1 files changed, 90 insertions, 0 deletions
diff --git a/drivers/acpi/x86/utils.c b/drivers/acpi/x86/utils.c
new file mode 100644
index 000000000000..bd86b809c848
--- /dev/null
+++ b/drivers/acpi/x86/utils.c
@@ -0,0 +1,90 @@
+/*
+ * X86 ACPI Utility Functions
+ *
+ * Copyright (C) 2017 Hans de Goede <hdegoede@redhat.com>
+ *
+ * Based on various non upstream patches to support the CHT Whiskey Cove PMIC:
+ * Copyright (C) 2013-2015 Intel Corporation. All rights reserved.
+ *
+ * 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 <asm/cpu_device_id.h>
+#include <asm/intel-family.h>
+#include "../internal.h"
+
+/*
+ * Some ACPI devices are hidden (status == 0x0) in recent BIOS-es because
+ * some recent Windows drivers bind to one device but poke at multiple
+ * devices at the same time, so the others get hidden.
+ * We work around this by always reporting ACPI_STA_DEFAULT for these
+ * devices. Note this MUST only be done for devices where this is safe.
+ *
+ * This forcing of devices to be present is limited to specific CPU (SoC)
+ * models both to avoid potentially causing trouble on other models and
+ * because some HIDs are re-used on different SoCs for completely
+ * different devices.
+ */
+struct always_present_id {
+	struct acpi_device_id hid[2];
+	struct x86_cpu_id cpu_ids[2];
+	const char *uid;
+};
+
+#define ICPU(model)	{ X86_VENDOR_INTEL, 6, model, X86_FEATURE_ANY, }
+
+#define ENTRY(hid, uid, cpu_models) {					\
+	{ { hid, }, {} },						\
+	{ cpu_models, {} },						\
+	uid,								\
+}
+
+static const struct always_present_id always_present_ids[] = {
+	/*
+	 * Bay / Cherry Trail PWM directly poked by GPU driver in win10,
+	 * but Linux uses a separate PWM driver, harmless if not used.
+	 */
+	ENTRY("80860F09", "1", ICPU(INTEL_FAM6_ATOM_SILVERMONT1)),
+	ENTRY("80862288", "1", ICPU(INTEL_FAM6_ATOM_AIRMONT)),
+	/*
+	 * The INT0002 device is necessary to clear wakeup interrupt sources
+	 * on Cherry Trail devices, without it we get nobody cared IRQ msgs.
+	 */
+	ENTRY("INT0002", "1", ICPU(INTEL_FAM6_ATOM_AIRMONT)),
+};
+
+bool acpi_device_always_present(struct acpi_device *adev)
+{
+	u32 *status = (u32 *)&adev->status;
+	u32 old_status = *status;
+	bool ret = false;
+	unsigned int i;
+
+	/* acpi_match_device_ids checks status, so set it to default */
+	*status = ACPI_STA_DEFAULT;
+	for (i = 0; i < ARRAY_SIZE(always_present_ids); i++) {
+		if (acpi_match_device_ids(adev, always_present_ids[i].hid))
+			continue;
+
+		if (!adev->pnp.unique_id ||
+		    strcmp(adev->pnp.unique_id, always_present_ids[i].uid))
+			continue;
+
+		if (!x86_match_cpu(always_present_ids[i].cpu_ids))
+			continue;
+
+		if (old_status != ACPI_STA_DEFAULT) /* Log only once */
+			dev_info(&adev->dev,
+				 "Device [%s] is in always present list\n",
+				 adev->pnp.bus_id);
+
+		ret = true;
+		break;
+	}
+	*status = old_status;
+
+	return ret;
+}