From ed85df3f60740bb4be23fbc2db283d59b361a834 Mon Sep 17 00:00:00 2001 From: =?utf8?q?Cl=C3=A9ment=20P=C3=A9ron?= Date: Fri, 10 Jul 2020 11:54:00 +0200 Subject: [PATCH] drm/panfrost: use spinlock instead of atomic MIME-Version: 1.0 Content-Type: text/plain; charset=utf8 Content-Transfer-Encoding: 8bit Convert busy_count to a simple int protected by spinlock. Reviewed-by: Steven Price Reviewed-by: Alyssa Rosenzweig Signed-off-by: Clément Péron Signed-off-by: Rob Herring Link: https://patchwork.freedesktop.org/patch/msgid/20200710095409.407087-6-peron.clem@gmail.com --- drivers/gpu/drm/panfrost/panfrost_devfreq.c | 43 +++++++++++++++++++++-------- drivers/gpu/drm/panfrost/panfrost_devfreq.h | 9 +++++- 2 files changed, 40 insertions(+), 12 deletions(-) diff --git a/drivers/gpu/drm/panfrost/panfrost_devfreq.c b/drivers/gpu/drm/panfrost/panfrost_devfreq.c index 9625503..78753cf 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 0697f8d..3392df1 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 #include struct devfreq; @@ -14,10 +15,16 @@ 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 between multiple jobs. + */ + spinlock_t lock; }; int panfrost_devfreq_init(struct panfrost_device *pfdev); -- 2.7.4