[Intel-gfx] [26/33] drm/i915/gt: Expose engine properties via sysfs

Steve Carbonari steven.carbonari at intel.com
Wed Jan 22 21:13:04 UTC 2020


On Thu, Dec 12, 2019 at 02:04:52PM +0000, Chris Wilson wrote:
> Preliminary stub to add engines underneath /sys/class/drm/cardN/, so
> that we can expose properties on each engine to the sysadmin.
> 
> To start with we have basic analogues of the i915_query ioctl so that we
> can pretty print engine discovery from the shell, and flesh out the
> directory structure. Later we will add writeable sysadmin properties such
> as per-engine timeout controls.
> 
> An example tree of the engine properties on Braswell:
>     /sys/class/drm/card0
>     └── engine
>         ├── bcs0
>         │   ├── capabilities
>         │   ├── class
>         │   ├── instance
>         │   ├── known_capabilities
>         │   └── name
>         ├── rcs0
>         │   ├── capabilities
>         │   ├── class
>         │   ├── instance
>         │   ├── known_capabilities
>         │   └── name
>         ├── vcs0
>         │   ├── capabilities
>         │   ├── class
>         │   ├── instance
>         │   ├── known_capabilities
>         │   └── name
>         └── vecs0
>             ├── capabilities
>             ├── class
>             ├── instance
>             ├── known_capabilities
>             └── name
> 
> v2: Include stringified capabilities
> v3: Include all known capabilities for futureproofing.
> v4: Combine the two caps loops into one
> 
> v5: Hide underneath Kconfig.unstable for wider discussion
> 
> Signed-off-by: Chris Wilson <chris at chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen at linux.intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio at intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Acked-by: Rodrigo Vivi <rodrigo.vivi at intel.com>
> Reviewed-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Code is correct and satisfies the interface requirements.
In addition, downloaded and tested the patch.
The directories and files show up with expected values.

Reviewed-by: Steve Carbonari <steven.carbonari at intel.com>
Tested-by: Steve Carbonari <stenve.carbonari at intel.com>

