gpu: nvgpu: debugfs code to dump HAL functions

Prints addresses of device-specific HAL functions to debugfs file
hal/gops.

The list of functions is produced by dumping the contents of the
gpu_ops substruct of the gk20a struct. This interface makes the
assumption that there are only function pointers in gpu_ops.

Companion Python script nvgpu_debug_hal.py analyzes gk20a.h to
determine operation counts and prettyify debugfs interface's
output.

Jira NVGPU-107

Change-Id: I0910e86638d144979e8630bbc5b330bccfd3ad94
Signed-off-by: Sunny He <suhe@nvidia.com>
Reviewed-on: https://git-master.nvidia.com/r/1542990
Reviewed-by: mobile promotions <svcmobile_promotions@nvidia.com>
Tested-by: mobile promotions <svcmobile_promotions@nvidia.com>

drivers/gpu/nvgpu/common/linux/debug.c

@@ -21,6 +21,7 @@
 #include "debug_kmem.h"
 #include "debug_pmu.h"
 #include "debug_sched.h"
+#include "debug_hal.h"
 #include "os_linux.h"
 
 #include "gk20a/gk20a.h"
@@ -386,6 +387,7 @@ void gk20a_debug_init(struct gk20a *g, const char *debugfs_symlink)
 	gk20a_cde_debugfs_init(g);
 	gk20a_ce_debugfs_init(g);
 	nvgpu_alloc_debugfs_init(g);
+	nvgpu_hal_debugfs_init(g);
 	gk20a_mm_debugfs_init(g);
 	gk20a_fifo_debugfs_init(g);
 	gk20a_sched_debugfs_init(g);

drivers/gpu/nvgpu/common/linux/debug_hal.c

@@ -0,0 +1,95 @@
+/*
+ * Copyright (C) 2017 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_hal.h"
+#include "os_linux.h"
+
+#include <linux/debugfs.h>
+#include <linux/seq_file.h>
+
+/* Format and print a single function pointer to the specified seq_file. */
+static void __hal_print_op(struct seq_file *s, void *op_ptr)
+{
+	seq_printf(s, "%pF\n", op_ptr);
+}
+
+/*
+ * Prints an array of function pointer addresses in op_ptrs to the
+ * specified seq_file
+ */
+static void __hal_print_ops(struct seq_file *s, void **op_ptrs, int num_ops)
+{
+	int i;
+
+	for (i = 0; i < num_ops; i++)
+		__hal_print_op(s, op_ptrs[i]);
+}
+
+/*
+ * Show file operation, which generates content of the file once. Prints a list
+ * of gpu operations as defined by gops and the corresponding function pointer
+ * destination addresses. Relies on no compiler reordering of struct fields and
+ * assumption that all members are function pointers.
+ */
+static int __hal_show(struct seq_file *s, void *unused)
+{
+	struct gpu_ops *gops = s->private;
+
+	__hal_print_ops(s, (void **)gops, sizeof(*gops) / sizeof(void *));
+
+	return 0;
+}
+
+static int __hal_open(struct inode *inode, struct file *file)
+{
+	return single_open(file, __hal_show, inode->i_private);
+}
+
+static const struct file_operations __hal_fops = {
+	.open = __hal_open,
+	.read = seq_read,
+	.llseek = seq_lseek,
+	.release = single_release,
+};
+
+void nvgpu_hal_debugfs_fini(struct gk20a *g)
+{
+	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
+
+	if (!(l->debugfs_hal == NULL))
+		debugfs_remove_recursive(l->debugfs_hal);
+}
+
+void nvgpu_hal_debugfs_init(struct gk20a *g)
+{
+	struct dentry *d;
+	struct nvgpu_os_linux *l = nvgpu_os_linux_from_gk20a(g);
+
+	if (!l->debugfs)
+		return;
+	l->debugfs_hal = debugfs_create_dir("hal", l->debugfs);
+	if (IS_ERR_OR_NULL(l->debugfs_hal)) {
+		l->debugfs_hal = NULL;
+		return;
+	}
+
+	/* Pass along reference to the gpu_ops struct as private data */
+	d = debugfs_create_file("gops", S_IRUGO, l->debugfs_hal,
+		&g->ops, &__hal_fops);
+	if (!d) {
+		nvgpu_err(g, "%s: Failed to make debugfs node\n", __func__);
+		debugfs_remove_recursive(l->debugfs_hal);
+		return;
+	}
+}

drivers/gpu/nvgpu/common/linux/debug_hal.h

@@ -0,0 +1,22 @@
+/*
+ * Copyright (C) 2017 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.
+ *
+ */
+
+#ifndef __NVGPU_DEBUG_HAL_H__
+#define __NVGPU_DEBUG_HAL_H__
+
+struct gk20a;
+void nvgpu_hal_debugfs_fini(struct gk20a *g);
+void nvgpu_hal_debugfs_init(struct gk20a *g);
+
+#endif /* __NVGPU_DEBUG_HAL_H__ */

drivers/gpu/nvgpu/common/linux/os_linux.h

@@ -102,6 +102,7 @@ struct nvgpu_os_linux {
 	struct dentry *debugfs_allocators;
 	struct dentry *debugfs_xve;
 	struct dentry *debugfs_kmem;
+	struct dentry *debugfs_hal;
 
 	struct dentry *debugfs_force_preemption_cilp;
 	struct dentry *debugfs_force_preemption_gfxp;