gpu: nvgpu: Add support for FECS ctxsw tracing

bug 1648908

This commit adds support for FECS ctxsw tracing. Code is compiled
conditionnaly under CONFIG_GK20_CTXSW_TRACE.
This feature requires an updated FECS ucode that writes one record to a ring
buffer on each context switch. On RM/Kernel side, the GPU driver reads records
from the master ring buffer and generates trace entries into a user-facing
VM ring buffer. For each record in the master ring buffer, RM/Kernel has
to retrieve the vmid+pid of the user process that submitted related work.

Features currently implemented:
- master ring buffer allocation
- debugfs to dump master ring buffer
- FECS record per context switch (with both current and new contexts)
- dedicated device for ctxsw tracing (access to VM ring buffer)
- SOF generation (and access to PTIMER)
- VM ring buffer allocation, and reconfiguration
- enable/disable tracing at user level
- event-based trace filtering
- context_ptr to vmid+pid mapping
- read system call for ctxsw dev
- mmap system call for ctxsw dev (direct access to VM ring buffer)
- poll system call for ctxsw dev
- save/restore register on ELPG/CG6
- separate user ring from FECS ring handling

Features requiring ucode changes:
- enable/disable tracing at FECS level
- actual busy time on engine (bug 1642354)
- master ring buffer threshold interrupt (P1)
- API for GPU to CPU timestamp conversion (P1)
- vmid/pid/uid based filtering (P1)

Change-Id: I8e39c648221ee0fa09d5df8524b03dca83fe24f3
Signed-off-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-on: http://git-master/r/1022737
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 4 insertions, 0 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
index 9b1f2987..0dd1fb8b 100644
--- a/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/channel_gk20a.c
@@ -28,6 +28,7 @@
 #include <linux/vmalloc.h>
 
 #include "debug_gk20a.h"
+#include "ctxsw_trace_gk20a.h"
 
 #include "gk20a.h"
 #include "dbg_gpu_gk20a.h"
@@ -920,6 +921,9 @@ static void gk20a_free_channel(struct channel_gk20a *ch)
 
         gk20a_free_error_notifiers(ch);
 
+        if (g->ops.fecs_trace.unbind_channel)
+                g->ops.fecs_trace.unbind_channel(g, ch);
+
         /* release channel ctx */
         g->ops.gr.free_channel_ctx(ch);