gpu: nvgpu: use nvgpu_udelay and optimize do while loop

- For interrupt context, use nvgpu_udelay()
  instead of nvgpu_usleep_range()
- Use while loop instead of do while loop for polling
  as this will help minimize overall delay

Bug 200350539

Change-Id: Icc05911082877df7f9e807da8f16e4d54e620cd8
Signed-off-by: Seema Khowala <seemaj@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1573303
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

1 files changed, 12 insertions, 10 deletions

diff --git a/drivers/gpu/nvgpu/gk20a/priv_ring_gk20a.c b/drivers/gpu/nvgpu/gk20a/priv_ring_gk20a.c
index 3ba5a2d2..1d764ad2 100644
--- a/drivers/gpu/nvgpu/gk20a/priv_ring_gk20a.c
+++ b/drivers/gpu/nvgpu/gk20a/priv_ring_gk20a.c
@@ -38,6 +38,8 @@ void gk20a_enable_priv_ring(struct gk20a *g)
         if (nvgpu_is_enabled(g, NVGPU_IS_FMODEL))
                 return;
 
+        nvgpu_log(g, gpu_dbg_info, "enabling priv ring");
+
         if (g->ops.clock_gating.slcg_priring_load_gating_prod)
                 g->ops.clock_gating.slcg_priring_load_gating_prod(g,
                                 g->slcg_enabled);
@@ -47,9 +49,7 @@ void gk20a_enable_priv_ring(struct gk20a *g)
 
         gk20a_writel(g, pri_ringstation_sys_decode_config_r(),
                         0x2);
-
         gk20a_readl(g, pri_ringstation_sys_decode_config_r());
-
 }
 
 void gk20a_priv_ring_isr(struct gk20a *g)
@@ -86,18 +86,20 @@ void gk20a_priv_ring_isr(struct gk20a *g)
                                 gk20a_readl(g, pri_ringstation_gpc_gpc0_priv_error_code_r() + gpc * gpc_stride));
                 }
         }
-
+        /* clear interrupt */
         cmd = gk20a_readl(g, pri_ringmaster_command_r());
         cmd = set_field(cmd, pri_ringmaster_command_cmd_m(),
                 pri_ringmaster_command_cmd_ack_interrupt_f());
         gk20a_writel(g, pri_ringmaster_command_r(), cmd);
-
-        do {
+        /* poll for clear interrupt done */
+        cmd = pri_ringmaster_command_cmd_v(
+                gk20a_readl(g, pri_ringmaster_command_r()));
+        while (cmd != pri_ringmaster_command_cmd_no_cmd_v() && retry) {
+                nvgpu_udelay(20);
+                retry--;
                 cmd = pri_ringmaster_command_cmd_v(
                         gk20a_readl(g, pri_ringmaster_command_r()));
-                nvgpu_usleep_range(20, 40);
-        } while (cmd != pri_ringmaster_command_cmd_no_cmd_v() && --retry);
-
-        if (retry <= 0)
-                nvgpu_warn(g, "priv ringmaster cmd ack too many retries");
+        }
+        if (retry == 0 && cmd != pri_ringmaster_command_cmd_no_cmd_v())
+                nvgpu_warn(g, "priv ringmaster intr ack too many retries");
 }