gpu: nvgpu: Fix gk20a_busy() in debug dump

When debug dump is called from an interrupt thread, we do not want
to call gk20a_busy() because it causes race in case rail gating is
being engaged at the same time. It has to be called from all debugfs
paths.

Bug 200198908
Bug 1770522

Change-Id: I7eda7d029b0a59cce0320ecc1b750dc2f4d7ccf0
Signed-off-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-on: http://git-master/r/1163440
GVS: Gerrit_Virtual_Submit
Tested-by: Deepak Nibade <dnibade@nvidia.com>
Reviewed-by: Bharat Nihalani <bnihalani@nvidia.com>

1 files changed, 21 insertions, 19 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/debug_gk20a.c b/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
index c02e9760..f1e1f98a 100644
--- a/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/debug_gk20a.c
@@ -165,16 +165,10 @@ void gk20a_debug_show_dump(struct gk20a *g, struct gk20a_debug_output *o)
 {
         struct fifo_gk20a *f = &g->fifo;
         u32 chid;
-        int i, err;
+        int i;
 
         struct ch_state **ch_state;
 
-        err = gk20a_busy(g->dev);
-        if (err) {
-                gk20a_debug_output(o, "failed to power on gpu: %d\n", err);
-                return;
-        }
-
         for (i = 0; i < fifo_pbdma_status__size_1_v(); i++) {
                 u32 status = gk20a_readl(g, fifo_pbdma_status_r(i));
                 u32 chan_status = fifo_pbdma_status_chan_status_v(status);
@@ -227,7 +221,7 @@ void gk20a_debug_show_dump(struct gk20a *g, struct gk20a_debug_output *o)
                                  * f->num_channels, GFP_KERNEL);
         if (!ch_state) {
                 gk20a_debug_output(o, "cannot alloc memory for channels\n");
-                goto done;
+                return;
         }
 
         for (chid = 0; chid < f->num_channels; chid++) {
@@ -262,8 +256,6 @@ void gk20a_debug_show_dump(struct gk20a *g, struct gk20a_debug_output *o)
                 }
         }
         kfree(ch_state);
-done:
-        gk20a_idle(g->dev);
 }
 
 static int gk20a_gr_dump_regs(struct device *dev,
@@ -271,18 +263,9 @@ static int gk20a_gr_dump_regs(struct device *dev,
 {
         struct gk20a_platform *platform = gk20a_get_platform(dev);
         struct gk20a *g = platform->g;
-        int err;
-
-        err = gk20a_busy(dev);
-        if (err) {
-                gk20a_err(dev, "failed to power on gpu: %d\n", err);
-                return -EINVAL;
-        }
 
         gr_gk20a_elpg_protected_call(g, g->ops.gr.dump_gr_regs(g, o));
 
-        gk20a_idle(dev);
-
         return 0;
 }
 
@@ -304,9 +287,18 @@ static int gk20a_gr_debug_show(struct seq_file *s, void *unused)
                 .fn = gk20a_debug_write_to_seqfile,
                 .ctx = s,
         };
+        int err;
+
+        err = gk20a_busy(dev);
+        if (err) {
+                gk20a_err(dev, "failed to power on gpu: %d", err);
+                return -EINVAL;
+        }
 
         gk20a_gr_dump_regs(dev, &o);
 
+        gk20a_idle(dev);
+
         return 0;
 }
 
@@ -334,11 +326,21 @@ static int gk20a_debug_show(struct seq_file *s, void *unused)
                 .ctx = s,
         };
         struct gk20a *g;
+        int err;
 
         g = gk20a_get_platform(dev)->g;
+
+        err = gk20a_busy(g->dev);
+        if (err) {
+                gk20a_err(g->dev, "failed to power on gpu: %d", err);
+                return -EFAULT;
+        }
+
         /* HAL only initialized after 1st power-on */
         if (g->ops.debug.show_dump)
                 g->ops.debug.show_dump(g, &o);
+
+        gk20a_idle(g->dev);
         return 0;
 }