Nicolas Boichat 09da319182 drm/panfrost: devfreq: Disable devfreq when num_supplies > 1
GPUs with more than a single regulator (e.g. G72 on MT8183) will
require platform-specific handling for devfreq, for 2 reasons:
 1. The opp core (drivers/opp/core.c:_generic_set_opp_regulator)
    does not support multiple regulators, so we'll need custom
    handlers.
 2. Generally, platforms with 2 regulators have platform-specific
    constraints on how the voltages should be set (e.g.
    minimum/maximum voltage difference between them), so we
    should not just create generic handlers that simply
    change the voltages without taking care of those constraints.

Disable devfreq for now on those GPUs.

Signed-off-by: Nicolas Boichat <drinkcat@chromium.org>
Reviewed-by: Tomeu Vizoso <tomeu.vizoso@collabora.com>
Reviewed-by: Steven Price <steven.price@arm.com>
Signed-off-by: Steven Price <steven.price@arm.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20210421132841.v13.3.I3af068abe30c9c85cabc4486385c52e56527a509@changeid
2021-05-14 16:29:14 +01:00

224 lines
5.3 KiB
C

// SPDX-License-Identifier: GPL-2.0
/* Copyright 2019 Collabora ltd. */
#include <linux/clk.h>
#include <linux/devfreq.h>
#include <linux/devfreq_cooling.h>
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include "panfrost_device.h"
#include "panfrost_devfreq.h"
static void panfrost_devfreq_update_utilization(struct panfrost_devfreq *pfdevfreq)
{
ktime_t now, last;
now = ktime_get();
last = pfdevfreq->time_last_update;
if (pfdevfreq->busy_count > 0)
pfdevfreq->busy_time += ktime_sub(now, last);
else
pfdevfreq->idle_time += ktime_sub(now, last);
pfdevfreq->time_last_update = now;
}
static int panfrost_devfreq_target(struct device *dev, unsigned long *freq,
u32 flags)
{
struct dev_pm_opp *opp;
opp = devfreq_recommended_opp(dev, freq, flags);
if (IS_ERR(opp))
return PTR_ERR(opp);
dev_pm_opp_put(opp);
return dev_pm_opp_set_rate(dev, *freq);
}
static void panfrost_devfreq_reset(struct panfrost_devfreq *pfdevfreq)
{
pfdevfreq->busy_time = 0;
pfdevfreq->idle_time = 0;
pfdevfreq->time_last_update = ktime_get();
}
static int panfrost_devfreq_get_dev_status(struct device *dev,
struct devfreq_dev_status *status)
{
struct panfrost_device *pfdev = dev_get_drvdata(dev);
struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
unsigned long irqflags;
status->current_frequency = clk_get_rate(pfdev->clock);
spin_lock_irqsave(&pfdevfreq->lock, irqflags);
panfrost_devfreq_update_utilization(pfdevfreq);
status->total_time = ktime_to_ns(ktime_add(pfdevfreq->busy_time,
pfdevfreq->idle_time));
status->busy_time = ktime_to_ns(pfdevfreq->busy_time);
panfrost_devfreq_reset(pfdevfreq);
spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
dev_dbg(pfdev->dev, "busy %lu total %lu %lu %% freq %lu MHz\n",
status->busy_time, status->total_time,
status->busy_time / (status->total_time / 100),
status->current_frequency / 1000 / 1000);
return 0;
}
static struct devfreq_dev_profile panfrost_devfreq_profile = {
.timer = DEVFREQ_TIMER_DELAYED,
.polling_ms = 50, /* ~3 frames */
.target = panfrost_devfreq_target,
.get_dev_status = panfrost_devfreq_get_dev_status,
};
int panfrost_devfreq_init(struct panfrost_device *pfdev)
{
int ret;
struct dev_pm_opp *opp;
unsigned long cur_freq;
struct device *dev = &pfdev->pdev->dev;
struct devfreq *devfreq;
struct thermal_cooling_device *cooling;
struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
if (pfdev->comp->num_supplies > 1) {
/*
* GPUs with more than 1 supply require platform-specific handling:
* continue without devfreq
*/
DRM_DEV_INFO(dev, "More than 1 supply is not supported yet\n");
return 0;
}
ret = devm_pm_opp_set_regulators(dev, pfdev->comp->supply_names,
pfdev->comp->num_supplies);
if (ret) {
/* Continue if the optional regulator is missing */
if (ret != -ENODEV) {
DRM_DEV_ERROR(dev, "Couldn't set OPP regulators\n");
return ret;
}
}
ret = devm_pm_opp_of_add_table(dev);
if (ret) {
/* Optional, continue without devfreq */
if (ret == -ENODEV)
ret = 0;
return ret;
}
pfdevfreq->opp_of_table_added = true;
spin_lock_init(&pfdevfreq->lock);
panfrost_devfreq_reset(pfdevfreq);
cur_freq = clk_get_rate(pfdev->clock);
opp = devfreq_recommended_opp(dev, &cur_freq, 0);
if (IS_ERR(opp))
return PTR_ERR(opp);
panfrost_devfreq_profile.initial_freq = cur_freq;
dev_pm_opp_put(opp);
/*
* Setup default thresholds for the simple_ondemand governor.
* The values are chosen based on experiments.
*/
pfdevfreq->gov_data.upthreshold = 45;
pfdevfreq->gov_data.downdifferential = 5;
devfreq = devm_devfreq_add_device(dev, &panfrost_devfreq_profile,
DEVFREQ_GOV_SIMPLE_ONDEMAND,
&pfdevfreq->gov_data);
if (IS_ERR(devfreq)) {
DRM_DEV_ERROR(dev, "Couldn't initialize GPU devfreq\n");
return PTR_ERR(devfreq);
}
pfdevfreq->devfreq = devfreq;
cooling = devfreq_cooling_em_register(devfreq, NULL);
if (IS_ERR(cooling))
DRM_DEV_INFO(dev, "Failed to register cooling device\n");
else
pfdevfreq->cooling = cooling;
return 0;
}
void panfrost_devfreq_fini(struct panfrost_device *pfdev)
{
struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
if (pfdevfreq->cooling) {
devfreq_cooling_unregister(pfdevfreq->cooling);
pfdevfreq->cooling = NULL;
}
}
void panfrost_devfreq_resume(struct panfrost_device *pfdev)
{
struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
if (!pfdevfreq->devfreq)
return;
panfrost_devfreq_reset(pfdevfreq);
devfreq_resume_device(pfdevfreq->devfreq);
}
void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
{
struct panfrost_devfreq *pfdevfreq = &pfdev->pfdevfreq;
if (!pfdevfreq->devfreq)
return;
devfreq_suspend_device(pfdevfreq->devfreq);
}
void panfrost_devfreq_record_busy(struct panfrost_devfreq *pfdevfreq)
{
unsigned long irqflags;
if (!pfdevfreq->devfreq)
return;
spin_lock_irqsave(&pfdevfreq->lock, irqflags);
panfrost_devfreq_update_utilization(pfdevfreq);
pfdevfreq->busy_count++;
spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
}
void panfrost_devfreq_record_idle(struct panfrost_devfreq *pfdevfreq)
{
unsigned long irqflags;
if (!pfdevfreq->devfreq)
return;
spin_lock_irqsave(&pfdevfreq->lock, irqflags);
panfrost_devfreq_update_utilization(pfdevfreq);
WARN_ON(--pfdevfreq->busy_count < 0);
spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
}