From: "Clément Péron" <peron.clem@gmail.com>
To: Rob Herring <robh@kernel.org>,
Tomeu Vizoso <tomeu.vizoso@collabora.com>,
Steven Price <steven.price@arm.com>,
Alyssa Rosenzweig <alyssa.rosenzweig@collabora.com>,
Viresh Kumar <vireshk@kernel.org>, Nishanth Menon <nm@ti.com>,
Stephen Boyd <sboyd@kernel.org>,
Maxime Ripard <mripard@kernel.org>, Chen-Yu Tsai <wens@csie.org>
Cc: dri-devel@lists.freedesktop.org, linux-kernel@vger.kernel.org,
"Clément Péron" <peron.clem@gmail.com>
Subject: [PATCH 05/15] drm/panfrost: use spinlock instead of atomic
Date: Sun, 10 May 2020 18:55:28 +0200 [thread overview]
Message-ID: <20200510165538.19720-6-peron.clem@gmail.com> (raw)
In-Reply-To: <20200510165538.19720-1-peron.clem@gmail.com>
Convert busy_count to a simple int protected by spinlock.
Signed-off-by: Clément Péron <peron.clem@gmail.com>
---
drivers/gpu/drm/panfrost/panfrost_devfreq.c | 43 +++++++++++++++------
drivers/gpu/drm/panfrost/panfrost_devfreq.h | 10 ++++-
2 files changed, 41 insertions(+), 12 deletions(-)
diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
index 962550363391..78753cfb59fb 100644
--- a/drivers/gpu/drm/panfrost/panfrost_devfreq.c
+++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.c
@@ -12,16 +12,12 @@
static void panfrost_devfreq_update_utilization(struct panfrost_devfreq *pfdevfreq)
{
- ktime_t now;
- ktime_t last;
-
- if (!pfdevfreq->devfreq)
- return;
+ ktime_t now, last;
now = ktime_get();
last = pfdevfreq->time_last_update;
- if (atomic_read(&pfdevfreq->busy_count) > 0)
+ if (pfdevfreq->busy_count > 0)
pfdevfreq->busy_time += ktime_sub(now, last);
else
pfdevfreq->idle_time += ktime_sub(now, last);
@@ -59,10 +55,14 @@ static int panfrost_devfreq_get_dev_status(struct device *dev,
{
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->current_frequency = clk_get_rate(pfdev->clock);
status->total_time = ktime_to_ns(ktime_add(pfdevfreq->busy_time,
pfdevfreq->idle_time));
@@ -70,6 +70,8 @@ static int panfrost_devfreq_get_dev_status(struct device *dev,
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),
@@ -100,6 +102,8 @@ int panfrost_devfreq_init(struct panfrost_device *pfdev)
else if (ret)
return ret;
+ spin_lock_init(&pfdevfreq->lock);
+
panfrost_devfreq_reset(pfdevfreq);
cur_freq = clk_get_rate(pfdev->clock);
@@ -162,15 +166,32 @@ void panfrost_devfreq_suspend(struct panfrost_device *pfdev)
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);
- atomic_inc(&pfdevfreq->busy_count);
+
+ pfdevfreq->busy_count++;
+
+ spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
}
void panfrost_devfreq_record_idle(struct panfrost_devfreq *pfdevfreq)
{
- int count;
+ unsigned long irqflags;
+
+ if (!pfdevfreq->devfreq)
+ return;
+
+ spin_lock_irqsave(&pfdevfreq->lock, irqflags);
panfrost_devfreq_update_utilization(pfdevfreq);
- count = atomic_dec_if_positive(&pfdevfreq->busy_count);
- WARN_ON(count < 0);
+
+ WARN_ON(--pfdevfreq->busy_count < 0);
+
+ spin_unlock_irqrestore(&pfdevfreq->lock, irqflags);
}
diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.h b/drivers/gpu/drm/panfrost/panfrost_devfreq.h
index 0697f8d5aa34..e6629900a618 100644
--- a/drivers/gpu/drm/panfrost/panfrost_devfreq.h
+++ b/drivers/gpu/drm/panfrost/panfrost_devfreq.h
@@ -4,6 +4,7 @@
#ifndef __PANFROST_DEVFREQ_H__
#define __PANFROST_DEVFREQ_H__
+#include <linux/spinlock.h>
#include <linux/ktime.h>
struct devfreq;
@@ -14,10 +15,17 @@ struct panfrost_device;
struct panfrost_devfreq {
struct devfreq *devfreq;
struct thermal_cooling_device *cooling;
+
ktime_t busy_time;
ktime_t idle_time;
ktime_t time_last_update;
- atomic_t busy_count;
+ int busy_count;
+ /*
+ * Protect busy_time, idle_time, time_last_update and busy_count
+ * because these can be updated concurrently, for example by the GP
+ * and PP interrupts.
