1// SPDX-License-Identifier: MIT
  2/*
  3 * Copyright © 2019 Intel Corporation
  4 */
  5
  6#include <linux/kernel.h>
  7
  8#include "i915_debugfs_params.h"
  9#include "i915_drv.h"
 10#include "i915_params.h"
 11
 12/* int param */
 13static int i915_param_int_show(struct seq_file *m, void *data)
 14{
 15	int *value = m->private;
 16
 17	seq_printf(m, "%d\n", *value);
 18
 19	return 0;
 20}
 21
 22static int i915_param_int_open(struct inode *inode, struct file *file)
 23{
 24	return single_open(file, i915_param_int_show, inode->i_private);
 25}
 26
 27static ssize_t i915_param_int_write(struct file *file,
 28				    const char __user *ubuf, size_t len,
 29				    loff_t *offp)
 30{
 31	struct seq_file *m = file->private_data;
 32	int *value = m->private;
 33	int ret;
 34
 35	ret = kstrtoint_from_user(ubuf, len, 0, value);
 36	if (ret) {
 37		/* support boolean values too */
 38		bool b;
 39
 40		ret = kstrtobool_from_user(ubuf, len, &b);
 41		if (!ret)
 42			*value = b;
 43	}
 44
 45	return ret ?: len;
 46}
 47
 48static const struct file_operations i915_param_int_fops = {
 49	.owner = THIS_MODULE,
 50	.open = i915_param_int_open,
 51	.read = seq_read,
 52	.write = i915_param_int_write,
 53	.llseek = default_llseek,
 54	.release = single_release,
 55};
 56
 57static const struct file_operations i915_param_int_fops_ro = {
 58	.owner = THIS_MODULE,
 59	.open = i915_param_int_open,
 60	.read = seq_read,
 61	.llseek = default_llseek,
 62	.release = single_release,
 63};
 64
 65/* unsigned int param */
 66static int i915_param_uint_show(struct seq_file *m, void *data)
 67{
 68	unsigned int *value = m->private;
 69
 70	seq_printf(m, "%u\n", *value);
 71
 72	return 0;
 73}
 74
 75static int i915_param_uint_open(struct inode *inode, struct file *file)
 76{
 77	return single_open(file, i915_param_uint_show, inode->i_private);
 78}
 79
 80static ssize_t i915_param_uint_write(struct file *file,
 81				     const char __user *ubuf, size_t len,
 82				     loff_t *offp)
 83{
 84	struct seq_file *m = file->private_data;
 85	unsigned int *value = m->private;
 86	int ret;
 87
 88	ret = kstrtouint_from_user(ubuf, len, 0, value);
 89	if (ret) {
 90		/* support boolean values too */
 91		bool b;
 92
 93		ret = kstrtobool_from_user(ubuf, len, &b);
 94		if (!ret)
 95			*value = b;
 96	}
 97
 98	return ret ?: len;
 99}
100
101static const struct file_operations i915_param_uint_fops = {
102	.owner = THIS_MODULE,
103	.open = i915_param_uint_open,
104	.read = seq_read,
105	.write = i915_param_uint_write,
106	.llseek = default_llseek,
107	.release = single_release,
108};
109
110static const struct file_operations i915_param_uint_fops_ro = {
111	.owner = THIS_MODULE,
112	.open = i915_param_uint_open,
113	.read = seq_read,
114	.llseek = default_llseek,
115	.release = single_release,
116};
117
118/* char * param */
119static int i915_param_charp_show(struct seq_file *m, void *data)
120{
121	const char **s = m->private;
122
123	seq_printf(m, "%s\n", *s);
124
125	return 0;
126}
127
128static int i915_param_charp_open(struct inode *inode, struct file *file)
129{
130	return single_open(file, i915_param_charp_show, inode->i_private);
131}
132
133static ssize_t i915_param_charp_write(struct file *file,
134				      const char __user *ubuf, size_t len,
135				      loff_t *offp)
136{
137	struct seq_file *m = file->private_data;
138	char **s = m->private;
139	char *new, *old;
140
141	old = *s;
142	new = strndup_user(ubuf, PAGE_SIZE);
143	if (IS_ERR(new)) {
144		len = PTR_ERR(new);
145		goto out;
146	}
147
148	*s = new;
149
150	kfree(old);
151out:
152	return len;
153}
154
155static const struct file_operations i915_param_charp_fops = {
156	.owner = THIS_MODULE,
157	.open = i915_param_charp_open,
158	.read = seq_read,
159	.write = i915_param_charp_write,
160	.llseek = default_llseek,
161	.release = single_release,
162};
163
164static const struct file_operations i915_param_charp_fops_ro = {
165	.owner = THIS_MODULE,
166	.open = i915_param_charp_open,
167	.read = seq_read,
168	.llseek = default_llseek,
169	.release = single_release,
170};
171
172#define RO(mode) (((mode) & 0222) == 0)
173
174static struct dentry *
175i915_debugfs_create_int(const char *name, umode_t mode,
176			struct dentry *parent, int *value)
177{
178	return debugfs_create_file_unsafe(name, mode, parent, value,
179					  RO(mode) ? &i915_param_int_fops_ro :
180					  &i915_param_int_fops);
181}
182
183static struct dentry *
184i915_debugfs_create_uint(const char *name, umode_t mode,
185			 struct dentry *parent, unsigned int *value)
186{
187	return debugfs_create_file_unsafe(name, mode, parent, value,
188					  RO(mode) ? &i915_param_uint_fops_ro :
189					  &i915_param_uint_fops);
190}
191
192static struct dentry *
193i915_debugfs_create_charp(const char *name, umode_t mode,
194			  struct dentry *parent, char **value)
195{
196	return debugfs_create_file(name, mode, parent, value,
197				   RO(mode) ? &i915_param_charp_fops_ro :
198				   &i915_param_charp_fops);
199}
200
201static __always_inline void
202_i915_param_create_file(struct dentry *parent, const char *name,
203			const char *type, int mode, void *value)
204{
205	if (!mode)
206		return;
207
208	if (!__builtin_strcmp(type, "bool"))
209		debugfs_create_bool(name, mode, parent, value);
210	else if (!__builtin_strcmp(type, "int"))
211		i915_debugfs_create_int(name, mode, parent, value);
212	else if (!__builtin_strcmp(type, "unsigned int"))
213		i915_debugfs_create_uint(name, mode, parent, value);
214	else if (!__builtin_strcmp(type, "unsigned long"))
215		debugfs_create_ulong(name, mode, parent, value);
216	else if (!__builtin_strcmp(type, "char *"))
217		i915_debugfs_create_charp(name, mode, parent, value);
218	else
219		WARN(1, "no debugfs fops defined for param type %s (i915.%s)\n",
220		     type, name);
221}
222
223/* add a subdirectory with files for each i915 param */
224struct dentry *i915_debugfs_params(struct drm_i915_private *i915)
225{
226	struct drm_minor *minor = i915->drm.primary;
227	struct i915_params *params = &i915->params;
228	struct dentry *dir;
229
230	dir = debugfs_create_dir("i915_params", minor->debugfs_root);
231	if (IS_ERR(dir))
232		return dir;
233
234	/*
235	 * Note: We could create files for params needing special handling
236	 * here. Set mode in params to 0 to skip the generic create file, or
237	 * just let the generic create file fail silently with -EEXIST.
238	 */
239
240#define REGISTER(T, x, unused, mode, ...) _i915_param_create_file(dir, #x, #T, mode, &params->x);
241	I915_PARAMS_FOR_EACH(REGISTER);
242#undef REGISTER
243
244	return dir;
245}