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#include <arch/i386/tsc.h>
#include <drivers/cmos.h>
#include <fs/devfs.h>
#include <interrupts.h>
#include <lib/sv.h>
#include <math.h>
#include <random.h>
#include <time.h>
#include <timer.h>
#include <typedefs.h>
int has_unix_time;
i64 start_unix_time;
u64 start_tsc_time;
void timer_start_init(void) {
tsc_init();
start_tsc_time = tsc_get();
random_add_entropy((u8 *)&start_tsc_time, sizeof(start_tsc_time));
enable_interrupts();
cmos_init();
cmos_start_call(1, &has_unix_time, &start_unix_time);
}
void timer_wait_for_init(void) {
enable_interrupts();
for (; !has_unix_time;)
;
}
u64 timer_current_uptime = 0; // This gets updated by the PIT handler
u64 timer_get_uptime(void) {
return timer_current_uptime;
}
void timer_get(struct timespec *tp) {
u64 offset_tsc = tsc_get() - start_tsc_time;
i64 current_unix_time_seconds =
start_unix_time + tsc_calculate_ms(offset_tsc) / 1000;
tp->tv_sec = current_unix_time_seconds;
tp->tv_nsec = tsc_calculate_ms(offset_tsc);
}
u64 timer_get_ms(void) {
u64 offset_tsc = tsc_get() - start_tsc_time;
return start_unix_time * 1000 + tsc_calculate_ms(offset_tsc);
}
int clock_read(u8 *buffer, u64 offset, u64 len, vfs_fd_t *fd) {
if (0 != offset) {
return 0;
}
u64 r = timer_get_ms();
return min(len, (u64)kbnprintf(buffer, len, "%llu", r));
}
int clock_write(u8 *buffer, u64 offset, u64 len, vfs_fd_t *fd) {
if (0 != offset) {
return 0;
}
struct sv string_view = sv_init(buffer, len);
u64 new_value_ms = sv_parse_unsigned_number(string_view, &string_view);
i64 new_value_seconds = new_value_ms / 1000;
u64 offset_tsc = tsc_get() - start_tsc_time;
i64 current_unix_time_seconds =
start_unix_time + tsc_calculate_ms(offset_tsc) / 1000;
i64 delta = new_value_seconds - current_unix_time_seconds;
start_unix_time += delta;
int done;
enable_interrupts();
cmos_start_call(0, &done, &new_value_seconds);
for (; !done;)
;
return sizeof(i64);
}
int always_has_data(vfs_inode_t *inode);
int always_can_write(vfs_inode_t *inode);
int timer_add_clock(void) {
devfs_add_file("/clock", clock_read, clock_write, NULL, always_has_data,
always_can_write, FS_TYPE_BLOCK_DEVICE);
return 1;
}
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