> ---
>  drivers/gpu/drm/i915/Kconfig.unstable        |   7 +
>  drivers/gpu/drm/i915/Makefile                |   1 +
>  drivers/gpu/drm/i915/gt/intel_engine_sysfs.c | 208 +++++++++++++++++++
>  drivers/gpu/drm/i915/gt/intel_engine_sysfs.h |  14 ++
>  drivers/gpu/drm/i915/i915_sysfs.c            |   3 +
>  5 files changed, 233 insertions(+)
>  create mode 100644 drivers/gpu/drm/i915/gt/intel_engine_sysfs.c
>  create mode 100644 drivers/gpu/drm/i915/gt/intel_engine_sysfs.h
> 
> diff --git a/drivers/gpu/drm/i915/Kconfig.unstable b/drivers/gpu/drm/i915/Kconfig.unstable
> index 0c2276155c2b..1f866cae943b 100644
> --- a/drivers/gpu/drm/i915/Kconfig.unstable
> +++ b/drivers/gpu/drm/i915/Kconfig.unstable
> @@ -27,3 +27,10 @@ config DRM_I915_UNSTABLE_FAKE_LMEM
>  	help
>  	  Convert some system memory into a fake local memory region for
>  	  testing.
> +
> +config DRM_I915_UNSTABLE_SYSFS
> +	bool "Enable the experimental sysfs properties"
> +	depends on DRM_I915_UNSTABLE
> +	default n
> +	help
> +	  Explore the HW property space from the shell command line!
> diff --git a/drivers/gpu/drm/i915/Makefile b/drivers/gpu/drm/i915/Makefile
> index 2083496a1193..d80fe6bf9fea 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -82,6 +82,7 @@ gt-y += \
>  	gt/intel_engine_heartbeat.o \
>  	gt/intel_engine_pm.o \
>  	gt/intel_engine_pool.o \
> +	gt/intel_engine_sysfs.o \
>  	gt/intel_engine_user.o \
>  	gt/intel_gt.o \
>  	gt/intel_gt_irq.o \
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c
> new file mode 100644
> index 000000000000..df263af3a9ea
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c
> @@ -0,0 +1,208 @@
> +/*
> + * SPDX-License-Identifier: MIT
> + *
> + * Copyright © 2019 Intel Corporation
> + */
> +
> +#include <linux/kobject.h>
> +#include <linux/sysfs.h>
> +
> +#include "i915_drv.h"
> +#include "intel_engine.h"
> +#include "intel_engine_sysfs.h"
> +
> +struct kobj_engine {
> +	struct kobject base;
> +	struct intel_engine_cs *engine;
> +};
> +
> +static struct intel_engine_cs *kobj_to_engine(struct kobject *kobj)
> +{
> +	return container_of(kobj, struct kobj_engine, base)->engine;
> +}
> +
> +static ssize_t
> +name_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "%s\n", kobj_to_engine(kobj)->name);
> +}
> +
> +static struct kobj_attribute name_attr =
> +__ATTR(name, 0444, name_show, NULL);
> +
> +static ssize_t
> +class_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "%d\n", kobj_to_engine(kobj)->uabi_class);
> +}
> +
> +static struct kobj_attribute class_attr =
> +__ATTR(class, 0444, class_show, NULL);
> +
> +static ssize_t
> +inst_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "%d\n", kobj_to_engine(kobj)->uabi_instance);
> +}
> +
> +static struct kobj_attribute inst_attr =
> +__ATTR(instance, 0444, inst_show, NULL);
> +
> +static const char * const vcs_caps[] = {
> +	[ilog2(I915_VIDEO_CLASS_CAPABILITY_HEVC)] = "hevc",
> +	[ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
> +};
> +
> +static const char * const vecs_caps[] = {
> +	[ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
> +};
> +
> +static ssize_t repr_trim(char *buf, ssize_t len)
> +{
> +	/* Trim off the trailing space and replace with a newline */
> +	if (len > PAGE_SIZE)
> +		len = PAGE_SIZE;
> +	if (len > 0)
> +		buf[len - 1] = '\n';
> +
> +	return len;
> +}
> +
> +static ssize_t
> +__caps_show(struct intel_engine_cs *engine,
> +	    typeof(engine->uabi_capabilities) caps,
> +	    char *buf, bool show_unknown)
> +{
> +	const char * const *repr;
> +	int count, n;
> +	ssize_t len;
> +
> +	switch (engine->class) {
> +	case VIDEO_DECODE_CLASS:
> +		repr = vcs_caps;
> +		count = ARRAY_SIZE(vcs_caps);
> +		break;
> +
> +	case VIDEO_ENHANCEMENT_CLASS:
> +		repr = vecs_caps;
> +		count = ARRAY_SIZE(vecs_caps);
> +		break;
> +
> +	default:
> +		repr = NULL;
> +		count = 0;
> +		break;
> +	}
> +	GEM_BUG_ON(count > BITS_PER_TYPE(typeof(caps)));
> +
> +	len = 0;
