On 11/10/2019 12:36, 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
│ └── name
├── rcs0
│ ├── capabilities
│ ├── class
│ ├── instance
│ └── name
├── vcs0
│ ├── capabilities
│ ├── class
│ ├── instance
│ └── name
└── vecs0
├── capabilities
├── class
├── instance
└── name
v2: Include stringified capabilities
Signed-off-by: Chris Wilson <chris@xxxxxxxxxxxxxxxxxx>
Cc: Joonas Lahtinen <joonas.lahtinen@xxxxxxxxxxxxxxx>
Cc: Tvrtko Ursulin <tvrtko.ursulin@xxxxxxxxx>
Cc: Daniele Ceraolo Spurio <daniele.ceraolospurio@xxxxxxxxx>
Cc: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
Acked-by: Rodrigo Vivi <rodrigo.vivi@xxxxxxxxx>
---
drivers/gpu/drm/i915/Makefile | 3 +-
drivers/gpu/drm/i915/gt/intel_engine_sysfs.c | 177 +++++++++++++++++++
drivers/gpu/drm/i915/gt/intel_engine_sysfs.h | 14 ++
drivers/gpu/drm/i915/i915_sysfs.c | 3 +
4 files changed, 196 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 e791d9323b51..cd9a10ba2516 100644
--- a/drivers/gpu/drm/i915/Makefile
+++ b/drivers/gpu/drm/i915/Makefile
@@ -78,8 +78,9 @@ 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..f6e4822f8928
--- /dev/null
+++ b/drivers/gpu/drm/i915/gt/intel_engine_sysfs.c
@@ -0,0 +1,177 @@
+/*
+ * 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 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 kobject *kobj, struct kobj_attribute *attr, char *buf)
+{
+ static const char *vcs_repr[] = {
+ [ilog2(I915_VIDEO_CLASS_CAPABILITY_HEVC)] = "hevc",
+ [ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
+ };
+ static const char *vecs_repr[] = {
+ [ilog2(I915_VIDEO_AND_ENHANCE_CLASS_CAPABILITY_SFC)] = "sfc",
+ };
+ struct intel_engine_cs *engine = kobj_to_engine(kobj);
+ const char **repr;
+ int num_repr, n;
+ ssize_t len;
+
+ switch (engine->class) {
+ case VIDEO_DECODE_CLASS:
+ repr = vcs_repr;
+ num_repr = ARRAY_SIZE(vcs_repr);
+ break;
+
+ case VIDEO_ENHANCEMENT_CLASS:
+ repr = vecs_repr;
+ num_repr = ARRAY_SIZE(vecs_repr);
+ break;
+
+ default:
+ repr = NULL;
+ num_repr = 0;
+ break;
+ }
+
+ len = 0;
+ for_each_set_bit(n,
+ (unsigned long *)&engine->uabi_capabilities,
+ BITS_PER_TYPE(typeof(engine->uabi_capabilities))) {
+ if (n < num_repr && repr[n])
+ len += snprintf(buf + len, PAGE_SIZE - len,
+ "%s ", repr[n]);
+ else
+ len += snprintf(buf + len, PAGE_SIZE - len,
+ "[%d] ", n);
Maybe we should also add a GEM_WARN_ON to reminds us to add new caps in
here during development? Presumes some IGT to exercise this of course,
or unfortunately. :)
Minor conversation point - hex or decimal?
+ }
+ return repr_trim(buf, len);
+}
+
+static struct kobj_attribute caps_attr =
+__ATTR(capabilities, 0444, 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,
+ 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;
Do we need to kobject_put in this case?
+
+ if (0) {
+err_engine:
+ dev_err(kdev, "Failed to add sysfs engine '%s'\n",
+ engine->name);
Maybe not error but warning? Driver continues to work fine but userspace
need to be aware.. hm.. tricky one.
+ 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 bf039b8ba593..7b665f69f301 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 "i915_drv.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)
Looks fine in principle.
I am tempted to go with some of the engine->flags from the start but I
don't have an use case apart from saying that it sounds like it makes sense.
Preemption cap may make sense in conjunction with heartbeat interval to
tell userspace something more?
Busy_stats might make sense for people interested in doing perf stat?
What worries me slightly is not being able to tell if a cap is supported
just not exported, or not supported but exported, if you are able to
follow. :) Which would happen if we decided to later add something from
flags.
Regards,
Tvrtko
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