gpu: nvgpu: IOCTL to disable timeouts

Add IOCTL NVGPU_DBG_GPU_IOCTL_TIMEOUT to support
disabling/re-enabling scheduler timeout from user space

If user space application is closed without re-enabling
the timeouts, kernel will restore the timeouts' state
while releasing the debug session

This is needed for debugging purpose

Bug 1514061

Change-Id: I32efb47ad09d793f3e7fd8f0aaa9720c8bc91272
Signed-off-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-on: http://git-master/r/788176
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

4 files changed, 84 insertions, 5 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c b/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
index 4a175a3c..1c351d9e 100644
--- a/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.c
@@ -91,6 +91,7 @@ static int gk20a_dbg_gpu_do_dev_open(struct inode *inode,
         dbg_session->g     = g;
         dbg_session->is_profiler = is_profiler;
         dbg_session->is_pg_disabled = false;
+        dbg_session->is_timeout_disabled = false;
         /* For vgpu, all power-gating features are currently disabled
          * in the server. Set is_pg_disable to true to reflect this
          * on the client side. */
@@ -264,6 +265,46 @@ void gk20a_dbg_gpu_post_events(struct channel_gk20a *ch)
 static int dbg_set_powergate(struct dbg_session_gk20a *dbg_s,
                                 __u32  powermode);
 
+static int nvgpu_dbg_timeout_enable(struct dbg_session_gk20a *dbg_s,
+                          int timeout_mode)
+{
+        struct gk20a *g = dbg_s->g;
+        int err = 0;
+
+        gk20a_dbg(gpu_dbg_gpu_dbg, "Timeouts mode requested : %d",
+                        timeout_mode);
+
+        switch (timeout_mode) {
+        case NVGPU_DBG_GPU_IOCTL_TIMEOUT_ENABLE:
+                if (dbg_s->is_timeout_disabled &&
+                    --g->dbg_timeout_disabled_refcount == 0) {
+                        g->timeouts_enabled = true;
+                }
+                dbg_s->is_timeout_disabled = false;
+                break;
+
+        case NVGPU_DBG_GPU_IOCTL_TIMEOUT_DISABLE:
+                if ((dbg_s->is_timeout_disabled == false) &&
+                    (g->dbg_timeout_disabled_refcount++ == 0)) {
+                        g->timeouts_enabled = false;
+                }
+                dbg_s->is_timeout_disabled = true;
+                break;
+
+        default:
+                gk20a_err(dev_from_gk20a(g),
+                           "unrecognized dbg gpu timeout mode : 0x%x",
+                           timeout_mode);
+                err = -EINVAL;
+                break;
+        }
+
+        gk20a_dbg(gpu_dbg_gpu_dbg, "Timeouts enabled : %s",
+                        g->timeouts_enabled ? "Yes" : "No");
+
+        return err;
+}
+
 static int dbg_unbind_channel_gk20a(struct dbg_session_gk20a *dbg_s)
 {
         struct channel_gk20a *ch_gk20a = dbg_s->ch;
@@ -305,12 +346,13 @@ int gk20a_dbg_gpu_dev_release(struct inode *inode, struct file *filp)
         if (dbg_s->ch)
                 dbg_unbind_channel_gk20a(dbg_s);
 
-        /* Powergate enable is called here as possibility of dbg_session
-         * which called powergate disable ioctl, to be killed without calling
-         * powergate enable ioctl
+        /* Powergate/Timeout enable is called here as possibility of dbg_session
+         * which called powergate/timeout disable ioctl, to be killed without
+         * calling powergate/timeout enable ioctl
          */
         mutex_lock(&g->dbg_sessions_lock);
         dbg_set_powergate(dbg_s, NVGPU_DBG_GPU_POWERGATE_MODE_ENABLE);
+        nvgpu_dbg_timeout_enable(dbg_s, NVGPU_DBG_GPU_IOCTL_TIMEOUT_ENABLE);
         mutex_unlock(&g->dbg_sessions_lock);
 
