gpu: nvgpu: use refcnt for ch mmu_debug_mode

Replaced ch->mmu_debug_mode_enabled with ch->mmu_debug_mode_refcnt.
If channel is enabled multiple times by userspace, then ref count is
updated accordingly. There is an expectation that enable/disable
calls are balanced for setting channel's mmu debug mode.
When unbinding the channel, decrease refcnt for the channel until it
reaches 0.
Also, removed tsg parameter from nvgpu_tsg_set_mmu_debug_mode as it
can be retrieved from ch.

Bug 2515097
Bug 2713590

Change-Id: If334e374a55bd14ae219edbfd3b1fce5ff25c226
Signed-off-by: Thomas Fleury <tfleury@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/2184702
(cherry picked from commit f422aee39387a5aa337de69cc21a67f16697ae0e)
Reviewed-on: https://git-master.nvidia.com/r/c/linux-nvgpu/+/2208772
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: Kajetan Dutka <kdutka@nvidia.com>
Reviewed-by: Alex Waterman <alexw@nvidia.com>
Reviewed-by: Winnie Hsu <whsu@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: Kajetan Dutka <kdutka@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
GVS: Gerrit_Virtual_Submit

5 files changed, 23 insertions, 16 deletions

diff --git a/drivers/gpu/nvgpu/common/fifo/tsg.c b/drivers/gpu/nvgpu/common/fifo/tsg.c
index 7f61b273..65cee225 100644
--- a/drivers/gpu/nvgpu/common/fifo/tsg.c
+++ b/drivers/gpu/nvgpu/common/fifo/tsg.c
@@ -446,13 +446,14 @@ void gk20a_tsg_update_sm_error_state_locked(struct tsg_gk20a *tsg,
                         sm_error_state->hww_warp_esr_report_mask;
 }
 
-int nvgpu_tsg_set_mmu_debug_mode(struct tsg_gk20a *tsg,
-                struct channel_gk20a *ch, bool enable)
+int nvgpu_tsg_set_mmu_debug_mode(struct channel_gk20a *ch, bool enable)
 {
         struct gk20a *g;
         int err = 0;
+        u32 ch_refcnt;
         u32 tsg_refcnt;
         u32 fb_refcnt;
+        struct tsg_gk20a *tsg = tsg_gk20a_from_ch(ch);
 
         if ((ch == NULL) || (tsg == NULL)) {
                 return -EINVAL;
@@ -465,17 +466,11 @@ int nvgpu_tsg_set_mmu_debug_mode(struct tsg_gk20a *tsg,
         }
 
         if (enable) {
-                if (ch->mmu_debug_mode_enabled) {
-                        /* already enabled for this channel */
-                        return 0;
-                }
+                ch_refcnt = ch->mmu_debug_mode_refcnt + 1U;
                 tsg_refcnt = tsg->mmu_debug_mode_refcnt + 1U;
                 fb_refcnt = g->mmu_debug_mode_refcnt + 1U;
         } else {
-                if (!ch->mmu_debug_mode_enabled) {
-                        /* already disabled for this channel */
-                        return 0;
-                }
+                ch_refcnt = ch->mmu_debug_mode_refcnt - 1U;
                 tsg_refcnt = tsg->mmu_debug_mode_refcnt - 1U;
                 fb_refcnt = g->mmu_debug_mode_refcnt - 1U;
         }
@@ -500,7 +495,7 @@ int nvgpu_tsg_set_mmu_debug_mode(struct tsg_gk20a *tsg,
                 g->ops.fb.set_mmu_debug_mode(g, fb_refcnt > 0U);
         }
 
-        ch->mmu_debug_mode_enabled = enable;
+        ch->mmu_debug_mode_refcnt = ch_refcnt;
         tsg->mmu_debug_mode_refcnt = tsg_refcnt;
         g->mmu_debug_mode_refcnt = fb_refcnt;
 
diff --git a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
index 1b18a8f9..4d62d8e9 100644
--- a/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/fifo_gk20a.c
@@ -1,7 +1,7 @@
 /*
  * GK20A Graphics FIFO (gr host)
  *
- * Copyright (c) 2011-2019, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2011-2020, NVIDIA CORPORATION.  All rights reserved.
  *
  * Permission is hereby granted, free of charge, to any person obtaining a
  * copy of this software and associated documentation files (the "Software"),
@@ -2250,6 +2250,15 @@ int gk20a_fifo_tsg_unbind_channel(struct channel_gk20a *ch)
                 goto fail_enable_tsg;
         }
 
+        while (ch->mmu_debug_mode_refcnt > 0U) {
+                err = nvgpu_tsg_set_mmu_debug_mode(ch, false);
+                if (err != 0) {
+                        nvgpu_err(g, "disable mmu debug mode failed ch:%u",
+                                ch->chid);
+                        break;
+                }
+        }
+
         /* Remove channel from TSG and re-enable rest of the channels */
         nvgpu_rwsem_down_write(&tsg->ch_list_lock);
         nvgpu_list_del(&ch->ch_entry);
diff --git a/drivers/gpu/nvgpu/include/nvgpu/channel.h b/drivers/gpu/nvgpu/include/nvgpu/channel.h
index e98af09b..764d047c 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/channel.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/channel.h
@@ -328,7 +328,11 @@ struct channel_gk20a {
         bool has_os_fence_framework_support;
 
         bool is_privileged_channel;
-        bool mmu_debug_mode_enabled;
+
+        /**
+         * MMU Debugger Mode is enabled for this channel if refcnt > 0
+         */
+        u32 mmu_debug_mode_refcnt;
 };
 
 static inline struct channel_gk20a *
diff --git a/drivers/gpu/nvgpu/include/nvgpu/tsg.h b/drivers/gpu/nvgpu/include/nvgpu/tsg.h
index b43a6b98..7cd97c97 100644
--- a/drivers/gpu/nvgpu/include/nvgpu/tsg.h
+++ b/drivers/gpu/nvgpu/include/nvgpu/tsg.h
@@ -127,7 +127,6 @@ gk20a_event_id_data_from_event_id_node(struct nvgpu_list_node *node)
                 ((uintptr_t)node - offsetof(struct gk20a_event_id_data, event_id_node));
 };
 
-int nvgpu_tsg_set_mmu_debug_mode(struct tsg_gk20a *tsg,
-                struct channel_gk20a *ch, bool enable);
+int nvgpu_tsg_set_mmu_debug_mode(struct channel_gk20a *ch, bool enable);
 
 #endif /* TSG_GK20A_H */
diff --git a/drivers/gpu/nvgpu/os/linux/ioctl_dbg.c b/drivers/gpu/nvgpu/os/linux/ioctl_dbg.c
index aeed07ce..dc732dc5 100644
--- a/drivers/gpu/nvgpu/os/linux/ioctl_dbg.c
+++ b/drivers/gpu/nvgpu/os/linux/ioctl_dbg.c
@@ -1112,7 +1112,7 @@ static int nvgpu_dbg_gpu_ioctl_set_mmu_debug_mode(
                 goto clean_up;
         }
 
-        err = nvgpu_tsg_set_mmu_debug_mode(tsg_gk20a_from_ch(ch), ch, enable);
+        err = nvgpu_tsg_set_mmu_debug_mode(ch, enable);
         if (err) {
                 nvgpu_err(g, "set mmu debug mode failed, err=%d", err);
         }