[PATCH 24/25] coresight: Support for ACPI bindings

[Suzuki K Poulose]

Add support for parsing the ACPI platform description
for CoreSight. The connections are encoded in a DSD graph
property with CoreSight specific variation of the property.

The ETMs are listed as the children device of the respective
CPU.

Cc: "Rafael J. Wysocki" <rjw@xxxxxxxxxxxxx>
Cc: Mathieu Poirier <mathieu.poirier@xxxxxxxxxx>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@xxxxxxx>
---
 drivers/hwtracing/coresight/coresight-platform.c | 402 +++++++++++++++++++++++
 1 file changed, 402 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index 5eee987..06b1188 100644
--- a/drivers/hwtracing/coresight/coresight-platform.c
+++ b/drivers/hwtracing/coresight/coresight-platform.c
@@ -3,6 +3,7 @@
  * Copyright (c) 2012, The Linux Foundation. All rights reserved.
  */
 
+#include <linux/acpi.h>
 #include <linux/types.h>
 #include <linux/err.h>
 #include <linux/slab.h>
@@ -289,10 +290,409 @@ of_get_coresight_platform_data(struct device *dev,
 }
 #endif
 
+#ifdef CONFIG_ACPI
+
+#include <acpi/actypes.h>
+#include <acpi/processor.h>
+
+/* ACPI Graph _DSD UUID : "ab02a46b-74c7-45a2-bd68-f7d344ef2153" */
+static const guid_t acpi_graph_uuid = GUID_INIT(0xab02a46b, 0x74c7, 0x45a2,
+						0xbd, 0x68, 0xf7, 0xd3,
+						0x44, 0xef, 0x21, 0x53);
+/* Coresight ACPI Graph UUID : "3ecbc8b6-1d0e-4fb3-8107-e627f805c6cd" */
+static const guid_t coresight_graph_uuid = GUID_INIT(0x3ecbc8b6, 0x1d0e, 0x4fb3,
+						     0x81, 0x07, 0xe6, 0x27,
+						     0xf8, 0x05, 0xc6, 0xcd);
+#define ACPI_CORESIGHT_LINK_SLAVE	0
+#define ACPI_CORESIGHT_LINK_MASTER	1
+
+static inline bool is_acpi_guid(const union acpi_object *obj)
+{
+	return (obj->type == ACPI_TYPE_BUFFER) && (obj->buffer.length == 16);
+}
+
+/*
+ * acpi_guid_matches	- Checks if the given object is a GUID object and
+ * that it matches the supplied the GUID.
+ */
+static inline bool acpi_guid_matches(const union acpi_object *obj,
+				   const guid_t *guid)
+{
+	return is_acpi_guid(obj) &&
+	       guid_equal((guid_t *)obj->buffer.pointer, guid);
+}
+
+static inline bool is_acpi_dsd_graph_guid(const union acpi_object *obj)
+{
+	return acpi_guid_matches(obj, &acpi_graph_uuid);
+}
+
+static inline bool is_acpi_coresight_graph_guid(const union acpi_object *obj)
+{
+	return acpi_guid_matches(obj, &coresight_graph_uuid);
+}
+
+static inline bool is_acpi_coresight_graph(const union acpi_object *obj)
+{
+	const union acpi_object *graphid, *guid, *links;
+
+	if (obj->type != ACPI_TYPE_PACKAGE ||
+	    obj->package.count < 3)
+		return false;
+
+	graphid = &obj->package.elements[0];
+	guid = &obj->package.elements[1];
+	links = &obj->package.elements[2];
+
+	if (graphid->type != ACPI_TYPE_INTEGER ||
+	    links->type != ACPI_TYPE_INTEGER)
+		return false;
+
+	return is_acpi_coresight_graph_guid(guid);
+}
+
+/*
+ * acpi_validate_dsd_graph	- Make sure the given _DSD graph conforms
+ * to the ACPI _DSD Graph specification.
+ *
+ * ACPI Devices Graph property has the following format:
