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

Mathieu Poirier
2019-03-29T19:09:57Z

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
>