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devmem: new applet

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This commit is contained in:
Denis Vlasenko 2008-10-26 11:08:14 +00:00
parent f3dcd3c30a
commit c94fa5651a
5 changed files with 141 additions and 0 deletions
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1
include/applets.h
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@ -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))

9
include/usage.h
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@ -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" \

7
miscutils/Config.in
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@ -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

1
miscutils/Kbuild
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@ -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

123
miscutils/devmem.c Normal file
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@ -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;
}