From 9d2e50de426ac6362d66f9ccb29a0415322e467f Mon Sep 17 00:00:00 2001
From: Kary Jin <karyj@nvidia.com>
Date: Mon, 15 Oct 2018 15:57:52 +0800
Subject: gpu: nvgpu: Add reboot handler

Add a reboot handler to make sure that nvgpu does not try to busy
the GPU if the system is going down. If the system is going down
then any number of subsystems nvgpu depends on may already have
been deinitialized.

Bug 200333709
Bug 200454316

Change-Id: I2ceaf7ca4fb88643310874b5b26937ef44c6e3dd
Signed-off-by: Kary Jin <karyj@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1927018
Reviewed-by: Automatic_Commit_Validation_User
GVS: Gerrit_Virtual_Submit
Reviewed-by: Vinayak Pane <vpane@nvidia.com>
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>
---
 drivers/gpu/nvgpu/os/linux/module.c | 38 +++++++++++++++++++++++++++++++++++--
 1 file changed, 36 insertions(+), 2 deletions(-)

(limited to 'drivers/gpu/nvgpu/os')

diff --git a/drivers/gpu/nvgpu/os/linux/module.c b/drivers/gpu/nvgpu/os/linux/module.c
index 1fd7f544..955481c8 100644
--- a/drivers/gpu/nvgpu/os/linux/module.c
+++ b/drivers/gpu/nvgpu/os/linux/module.c
@@ -24,6 +24,8 @@
 #include <linux/interrupt.h>
 #include <linux/pm_runtime.h>
 #include <linux/reset.h>
+#include <linux/reboot.h>
+#include <linux/notifier.h>
 #include <linux/platform/tegra/common.h>
 #include <linux/pci.h>
 
@@ -76,6 +78,14 @@
 #define CREATE_TRACE_POINTS
 #include <trace/events/gk20a.h>
 
+static int nvgpu_kernel_shutdown_notification(struct notifier_block *nb,
+					unsigned long event, void *unused)
+{
+	struct gk20a *g = container_of(nb, struct gk20a, nvgpu_reboot_nb);
+
+	__nvgpu_set_enabled(g, NVGPU_KERNEL_IS_DYING, true);
+	return NOTIFY_DONE;
+}
 
 struct device_node *nvgpu_get_node(struct gk20a *g)
 {
@@ -98,6 +108,22 @@ void gk20a_busy_noresume(struct gk20a *g)
 	pm_runtime_get_noresume(dev_from_gk20a(g));
 }
 
+/*
+ * Check if the device can go busy.
+ */
+static int nvgpu_can_busy(struct gk20a *g)
+{
+	/* Can't do anything if the system is rebooting/shutting down. */
+	if (nvgpu_is_enabled(g, NVGPU_KERNEL_IS_DYING))
+		return 0;
+
+	/* Can't do anything if the driver is restarting. */
+	if (nvgpu_is_enabled(g, NVGPU_DRIVER_IS_DYING))
+		return 0;
+
+	return 1;
+}
+
 int gk20a_busy(struct gk20a *g)
 {
 	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
@@ -111,7 +137,7 @@ int gk20a_busy(struct gk20a *g)
 
 	down_read(&l->busy_lock);
 
-	if (!gk20a_can_busy(g)) {
+	if (!nvgpu_can_busy(g)) {
 		ret = -ENODEV;
 		atomic_dec(&g->usage_count.atomic_var);
 		goto fail;
@@ -158,7 +184,7 @@ void gk20a_idle(struct gk20a *g)
 
 	dev = dev_from_gk20a(g);
 
-	if (!(dev && gk20a_can_busy(g)))
+	if (!(dev && nvgpu_can_busy(g)))
 		return;
 
 	if (pm_runtime_enabled(dev)) {
@@ -1289,6 +1315,12 @@ static int gk20a_probe(struct platform_device *dev)
 		goto return_err;
 	}
 
+	gk20a->nvgpu_reboot_nb.notifier_call =
+		nvgpu_kernel_shutdown_notification;
+	err = register_reboot_notifier(&gk20a->nvgpu_reboot_nb);
+	if (err)
+		goto return_err;
+
 	return 0;
 
 return_err:
@@ -1368,6 +1400,8 @@ static int __exit gk20a_remove(struct platform_device *pdev)
 
 	err = nvgpu_remove(dev, &nvgpu_class);
 
+	unregister_reboot_notifier(&g->nvgpu_reboot_nb);
+
 	set_gk20a(pdev, NULL);
 
 	gk20a_put(g);
-- 
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