gpu: nvgpu: shutdown nvlink in driver remove

During driver remove, if nvlink is set up, gracefully
shut it down so that it can be enumerated again.

Bug 1987855

Change-Id: Ibd83a5e29364b22264e689aa879569a9cccf0f79
Signed-off-by: Nitin Kumbhar <nkumbhar@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1746073
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

3 files changed, 53 insertions, 3 deletions

diff --git a/drivers/gpu/nvgpu/os/linux/nvlink.c b/drivers/gpu/nvgpu/os/linux/nvlink.c
index c93514c0..0db483d6 100644
--- a/drivers/gpu/nvgpu/os/linux/nvlink.c
+++ b/drivers/gpu/nvgpu/os/linux/nvlink.c
@@ -14,6 +14,10 @@
  * along with this program.  If not, see <http://www.gnu.org/licenses/>.
  */
 
+#ifdef CONFIG_TEGRA_NVLINK
+#include <linux/platform/tegra/tegra-nvlink.h>
+#endif
+
 #include <gk20a/gk20a.h>
 #include <nvgpu/nvlink.h>
 #include <nvgpu/enabled.h>
@@ -104,3 +108,25 @@ void nvgpu_mss_nvlink_init_credits(struct gk20a *g)
                 val = readl_relaxed(soc4 + 4);
                 writel_relaxed(val, soc4 + 4);
 }
+
+int nvgpu_nvlink_deinit(struct gk20a *g)
+{
+#ifdef CONFIG_TEGRA_NVLINK
+        struct nvlink_device *ndev = g->nvlink.priv;
+        int err;
+
+        if (!nvgpu_is_enabled(g, NVGPU_SUPPORT_NVLINK))
+                return -ENODEV;
+
+        err = nvlink_shutdown(ndev);
+        if (err) {
+                nvgpu_err(g, "failed to shut down nvlink");
+                return err;
+        }
+
+        nvgpu_nvlink_remove(g);
+
+        return 0;
+#endif
+        return -ENODEV;
+}
diff --git a/drivers/gpu/nvgpu/os/linux/nvlink.h b/drivers/gpu/nvgpu/os/linux/nvlink.h
new file mode 100644
index 00000000..4dc54f6f
--- /dev/null
+++ b/drivers/gpu/nvgpu/os/linux/nvlink.h
@@ -0,0 +1,22 @@
+/*
+ * Copyright (c) 2018, NVIDIA CORPORATION. All rights reserved.
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms and conditions of the GNU General Public License,
+ * version 2, as published by the Free Software Foundation.
+ *
+ * This program is distributed in the hope it will be useful, but WITHOUT
+ * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
+ * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
+ * more details.
+ *
+ * You should have received a copy of the GNU General Public License
+ * along with this program.  If not, see <http://www.gnu.org/licenses/>.
+ */
+
+#ifndef NVGPU_OS_LINUX_NVLINK_H
+
+struct gk20a;
+int nvgpu_nvlink_deinit(struct gk20a *g);
+
+#endif
diff --git a/drivers/gpu/nvgpu/os/linux/pci.c b/drivers/gpu/nvgpu/os/linux/pci.c
index 41fb69a0..ee4bcf8c 100644
--- a/drivers/gpu/nvgpu/os/linux/pci.c
+++ b/drivers/gpu/nvgpu/os/linux/pci.c
@@ -26,7 +26,9 @@
 #include <nvgpu/enabled.h>
 #include <nvgpu/nvlink.h>
 #include <nvgpu/soc.h>
+#include <nvgpu/sim.h>
 
+#include "nvlink.h"
 #include "gk20a/gk20a.h"
 #include "clk/clk.h"
 #include "clk/clk_mclk.h"
@@ -35,12 +37,10 @@
 #include "sysfs.h"
 #include "os_linux.h"
 #include "platform_gk20a.h"
-#include <nvgpu/sim.h>
 
 #include "pci.h"
 #include "pci_usermode.h"
 
-#include "os_linux.h"
 #include "driver_common.h"
 
 #define PCI_INTERFACE_NAME "card-%s%%s"
@@ -828,9 +828,11 @@ static void nvgpu_pci_remove(struct pci_dev *pdev)
         if (gk20a_gpu_is_virtual(dev))
                 return;
 
-        nvgpu_nvlink_remove(g);
+        err = nvgpu_nvlink_deinit(g);
+        WARN(err, "gpu failed to remove nvlink");
 
         gk20a_driver_start_unload(g);
+
         err = nvgpu_quiesce(g);
         /* TODO: handle failure to idle */
         WARN(err, "gpu failed to idle during driver removal");