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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[] = {
{ "ACPI000E", 1 }, /* ACPI Time and Alarm Device (TAD) */
ACPI_CMOS_RTC_IDS
};
bool cmos_rtc_platform_device_present;
static acpi_status acpi_cmos_rtc_space_handler(u32 function,
acpi_physical_address address,
u32 bits, u64 *value64,
void *handler_context,
void *region_context)
{
unsigned int i, bytes = DIV_ROUND_UP(bits, 8);
u8 *value = (u8 *)value64;
if (address > 0xff || !value64)
return AE_BAD_PARAMETER;
guard(spinlock_irq)(&rtc_lock);
if (function == ACPI_WRITE) {
for (i = 0; i < bytes; i++, address++, value++)
CMOS_WRITE(*value, address);
return AE_OK;
}
if (function == ACPI_READ) {
for (i = 0; i < bytes; i++, address++, value++)
*value = CMOS_READ(address);
return AE_OK;
}
return AE_BAD_PARAMETER;
}
static int acpi_install_cmos_rtc_space_handler(acpi_handle handle)
{
static bool cmos_rtc_space_handler_present __read_mostly;
acpi_status status;
if (cmos_rtc_space_handler_present)
return 0;
status = acpi_install_address_space_handler(handle,
ACPI_ADR_SPACE_CMOS,
acpi_cmos_rtc_space_handler,
NULL, NULL);
if (ACPI_FAILURE(status)) {
pr_err("Failed to install CMOS-RTC address space handler\n");
return -ENODEV;
}
cmos_rtc_space_handler_present = true;
return 1;
}
static int acpi_cmos_rtc_attach(struct acpi_device *adev,
const struct acpi_device_id *id)
{
int ret;
ret = acpi_install_cmos_rtc_space_handler(adev->handle);
if (ret < 0)
return ret;
if (IS_ERR_OR_NULL(acpi_create_platform_device(adev, NULL))) {
pr_err("Failed to create a platform device for %s\n", (char *)id->id);
return 0;
} else if (!id->driver_data) {
cmos_rtc_platform_device_present = true;
}
return 1;
}
static struct acpi_scan_handler cmos_rtc_handler = {
.ids = acpi_cmos_rtc_ids,
.attach = acpi_cmos_rtc_attach,
};
void __init acpi_cmos_rtc_init(void)
{
acpi_scan_add_handler(&cmos_rtc_handler);
}
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