1 /*
2 * Copyright (c) 2019 Travis Geiselbrecht
3 *
4 * Permission is hereby granted, free of charge, to any person obtaining
5 * a copy of this software and associated documentation files
6 * (the "Software"), to deal in the Software without restriction,
7 * including without limitation the rights to use, copy, modify, merge,
8 * publish, distribute, sublicense, and/or sell copies of the Software,
9 * and to permit persons to whom the Software is furnished to do so,
10 * subject to the following conditions:
11 *
12 * The above copyright notice and this permission notice shall be
13 * included in all copies or substantial portions of the Software.
14 *
15 * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
16 * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
17 * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT.
18 * IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY
19 * CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT,
20 * TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE
21 * SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE.
22 */
23 #include <platform/cmos.h>
24
25 #include <lk/trace.h>
26 #include <lk/debug.h>
27 #include <kernel/spinlock.h>
28 #include <platform/pc.h>
29
30 static spin_lock_t lock = SPIN_LOCK_INITIAL_VALUE;
31
cmos_read(uint8_t reg)32 uint8_t cmos_read(uint8_t reg) {
33 spin_lock_saved_state_t state;
34 spin_lock_irqsave(&lock, state);
35
36 outp(CMOS_CONTROL_REG, reg | 0x80);
37 uint8_t val = inp(CMOS_DATA_REG);
38
39 spin_unlock_irqrestore(&lock, state);
40
41 return val;
42 }
43
44
45