107 lines
2.4 KiB
C
107 lines
2.4 KiB
C
// SPDX-License-Identifier: GPL-2.0-only
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/*
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* ACPI support for CMOS RTC Address Space access
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*
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* Copyright (C) 2013, Intel Corporation
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* Authors: Lan Tianyu <tianyu.lan@intel.com>
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*/
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#define pr_fmt(fmt) "ACPI: " fmt
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#include <linux/acpi.h>
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#include <linux/device.h>
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#include <linux/err.h>
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#include <linux/kernel.h>
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#include <linux/module.h>
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#include <linux/mc146818rtc.h>
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#include "../internal.h"
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static const struct acpi_device_id acpi_cmos_rtc_ids[] = {
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{ "ACPI000E", 1 }, /* ACPI Time and Alarm Device (TAD) */
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ACPI_CMOS_RTC_IDS
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};
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bool cmos_rtc_platform_device_present;
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static acpi_status acpi_cmos_rtc_space_handler(u32 function,
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acpi_physical_address address,
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u32 bits, u64 *value64,
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void *handler_context,
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void *region_context)
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{
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unsigned int i, bytes = DIV_ROUND_UP(bits, 8);
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u8 *value = (u8 *)value64;
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if (address > 0xff || !value64)
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return AE_BAD_PARAMETER;
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guard(spinlock_irq)(&rtc_lock);
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if (function == ACPI_WRITE) {
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for (i = 0; i < bytes; i++, address++, value++)
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CMOS_WRITE(*value, address);
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return AE_OK;
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}
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if (function == ACPI_READ) {
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for (i = 0; i < bytes; i++, address++, value++)
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*value = CMOS_READ(address);
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return AE_OK;
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}
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return AE_BAD_PARAMETER;
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}
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static int acpi_install_cmos_rtc_space_handler(acpi_handle handle)
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{
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static bool cmos_rtc_space_handler_present __read_mostly;
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acpi_status status;
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if (cmos_rtc_space_handler_present)
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return 0;
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status = acpi_install_address_space_handler(handle,
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ACPI_ADR_SPACE_CMOS,
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acpi_cmos_rtc_space_handler,
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NULL, NULL);
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if (ACPI_FAILURE(status)) {
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pr_err("Failed to install CMOS-RTC address space handler\n");
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return -ENODEV;
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}
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cmos_rtc_space_handler_present = true;
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return 1;
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}
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static int acpi_cmos_rtc_attach(struct acpi_device *adev,
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const struct acpi_device_id *id)
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{
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int ret;
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ret = acpi_install_cmos_rtc_space_handler(adev->handle);
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if (ret < 0)
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return ret;
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if (IS_ERR_OR_NULL(acpi_create_platform_device(adev, NULL))) {
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pr_err("Failed to create a platform device for %s\n", (char *)id->id);
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return 0;
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} else if (!id->driver_data) {
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cmos_rtc_platform_device_present = true;
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}
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return 1;
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}
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static struct acpi_scan_handler cmos_rtc_handler = {
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.ids = acpi_cmos_rtc_ids,
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.attach = acpi_cmos_rtc_attach,
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};
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void __init acpi_cmos_rtc_init(void)
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{
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acpi_scan_add_handler(&cmos_rtc_handler);
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}
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