gpu: nvgpu: add pm_rumtime fixes

Runtime PM is enabled only for iGPU and not for dGPU. For dGPU,
the .probe() of driver pm_runtime_disable()s, if rail-gating is
not enabled. With nvgpu kernel module load/unload, .probe() is
called multiple times for same struct device *. This results
in an overflow of disable_depth (3 bit refcount) and enables
runtime PM on 8th iteration and calls RTPM routines even if it's
disabled.

To effectively manage pm_runtime_disable(), move it from common
nvgpu_remove() to iGPU/dGPU specific routines.

Also, add restore pm_runtime state of device on driver .remove().

Bug 1987855

Change-Id: I781278da546ef9c9ef7d7da7dbea0757df32716f
Signed-off-by: Nitin Kumbhar <nkumbhar@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1770804
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

2 files changed, 44 insertions, 8 deletions

diff --git a/drivers/gpu/nvgpu/os/linux/module.c b/drivers/gpu/nvgpu/os/linux/module.c
index a59ac1f1..e3667947 100644
--- a/drivers/gpu/nvgpu/os/linux/module.c
+++ b/drivers/gpu/nvgpu/os/linux/module.c
@@ -1060,6 +1060,13 @@ static int gk20a_pm_init(struct device *dev)
         return err;
 }
 
+static int gk20a_pm_deinit(struct device *dev)
+{
+        pm_runtime_dont_use_autosuspend(dev);
+        pm_runtime_disable(dev);
+        return 0;
+}
+
 /*
  * Start the process for unloading the driver. Set NVGPU_DRIVER_IS_DYING.
  */
@@ -1309,9 +1316,6 @@ int nvgpu_remove(struct device *dev, struct class *class)
                 platform->secure_buffer.destroy(g,
                                 &platform->secure_buffer);
 
-        if (pm_runtime_enabled(dev))
-                pm_runtime_disable(dev);
-
         if (platform->remove)
                 platform->remove(dev);
 
@@ -1332,8 +1336,11 @@ static int __exit gk20a_remove(struct platform_device *pdev)
         err = nvgpu_remove(dev, &nvgpu_class);
 
         set_gk20a(pdev, NULL);
+
         gk20a_put(g);
 
+        gk20a_pm_deinit(dev);
+
         return err;
 }
 
diff --git a/drivers/gpu/nvgpu/os/linux/pci.c b/drivers/gpu/nvgpu/os/linux/pci.c
index dba8a5df..3493b105 100644
--- a/drivers/gpu/nvgpu/os/linux/pci.c
+++ b/drivers/gpu/nvgpu/os/linux/pci.c
@@ -590,11 +590,21 @@ static int nvgpu_pci_pm_runtime_suspend(struct device *dev)
         return 0;
 }
 
+static int nvgpu_pci_pm_resume(struct device *dev)
+{
+        return gk20a_pm_finalize_poweron(dev);
+}
+
+static int nvgpu_pci_pm_suspend(struct device *dev)
+{
+        return 0;
+}
+
 static const struct dev_pm_ops nvgpu_pci_pm_ops = {
         .runtime_resume = nvgpu_pci_pm_runtime_resume,
         .runtime_suspend = nvgpu_pci_pm_runtime_suspend,
-        .resume = nvgpu_pci_pm_runtime_resume,
-        .suspend = nvgpu_pci_pm_runtime_suspend,
+        .resume = nvgpu_pci_pm_resume,
+        .suspend = nvgpu_pci_pm_suspend,
 };
 #endif
 
@@ -611,10 +621,15 @@ static int nvgpu_pci_pm_init(struct device *dev)
                                 g->railgate_delay);
 
                 /*
-                 * Runtime PM for PCI devices is disabled by default,
-                 * so we need to enable it first
+                 * set gpu dev's use_autosuspend flag to allow
+                 * runtime power management of GPU
                  */
                 pm_runtime_use_autosuspend(dev);
+
+                /*
+                 * runtime PM for PCI devices is forbidden
+                 * by default, so unblock RTPM of GPU
+                 */
                 pm_runtime_put_noidle(dev);
                 pm_runtime_allow(dev);
         }
@@ -622,6 +637,19 @@ static int nvgpu_pci_pm_init(struct device *dev)
         return 0;
 }
 
+static int nvgpu_pci_pm_deinit(struct device *dev)
+{
+#ifdef CONFIG_PM
+        struct gk20a *g = get_gk20a(dev);
+
+        if (!nvgpu_is_enabled(g, NVGPU_CAN_RAILGATE))
+                pm_runtime_enable(dev);
+        else
+                pm_runtime_forbid(dev);
+#endif
+        return 0;
+}
+
 static int nvgpu_pci_probe(struct pci_dev *pdev,
                            const struct pci_device_id *pent)
 {
@@ -826,11 +854,12 @@ static void nvgpu_pci_remove(struct pci_dev *pdev)
                 enable_irq(g->irq_stall);
         }
 #endif
+        nvgpu_pci_pm_deinit(&pdev->dev);
 
         /* free allocated platform data space */
+        gk20a_get_platform(&pdev->dev)->g = NULL;
         nvgpu_kfree(g, gk20a_get_platform(&pdev->dev));
 
-        gk20a_get_platform(&pdev->dev)->g = NULL;
         gk20a_put(g);
 }