gpu: nvgpu: support binding multiple channels to a debug session

We currently bind only one channel to a debug session
But some use cases might need multiple channels bound
to same debug session

Add this support by adding a list of channels to debug session.
List structure is implemented as struct dbg_session_channel_data

List node dbg_s_list_node is currently defined in struct
dbg_session_gk20a. But this is inefficient when we need to
add debug session to multiple channels

Hence add new reference structure dbg_session_data to
store dbg_session pointer and list entry

For each NVGPU_DBG_GPU_IOCTL_BIND_CHANNEL call, create
two reference structure dbg_session_channel_data for channel
and dbg_session_data for debug session and bind them together

Define API nvgpu_dbg_gpu_get_session_channel() which will
get first channel in the list of debug session
Use this API wherever we refer to channel bound to debug
session

Remove dbg_sessions define in struct gk20a since it is
not being used anywhere

Add new API NVGPU_DBG_GPU_IOCTL_UNBIND_CHANNEL to support
unbinding of channel from debug sesssion

Bug 200156699

Change-Id: I3bfa6f9cd5b90e7254a75c7e64ac893739776b7f
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/1120331
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 18 insertions, 3 deletions

diff --git a/include/uapi/linux/nvgpu.h b/include/uapi/linux/nvgpu.h
index 89871b53..36616913 100644
--- a/include/uapi/linux/nvgpu.h
+++ b/include/uapi/linux/nvgpu.h
@@ -496,8 +496,7 @@ struct nvgpu_gpu_get_gpu_time_args {
  * Binding/attaching a debugger session to an nvgpu channel
  *
  * The 'channel_fd' given here is the fd used to allocate the
- * gpu channel context.  To detach/unbind the debugger session
- * use a channel_fd of -1.
+ * gpu channel context.
  *
  */
 struct nvgpu_dbg_gpu_bind_channel_args {
@@ -510,6 +509,8 @@ struct nvgpu_dbg_gpu_bind_channel_args {
 
 /*
  * Register operations
+ * All operations are targeted towards first channel
+ * attached to debug session
  */
 /* valid op values */
 #define NVGPU_DBG_GPU_REG_OP_READ_32                             (0x00000000)
@@ -722,9 +723,23 @@ struct nvgpu_dbg_gpu_write_single_sm_error_state_args {
 #define NVGPU_DBG_GPU_IOCTL_WRITE_SINGLE_SM_ERROR_STATE                 \
         _IOW(NVGPU_DBG_GPU_IOCTL_MAGIC, 16, struct nvgpu_dbg_gpu_write_single_sm_error_state_args)
 
+/*
+ * Unbinding/detaching a debugger session from a nvgpu channel
+ *
+ * The 'channel_fd' given here is the fd used to allocate the
+ * gpu channel context.
+ */
+struct nvgpu_dbg_gpu_unbind_channel_args {
+        __u32 channel_fd; /* in */
+        __u32 _pad0[1];
+};
+
+#define NVGPU_DBG_GPU_IOCTL_UNBIND_CHANNEL                              \
+        _IOW(NVGPU_DBG_GPU_IOCTL_MAGIC, 17, struct nvgpu_dbg_gpu_unbind_channel_args)
+
 
 #define NVGPU_DBG_GPU_IOCTL_LAST                \
-        _IOC_NR(NVGPU_DBG_GPU_IOCTL_WRITE_SINGLE_SM_ERROR_STATE)
+        _IOC_NR(NVGPU_DBG_GPU_IOCTL_UNBIND_CHANNEL)
 
 #define NVGPU_DBG_GPU_IOCTL_MAX_ARG_SIZE                \
         sizeof(struct nvgpu_dbg_gpu_perfbuf_map_args)