1/*
  2 * Copyright (C) 2013 Red Hat
  3 * Author: Rob Clark <robdclark@gmail.com>
  4 *
  5 * This program is free software; you can redistribute it and/or modify it
  6 * under the terms of the GNU General Public License version 2 as published by
  7 * the Free Software Foundation.
  8 *
  9 * This program is distributed in the hope that it will be useful, but WITHOUT
 10 * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
 11 * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
 12 * more details.
 13 *
 14 * You should have received a copy of the GNU General Public License along with
 15 * this program.  If not, see <http://www.gnu.org/licenses/>.
 16 */
 17
 18/* For profiling, userspace can:
 19 *
 20 *   tail -f /sys/kernel/debug/dri/<minor>/gpu
 21 *
 22 * This will enable performance counters/profiling to track the busy time
 23 * and any gpu specific performance counters that are supported.
 24 */
 25
 26#ifdef CONFIG_DEBUG_FS
 27
 28#include <linux/debugfs.h>
 29
 30#include "msm_drv.h"
 31#include "msm_gpu.h"
 32
 33struct msm_perf_state {
 34	struct drm_device *dev;
 35
 36	bool open;
 37	int cnt;
 38	struct mutex read_lock;
 39
 40	char buf[256];
 41	int buftot, bufpos;
 42
 43	unsigned long next_jiffies;
 44};
 45
 46#define SAMPLE_TIME (HZ/4)
 47
 48/* wait for next sample time: */
 49static int wait_sample(struct msm_perf_state *perf)
 50{
 51	unsigned long start_jiffies = jiffies;
 52
 53	if (time_after(perf->next_jiffies, start_jiffies)) {
 54		unsigned long remaining_jiffies =
 55			perf->next_jiffies - start_jiffies;
 56		int ret = schedule_timeout_interruptible(remaining_jiffies);
 57		if (ret > 0) {
 58			/* interrupted */
 59			return -ERESTARTSYS;
 60		}
 61	}
 62	perf->next_jiffies += SAMPLE_TIME;
 63	return 0;
 64}
 65
 66static int refill_buf(struct msm_perf_state *perf)
 67{
 68	struct msm_drm_private *priv = perf->dev->dev_private;
 69	struct msm_gpu *gpu = priv->gpu;
 70	char *ptr = perf->buf;
 71	int rem = sizeof(perf->buf);
 72	int i, n;
 73
 74	if ((perf->cnt++ % 32) == 0) {
 75		/* Header line: */
 76		n = snprintf(ptr, rem, "%%BUSY");
 77		ptr += n;
 78		rem -= n;
 79
 80		for (i = 0; i < gpu->num_perfcntrs; i++) {
 81			const struct msm_gpu_perfcntr *perfcntr = &gpu->perfcntrs[i];
 82			n = snprintf(ptr, rem, "\t%s", perfcntr->name);
 83			ptr += n;
 84			rem -= n;
 85		}
 86	} else {
 87		/* Sample line: */
 88		uint32_t activetime = 0, totaltime = 0;
 89		uint32_t cntrs[5];
 90		uint32_t val;
 91		int ret;
 92
 93		/* sleep until next sample time: */
 94		ret = wait_sample(perf);
 95		if (ret)
 96			return ret;
 97
 98		ret = msm_gpu_perfcntr_sample(gpu, &activetime, &totaltime,
 99				ARRAY_SIZE(cntrs), cntrs);
100		if (ret < 0)
101			return ret;
102
103		val = totaltime ? 1000 * activetime / totaltime : 0;
104		n = snprintf(ptr, rem, "%3d.%d%%", val / 10, val % 10);
105		ptr += n;
106		rem -= n;
107
108		for (i = 0; i < ret; i++) {
109			/* cycle counters (I think).. convert to MHz.. */
110			val = cntrs[i] / 10000;