         kfree(dbg_s);
@@ -391,6 +433,22 @@ static int gk20a_dbg_pc_sampling(struct dbg_session_gk20a *dbg_s,
         return g->ops.gr.update_pc_sampling ?
                 g->ops.gr.update_pc_sampling(ch, args->enable) : -EINVAL;
 }
+
+static int nvgpu_dbg_gpu_ioctl_timeout(struct dbg_session_gk20a *dbg_s,
+                         struct nvgpu_dbg_gpu_timeout_args *args)
+{
+        int err;
+        struct gk20a *g = get_gk20a(dbg_s->pdev);
+
+        gk20a_dbg_fn("powergate mode = %d", args->enable);
+
+        mutex_lock(&g->dbg_sessions_lock);
+        err = nvgpu_dbg_timeout_enable(dbg_s, args->enable);
+        mutex_unlock(&g->dbg_sessions_lock);
+
+        return err;
+}
+
 long gk20a_dbg_gpu_dev_ioctl(struct file *filp, unsigned int cmd,
                              unsigned long arg)
 {
@@ -468,6 +526,11 @@ long gk20a_dbg_gpu_dev_ioctl(struct file *filp, unsigned int cmd,
                            (struct nvgpu_dbg_gpu_pc_sampling_args *)buf);
                 break;
 
+        case NVGPU_DBG_GPU_IOCTL_TIMEOUT:
+                err = nvgpu_dbg_gpu_ioctl_timeout(dbg_s,
+                           (struct nvgpu_dbg_gpu_timeout_args *)buf);
+                break;
+
         default:
                 gk20a_err(dev_from_gk20a(g),
                            "unrecognized dbg gpu ioctl cmd: 0x%x",
diff --git a/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.h b/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.h
index 27084c0d..fc1f2982 100644
--- a/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/dbg_gpu_gk20a.h
@@ -1,7 +1,7 @@
 /*
  * Tegra GK20A GPU Debugger Driver
  *
- * Copyright (c) 2013-2014, NVIDIA CORPORATION.  All rights reserved.
+ * Copyright (c) 2013-2015, NVIDIA CORPORATION.  All rights reserved.
  *
  * This program is free software; you can redistribute it and/or modify it
  * under the terms and conditions of the GNU General Public License,
@@ -53,6 +53,9 @@ struct dbg_session_gk20a {
         /* power enabled or disabled */
         bool is_pg_disabled;
 
+        /* timeouts enabled or disabled */
+        bool is_timeout_disabled;
+
         /*
          * There can be different versions of the whitelists
          * between both global and per-context sets; as well
diff --git a/drivers/gpu/nvgpu/gk20a/gk20a.h b/drivers/gpu/nvgpu/gk20a/gk20a.h
index 328bb73b..e106c479 100644
--- a/drivers/gpu/nvgpu/gk20a/gk20a.h
+++ b/drivers/gpu/nvgpu/gk20a/gk20a.h
@@ -532,6 +532,7 @@ struct gk20a {
         struct mutex dbg_sessions_lock;
         int dbg_sessions; /* number attached */
         int dbg_powergating_disabled_refcount; /*refcount for pg disable */
+        int dbg_timeout_disabled_refcount; /*refcount for timeout disable */
 
         void (*remove_support)(struct platform_device *);
 
diff --git a/include/uapi/linux/nvgpu.h b/include/uapi/linux/nvgpu.h
index 6fdf4025..f55346db 100644
--- a/include/uapi/linux/nvgpu.h
+++ b/include/uapi/linux/nvgpu.h
@@ -547,8 +547,20 @@ struct nvgpu_dbg_gpu_pc_sampling_args {
 #define NVGPU_DBG_GPU_IOCTL_PC_SAMPLING \
         _IOW(NVGPU_DBG_GPU_IOCTL_MAGIC,  9, struct nvgpu_dbg_gpu_pc_sampling_args)
 
+/* Enable/Disable timeouts */
+#define NVGPU_DBG_GPU_IOCTL_TIMEOUT_ENABLE                                   1
+#define NVGPU_DBG_GPU_IOCTL_TIMEOUT_DISABLE                                  0
+
+struct nvgpu_dbg_gpu_timeout_args {
+        __u32 enable;
+        __u32 padding;
+};
+
+#define NVGPU_DBG_GPU_IOCTL_TIMEOUT \
+        _IOW(NVGPU_DBG_GPU_IOCTL_MAGIC, 10, struct nvgpu_dbg_gpu_timeout_args)
+
 #define NVGPU_DBG_GPU_IOCTL_LAST                \
-        _IOC_NR(NVGPU_DBG_GPU_IOCTL_PC_SAMPLING)
+        _IOC_NR(NVGPU_DBG_GPU_IOCTL_TIMEOUT)
 #define NVGPU_DBG_GPU_IOCTL_MAX_ARG_SIZE                \
         sizeof(struct nvgpu_dbg_gpu_perfbuf_map_args)