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>

drivers/gpu/nvgpu/common/nvlink.c

@@ -92,6 +92,16 @@ static int nvgpu_nvlink_interface_init(struct nvlink_device *ndev)
 	return err;
 }
 
+static int nvgpu_nvlink_interface_disable(struct nvlink_device *ndev)
+{
+	int err = 0;
+	struct gk20a *g = (struct gk20a *) ndev->priv;
+
+	if (g->ops.nvlink.interface_disable)
+		err = g->ops.nvlink.interface_disable(g);
+	return err;
+}
+
 static int nvgpu_nvlink_shutdown(struct nvlink_device *ndev)
 {
 	int err;
@@ -401,6 +411,7 @@ static int nvgpu_nvlink_init_ops(struct gk20a *g)
 	ndev->dev_ops.dev_early_init = nvgpu_nvlink_early_init;
 	ndev->dev_ops.dev_interface_init = nvgpu_nvlink_interface_init;
 	ndev->dev_ops.dev_reg_init = nvgpu_nvlink_reg_init;
+	ndev->dev_ops.dev_interface_disable = nvgpu_nvlink_interface_disable;
 	ndev->dev_ops.dev_shutdown = nvgpu_nvlink_shutdown;
 
 	/* Fill in the link struct */

drivers/gpu/nvgpu/gk20a/gk20a.h

@@ -1267,6 +1267,7 @@ struct gpu_ops {
 		int (*set_sublink_mode)(struct gk20a *g, u32 link_id,
 			bool is_rx_sublink, u32 mode);
 		int (*interface_init)(struct gk20a *g);
+		int (*interface_disable)(struct gk20a *g);
 		int (*reg_init)(struct gk20a *g);
 		int (*shutdown)(struct gk20a *g);
 		int (*early_init)(struct gk20a *g);

drivers/gpu/nvgpu/gv100/hal_gv100.c

@@ -896,6 +896,7 @@ static const struct gpu_ops gv100_ops = {
 		.get_rx_sublink_state = gv100_nvlink_link_get_rx_sublink_state,
 		.set_sublink_mode = gv100_nvlink_link_set_sublink_mode,
 		.interface_init = gv100_nvlink_interface_init,
+		.interface_disable = gv100_nvlink_interface_disable,
 		.reg_init = gv100_nvlink_reg_init,
 		.shutdown = gv100_nvlink_shutdown,
 		.early_init = gv100_nvlink_early_init,

drivers/gpu/nvgpu/gv100/nvlink_gv100.c

@@ -2269,6 +2269,11 @@ int gv100_nvlink_interface_init(struct gk20a *g)
 	return 0;
 }
 
+int gv100_nvlink_interface_disable(struct gk20a *g)
+{
+	return 0;
+}
+
 int gv100_nvlink_reg_init(struct gk20a *g)
 {
 	u32 i = 0;

drivers/gpu/nvgpu/gv100/nvlink_gv100.h

@@ -50,6 +50,7 @@ u32 gv100_nvlink_link_get_rx_sublink_state(struct gk20a *g, u32 link_id);
 int gv100_nvlink_link_set_sublink_mode(struct gk20a *g, u32 link_id,
 	bool is_rx_sublink, u32 mode);
 int gv100_nvlink_interface_init(struct gk20a *g);
+int gv100_nvlink_interface_disable(struct gk20a *g);
 int gv100_nvlink_reg_init(struct gk20a *g);
 int gv100_nvlink_shutdown(struct gk20a *g);
 int gv100_nvlink_early_init(struct gk20a *g);

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;
+}

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

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");