+ *	Revision	- Integer, must be 0
+ *	NumberOfGraphs	- Integer, N indicating the following list.
+ *	Graph[1],
+ *	 ...
+ *	Graph[N]
+ *
+ * And each Graph entry has the following format:
+ *	GraphID		- Integer, identifying a graph the device belongs to.
+ *	UUID		- UUID identifying the specification that governs
+ *			  this graph. (e.g, see is_acpi_coresight_graph())
+ *	NumberOfLinks	- Number "N" of connections on this node of the graph.
+ *	Links[1]
+ *	...
+ *	Links[N]
+ */
+static inline bool acpi_validate_dsd_graph(const union acpi_object *graph)
+{
+	int i, n;
+	const union acpi_object *rev, *nr_graphs;
+
+	/* The graph must contain at least the Revision and Number of Graphs */
+	if (graph->package.count < 2)
+		return false;
+
+	rev = &graph->package.elements[0];
+	nr_graphs = &graph->package.elements[1];
+
+	if (rev->type != ACPI_TYPE_INTEGER ||
+	    nr_graphs->type != ACPI_TYPE_INTEGER)
+		return false;
+
+	/* We only support revision 0 */
+	if (rev->integer.value != 0)
+		return false;
+
+	n = nr_graphs->integer.value;
+	/* Make sure the package has right number of elements */
+	if (graph->package.count != (n + 2))
+		return false;
+
+	/* Each entry must be a graph package with at least 3 members */
+	for (i = 2; i < n + 2; i++) {
+		const union acpi_object *obj = &graph->package.elements[i];
+
+		if (obj->type != ACPI_TYPE_PACKAGE ||
+		    obj->package.count < 3)
+			return false;
+	}
+
+	return true;
+}
+
+/* acpi_get_dsd_graph	- Find the _DSD Graph property for the given device. */
+const union acpi_object *
+acpi_get_dsd_graph(struct acpi_device *adev)
+{
+	int i;
+	struct acpi_buffer buf = { ACPI_ALLOCATE_BUFFER };
+	acpi_status status;
+	const union acpi_object *dsd;
+
+	status = acpi_evaluate_object_typed(adev->handle, "_DSD", NULL,
+					    &buf, ACPI_TYPE_PACKAGE);
+	if (ACPI_FAILURE(status))
+		return NULL;
+
+	dsd = buf.pointer;
+	for (i = 0; i + 1 < dsd->package.count; i += 2) {
+		const union acpi_object *guid, *package;
+
+		guid = &dsd->package.elements[i];
+		package = &dsd->package.elements[i + 1];
+
+		/* All _DSD elements must have a UUID and a Package */
+		if (!is_acpi_guid(guid) || package->type != ACPI_TYPE_PACKAGE)
+			break;
+		/* Skip the non-Graph _DSD packages */
+		if (!is_acpi_dsd_graph_guid(guid))
+			continue;
+		if (acpi_validate_dsd_graph(package))
+			return package;
+		/* Invalid graph format, continue */
+		dev_warn(&adev->dev, "Invalid Graph _DSD property\n");
+	}
+
+	return NULL;
+}
+
+static inline bool
+acpi_validate_coresight_graph(const union acpi_object *cs_graph)
+{
+	int nlinks;
+
+	nlinks = cs_graph->package.elements[2].integer.value;
+	if (cs_graph->package.count != (nlinks + 3))
+		return false;
+	/* The links are validated in acpi_coresight_parse_link() */
+	return true;
+}
+
+/*
+ * acpi_get_coresight_graph	- Parse the device _DSD tables and find
+ * the Graph property matching the CoreSight Graphs.
+ *
+ * Returns the pointer to the CoreSight Graph Package when found. Otherwise
+ * returns NULL.
+ */
+const union acpi_object *
