ardupilot/libraries/AP_HAL_Linux/Storage.cpp

240 lines
5.5 KiB
C++

#include <AP_HAL.h>
#if CONFIG_HAL_BOARD == HAL_BOARD_LINUX
#include <assert.h>
#include <sys/types.h>
#include <sys/stat.h>
#include <fcntl.h>
#include <unistd.h>
#include <errno.h>
#include <stdio.h>
#include "Storage.h"
using namespace Linux;
/*
This stores 'eeprom' data on the SD card, with a 4k size, and a
in-memory buffer. This keeps the latency down.
*/
// name the storage file after the sketch so you can use the same board
// card for ArduCopter and ArduPlane
#define STORAGE_DIR "/var/APM"
#define STORAGE_FILE STORAGE_DIR "/" SKETCHNAME ".stg"
extern const AP_HAL::HAL& hal;
void LinuxStorage::_storage_create(void)
{
mkdir(STORAGE_DIR, 0777);
unlink(STORAGE_FILE);
int fd = open(STORAGE_FILE, O_RDWR|O_CREAT, 0666);
if (fd == -1) {
hal.scheduler->panic("Failed to create " STORAGE_FILE);
}
for (uint16_t loc=0; loc<sizeof(_buffer); loc += LINUX_STORAGE_MAX_WRITE) {
if (write(fd, &_buffer[loc], LINUX_STORAGE_MAX_WRITE) != LINUX_STORAGE_MAX_WRITE) {
hal.scheduler->panic("Error filling " STORAGE_FILE);
}
}
// ensure the directory is updated with the new size
fsync(fd);
close(fd);
}
void LinuxStorage::_storage_open(void)
{
if (_initialised) {
return;
}
_dirty_mask = 0;
int fd = open(STORAGE_FILE, O_RDONLY);
if (fd == -1) {
_storage_create();
fd = open(STORAGE_FILE, O_RDONLY);
if (fd == -1) {
hal.scheduler->panic("Failed to open " STORAGE_FILE);
}
}
if (read(fd, _buffer, sizeof(_buffer)) != sizeof(_buffer)) {
close(fd);
_storage_create();
fd = open(STORAGE_FILE, O_RDONLY);
if (fd == -1) {
hal.scheduler->panic("Failed to open " STORAGE_FILE);
}
if (read(fd, _buffer, sizeof(_buffer)) != sizeof(_buffer)) {
hal.scheduler->panic("Failed to read " STORAGE_FILE);
}
}
close(fd);
_initialised = true;
}
/*
mark some lines as dirty. Note that there is no attempt to avoid
the race condition between this code and the _timer_tick() code
below, which both update _dirty_mask. If we lose the race then the
result is that a line is written more than once, but it won't result
in a line not being written.
*/
void LinuxStorage::_mark_dirty(uint16_t loc, uint16_t length)
{
uint16_t end = loc + length;
while (loc < end) {
uint8_t line = (loc >> LINUX_STORAGE_LINE_SHIFT);
_dirty_mask |= 1 << line;
loc += LINUX_STORAGE_LINE_SIZE;
}
}
uint8_t LinuxStorage::read_byte(uint16_t loc)
{
if (loc >= sizeof(_buffer)) {
return 0;
}
_storage_open();
return _buffer[loc];
}
uint16_t LinuxStorage::read_word(uint16_t loc)
{
uint16_t value;
if (loc >= sizeof(_buffer)-(sizeof(value)-1)) {
return 0;
}
_storage_open();
memcpy(&value, &_buffer[loc], sizeof(value));
return value;
}
uint32_t LinuxStorage::read_dword(uint16_t loc)
{
uint32_t value;
if (loc >= sizeof(_buffer)-(sizeof(value)-1)) {
return 0;
}
_storage_open();
memcpy(&value, &_buffer[loc], sizeof(value));
return value;
}
void LinuxStorage::read_block(void *dst, uint16_t loc, size_t n)
{
if (loc >= sizeof(_buffer)-(n-1)) {
return;
}
_storage_open();
memcpy(dst, &_buffer[loc], n);
}
void LinuxStorage::write_byte(uint16_t loc, uint8_t value)
{
if (loc >= sizeof(_buffer)) {
return;
}
if (_buffer[loc] != value) {
_storage_open();
_buffer[loc] = value;
_mark_dirty(loc, sizeof(value));
}
}
void LinuxStorage::write_word(uint16_t loc, uint16_t value)
{
if (loc >= sizeof(_buffer)-(sizeof(value)-1)) {
return;
}
if (memcmp(&value, &_buffer[loc], sizeof(value)) != 0) {
_storage_open();
memcpy(&_buffer[loc], &value, sizeof(value));
_mark_dirty(loc, sizeof(value));
}
}
void LinuxStorage::write_dword(uint16_t loc, uint32_t value)
{
if (loc >= sizeof(_buffer)-(sizeof(value)-1)) {
return;
}
if (memcmp(&value, &_buffer[loc], sizeof(value)) != 0) {
_storage_open();
memcpy(&_buffer[loc], &value, sizeof(value));
_mark_dirty(loc, sizeof(value));
}
}
void LinuxStorage::write_block(uint16_t loc, const void *src, size_t n)
{
if (loc >= sizeof(_buffer)-(n-1)) {
return;
}
if (memcmp(src, &_buffer[loc], n) != 0) {
_storage_open();
memcpy(&_buffer[loc], src, n);
_mark_dirty(loc, n);
}
}
void LinuxStorage::_timer_tick(void)
{
if (!_initialised || _dirty_mask == 0) {
return;
}
if (_fd == -1) {
_fd = open(STORAGE_FILE, O_WRONLY);
if (_fd == -1) {
return;
}
}
// write out the first dirty set of lines. We don't write more
// than one to keep the latency of this call to a minimum
uint8_t i, n;
for (i=0; i<LINUX_STORAGE_NUM_LINES; i++) {
if (_dirty_mask & (1<<i)) {
break;
}
}
if (i == LINUX_STORAGE_NUM_LINES) {
// this shouldn't be possible
return;
}
uint32_t write_mask = (1U<<i);
// see how many lines to write
for (n=1; (i+n) < LINUX_STORAGE_NUM_LINES &&
n < (LINUX_STORAGE_MAX_WRITE>>LINUX_STORAGE_LINE_SHIFT); n++) {
if (!(_dirty_mask & (1<<(n+i)))) {
break;
}
// mark that line clean
write_mask |= (1<<(n+i));
}
/*
write the lines. This also updates _dirty_mask. Note that
because this is a SCHED_FIFO thread it will not be preempted
by the main task except during blocking calls. This means we
don't need a semaphore around the _dirty_mask updates.
*/
if (lseek(_fd, i<<LINUX_STORAGE_LINE_SHIFT, SEEK_SET) == (i<<LINUX_STORAGE_LINE_SHIFT)) {
_dirty_mask &= ~write_mask;
if (write(_fd, &_buffer[i<<LINUX_STORAGE_LINE_SHIFT], n<<LINUX_STORAGE_LINE_SHIFT) != n<<LINUX_STORAGE_LINE_SHIFT) {
// write error - likely EINTR
_dirty_mask |= write_mask;
close(_fd);
_fd = -1;
}
if (_dirty_mask == 0) {
if (fsync(_fd) != 0) {
close(_fd);
_fd = -1;
}
}
}
}
#endif // CONFIG_HAL_BOARD