1 | // SPDX-License-Identifier: GPL-2.0-only |
2 | /* |
3 | * ACPI support for CMOS RTC Address Space access |
4 | * |
5 | * Copyright (C) 2013, Intel Corporation |
6 | * Authors: Lan Tianyu <tianyu.lan@intel.com> |
7 | */ |
8 | |
9 | #define pr_fmt(fmt) "ACPI: " fmt |
10 | |
11 | #include <linux/acpi.h> |
12 | #include <linux/device.h> |
13 | #include <linux/err.h> |
14 | #include <linux/kernel.h> |
15 | #include <linux/module.h> |
16 | #include <linux/mc146818rtc.h> |
17 | |
18 | #include "internal.h" |
19 | |
20 | static const struct acpi_device_id acpi_cmos_rtc_ids[] = { |
21 | { "PNP0B00" }, |
22 | { "PNP0B01" }, |
23 | { "PNP0B02" }, |
24 | {} |
25 | }; |
26 | |
27 | static acpi_status |
28 | acpi_cmos_rtc_space_handler(u32 function, acpi_physical_address address, |
29 | u32 bits, u64 *value64, |
30 | void *handler_context, void *region_context) |
31 | { |
32 | int i; |
33 | u8 *value = (u8 *)value64; |
34 | |
35 | if (address > 0xff || !value64) |
36 | return AE_BAD_PARAMETER; |
37 | |
38 | if (function != ACPI_WRITE && function != ACPI_READ) |
39 | return AE_BAD_PARAMETER; |
40 | |
41 | spin_lock_irq(lock: &rtc_lock); |
42 | |
43 | for (i = 0; i < DIV_ROUND_UP(bits, 8); ++i, ++address, ++value) |
44 | if (function == ACPI_READ) |
45 | *value = CMOS_READ(address); |
46 | else |
47 | CMOS_WRITE(*value, address); |
48 | |
49 | spin_unlock_irq(lock: &rtc_lock); |
50 | |
51 | return AE_OK; |
52 | } |
53 | |
54 | int acpi_install_cmos_rtc_space_handler(acpi_handle handle) |
55 | { |
56 | acpi_status status; |
57 | |
58 | status = acpi_install_address_space_handler(device: handle, |
59 | ACPI_ADR_SPACE_CMOS, |
60 | handler: &acpi_cmos_rtc_space_handler, |
61 | NULL, NULL); |
62 | if (ACPI_FAILURE(status)) { |
63 | pr_err("Error installing CMOS-RTC region handler\n" ); |
64 | return -ENODEV; |
65 | } |
66 | |
67 | return 1; |
68 | } |
69 | EXPORT_SYMBOL_GPL(acpi_install_cmos_rtc_space_handler); |
70 | |
71 | void acpi_remove_cmos_rtc_space_handler(acpi_handle handle) |
72 | { |
73 | if (ACPI_FAILURE(acpi_remove_address_space_handler(handle, |
74 | ACPI_ADR_SPACE_CMOS, &acpi_cmos_rtc_space_handler))) |
75 | pr_err("Error removing CMOS-RTC region handler\n" ); |
76 | } |
77 | EXPORT_SYMBOL_GPL(acpi_remove_cmos_rtc_space_handler); |
78 | |
79 | static int acpi_cmos_rtc_attach_handler(struct acpi_device *adev, const struct acpi_device_id *id) |
80 | { |
81 | return acpi_install_cmos_rtc_space_handler(adev->handle); |
82 | } |
83 | |
84 | static void acpi_cmos_rtc_detach_handler(struct acpi_device *adev) |
85 | { |
86 | acpi_remove_cmos_rtc_space_handler(adev->handle); |
87 | } |
88 | |
89 | static struct acpi_scan_handler cmos_rtc_handler = { |
90 | .ids = acpi_cmos_rtc_ids, |
91 | .attach = acpi_cmos_rtc_attach_handler, |
92 | .detach = acpi_cmos_rtc_detach_handler, |
93 | }; |
94 | |
95 | void __init acpi_cmos_rtc_init(void) |
96 | { |
97 | acpi_scan_add_handler(handler: &cmos_rtc_handler); |
98 | } |
99 | |