+ */
+ spinlock_t lock;
};
int panfrost_devfreq_init(struct panfrost_device *pfdev);
--
2.20.1
next prev parent reply other threads:[~2020-05-10 16:55 UTC|newest]
Thread overview: 36+ messages / expand[flat|nested] mbox.gz Atom feed top
2020-05-10 16:55 [PATCH 00/15][RFC] Add regulator devfreq support to Panfrost Clément Péron
2020-05-10 16:55 ` [PATCH 01/15] drm/panfrost: avoid static declaration Clément Péron
2020-05-28 13:22 ` Steven Price
2020-05-10 16:55 ` [PATCH 02/15] drm/panfrost: clean headers in devfreq Clément Péron
2020-05-28 13:22 ` Steven Price
2020-05-10 16:55 ` [PATCH 03/15] drm/panfrost: don't use pfdevfreq.busy_count to know if hw is idle Clément Péron
2020-05-28 13:22 ` Steven Price
2020-05-10 16:55 ` [PATCH 04/15] drm/panfrost: introduce panfrost_devfreq struct Clément Péron
2020-05-28 13:22 ` Steven Price
2020-05-10 16:55 ` Clément Péron [this message]
2020-05-28 13:22 ` [PATCH 05/15] drm/panfrost: use spinlock instead of atomic Steven Price
2020-05-29 12:20 ` Robin Murphy
2020-05-29 12:35 ` Clément Péron
2020-05-29 12:47 ` Steven Price
2020-05-10 16:55 ` [PATCH 06/15] drm/panfrost: properly handle error in probe Clément Péron
2020-05-28 13:22 ` Steven Price
2020-05-10 16:55 ` [PATCH 07/15] drm/panfrost: use device_property_present to check for OPP Clément Péron
2020-05-28 13:22 ` Steven Price
2020-05-29 12:45 ` Clément Péron
2020-05-10 16:55 ` [PATCH 08/15] drm/panfrost: move devfreq_init()/fini() in device Clément Péron
2020-05-28 13:22 ` Steven Price
2020-05-29 12:38 ` Clément Péron
2020-06-08 11:55 ` Tomeu Vizoso
2020-05-10 16:55 ` [PATCH 09/15] drm/panfrost: dynamically alloc regulators Clément Péron
2020-05-28 13:22 ` Steven Price
2020-05-10 16:55 ` [PATCH 10/15] drm/panfrost: add regulators to devfreq Clément Péron
2020-05-28 13:23 ` Steven Price
2020-05-29 12:37 ` Clément Péron
2020-05-10 16:55 ` [PATCH 11/15] drm/panfrost: set devfreq clock name Clément Péron
2020-05-28 13:23 ` Steven Price
2020-05-29 12:35 ` Clément Péron
2020-05-10 16:55 ` [PATCH 12/15] arm64: defconfig: Enable devfreq cooling device Clément Péron
2020-05-10 16:55 ` [PATCH 13/15] arm64: dts: allwinner: h6: Add cooling map for GPU Clément Péron
2020-05-10 16:55 ` [PATCH 14/15] [DO NOT MERGE] arm64: dts: allwinner: h6: Add GPU OPP table Clément Péron
2020-05-10 16:55 ` [PATCH 15/15] [DO NOT MERGE] arm64: dts: allwinner: force GPU regulator to be always Clément Péron
2020-05-11 5:43 ` [PATCH 00/15][RFC] Add regulator devfreq support to Panfrost Tomeu Vizoso
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