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

On Wed, Mar 20, 2019 at 06:49:41PM +0000, Suzuki K Poulose wrote:

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 | 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

This looks a little weird... I think all tabs should be drop in the comments.

• • 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;
  

If we are here dev is valid. Otherwise things would have blown up in coresight_get_platform_data() when calling is_acpi_device_node().

• 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;

If we failed both of and acpi discovery method I'd return an error.

I've only reviewed the bottom half of this patch but I'm out of time for today. I will continue next week.

Thanks, Mathieu

} 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