1 files changed, 85 insertions, 0 deletions
diff --git a/drivers/acpi/acpi_cmos_rtc.c b/drivers/acpi/acpi_cmos_rtc.c
new file mode 100644
index 000000000..67f1d33d1
--- /dev/null
+++ b/drivers/acpi/acpi_cmos_rtc.c
@@ -0,0 +1,85 @@
+// 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>
+ */
+
+#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(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);
+}