Re: [PATCH 14/27] drm/i915: Expose engine properties via sysfs

[Rodrigo Vivi <rodrigo.vivi@intel.com>]

On Wed, Sep 25, 2019 at 11:01:24AM +0100, 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
>         │   ├── class
>         │   ├── heartbeat_interval_ms
>         │   ├── instance
>         │   ├── mmio_base
>         │   └── name
>         ├── rcs0
>         │   ├── class
>         │   ├── heartbeat_interval_ms
>         │   ├── instance
>         │   ├── mmio_base
>         │   └── name
>         ├── vcs0
>         │   ├── class
>         │   ├── heartbeat_interval_ms
>         │   ├── instance
>         │   ├── mmio_base
>         │   └── name
>         └── vecs0
>             ├── class
>             ├── heartbeat_interval_ms
>             ├── instance
>             ├── mmio_base
>             └── name
> 


Acked-by: Rodrigo Vivi <rodrigo.vivi@intel.com>



> Signed-off-by: Chris Wilson <chris@chris-wilson.co.uk>
> Cc: Joonas Lahtinen <joonas.lahtinen@linux.intel.com>
> Cc: Tvrtko Ursulin <tvrtko.ursulin@intel.com>
> Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@intel.com>
> Cc: Rodrigo Vivi <rodrigo.vivi@intel.com>
> ---
>  drivers/gpu/drm/i915/Makefile                |   3 +-
>  drivers/gpu/drm/i915/gt/intel_engine_sysfs.c | 119 +++++++++++++++++++
>  drivers/gpu/drm/i915/gt/intel_engine_sysfs.h |  14 +++
>  drivers/gpu/drm/i915/i915_sysfs.c            |   4 +
>  4 files changed, 139 insertions(+), 1 deletion(-)
>  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/Makefile b/drivers/gpu/drm/i915/Makefile
> index cba19470feb5..ba98a2067433 100644
> --- a/drivers/gpu/drm/i915/Makefile
> +++ b/drivers/gpu/drm/i915/Makefile
> @@ -76,8 +76,9 @@ gt-y += \
>  	gt/intel_breadcrumbs.o \
>  	gt/intel_context.o \
>  	gt/intel_engine_cs.o \
> -	gt/intel_engine_pool.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..cbe9ec59beeb
> --- /dev/null
> +++ b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c
> @@ -0,0 +1,119 @@
> +/*
> + * 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 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 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 ssize_t
> +mmio_show(struct kobject *kobj, struct kobj_attribute *attr, char *buf)
> +{
> +	return sprintf(buf, "0x%x\n", kobj_to_engine(kobj)->mmio_base);
> +}
> +
> +static struct kobj_attribute name_attr = __ATTR(name, 0444, name_show, NULL);
> +static struct kobj_attribute class_attr = __ATTR(class, 0444, class_show, NULL);
> +static struct kobj_attribute inst_attr = __ATTR(instance, 0444, inst_show, NULL);
> +static struct kobj_attribute mmio_attr = __ATTR(mmio_base, 0444, mmio_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,
> +		&mmio_attr.attr,
> +		NULL
> +	};
> +
> +	struct device *kdev = i915->drm.primary->kdev;
> +	struct intel_engine_cs *engine;
> +	struct kobject *dir;
> +
> +	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_engine;
> +
> +		if (0) {
> +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 d8a3b180c084..6b88d934927a 100644
> --- a/drivers/gpu/drm/i915/i915_sysfs.c
> +++ b/drivers/gpu/drm/i915/i915_sysfs.c
> @@ -30,6 +30,8 @@
>  #include <linux/stat.h>
>  #include <linux/sysfs.h>
>  
> +#include "gt/intel_engine_sysfs.h"
> +
>  #include "i915_drv.h"
>  #include "i915_sysfs.h"
>  #include "intel_pm.h"
> @@ -618,6 +620,8 @@ 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)
> -- 
> 2.23.0
> 
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