gpu: nvgpu: Unify remove/shutdown codepaths

The following changes are part of the porting of the bind/unbind
functionality.

These changes reuse the shutdown codepaths in iGPU and dGPU and fix a locking
issue with in gk20a_busy() where the usage count can lead to a deadlock during
the driver shutdown. It fixes a racing condition with the gr/mm code by
invalidating the sw ready flag while holding the busy lock

JIRA: EVLR-1739

Change-Id: I62ce47378436b21f447f4cd93388759ed3f9bad1
Signed-off-by: David Nieto <dmartineznie@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1554959
Reviewed-by: svc-mobile-coverity <svc-mobile-coverity@nvidia.com>
Reviewed-by: Automatic_Commit_Validation_User
Reviewed-by: svccoveritychecker <svccoveritychecker@nvidia.com>
GVS: Gerrit_Virtual_Submit
Reviewed-by: Terje Bergstrom <tbergstrom@nvidia.com>

1 files changed, 66 insertions, 42 deletions

diff --git a/drivers/gpu/nvgpu/common/linux/module.c b/drivers/gpu/nvgpu/common/linux/module.c
index 509930c7..46b89ad0 100644
--- a/drivers/gpu/nvgpu/common/linux/module.c
+++ b/drivers/gpu/nvgpu/common/linux/module.c
@@ -640,6 +640,48 @@ static int gk20a_pm_unrailgate(struct device *dev)
         return ret;
 }
 
+/*
+ * Idle the GPU in preparation of shutdown/remove.
+ * gk20a_driver_start_unload() does not idle the GPU, but instead changes the SW
+ * state to prevent further activity on the driver SW side.
+ * On driver removal quiesce() should be called after start_unload()
+ */
+int nvgpu_quiesce(struct gk20a *g)
+{
+        int err;
+        struct device *dev = dev_from_gk20a(g);
+
+        err = gk20a_wait_for_idle(g);
+        if (err) {
+                nvgpu_err(g, "failed to idle GPU, err=%d", err);
+                return err;
+        }
+
+        err = gk20a_fifo_disable_all_engine_activity(g, true);
+        if (err) {
+                nvgpu_err(g, "failed to disable engine activity, err=%d",
+                        err);
+                return err;
+        }
+
+        err = gk20a_fifo_wait_engine_idle(g);
+        if (err) {
+                nvgpu_err(g, "failed to idle engines, err=%d",
+                        err);
+                return err;
+        }
+
+        if (gk20a_gpu_is_virtual(dev))
+                err = vgpu_pm_prepare_poweroff(dev);
+        else
+                err = gk20a_pm_prepare_poweroff(dev);
+
+        if (err)
+                nvgpu_err(g, "failed to prepare for poweroff, err=%d",
+                        err);
+        return err;
+}
+
 static void gk20a_pm_shutdown(struct platform_device *pdev)
 {
         struct gk20a_platform *platform = platform_get_drvdata(pdev);
@@ -668,35 +710,9 @@ static void gk20a_pm_shutdown(struct platform_device *pdev)
         /* Prevent more requests by disabling Runtime PM */
         __pm_runtime_disable(&pdev->dev, false);
 
-        err = gk20a_wait_for_idle(g);
-        if (err) {
-                nvgpu_err(g, "failed to idle GPU, err=%d", err);
-                goto finish;
-        }
-
-        err = gk20a_fifo_disable_all_engine_activity(g, true);
-        if (err) {
-                nvgpu_err(g, "failed to disable engine activity, err=%d",
-                        err);
-                goto finish;
-        }
-
-        err = gk20a_fifo_wait_engine_idle(g);
-        if (err) {
-                nvgpu_err(g, "failed to idle engines, err=%d",
-                        err);
-                goto finish;
-        }
-
-        if (gk20a_gpu_is_virtual(&pdev->dev))
-                err = vgpu_pm_prepare_poweroff(&pdev->dev);
-        else
-                err = gk20a_pm_prepare_poweroff(&pdev->dev);
-        if (err) {
-                nvgpu_err(g, "failed to prepare for poweroff, err=%d",
-                        err);
+        err = nvgpu_quiesce(g);
+        if (err)
                 goto finish;
-        }
 
         err = gk20a_pm_railgate(&pdev->dev);
         if (err)
@@ -854,6 +870,9 @@ void gk20a_driver_start_unload(struct gk20a *g)
 
         down_write(&g->busy_lock);
         __nvgpu_set_enabled(g, NVGPU_DRIVER_IS_DYING, true);
+        /* GR SW ready needs to be invalidated at this time with the busy lock
+         * held to prevent a racing condition on the gr/mm code */
+        g->gr.sw_ready = false;
         up_write(&g->busy_lock);
 
         if (g->is_virtual)
@@ -979,18 +998,14 @@ static int gk20a_probe(struct platform_device *dev)
         return 0;
 }
 
-static int __exit gk20a_remove(struct platform_device *pdev)
+int nvgpu_remove(struct device *dev, struct class *class)
 {
-        struct device *dev = &pdev->dev;
         struct gk20a *g = get_gk20a(dev);
         struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
         struct gk20a_platform *platform = gk20a_get_platform(dev);
 
         gk20a_dbg_fn("");
 
-        if (gk20a_gpu_is_virtual(dev))
-                return vgpu_remove(pdev);
-
         if (platform->has_cde)
                 gk20a_cde_destroy(l);
 
@@ -1001,16 +1016,11 @@ static int __exit gk20a_remove(struct platform_device *pdev)
         if (IS_ENABLED(CONFIG_GK20A_DEVFREQ))
                 gk20a_scale_exit(dev);
 
-        if (g->remove_support)
-                g->remove_support(g);
-
-        gk20a_ce_destroy(g);
-
 #ifdef CONFIG_ARCH_TEGRA_18x_SOC
         nvgpu_clk_arb_cleanup_arbiter(g);
 #endif
 
-        gk20a_user_deinit(dev, &nvgpu_class);
+        gk20a_user_deinit(dev, class);
 
         gk20a_debug_deinit(g);
 
@@ -1026,14 +1036,28 @@ static int __exit gk20a_remove(struct platform_device *pdev)
         if (platform->remove)
                 platform->remove(dev);
 
-        set_gk20a(pdev, NULL);
-        gk20a_put(g);
-
         gk20a_dbg_fn("removed");
 
         return 0;
 }
 
+static int __exit gk20a_remove(struct platform_device *pdev)
+{
+        int err;
+        struct device *dev = &pdev->dev;
+        struct gk20a *g = get_gk20a(dev);
+
+        if (gk20a_gpu_is_virtual(dev))
+                return vgpu_remove(pdev);
+
+        err = nvgpu_remove(dev, &nvgpu_class);
+
+        set_gk20a(pdev, NULL);
+        gk20a_put(g);
+
+        return err;
+}
+
 static struct platform_driver gk20a_driver = {
         .probe = gk20a_probe,
         .remove = __exit_p(gk20a_remove),