1*4882a593Smuzhiyun // SPDX-License-Identifier: GPL-2.0-only
2*4882a593Smuzhiyun /*
3*4882a593Smuzhiyun * ACPI support for CMOS RTC Address Space access
4*4882a593Smuzhiyun *
5*4882a593Smuzhiyun * Copyright (C) 2013, Intel Corporation
6*4882a593Smuzhiyun * Authors: Lan Tianyu <tianyu.lan@intel.com>
7*4882a593Smuzhiyun */
8*4882a593Smuzhiyun
9*4882a593Smuzhiyun #include <linux/acpi.h>
10*4882a593Smuzhiyun #include <linux/device.h>
11*4882a593Smuzhiyun #include <linux/err.h>
12*4882a593Smuzhiyun #include <linux/kernel.h>
13*4882a593Smuzhiyun #include <linux/module.h>
14*4882a593Smuzhiyun #include <linux/mc146818rtc.h>
15*4882a593Smuzhiyun
16*4882a593Smuzhiyun #include "internal.h"
17*4882a593Smuzhiyun
18*4882a593Smuzhiyun static const struct acpi_device_id acpi_cmos_rtc_ids[] = {
19*4882a593Smuzhiyun { "PNP0B00" },
20*4882a593Smuzhiyun { "PNP0B01" },
21*4882a593Smuzhiyun { "PNP0B02" },
22*4882a593Smuzhiyun {}
23*4882a593Smuzhiyun };
24*4882a593Smuzhiyun
25*4882a593Smuzhiyun static acpi_status
acpi_cmos_rtc_space_handler(u32 function,acpi_physical_address address,u32 bits,u64 * value64,void * handler_context,void * region_context)26*4882a593Smuzhiyun acpi_cmos_rtc_space_handler(u32 function, acpi_physical_address address,
27*4882a593Smuzhiyun u32 bits, u64 *value64,
28*4882a593Smuzhiyun void *handler_context, void *region_context)
29*4882a593Smuzhiyun {
30*4882a593Smuzhiyun int i;
31*4882a593Smuzhiyun u8 *value = (u8 *)value64;
32*4882a593Smuzhiyun
33*4882a593Smuzhiyun if (address > 0xff || !value64)
34*4882a593Smuzhiyun return AE_BAD_PARAMETER;
35*4882a593Smuzhiyun
36*4882a593Smuzhiyun if (function != ACPI_WRITE && function != ACPI_READ)
37*4882a593Smuzhiyun return AE_BAD_PARAMETER;
38*4882a593Smuzhiyun
39*4882a593Smuzhiyun spin_lock_irq(&rtc_lock);
40*4882a593Smuzhiyun
41*4882a593Smuzhiyun for (i = 0; i < DIV_ROUND_UP(bits, 8); ++i, ++address, ++value)
42*4882a593Smuzhiyun if (function == ACPI_READ)
43*4882a593Smuzhiyun *value = CMOS_READ(address);
44*4882a593Smuzhiyun else
45*4882a593Smuzhiyun CMOS_WRITE(*value, address);
46*4882a593Smuzhiyun
47*4882a593Smuzhiyun spin_unlock_irq(&rtc_lock);
48*4882a593Smuzhiyun
49*4882a593Smuzhiyun return AE_OK;
50*4882a593Smuzhiyun }
51*4882a593Smuzhiyun
acpi_install_cmos_rtc_space_handler(struct acpi_device * adev,const struct acpi_device_id * id)52*4882a593Smuzhiyun static int acpi_install_cmos_rtc_space_handler(struct acpi_device *adev,
53*4882a593Smuzhiyun const struct acpi_device_id *id)
54*4882a593Smuzhiyun {
55*4882a593Smuzhiyun acpi_status status;
56*4882a593Smuzhiyun
57*4882a593Smuzhiyun status = acpi_install_address_space_handler(adev->handle,
58*4882a593Smuzhiyun ACPI_ADR_SPACE_CMOS,
59*4882a593Smuzhiyun &acpi_cmos_rtc_space_handler,
60*4882a593Smuzhiyun NULL, NULL);
61*4882a593Smuzhiyun if (ACPI_FAILURE(status)) {
62*4882a593Smuzhiyun pr_err(PREFIX "Error installing CMOS-RTC region handler\n");
63*4882a593Smuzhiyun return -ENODEV;
64*4882a593Smuzhiyun }
65*4882a593Smuzhiyun
66*4882a593Smuzhiyun return 1;
67*4882a593Smuzhiyun }
68*4882a593Smuzhiyun
acpi_remove_cmos_rtc_space_handler(struct acpi_device * adev)69*4882a593Smuzhiyun static void acpi_remove_cmos_rtc_space_handler(struct acpi_device *adev)
70*4882a593Smuzhiyun {
71*4882a593Smuzhiyun if (ACPI_FAILURE(acpi_remove_address_space_handler(adev->handle,
72*4882a593Smuzhiyun ACPI_ADR_SPACE_CMOS, &acpi_cmos_rtc_space_handler)))
73*4882a593Smuzhiyun pr_err(PREFIX "Error removing CMOS-RTC region handler\n");
74*4882a593Smuzhiyun }
75*4882a593Smuzhiyun
76*4882a593Smuzhiyun static struct acpi_scan_handler cmos_rtc_handler = {
77*4882a593Smuzhiyun .ids = acpi_cmos_rtc_ids,
78*4882a593Smuzhiyun .attach = acpi_install_cmos_rtc_space_handler,
79*4882a593Smuzhiyun .detach = acpi_remove_cmos_rtc_space_handler,
80*4882a593Smuzhiyun };
81*4882a593Smuzhiyun
acpi_cmos_rtc_init(void)82*4882a593Smuzhiyun void __init acpi_cmos_rtc_init(void)
83*4882a593Smuzhiyun {
84*4882a593Smuzhiyun acpi_scan_add_handler(&cmos_rtc_handler);
85*4882a593Smuzhiyun }
86