gpu: nvgpu: debugfs node to enable/disable ltc_illegal_compstat intr

Added debugfs node under ltc directory with name:
intr_illegal_compstat_enable

Enabling/disabling of ltc_illegal_compstat intr is
possible through debugfs node.

Since ltc state is lost with rail gate, this setting is
cached and will be populated during ltc initialization.

Bug 2099406

Change-Id: I4bf62228dfd2bbb94f87f923f9f4f6e5ad0b07f0
Signed-off-by: seshendra Gadagottu <sgadagottu@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1774683
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/os/linux/debug_ltc.c

@@ -0,0 +1,93 @@
+/*
+ * Copyright (C) 2018 NVIDIA Corporation.  All rights reserved.
+ *
+ * This software is licensed under the terms of the GNU General Public
+ * License version 2, as published by the Free Software Foundation, and
+ * may be copied, distributed, and modified under those terms.
+ *
+ * This program is distributed in the hope that 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.
+ *
+ */
+
+#include "debug_ltc.h"
+#include "os_linux.h"
+#include "gk20a/gk20a.h"
+
+#include <linux/debugfs.h>
+#include <linux/uaccess.h>
+
+static ssize_t ltc_intr_illegal_compstat_read(struct file *file,
+			char __user *user_buf, size_t count, loff_t *ppos)
+{
+	char buf[3];
+	struct gk20a *g = file->private_data;
+
+	if (g->ltc_intr_en_illegal_compstat)
+		buf[0] = 'Y';
+	else
+		buf[0] = 'N';
+	buf[1] = '\n';
+	buf[2] = 0x00;
+
+	return simple_read_from_buffer(user_buf, count, ppos, buf, 2);
+}
+
+static ssize_t ltc_intr_illegal_compstat_write(struct file *file,
+			const char __user *user_buf, size_t count, loff_t *ppos)
+{
+	char buf[3];
+	int buf_size;
+	bool intr_illegal_compstat_enabled;
+	struct gk20a *g = file->private_data;
+	int err;
+
+	if (!g->ops.ltc.intr_en_illegal_compstat)
+		return -EINVAL;
+
+	buf_size = min(count, (sizeof(buf)-1));
+	if (copy_from_user(buf, user_buf, buf_size))
+		return -EFAULT;
+
+	err = gk20a_busy(g);
+	if (err)
+		return err;
+
+	if (strtobool(buf, &intr_illegal_compstat_enabled) == 0) {
+		g->ops.ltc.intr_en_illegal_compstat(g,
+				intr_illegal_compstat_enabled);
+		g->ltc_intr_en_illegal_compstat = intr_illegal_compstat_enabled;
+	}
+
+	gk20a_idle(g);
+
+	return buf_size;
+}
+
+static const struct file_operations ltc_intr_illegal_compstat_fops = {
+	.open = simple_open,
+	.read = ltc_intr_illegal_compstat_read,
+	.write = ltc_intr_illegal_compstat_write,
+};
+
+int nvgpu_ltc_debugfs_init(struct gk20a *g)
+{
+	struct dentry *d;
+	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
+	struct dentry *gpu_root = l->debugfs;
+
+	l->debugfs_ltc = debugfs_create_dir("ltc", gpu_root);
+	if (IS_ERR_OR_NULL(l->debugfs_ltc))
+		return -ENODEV;
+
+	/* Debug fs node to enable/disable illegal_compstat */
+	d = debugfs_create_file("intr_illegal_compstat_enable", 0600,
+			    l->debugfs_ltc, g,
+			    &ltc_intr_illegal_compstat_fops);
+	if (!d)
+		return -ENOMEM;
+
+	return 0;
+}