/*
- * Licensed under the GPL v2 or later, see the file LICENSE in this tarball.
+ * Licensed under GPLv2 or later, see file LICENSE in this source tree.
* Copyright (C) 2000, Jan-Derk Bakker (J.D.Bakker@its.tudelft.nl)
* Copyright (C) 2008, BusyBox Team. -solar 4/26/08
*/
-#include "libbb.h"
+//usage:#define devmem_trivial_usage
+//usage: "ADDRESS [WIDTH [VALUE]]"
+//usage:#define devmem_full_usage "\n\n"
+//usage: "Read/write from physical address\n"
+//usage: "\n ADDRESS Address to act upon"
+//usage: "\n WIDTH Width (8/16/...)"
+//usage: "\n VALUE Data to be written"
-#define DEVMEM_MAP_SIZE 4096
-#define DEVMEM_MAP_MASK (off_t)(DEVMEM_MAP_SIZE - 1)
+#include "libbb.h"
int devmem_main(int argc, char **argv) MAIN_EXTERNALLY_VISIBLE;
int devmem_main(int argc UNUSED_PARAM, char **argv)
uint64_t read_result;
uint64_t writeval = writeval; /* for compiler */
off_t target;
+ unsigned page_size, mapped_size, offset_in_page;
int fd;
- int width = 8 * sizeof(int);
+ unsigned width = 8 * sizeof(int);
/* devmem ADDRESS [WIDTH [VALUE]] */
+// TODO: options?
+// -r: read and output only the value in hex, with 0x prefix
+// -w: write only, no reads before or after, and no output
+// or make this behavior default?
+// Let's try this and see how users react.
/* ADDRESS */
if (!argv[1])
if (argv[3])
writeval = bb_strtoull(argv[3], NULL, 0);
} else { /* argv[2] == NULL */
- /* make argv[3] to be a valid thing to use */
+ /* make argv[3] to be a valid thing to fetch */
argv--;
}
if (errno)
- bb_show_usage(); /* bb_strtouXX failed */
+ bb_show_usage(); /* one of bb_strtouXX failed */
fd = xopen("/dev/mem", argv[3] ? (O_RDWR | O_SYNC) : (O_RDONLY | O_SYNC));
-
+ mapped_size = page_size = getpagesize();
+ offset_in_page = (unsigned)target & (page_size - 1);
+ if (offset_in_page + width > page_size) {
+ /* This access spans pages.
+ * Must map two pages to make it possible: */
+ mapped_size *= 2;
+ }
map_base = mmap(NULL,
- DEVMEM_MAP_SIZE * 2 /* in case value spans page */,
+ mapped_size,
argv[3] ? (PROT_READ | PROT_WRITE) : PROT_READ,
MAP_SHARED,
fd,
- target & ~DEVMEM_MAP_MASK);
+ target & ~(off_t)(page_size - 1));
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);
+ virt_addr = (char*)map_base + offset_in_page;
- if (argv[3]) {
+ 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;
+ 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);
+ /* Zero-padded output shows the width of access just done */
+ printf("0x%0*llX\n", (width >> 2), (unsigned long long)read_result);
+ } else {
+ 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;
+ default:
+ bb_error_msg_and_die("bad width");
}
- printf("Written 0x%llX; readback 0x%llX\n",
- (unsigned long long)writeval,
- (unsigned long long)read_result);
+// 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)
+ if (munmap(map_base, mapped_size) == -1)
bb_perror_msg_and_die("munmap");
close(fd);
}
projects / platform / upstream / busybox.git / blobdiff