acrn-hypervisor/hypervisor/dm/vrtc.c

82 lines
1.5 KiB
C

/*
* Copyright (C) 2018 Intel Corporation. All rights reserved.
*
* SPDX-License-Identifier: BSD-3-Clause
*/
#include <hypervisor.h>
#define CMOS_ADDR_PORT 0x70U
#define CMOS_DATA_PORT 0x71U
#define RTC_STATUSA 0x0AU /* status register A */
#define RTCSA_TUP 0x80U /* time update, don't look now */
static spinlock_t cmos_lock = { .head = 0U, .tail = 0U };
static uint8_t cmos_read(uint8_t addr)
{
pio_write8(addr, CMOS_ADDR_PORT);
return pio_read8(CMOS_DATA_PORT);
}
static bool cmos_update_in_progress(void)
{
return (cmos_read(RTC_STATUSA) & RTCSA_TUP)?1:0;
}
static uint8_t cmos_get_reg_val(uint8_t addr)
{
uint8_t reg;
int tries = 2000U;
spinlock_obtain(&cmos_lock);
/* Make sure an update isn't in progress */
while (cmos_update_in_progress() && tries--)
;
reg = cmos_read(addr);
spinlock_release(&cmos_lock);
return reg;
}
static uint32_t vrtc_read(struct vm *vm, uint16_t addr, __unused size_t width)
{
uint8_t reg;
uint8_t offset;
offset = vm->vrtc_offset;
if (addr == CMOS_ADDR_PORT) {
return vm->vrtc_offset;
}
reg = cmos_get_reg_val(offset);
return reg;
}
static void vrtc_write(struct vm *vm, uint16_t addr, size_t width,
uint32_t value)
{
if (width != 1U)
return;
if (addr == CMOS_ADDR_PORT) {
vm->vrtc_offset = value & 0x7FU;
}
}
void vrtc_init(struct vm *vm)
{
struct vm_io_range range = {
.flags = IO_ATTR_RW, .base = CMOS_ADDR_PORT, .len = 2U};
/* Initializing the CMOS RAM offset to 0U */
vm->vrtc_offset = 0U;
register_io_emulation_handler(vm, &range, vrtc_read, vrtc_write);
}