> +	for_each_set_bit(n,
> +			 (unsigned long *)&caps,
> +			 show_unknown ? BITS_PER_TYPE(typeof(caps)) : count) {
> +		if (n >= count || !repr[n]) {
> +			if (GEM_WARN_ON(show_unknown))
> +				len += snprintf(buf + len, PAGE_SIZE - len,
> +						"[%x] ", n);
> +		} else {
> +			len += snprintf(buf + len, PAGE_SIZE - len,
> +					"%s ", repr[n]);
> +		}
> +		if (GEM_WARN_ON(len >= PAGE_SIZE))
> +			break;
> +	}
> +	return repr_trim(buf, len);
> +}
> +
> +static ssize_t
> +caps_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	struct intel_engine_cs *engine = kobj_to_engine(kobj);
> +
> +	return __caps_show(engine, engine->uabi_capabilities, buf, true);
> +}
> +
> +static struct kobj_attribute caps_attr =
> +__ATTR(capabilities, 0444, caps_show, NULL);
> +
> +static ssize_t
> +all_caps_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return __caps_show(kobj_to_engine(kobj), -1, buf, false);
> +}
> +
> +static struct kobj_attribute all_caps_attr =
> +__ATTR(known_capabilities, 0444, all_caps_show, NULL);
> +
> +static void kobj_engine_release(struct kobject *kobj)
> +{
> +	kfree(kobj);
> +}
> +
> +static struct kobj_type kobj_engine_type = {
> +	.release = kobj_engine_release,
> +	.sysfs_ops = &kobj_sysfs_ops
> +};
> +
> +static struct kobject *
> +kobj_engine(struct kobject *dir, struct intel_engine_cs *engine)
> +{
> +	struct kobj_engine *ke;
> +
> +	ke = kzalloc(sizeof(*ke), GFP_KERNEL);
> +	if (!ke)
> +		return NULL;
> +
> +	kobject_init(&ke->base, &kobj_engine_type);
> +	ke->engine = engine;
> +
> +	if (kobject_add(&ke->base, dir, "%s", engine->name)) {
> +		kobject_put(&ke->base);
> +		return NULL;
> +	}
> +
> +	/* xfer ownership to sysfs tree */
> +	return &ke->base;
> +}
> +
> +void intel_engines_add_sysfs(struct drm_i915_private *i915)
> +{
> +	static const struct attribute *files[] = {
> +		&name_attr.attr,
> +		&class_attr.attr,
> +		&inst_attr.attr,
> +		&caps_attr.attr,
> +		&all_caps_attr.attr,
> +		NULL
> +	};
> +
> +	struct device *kdev = i915->drm.primary->kdev;
> +	struct intel_engine_cs *engine;
> +	struct kobject *dir;
> +
> +	if (!IS_ENABLED(CONFIG_DRM_I915_UNSTABLE_SYSFS))
> +		return;
> +
> +	dir = kobject_create_and_add("engine", &kdev->kobj);
> +	if (!dir)
> +		return;
> +
> +	for_each_uabi_engine(engine, i915) {
> +		struct kobject *kobj;
> +
> +		kobj = kobj_engine(dir, engine);
> +		if (!kobj)
> +			goto err_engine;
> +
> +		if (sysfs_create_files(kobj, files))
> +			goto err_object;
> +
> +		if (0) {
> +err_object:
> +			kobject_put(kobj);
> +err_engine:
> +			dev_err(kdev, "Failed to add sysfs engine '%s'\n",
> +				engine->name);
> +			break;
> +		}
> +	}
> +}
> diff --git a/drivers/gpu/drm/i915/gt/intel_engine_sysfs.h b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.h
> new file mode 100644
> index 000000000000..ef44a745b70a
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.h
> @@ -0,0 +1,14 @@
> +/*
> + * SPDX-License-Identifier: MIT
> + *
> + * Copyright © 2019 Intel Corporation
> + */
> +
> +#ifndef INTEL_ENGINE_SYSFS_H
> +#define INTEL_ENGINE_SYSFS_H
> +
> +struct drm_i915_private;
> +
> +void intel_engines_add_sysfs(struct drm_i915_private *i915);
> +
> +#endif /* INTEL_ENGINE_SYSFS_H */
> diff --git a/drivers/gpu/drm/i915/i915_sysfs.c b/drivers/gpu/drm/i915/i915_sysfs.c
> index 65476909d1bf..26738c5c7d23 100644
> --- a/drivers/gpu/drm/i915/i915_sysfs.c
> +++ b/drivers/gpu/drm/i915/i915_sysfs.c
> @@ -30,6 +30,7 @@
>  #include <linux/stat.h>
>  #include <linux/sysfs.h>
>  
> +#include "gt/intel_engine_sysfs.h"
>  #include "gt/intel_rc6.h"
>  #include "gt/intel_rps.h"
>  
> @@ -616,6 +617,8 @@ void i915_setup_sysfs(struct drm_i915_private *dev_priv)
>  		DRM_ERROR("RPS sysfs setup failed\n");
>  
>  	i915_setup_error_capture(kdev);
> +
> +	intel_engines_add_sysfs(dev_priv);
>  }
>  
>  void i915_teardown_sysfs(struct drm_i915_private *dev_priv)


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