1 // SPDX-License-Identifier: GPL-2.0-only
2 /*
3 * Copyright (C) 2013 Red Hat
4 * Author: Rob Clark <robdclark@gmail.com>
5 */
6
7 /* For profiling, userspace can:
8 *
9 * tail -f /sys/kernel/debug/dri/<minor>/gpu
10 *
11 * This will enable performance counters/profiling to track the busy time
12 * and any gpu specific performance counters that are supported.
13 */
14
15 #ifdef CONFIG_DEBUG_FS
16
17 #include <linux/debugfs.h>
18 #include <linux/uaccess.h>
19
20 #include <drm/drm_file.h>
21
22 #include "msm_drv.h"
23 #include "msm_gpu.h"
24
25 struct msm_perf_state {
26 struct drm_device *dev;
27
28 bool open;
29 int cnt;
30 struct mutex read_lock;
31
32 char buf[256];
33 int buftot, bufpos;
34
35 unsigned long next_jiffies;
36 };
37
38 #define SAMPLE_TIME (HZ/4)
39
40 /* wait for next sample time: */
wait_sample(struct msm_perf_state * perf)41 static int wait_sample(struct msm_perf_state *perf)
42 {
43 unsigned long start_jiffies = jiffies;
44
45 if (time_after(perf->next_jiffies, start_jiffies)) {
46 unsigned long remaining_jiffies =
47 perf->next_jiffies - start_jiffies;
48 int ret = schedule_timeout_interruptible(remaining_jiffies);
49 if (ret > 0) {
50 /* interrupted */
51 return -ERESTARTSYS;
52 }
53 }
54 perf->next_jiffies += SAMPLE_TIME;
55 return 0;
56 }
57
refill_buf(struct msm_perf_state * perf)58 static int refill_buf(struct msm_perf_state *perf)
59 {
60 struct msm_drm_private *priv = perf->dev->dev_private;
61 struct msm_gpu *gpu = priv->gpu;
62 char *ptr = perf->buf;
63 int rem = sizeof(perf->buf);
64 int i, n;
65
66 if ((perf->cnt++ % 32) == 0) {
67 /* Header line: */
68 n = snprintf(ptr, rem, "%%BUSY");
69 ptr += n;
70 rem -= n;
71
72 for (i = 0; i < gpu->num_perfcntrs; i++) {
73 const struct msm_gpu_perfcntr *perfcntr = &gpu->perfcntrs[i];
74 n = snprintf(ptr, rem, "\t%s", perfcntr->name);
75 ptr += n;
76 rem -= n;
77 }
78 } else {
79 /* Sample line: */
80 uint32_t activetime = 0, totaltime = 0;
81 uint32_t cntrs[5];
82 uint32_t val;
83 int ret;
84
85 /* sleep until next sample time: */
86 ret = wait_sample(perf);
87 if (ret)
88 return ret;
89
90 ret = msm_gpu_perfcntr_sample(gpu, &activetime, &totaltime,
91 ARRAY_SIZE(cntrs), cntrs);
92 if (ret < 0)
93 return ret;
94
95 val = totaltime ? 1000 * activetime / totaltime : 0;
96 n = snprintf(ptr, rem, "%3d.%d%%", val / 10, val % 10);
97 ptr += n;
98 rem -= n;
99
100 for (i = 0; i < ret; i++) {
101 /* cycle counters (I think).. convert to MHz.. */
102 val = cntrs[i] / 10000;
103 n = snprintf(ptr, rem, "\t%5d.%02d",
104 val / 100, val % 100);
105 ptr += n;
106 rem -= n;
107 }
108 }
109
110 n = snprintf(ptr, rem, "\n");
111 ptr += n;
112 rem -= n;
113
114 perf->bufpos = 0;
115 perf->buftot = ptr - perf->buf;
116
117 return 0;
118 }
119
perf_read(struct file * file,char __user * buf,size_t sz,loff_t * ppos)120 static ssize_t perf_read(struct file *file, char __user *buf,
121 size_t sz, loff_t *ppos)
122 {
123 struct msm_perf_state *perf = file->private_data;
124 int n = 0, ret = 0;
125
126 mutex_lock(&perf->read_lock);
127
128 if (perf->bufpos >= perf->buftot) {
129 ret = refill_buf(perf);
130 if (ret)
131 goto out;
132 }
133
134 n = min((int)sz, perf->buftot - perf->bufpos);
135 if (copy_to_user(buf, &perf->buf[perf->bufpos], n)) {
136 ret = -EFAULT;
137 goto out;
138 }
139
140 perf->bufpos += n;
141 *ppos += n;
142
143 out:
144 mutex_unlock(&perf->read_lock);
145 if (ret)
146 return ret;
147 return n;
148 }
149
perf_open(struct inode * inode,struct file * file)150 static int perf_open(struct inode *inode, struct file *file)
151 {
152 struct msm_perf_state *perf = inode->i_private;
153 struct drm_device *dev = perf->dev;
154 struct msm_drm_private *priv = dev->dev_private;
155 struct msm_gpu *gpu = priv->gpu;
156 int ret = 0;
157
158 mutex_lock(&dev->struct_mutex);
159
160 if (perf->open || !gpu) {
161 ret = -EBUSY;
162 goto out;
163 }
164
165 file->private_data = perf;
166 perf->open = true;
167 perf->cnt = 0;
168 perf->buftot = 0;
169 perf->bufpos = 0;
170 msm_gpu_perfcntr_start(gpu);
171 perf->next_jiffies = jiffies + SAMPLE_TIME;
172
173 out:
174 mutex_unlock(&dev->struct_mutex);
175 return ret;
176 }
177
perf_release(struct inode * inode,struct file * file)178 static int perf_release(struct inode *inode, struct file *file)
179 {
180 struct msm_perf_state *perf = inode->i_private;
181 struct msm_drm_private *priv = perf->dev->dev_private;
182 msm_gpu_perfcntr_stop(priv->gpu);
183 perf->open = false;
184 return 0;
185 }
186
187
188 static const struct file_operations perf_debugfs_fops = {
189 .owner = THIS_MODULE,
190 .open = perf_open,
191 .read = perf_read,
192 .llseek = no_llseek,
193 .release = perf_release,
194 };
195
msm_perf_debugfs_init(struct drm_minor * minor)196 int msm_perf_debugfs_init(struct drm_minor *minor)
197 {
198 struct msm_drm_private *priv = minor->dev->dev_private;
199 struct msm_perf_state *perf;
200
201 /* only create on first minor: */
202 if (priv->perf)
203 return 0;
204
205 perf = kzalloc(sizeof(*perf), GFP_KERNEL);
206 if (!perf)
207 return -ENOMEM;
208
209 perf->dev = minor->dev;
210
211 mutex_init(&perf->read_lock);
212 priv->perf = perf;
213
214 debugfs_create_file("perf", S_IFREG | S_IRUGO, minor->debugfs_root,
215 perf, &perf_debugfs_fops);
216 return 0;
217 }
218
msm_perf_debugfs_cleanup(struct msm_drm_private * priv)219 void msm_perf_debugfs_cleanup(struct msm_drm_private *priv)
220 {
221 struct msm_perf_state *perf = priv->perf;
222
223 if (!perf)
224 return;
225
226 priv->perf = NULL;
227
228 mutex_destroy(&perf->read_lock);
229
230 kfree(perf);
231 }
232
233 #endif
234