111			n = snprintf(ptr, rem, "\t%5d.%02d",
112					val / 100, val % 100);
113			ptr += n;
114			rem -= n;
115		}
116	}
117
118	n = snprintf(ptr, rem, "\n");
119	ptr += n;
120	rem -= n;
121
122	perf->bufpos = 0;
123	perf->buftot = ptr - perf->buf;
124
125	return 0;
126}
127
128static ssize_t perf_read(struct file *file, char __user *buf,
129		size_t sz, loff_t *ppos)
130{
131	struct msm_perf_state *perf = file->private_data;
132	int n = 0, ret = 0;
133
134	mutex_lock(&perf->read_lock);
135
136	if (perf->bufpos >= perf->buftot) {
137		ret = refill_buf(perf);
138		if (ret)
139			goto out;
140	}
141
142	n = min((int)sz, perf->buftot - perf->bufpos);
143	if (copy_to_user(buf, &perf->buf[perf->bufpos], n)) {
144		ret = -EFAULT;
145		goto out;
146	}
147
148	perf->bufpos += n;
149	*ppos += n;
150
151out:
152	mutex_unlock(&perf->read_lock);
153	if (ret)
154		return ret;
155	return n;
156}
157
158static int perf_open(struct inode *inode, struct file *file)
159{
160	struct msm_perf_state *perf = inode->i_private;
161	struct drm_device *dev = perf->dev;
162	struct msm_drm_private *priv = dev->dev_private;
163	struct msm_gpu *gpu = priv->gpu;
164	int ret = 0;
165
166	mutex_lock(&dev->struct_mutex);
167
168	if (perf->open || !gpu) {
169		ret = -EBUSY;
170		goto out;
171	}
172
173	file->private_data = perf;
174	perf->open = true;
175	perf->cnt = 0;
176	perf->buftot = 0;
177	perf->bufpos = 0;
178	msm_gpu_perfcntr_start(gpu);
179	perf->next_jiffies = jiffies + SAMPLE_TIME;
180
181out:
182	mutex_unlock(&dev->struct_mutex);
183	return ret;
184}
185
186static int perf_release(struct inode *inode, struct file *file)
187{
188	struct msm_perf_state *perf = inode->i_private;
189	struct msm_drm_private *priv = perf->dev->dev_private;
190	msm_gpu_perfcntr_stop(priv->gpu);
191	perf->open = false;
192	return 0;
193}
194
195
196static const struct file_operations perf_debugfs_fops = {
197	.owner = THIS_MODULE,
198	.open = perf_open,
199	.read = perf_read,
200	.llseek = no_llseek,
201	.release = perf_release,
202};
203
204int msm_perf_debugfs_init(struct drm_minor *minor)
205{
206	struct msm_drm_private *priv = minor->dev->dev_private;
207	struct msm_perf_state *perf;
208	struct dentry *ent;
209
210	/* only create on first minor: */
211	if (priv->perf)
212		return 0;
213
214	perf = kzalloc(sizeof(*perf), GFP_KERNEL);
215	if (!perf)
216		return -ENOMEM;
217
218	perf->dev = minor->dev;
219
220	mutex_init(&perf->read_lock);
221	priv->perf = perf;
222
223	ent = debugfs_create_file("perf", S_IFREG | S_IRUGO,
224			minor->debugfs_root, perf, &perf_debugfs_fops);
225	if (!ent) {
226		DRM_ERROR("Cannot create /sys/kernel/debug/dri/%pd/perf\n",
227				minor->debugfs_root);
228		goto fail;
229	}
230
231	return 0;
232
233fail:
234	msm_perf_debugfs_cleanup(priv);
235	return -1;
236}
237
238void msm_perf_debugfs_cleanup(struct msm_drm_private *priv)
239{
240	struct msm_perf_state *perf = priv->perf;
241
242	if (!perf)
243		return;
244
245	priv->perf = NULL;
246
247	mutex_destroy(&perf->read_lock);
248
249	kfree(perf);
250}
251
252#endif