intel_th: Add ACPI glue layer

The Trace Hub devices now can be enumerated as ACPI devices, which
translates into "Host Debugger mode". There are two IDs: one for
PCH Trace Hub, and one for the uncore Trace Hub. These are expected
to stay the same across all platforms.

Signed-off-by: Alexander Shishkin <alexander.shishkin@linux.intel.com>

drivers/hwtracing/intel_th/Kconfig

@@ -25,6 +25,18 @@ config INTEL_TH_PCI
 
 	  Say Y here to enable PCI Intel TH support.
 
+config INTEL_TH_ACPI
+	tristate "Intel(R) Trace Hub ACPI controller"
+	depends on ACPI
+	help
+	  Intel(R) Trace Hub may exist as an ACPI device. This option enables
+	  support glue layer for ACPI-based Intel TH. This typically implies
+	  'host debugger' mode, that is, the trace configuration and capture
+	  is handled by an external debug host and corresponding controls will
+	  not be available on the target.
+
+	  Say Y here to enable ACPI Intel TH support.
+
 config INTEL_TH_GTH
 	tristate "Intel(R) Trace Hub Global Trace Hub"
 	help

drivers/hwtracing/intel_th/Makefile

@@ -6,6 +6,9 @@ intel_th-$(CONFIG_INTEL_TH_DEBUG) += debug.o
 obj-$(CONFIG_INTEL_TH_PCI)	+= intel_th_pci.o
 intel_th_pci-y			:= pci.o
 
+obj-$(CONFIG_INTEL_TH_ACPI)	+= intel_th_acpi.o
+intel_th_acpi-y			:= acpi.o
+
 obj-$(CONFIG_INTEL_TH_GTH)	+= intel_th_gth.o
 intel_th_gth-y			:= gth.o
 

drivers/hwtracing/intel_th/acpi.c

@@ -0,0 +1,79 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Intel(R) Trace Hub ACPI driver
+ *
+ * Copyright (C) 2017 Intel Corporation.
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/types.h>
+#include <linux/module.h>
+#include <linux/device.h>
+#include <linux/sysfs.h>
+#include <linux/platform_device.h>
+#include <linux/acpi.h>
+
+#include "intel_th.h"
+
+#define DRIVER_NAME "intel_th_acpi"
+
+static const struct intel_th_drvdata intel_th_acpi_pch = {
+	.host_mode_only	= 1,
+};
+
+static const struct intel_th_drvdata intel_th_acpi_uncore = {
+	.host_mode_only	= 1,
+};
+
+static const struct acpi_device_id intel_th_acpi_ids[] = {
+	{ "INTC1000",	(kernel_ulong_t)&intel_th_acpi_uncore },
+	{ "INTC1001",	(kernel_ulong_t)&intel_th_acpi_pch },
+	{ "",		0 },
+};
+
+MODULE_DEVICE_TABLE(acpi, intel_th_acpi_ids);
+
+static int intel_th_acpi_probe(struct platform_device *pdev)
+{
+	struct acpi_device *adev = ACPI_COMPANION(&pdev->dev);
+	const struct acpi_device_id *id;
+	struct intel_th *th;
+
+	id = acpi_match_device(intel_th_acpi_ids, &pdev->dev);
+	if (!id)
+		return -ENODEV;
+
+	th = intel_th_alloc(&pdev->dev, (void *)id->driver_data,
+			    pdev->resource, pdev->num_resources, -1);
+	if (IS_ERR(th))
+		return PTR_ERR(th);
+
+	adev->driver_data = th;
+
+	return 0;
+}
+
+static int intel_th_acpi_remove(struct platform_device *pdev)
+{
+	struct intel_th *th = platform_get_drvdata(pdev);
+
+	intel_th_free(th);
+
+	return 0;
+}
+
+static struct platform_driver intel_th_acpi_driver = {
+	.probe		= intel_th_acpi_probe,
+	.remove		= intel_th_acpi_remove,
+	.driver		= {
+		.name			= DRIVER_NAME,
+		.acpi_match_table	= intel_th_acpi_ids,
+	},
+};
+
+module_platform_driver(intel_th_acpi_driver);
+
+MODULE_LICENSE("GPL v2");
+MODULE_DESCRIPTION("Intel(R) Trace Hub ACPI controller driver");
+MODULE_AUTHOR("Alexander Shishkin <alexander.shishkin@intel.com>");