c94fa5651
Denis Vlasenko
2008-10-26
Subject
devmem: new applet
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Commit Diff GitHub →
include/applets.h +1 -0include/usage.h +9 -0miscutils/Config.in +7 -0miscutils/Kbuild +1 -0miscutils/devmem.c +123 -0
include/applets.h+1 -0
| @@ -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)) | |
include/usage.h+9 -0
| @@ -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" \ | |
miscutils/Config.in+7 -0
| @@ -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 | |
miscutils/Kbuild+1 -0
| @@ -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 | |
miscutils/devmem.c+123 -0
| @@ -0,0 +1,123 @@ | |
| + | /* |
| + | * Licensed under the GPL v2 or later, see the file LICENSE in this tarball. |
| + | * Copyright (C) 2000, Jan-Derk Bakker ([email protected]) |
| + | * 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; |
| + | } |