gpu: nvgpu: railgate returns early if no platform implementation

If platform didn't set railgate/unrailgate callbacks, it means it does
not support railgate.

It avoids vgpu calling tegra_fuse_clock_disable/enable.

Bug 200436689
Jira EVLR-2983

Change-Id: I759dc23145429a59f40cec6e9c1de9536dcf43c4
Signed-off-by: Richard Zhao <rizhao@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1821663
Reviewed-by: svc-misra-checker <svc-misra-checker@nvidia.com>
Reviewed-by: Seshendra Gadagottu <sgadagottu@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vinod Gopalakrishnakurup <vinodg@nvidia.com>
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, 7 deletions

diff --git a/drivers/gpu/nvgpu/os/linux/module.c b/drivers/gpu/nvgpu/os/linux/module.c
index ff4d9a4c..0d4cd7f1 100644
--- a/drivers/gpu/nvgpu/os/linux/module.c
+++ b/drivers/gpu/nvgpu/os/linux/module.c
@@ -766,6 +766,10 @@ static int gk20a_pm_railgate(struct device *dev)
         int ret = 0;
         struct gk20a *g = get_gk20a(dev);
 
+        /* return early if platform didn't implement railgate */
+        if (!platform->railgate)
+                return 0;
+
         /* if platform is already railgated, then just return */
         if (platform->is_railgated && platform->is_railgated(dev))
                 return ret;
@@ -780,8 +784,7 @@ static int gk20a_pm_railgate(struct device *dev)
                                         g->pstats.last_rail_ungate_complete);
 #endif
 
-        if (platform->railgate)
-                ret = platform->railgate(dev);
+        ret = platform->railgate(dev);
         if (ret) {
                 nvgpu_err(g, "failed to railgate platform, err=%d", ret);
                 return ret;
@@ -803,6 +806,10 @@ static int gk20a_pm_unrailgate(struct device *dev)
         int ret = 0;
         struct gk20a *g = get_gk20a(dev);
 
+        /* return early if platform didn't implement unrailgate */
+        if (!platform->unrailgate)
+                return 0;
+
         ret = tegra_fuse_clock_enable();
         if (ret) {
                 nvgpu_err(g, "failed to enable tegra fuse clock, err=%d", ret);
@@ -821,11 +828,9 @@ static int gk20a_pm_unrailgate(struct device *dev)
 
         trace_gk20a_pm_unrailgate(dev_name(dev));
 
-        if (platform->unrailgate) {
-                nvgpu_mutex_acquire(&platform->railgate_lock);
-                ret = platform->unrailgate(dev);
-                nvgpu_mutex_release(&platform->railgate_lock);
-        }
+        nvgpu_mutex_acquire(&platform->railgate_lock);
+        ret = platform->unrailgate(dev);
+        nvgpu_mutex_release(&platform->railgate_lock);
 
 #ifdef CONFIG_DEBUG_FS
         g->pstats.last_rail_ungate_complete = jiffies;