[24/25] coresight: Support for ACPI bindings

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(+)

-- 
2.7.4

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

>