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// SPDX-License-Identifier: GPL-2.0-only
/*
* Copyright (C) 2013 Red Hat
* Author: Rob Clark <robdclark@gmail.com>
*/
/* For profiling, userspace can:
*
* tail -f /sys/kernel/debug/dri/<minor>/gpu
*
* This will enable performance counters/profiling to track the busy time
* and any gpu specific performance counters that are supported.
*/
#ifdef CONFIG_DEBUG_FS
#include <linux/debugfs.h>
#include <linux/uaccess.h>
#include <drm/drm_file.h>
#include "msm_drv.h"
#include "msm_gpu.h"
struct msm_perf_state {
struct drm_device *dev;
bool open;
int cnt;
struct mutex read_lock;
char buf[256];
int buftot, bufpos;
unsigned long next_jiffies;
};
#define SAMPLE_TIME (HZ/4)
/* wait for next sample time: */
static int wait_sample(struct msm_perf_state *perf)
{
unsigned long start_jiffies = jiffies;
if (time_after(perf->next_jiffies, start_jiffies)) {
unsigned long remaining_jiffies =
perf->next_jiffies - start_jiffies;
int ret = schedule_timeout_interruptible(remaining_jiffies);
if (ret > 0) {
/* interrupted */
return -ERESTARTSYS;
}
}
perf->next_jiffies += SAMPLE_TIME;
return 0;
}
static int refill_buf(struct msm_perf_state *perf)
{
struct msm_drm_private *priv = perf->dev->dev_private;
struct msm_gpu *gpu = priv->gpu;
char *ptr = perf->buf;
int rem = sizeof(perf->buf);
int i, n;
if ((perf->cnt++ % 32) == 0) {
/* Header line: */
n = snprintf(ptr, rem, "%%BUSY");
ptr += n;
rem -= n;
for (i = 0; i < gpu->num_perfcntrs; i++) {
const struct msm_gpu_perfcntr *perfcntr = &gpu->perfcntrs[i];
n = snprintf(ptr, rem, "\t%s", perfcntr->name);
ptr += n;
rem -= n;
}
} else {
/* Sample line: */
uint32_t activetime = 0, totaltime = 0;
uint32_t cntrs[5];
uint32_t val;
int ret;
/* sleep until next sample time: */
ret = wait_sample(perf);
if (ret)
return ret;
ret = msm_gpu_perfcntr_sample(gpu, &activetime, &totaltime,
ARRAY_SIZE(cntrs), cntrs);
if (ret < 0)
return ret;
val = totaltime ? 1000 * activetime / totaltime : 0;
n = snprintf(ptr, rem, "%3d.%d%%", val / 10, val % 10);
ptr += n;
rem -= n;
for (i = 0; i < ret; i++) {
/* cycle counters (I think).. convert to MHz.. */
val = cntrs[i] / 10000;
n = snprintf(ptr, rem, "\t%5d.%02d",
val / 100, val % 100);
ptr += n;
rem -= n;
}
}
n = snprintf(ptr, rem, "\n");
ptr += n;
rem -= n;
perf->bufpos = 0;
perf->buftot = ptr - perf->buf;
return 0;
}
static ssize_t perf_read(struct file *file, char __user *buf,
size_t sz, loff_t *ppos)
{
struct msm_perf_state *perf = file->private_data;
int n = 0, ret = 0;
mutex_lock(&perf->read_lock);
if (perf->bufpos >= perf->buftot) {
ret = refill_buf(perf);
if (ret)
goto out;
}
n = min((int)sz, perf->buftot - perf->bufpos);
if (copy_to_user(buf, &perf->buf[perf->bufpos], n)) {
ret = -EFAULT;
goto out;
}
perf->bufpos += n;
*ppos += n;
out:
mutex_unlock(&perf->read_lock);
if (ret)
return ret;
return n;
}
static int perf_open(struct inode *inode, struct file *file)
{
struct msm_perf_state *perf = inode->i_private;
struct drm_device *dev = perf->dev;
struct msm_drm_private *priv = dev->dev_private;
struct msm_gpu *gpu = priv->gpu;
int ret = 0;
mutex_lock(&dev->struct_mutex);
if (perf->open || !gpu) {
ret = -EBUSY;
goto out;
}
file->private_data = perf;
perf->open = true;
perf->cnt = 0;
perf->buftot = 0;
perf->bufpos = 0;
msm_gpu_perfcntr_start(gpu);
perf->next_jiffies = jiffies + SAMPLE_TIME;
out:
mutex_unlock(&dev->struct_mutex);
return ret;
}
static int perf_release(struct inode *inode, struct file *file)
{
struct msm_perf_state *perf = inode->i_private;
struct msm_drm_private *priv = perf->dev->dev_private;
msm_gpu_perfcntr_stop(priv->gpu);
perf->open = false;
return 0;
}
static const struct file_operations perf_debugfs_fops = {
.owner = THIS_MODULE,
.open = perf_open,
.read = perf_read,
.llseek = no_llseek,
.release = perf_release,
};
int msm_perf_debugfs_init(struct drm_minor *minor)
{
struct msm_drm_private *priv = minor->dev->dev_private;
struct msm_perf_state *perf;
/* only create on first minor: */
if (priv->perf)
return 0;
perf = kzalloc(sizeof(*perf), GFP_KERNEL);
if (!perf)
return -ENOMEM;
perf->dev = minor->dev;
mutex_init(&perf->read_lock);
priv->perf = perf;
debugfs_create_file("perf", S_IFREG | S_IRUGO, minor->debugfs_root,
perf, &perf_debugfs_fops);
return 0;
}
void msm_perf_debugfs_cleanup(struct msm_drm_private *priv)
{
struct msm_perf_state *perf = priv->perf;
if (!perf)
return;
priv->perf = NULL;
mutex_destroy(&perf->read_lock);
kfree(perf);
}
#endif
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