,7 @@
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
--- 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
--- a/miscutils/Config.in
+++ b/miscutils/Config.in
@@ -196,6 +196,13 @@
/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
--- a/miscutils/Kbuild
+++ b/miscutils/Kbuild
@@ -13,6 +13,7 @@
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
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;
+}