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 if (!gpu)
159 return -ENODEV;
160
161 mutex_lock(&gpu->lock);
162
163 if (perf->open) {
164 ret = -EBUSY;
165 goto out;
166 }
167
168 file->private_data = perf;
169 perf->open = true;
170 perf->cnt = 0;
171 perf->buftot = 0;
172 perf->bufpos = 0;
173 msm_gpu_perfcntr_start(gpu);
174 perf->next_jiffies = jiffies + SAMPLE_TIME;
175
176 out:
177 mutex_unlock(&gpu->lock);
178 return ret;
179 }
180
perf_release(struct inode * inode,struct file * file)181 static int perf_release(struct inode *inode, struct file *file)
182 {
183 struct msm_perf_state *perf = inode->i_private;
184 struct msm_drm_private *priv = perf->dev->dev_private;
185 msm_gpu_perfcntr_stop(priv->gpu);
186 perf->open = false;
187 return 0;
188 }
189
190
191 static const struct file_operations perf_debugfs_fops = {
192 .owner = THIS_MODULE,
193 .open = perf_open,
194 .read = perf_read,
195 .llseek = no_llseek,
196 .release = perf_release,
197 };
198
msm_perf_debugfs_init(struct drm_minor * minor)199 int msm_perf_debugfs_init(struct drm_minor *minor)
200 {
201 struct msm_drm_private *priv = minor->dev->dev_private;
202 struct msm_perf_state *perf;
203
204 /* only create on first minor: */
205 if (priv->perf)
206 return 0;
207
208 perf = kzalloc(sizeof(*perf), GFP_KERNEL);
209 if (!perf)
210 return -ENOMEM;
211
212 perf->dev = minor->dev;
213
214 mutex_init(&perf->read_lock);
215 priv->perf = perf;
216
217 debugfs_create_file("perf", S_IFREG | S_IRUGO, minor->debugfs_root,
218 perf, &perf_debugfs_fops);
219 return 0;
220 }
221
msm_perf_debugfs_cleanup(struct msm_drm_private * priv)222 void msm_perf_debugfs_cleanup(struct msm_drm_private *priv)
223 {
224 struct msm_perf_state *perf = priv->perf;
225
226 if (!perf)
227 return;
228
229 priv->perf = NULL;
230
231 mutex_destroy(&perf->read_lock);
232
233 kfree(perf);
234 }
235
236 #endif
237