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// SPDX-License-Identifier: GPL-2.0-only
/*
* ACPI support for CMOS RTC Address Space access
*
* Copyright (C) 2013, Intel Corporation
* Authors: Lan Tianyu <tianyu.lan@intel.com>
*/
#define pr_fmt(fmt) "ACPI: " fmt
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <linux/mc146818rtc.h>
#include "internal.h"
static const struct acpi_device_id acpi_cmos_rtc_ids[] = {
{ "PNP0B00" },
{ "PNP0B01" },
{ "PNP0B02" },
{}
};
static acpi_status
acpi_cmos_rtc_space_handler(u32 function, acpi_physical_address address,
u32 bits, u64 *value64,
void *handler_context, void *region_context)
{
int i;
u8 *value = (u8 *)value64;
if (address > 0xff || !value64)
return AE_BAD_PARAMETER;
if (function != ACPI_WRITE && function != ACPI_READ)
return AE_BAD_PARAMETER;
spin_lock_irq(&rtc_lock);
for (i = 0; i < DIV_ROUND_UP(bits, 8); ++i, ++address, ++value)
if (function == ACPI_READ)
*value = CMOS_READ(address);
else
CMOS_WRITE(*value, address);
spin_unlock_irq(&rtc_lock);
return AE_OK;
}
static int acpi_install_cmos_rtc_space_handler(struct acpi_device *adev,
const struct acpi_device_id *id)
{
acpi_status status;
status = acpi_install_address_space_handler(adev->handle,
ACPI_ADR_SPACE_CMOS,
&acpi_cmos_rtc_space_handler,
NULL, NULL);
if (ACPI_FAILURE(status)) {
pr_err("Error installing CMOS-RTC region handler\n");
return -ENODEV;
}
return 1;
}
static void acpi_remove_cmos_rtc_space_handler(struct acpi_device *adev)
{
if (ACPI_FAILURE(acpi_remove_address_space_handler(adev->handle,
ACPI_ADR_SPACE_CMOS, &acpi_cmos_rtc_space_handler)))
pr_err("Error removing CMOS-RTC region handler\n");
}
static struct acpi_scan_handler cmos_rtc_handler = {
.ids = acpi_cmos_rtc_ids,
.attach = acpi_install_cmos_rtc_space_handler,
.detach = acpi_remove_cmos_rtc_space_handler,
};
void __init acpi_cmos_rtc_init(void)
{
acpi_scan_add_handler(&cmos_rtc_handler);
}
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