+acpi_get_coresight_graph(struct acpi_device *adev)
+{
+	const union acpi_object *graph_list, *graph;
+	int i, nr_graphs;
+
+	graph_list = acpi_get_dsd_graph(adev);
+	if (!graph_list)
+		return graph_list;
+
+	nr_graphs = graph_list->package.elements[1].integer.value;
+
+	for (i = 2; i < nr_graphs + 2; i++) {
+		graph = &graph_list->package.elements[i];
+		if (!is_acpi_coresight_graph(graph))
+			continue;
+		if (acpi_validate_coresight_graph(graph))
+			return graph;
+		/* Invalid graph format */
+		break;
+	}
+
+	return NULL;
+}
+
+/*
+ * acpi_coresight_parse_link	- Parse the given Graph connection
+ * of the device and populate the coresight_connection for an output
+ * connection.
+ *
+ * CoreSight Graph specification mandates that the direction of the data
+ * flow must be specified in the link. i.e,
+ *
+ *	SourcePortAddress,	// Integer
+ *	DestinationPortAddress,	// Integer
+ *	DestinationDeviceName,	// Reference to another device
+ *	DirectionOfFlow,	// 1 for output(master), 0 for input(slave)
+ *
+ * Returns the direction of the data flow [ Input(slave) or Output(master) ]
+ * upon success.
+ * Returns an negative error number otherwise.
+ */
+static int acpi_coresight_parse_link(struct acpi_device *adev,
+				     const union acpi_object *link,
+				     struct coresight_connection *conn)
+{
+	int rc, dir;
+	const union acpi_object *fields;
+	struct acpi_device *r_adev;
+	struct device *rdev;
+
+	if (link->type != ACPI_TYPE_PACKAGE ||
+	    link->package.count != 4)
+		return -EINVAL;
+
+	fields = link->package.elements;
+
+	if (fields[0].type != ACPI_TYPE_INTEGER ||
+	    fields[1].type != ACPI_TYPE_INTEGER ||
+	    fields[2].type != ACPI_TYPE_LOCAL_REFERENCE ||
+	    fields[3].type != ACPI_TYPE_INTEGER)
+		return -EINVAL;
+
+	rc = acpi_bus_get_device(fields[2].reference.handle, &r_adev);
+	if (rc)
+		return rc;
+
+	dir = fields[3].integer.value;
+	if (dir == ACPI_CORESIGHT_LINK_MASTER) {
+		conn->outport = fields[0].integer.value;
+		conn->child_port = fields[1].integer.value;
+		rdev = coresight_find_device_by_fwnode(&r_adev->fwnode);
+		if (!rdev)
+			return -EPROBE_DEFER;
+		conn->child_fwnode = fwnode_handle_get(&r_adev->fwnode);
+	}
+
+	return dir;
+}
+
+/*
+ * acpi_coresight_parse_graph	- Parse the _DSD CoreSight graph
+ * connection information and populate the supplied coresight_platform_data
+ * instance.
+ */
+static int acpi_coresight_parse_graph(struct acpi_device *adev,
+				      struct coresight_platform_data *pdata)
+{
+	int rc, i, nlinks;
+	const union acpi_object *graph;
+	struct coresight_connection *conns, *ptr;
+
+	pdata->nr_inport = pdata->nr_outport = 0;
+	graph = acpi_get_coresight_graph(adev);
+	if (!graph)
+		return -ENOENT;
+
+	nlinks = graph->package.elements[2].integer.value;
+	if (!nlinks)
+		return 0;
+
+	/*
+	 * To avoid scanning the table twice (once for finding the number of
+	 * output links and then later for parsing the output links),
+	 * cache the links information in one go and then later copy
+	 * it to the pdata.
+	 */
