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>
diff --git a/drivers/acpi/acpi_cmos_rtc.c b/drivers/acpi/acpi_cmos_rtc.c
new file mode 100644
index 0000000..84190ed
--- /dev/null
+++ b/drivers/acpi/acpi_cmos_rtc.c
@@ -0,0 +1,92 @@
+/*
+ * 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);
+}