/* * 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 <linux/mc146818rtc.h> #include "internal.h" 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 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(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); }