+	conns = devm_kcalloc(&adev->dev, nlinks, sizeof(*conns), GFP_KERNEL);
+	if (!conns)
+		return -ENOMEM;
+	ptr = conns;
+	for (i = 0; i < nlinks; i++) {
+		const union acpi_object *link = &graph->package.elements[3 + i];
+		int dir;
+
+		dir = acpi_coresight_parse_link(adev, link, ptr);
+		if (dir < 0)
+			return dir;
+
+		if (dir == ACPI_CORESIGHT_LINK_MASTER) {
+			pdata->nr_outport++;
+			ptr++;
+		} else {
+			pdata->nr_inport++;
+		}
+	}
+
+	rc = coresight_alloc_conns(&adev->dev, pdata);
+	if (rc)
+		return rc;
+
+	/* Copy the connection information to the final location */
+	for (i = 0; i < pdata->nr_outport; i++)
+		pdata->conns[i] = conns[i];
+
+	devm_kfree(&adev->dev, conns);
+	return 0;
+}
+
+/*
+ * acpi_handle_to_logical_cpuid	- Map a given acpi_handle to the
+ * logical CPU id of the corresponding CPU device.
+ *
+ * Returns the logical CPU id when found. Otherwise returns >= nr_cpus_id.
+ */
+static int
+acpi_handle_to_logical_cpuid(acpi_handle handle)
+{
+	int i;
+	struct acpi_processor *pr;
+
+	for_each_possible_cpu(i) {
+		pr = per_cpu(processors, i);
+		if (pr && pr->handle == handle)
+			break;
+	}
+
+	return i;
+}
+
+/*
+ * acpi_coresigh_get_cpu - Find the logical CPU id of the CPU associated
+ * with this coresight device. With ACPI bindings, the CoreSight components
+ * are listed as child device of the associated CPU.
+ *
+ * Returns the logical CPU id when found. Otherwise returns < 0.
+ */
+static int acpi_coresight_get_cpu(struct device *dev)
+{
+	int cpu;
+	acpi_handle cpu_handle;
+	acpi_status status;
+	struct acpi_device *adev = ACPI_COMPANION(dev);
+
+	if (!adev)
+		return 0;
+	status = acpi_get_parent(adev->handle, &cpu_handle);
+	if (ACPI_FAILURE(status))
+		return 0;
+
+	cpu = acpi_handle_to_logical_cpuid(cpu_handle);
+	if (cpu >= nr_cpu_ids)
+		return 0;
+	return cpu;
+}
+
+static struct coresight_platform_data *
+acpi_get_coresight_platform_data(struct device *dev,
+				 struct coresight_platform_data *pdata)
+{
+	int rc = -EINVAL;
+	struct acpi_device *adev;
+
+	if (!dev)
+		goto out;
+
+	adev = ACPI_COMPANION(dev);
+	if (!adev)
+		goto out;
+
+	rc = acpi_coresight_parse_graph(adev, pdata);
+	if (rc)
+		goto out;
+out:
+	if (rc)
+		return ERR_PTR(rc);
+	return pdata;
+}
+
+#else
+
+static inline struct coresight_platform_data *
+acpi_get_coresight_platform_data(struct device *dev,
+				 struct coresight_platform_data *pdata)
+{
+	return NULL;
+}
+
+static inline int acpi_coresight_get_cpu(struct device *dev)
+{
+	return 0;
+}
+#endif
+
 int coresight_get_cpu(struct device *dev)
 {
 	if (is_of_node(dev->fwnode))
 		return of_coresight_get_cpu(dev);
+	else if (is_acpi_device_node(dev->fwnode))
+		return acpi_coresight_get_cpu(dev);
 	return 0;
 }
 EXPORT_SYMBOL_GPL(coresight_get_cpu);
@@ -315,6 +715,8 @@ coresight_get_platform_data(struct device *dev)
 
 	if (is_of_node(dev->fwnode))
 		return of_get_coresight_platform_data(dev, pdata);
+	else if (is_acpi_device_node(dev->fwnode))
+		return acpi_get_coresight_platform_data(dev, pdata);
 
 	return ERR_PTR(-ENOENT);
 }
-- 
2.7.4