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1// SPDX-License-Identifier: GPL-2.0-only2/*3 * Copyright (C) 2013 Red Hat4 * Author: Rob Clark <robdclark@gmail.com>5 */6 7/* For profiling, userspace can:8 *9 * tail -f /sys/kernel/debug/dri/<minor>/gpu10 *11 * This will enable performance counters/profiling to track the busy time12 * and any gpu specific performance counters that are supported.13 */14 15#ifdef CONFIG_DEBUG_FS16 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 25struct 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: */41static 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 58static 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 120static 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 143out:144 mutex_unlock(&perf->read_lock);145 if (ret)146 return ret;147 return n;148}149 150static 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 176out:177 mutex_unlock(&gpu->lock);178 return ret;179}180 181static 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 191static const struct file_operations perf_debugfs_fops = {192 .owner = THIS_MODULE,193 .open = perf_open,194 .read = perf_read,195 .release = perf_release,196};197 198int msm_perf_debugfs_init(struct drm_minor *minor)199{200 struct msm_drm_private *priv = minor->dev->dev_private;201 struct msm_perf_state *perf;202 203 /* only create on first minor: */204 if (priv->perf)205 return 0;206 207 perf = kzalloc(sizeof(*perf), GFP_KERNEL);208 if (!perf)209 return -ENOMEM;210 211 perf->dev = minor->dev;212 213 mutex_init(&perf->read_lock);214 priv->perf = perf;215 216 debugfs_create_file("perf", S_IFREG | S_IRUGO, minor->debugfs_root,217 perf, &perf_debugfs_fops);218 return 0;219}220 221void msm_perf_debugfs_cleanup(struct msm_drm_private *priv)222{223 struct msm_perf_state *perf = priv->perf;224 225 if (!perf)226 return;227 228 priv->perf = NULL;229 230 mutex_destroy(&perf->read_lock);231 232 kfree(perf);233}234 235#endif236