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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * ACPI support for CMOS RTC Address Space access4 *5 * Copyright (C) 2013, Intel Corporation6 * Authors: Lan Tianyu <tianyu.lan@intel.com>7 */8 9#define pr_fmt(fmt) "ACPI: " fmt10 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 20static const struct acpi_device_id acpi_cmos_rtc_ids[] = {21 { "PNP0B00" },22 { "PNP0B01" },23 { "PNP0B02" },24 {}25};26 27static acpi_status28acpi_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(&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 else47 CMOS_WRITE(*value, address);48 49 spin_unlock_irq(&rtc_lock);50 51 return AE_OK;52}53 54int acpi_install_cmos_rtc_space_handler(acpi_handle handle)55{56 acpi_status status;57 58 status = acpi_install_address_space_handler(handle,59 ACPI_ADR_SPACE_CMOS,60 &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}69EXPORT_SYMBOL_GPL(acpi_install_cmos_rtc_space_handler);70 71void 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}77EXPORT_SYMBOL_GPL(acpi_remove_cmos_rtc_space_handler);78 79static 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 84static void acpi_cmos_rtc_detach_handler(struct acpi_device *adev)85{86 acpi_remove_cmos_rtc_space_handler(adev->handle);87}88 89static 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 95void __init acpi_cmos_rtc_init(void)96{97 acpi_scan_add_handler(&cmos_rtc_handler);98}99