[RFC] drm/amdgpu: Convert to common fdinfo format

[Tvrtko Ursulin]

From: Tvrtko Ursulin <tvrtko.ursulin at intel.com>

Convert fdinfo format to one documented in drm-usage-stats.rst.

Opens/TODO:
 * Does someone from AMD want to take over this patch?
    (I have no access to amdgpu hardware so won't be able to test
     any hypothetical gputop work.)
 * What are the semantics of AMD engine utilisation reported in percents?
    * Can it align with what i915 does (same what msm will do) or need
      to document the alternative in the specification document? Both
      option are workable with instantaneous percent only needing support
      to be added to vendor agnostic gputop.
 * Can amdgpu expose drm-client-id? Without it gputop will not work.
 * drm-engine-capacity - does the concept translate etc.

Signed-off-by: Tvrtko Ursulin <tvrtko.ursulin at intel.com>
Cc: David M Nieto <David.Nieto at amd.com>
Cc: Christian König <christian.koenig at amd.com>
Cc: Daniel Vetter <daniel at ffwll.ch>
Acked-by: Christian König <christian.koenig at amd.com>
---
 Documentation/gpu/amdgpu/usage-stats.rst   | 28 ++++++++++++++++++++++
 Documentation/gpu/drm-usage-stats.rst      |  7 +++++-
 drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c | 18 ++++++++++----
 3 files changed, 47 insertions(+), 6 deletions(-)
 create mode 100644 Documentation/gpu/amdgpu/usage-stats.rst

diff --git a/Documentation/gpu/amdgpu/usage-stats.rst b/Documentation/gpu/amdgpu/usage-stats.rst
new file mode 100644
index 000000000000..8be5009bd1a9
--- /dev/null
+++ b/Documentation/gpu/amdgpu/usage-stats.rst
@@ -0,0 +1,28 @@
+.. _amdgpu-usage-stats:
+
+============================================
+AMDGPU DRM client usage stats implementation
+============================================
+
+The amdgpu driver implements the DRM client usage stats specification as
+documented in :ref:`drm-client-usage-stats`.
+
+Example of the output showing the implemented key value pairs and entirety of
+the currenly possible format options:
+
+::
+
+      pos:    0
+      flags:  0100002
+      mnt_id: 21
+      drm-driver: amdgpu
+      drm-pdev:   0000:03:00.0
+      drm-memory-vram: 0 KiB
+      drm-memory-gtt: 0 KiB
+      drm-memory-cpu: 0 KiB
+      drm-engine-...: 0 %
+                 ...
+
+Possible `drm-memory-` key names are: `vram`, `gtt`, `cpu`.
+
+Possible `drm-engine-` key names are: ``.
diff --git a/Documentation/gpu/drm-usage-stats.rst b/Documentation/gpu/drm-usage-stats.rst
index 6c9f166a8d6f..2d0ff6f2cc74 100644
--- a/Documentation/gpu/drm-usage-stats.rst
+++ b/Documentation/gpu/drm-usage-stats.rst
@@ -69,7 +69,7 @@ scope of each device, in which case `drm-pdev` shall be present as well.
 Userspace should make sure to not double account any usage statistics by using
 the above described criteria in order to associate data to individual clients.
 
-- drm-engine-<str>: <uint> ns
+- drm-engine-<str>: <uint> [ns|%]
 
 GPUs usually contain multiple execution engines. Each shall be given a stable
 and unique name (str), with possible values documented in the driver specific
@@ -84,6 +84,9 @@ larger value within a reasonable period. Upon observing a value lower than what
 was previously read, userspace is expected to stay with that larger previous
 value until a monotonic update is seen.
 
+Where time unit is given as a percentage...[AMD folks to fill the semantics
+and interpretation of that]...
+
 - drm-engine-capacity-<str>: <uint>
 
 Engine identifier string must be the same as the one specified in the
@@ -110,3 +113,5 @@ Driver specific implementations
 ===============================
 
 :ref:`i915-usage-stats`
+
+:ref:`amdgpu-usage-stats`
diff --git a/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c b/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
index 5a6857c44bb6..8cbae61f1b3b 100644
--- a/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
+++ b/drivers/gpu/drm/amd/amdgpu/amdgpu_fdinfo.c
@@ -32,6 +32,7 @@
 
 #include <drm/amdgpu_drm.h>
 #include <drm/drm_debugfs.h>
+#include <drm/drm_drv.h>
 
 #include "amdgpu.h"
 #include "amdgpu_vm.h"
@@ -83,11 +84,18 @@ void amdgpu_show_fdinfo(struct seq_file *m, struct file *f)
 	amdgpu_bo_unreserve(root);
 	amdgpu_bo_unref(&root);
 
-	seq_printf(m, "pdev:\t%04x:%02x:%02x.%d\npasid:\t%u\n", domain, bus,
+	/*
+	 * ******************************************************************
+	 * For text output format description please see drm-usage-stats.rst!
+	 * ******************************************************************
+	 */
+
+	seq_printf(m, "drm-driver:\t%s\n", file->minor->dev->driver->name);
+	seq_printf(m, "drm-pdev:\t%04x:%02x:%02x.%d\npasid:\t%u\n", domain, bus,
 			dev, fn, fpriv->vm.pasid);
-	seq_printf(m, "vram mem:\t%llu kB\n", vram_mem/1024UL);
-	seq_printf(m, "gtt mem:\t%llu kB\n", gtt_mem/1024UL);
-	seq_printf(m, "cpu mem:\t%llu kB\n", cpu_mem/1024UL);
+	seq_printf(m, "drm-memory-vram:\t%llu KiB\n", vram_mem/1024UL);
+	seq_printf(m, "drm-memory-gtt:\t%llu KiB\n", gtt_mem/1024UL);
+	seq_printf(m, "drm-memory-cpu:\t%llu KiB\n", cpu_mem/1024UL);
 	for (i = 0; i < AMDGPU_HW_IP_NUM; i++) {
 		uint32_t count = amdgpu_ctx_num_entities[i];
 		int idx = 0;
@@ -103,7 +111,7 @@ void amdgpu_show_fdinfo(struct seq_file *m, struct file *f)
 			perc = div64_u64(10000 * total, min);
 			frac = perc % 100;
 
-			seq_printf(m, "%s%d:\t%d.%d%%\n",
+			seq_printf(m, "drm-engine-%s%d:\t%d.%d %%\n",
 					amdgpu_ip_name[i],
 					idx, perc/100, frac);
 		}
-- 
2.32.0