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Subject[PATCH v2 32/36] coresight: Support for ACPI bindings
Date
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@rjwysocki.net>
Cc: Mathieu Poirier <mathieu.poirier@linaro.org>
Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com>
---
drivers/hwtracing/coresight/coresight-platform.c | 409 +++++++++++++++++++++++
1 file changed, 409 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-platform.c b/drivers/hwtracing/coresight/coresight-platform.c
index c9a59fb..224f698 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>
@@ -297,10 +298,414 @@ 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;
+ /*
+ * Hold the refcount to the target device. This could be
+ * released via:
+ * 1) coresight_release_platform_data() if the probe fails or
+ * this device is unregistered.
+ * 2) While removing the target device via
+ * coresight_remove_match().
+ */
+ 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;
+
+ 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);
@@ -320,6 +725,10 @@ coresight_get_platform_data(struct device *dev)

if (is_of_node(fwnode))
ret = of_get_coresight_platform_data(dev, pdata);
+ else if (is_acpi_device_node(fwnode))
+ ret = acpi_get_coresight_platform_data(dev, pdata);
+ else
+ return ERR_PTR(-ENOENT);

if (!IS_ERR_OR_NULL(ret))
return pdata;
--
2.7.4
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