linux/drivers/acpi/acpi_cmos_rtc.c
Lan Tianyu 2fa97feb44 ACPI: Add CMOS RTC Operation Region handler support
On HP Folio 13-2000, the BIOS defines a CMOS RTC Operation Region and
the EC's _REG methord accesses that region.  Thus an appropriate
address space handler must be registered for that region before the
EC driver is loaded.

Introduce a mechanism for adding CMOS RTC address space handlers.
Register an ACPI scan handler for CMOS RTC devices such that, when
a device of that kind is detected during an ACPI namespace scan, a
common CMOS RTC operation region address space handler will be
installed for it.

References: https://bugzilla.kernel.org/show_bug.cgi?id=54621
Reported-and-tested-by: Stefan Nagy <public@stefan-nagy.at>
Signed-off-by: Lan Tianyu <tianyu.lan@intel.com>
Cc: 3.9+ <stable@vger.kernel.org>
Signed-off-by: Rafael J. Wysocki <rafael.j.wysocki@intel.com>
2013-06-27 21:35:37 +02:00

93 lines
2.2 KiB
C

/*
* ACPI support for CMOS RTC Address Space access
*
* Copyright (C) 2013, Intel Corporation
* Authors: Lan Tianyu <tianyu.lan@intel.com>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License version 2 as
* published by the Free Software Foundation.
*/
#include <linux/acpi.h>
#include <linux/device.h>
#include <linux/err.h>
#include <linux/kernel.h>
#include <linux/module.h>
#include <asm-generic/rtc.h>
#include "internal.h"
#define PREFIX "ACPI: "
ACPI_MODULE_NAME("cmos rtc");
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(PREFIX "Error installing CMOS-RTC region handler\n");
return -ENODEV;
}
return 0;
}
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(PREFIX "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);
}