From: Dmitry Osipenko <digetx@gmail.com>
To: Thierry Reding <thierry.reding@gmail.com>,
MyungJoo Ham <myungjoo.ham@samsung.com>,
Kyungmin Park <kyungmin.park@samsung.com>,
Chanwoo Choi <cw00.choi@samsung.com>,
Jonathan Hunter <jonathanh@nvidia.com>,
Tomeu Vizoso <tomeu.vizoso@collabora.com>
Cc: linux-pm@vger.kernel.org, linux-tegra@vger.kernel.org,
linux-kernel@vger.kernel.org
Subject: [PATCH v3 07/22] PM / devfreq: tegra30: Use CPUFreq notifier
Date: Fri, 28 Jun 2019 00:11:00 +0300 [thread overview]
Message-ID: <20190627211115.21138-8-digetx@gmail.com> (raw)
In-Reply-To: <20190627211115.21138-1-digetx@gmail.com>
The CPU's client need to take into account that CPUFreq may change
while memory activity not, staying high. Thus an appropriate frequency
notifier should be used in addition to the clk-notifier.
Signed-off-by: Dmitry Osipenko <digetx@gmail.com>
---
drivers/devfreq/tegra30-devfreq.c | 105 +++++++++++++++++++++++++-----
1 file changed, 88 insertions(+), 17 deletions(-)
diff --git a/drivers/devfreq/tegra30-devfreq.c b/drivers/devfreq/tegra30-devfreq.c
index 7662e54f0e70..502511ac4602 100644
--- a/drivers/devfreq/tegra30-devfreq.c
+++ b/drivers/devfreq/tegra30-devfreq.c
@@ -17,6 +17,7 @@
#include <linux/platform_device.h>
#include <linux/pm_opp.h>
#include <linux/reset.h>
+#include <linux/workqueue.h>
#include "governor.h"
@@ -154,7 +155,10 @@ struct tegra_devfreq {
struct clk *emc_clock;
unsigned long max_freq;
- struct notifier_block rate_change_nb;
+ struct notifier_block clk_rate_change_nb;
+
+ struct work_struct update_work;
+ struct notifier_block cpu_rate_change_nb;
struct tegra_devfreq_device devices[ARRAY_SIZE(actmon_device_configs)];
@@ -455,8 +459,8 @@ static irqreturn_t actmon_thread_isr(int irq, void *data)
return handled ? IRQ_HANDLED : IRQ_NONE;
}
-static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
- unsigned long action, void *ptr)
+static int tegra_actmon_clk_notify_cb(struct notifier_block *nb,
+ unsigned long action, void *ptr)
{
struct clk_notifier_data *data = ptr;
struct tegra_devfreq_device *dev;
@@ -466,7 +470,7 @@ static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
if (action != POST_RATE_CHANGE)
return NOTIFY_OK;
- tegra = container_of(nb, struct tegra_devfreq, rate_change_nb);
+ tegra = container_of(nb, struct tegra_devfreq, clk_rate_change_nb);
/*
* EMC rate could change due to three reasons:
@@ -495,6 +499,37 @@ static int tegra_actmon_rate_notify_cb(struct notifier_block *nb,
return NOTIFY_OK;
}
+static void tegra_actmon_delayed_update(struct work_struct *work)
+{
+ struct tegra_devfreq *tegra = container_of(work, struct tegra_devfreq,
+ update_work);
+
+ mutex_lock(&tegra->devfreq->lock);
+ update_devfreq(tegra->devfreq);
+ mutex_unlock(&tegra->devfreq->lock);
+}
+
+static int tegra_actmon_cpu_notify_cb(struct notifier_block *nb,
+ unsigned long action, void *ptr)
+{
+ struct tegra_devfreq *tegra;
+
+ if (action != CPUFREQ_POSTCHANGE)
+ return NOTIFY_OK;
+
+ tegra = container_of(nb, struct tegra_devfreq, cpu_rate_change_nb);
+
+ /*
+ * CPUFreq driver should support CPUFREQ_ASYNC_NOTIFICATION in order
+ * to allow asynchronous notifications. This means we can't block
+ * here for too long, otherwise CPUFreq's core will complain with a
+ * warning splat.
+ */
+ schedule_work(&tegra->update_work);
+
+ return NOTIFY_OK;
+}
+
static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
struct tegra_devfreq_device *dev)
{
@@ -526,9 +561,16 @@ static void tegra_actmon_configure_device(struct tegra_devfreq *tegra,
device_writel(dev, val, ACTMON_DEV_CTRL);
}
-static void tegra_actmon_start(struct tegra_devfreq *tegra)
+static void tegra_actmon_stop_device(struct tegra_devfreq_device *dev)
+{
+ device_writel(dev, 0x00000000, ACTMON_DEV_CTRL);
+ device_writel(dev, ACTMON_INTR_STATUS_CLEAR, ACTMON_DEV_INTR_STATUS);
+}
+
+static int tegra_actmon_start(struct tegra_devfreq *tegra)
{
unsigned int i;
+ int err;
actmon_writel(tegra, ACTMON_SAMPLING_PERIOD - 1,
ACTMON_GLB_PERIOD_CTRL);
@@ -536,7 +578,30 @@ static void tegra_actmon_start(struct tegra_devfreq *tegra)
for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
tegra_actmon_configure_device(tegra, &tegra->devices[i]);
+ /*
+ * We are estimating CPU's memory bandwidth requirement based on
+ * amount of memory accesses and system's load, judging by CPU's
+ * frequency. We also don't want to receive events about CPU's
+ * frequency transaction when governor is stopped, hence notifier
+ * is registered dynamically.
+ */
+ err = cpufreq_register_notifier(&tegra->cpu_rate_change_nb,
+ CPUFREQ_TRANSITION_NOTIFIER);
+ if (err) {
+ dev_err(tegra->devfreq->dev.parent,
+ "Failed to register rate change notifier: %d\n", err);
+ goto err_stop;
+ }
+
enable_irq(tegra->irq);
+
+ return 0;
+
+err_stop:
+ for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
+ tegra_actmon_stop_device(&tegra->devices[i]);
+
+ return err;
}
static void tegra_actmon_stop(struct tegra_devfreq *tegra)
@@ -545,11 +610,13 @@ static void tegra_actmon_stop(struct tegra_devfreq *tegra)
disable_irq(tegra->irq);
- for (i = 0; i < ARRAY_SIZE(tegra->devices); i++) {
- device_writel(&tegra->devices[i], 0x00000000, ACTMON_DEV_CTRL);
- device_writel(&tegra->devices[i], ACTMON_INTR_STATUS_CLEAR,
- ACTMON_DEV_INTR_STATUS);
- }
+ cpufreq_unregister_notifier(&tegra->cpu_rate_change_nb,
+ CPUFREQ_TRANSITION_NOTIFIER);
+
+ cancel_work_sync(&tegra->update_work);
+
+ for (i = 0; i < ARRAY_SIZE(tegra->devices); i++)
+ tegra_actmon_stop_device(&tegra->devices[i]);
}
static int tegra_devfreq_target(struct device *dev, unsigned long *freq,
@@ -658,6 +725,7 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
unsigned int event, void *data)
{
struct tegra_devfreq *tegra = dev_get_drvdata(devfreq->dev.parent);
+ int ret = 0;
/*
* Couple device with the governor early as it is needed at
@@ -668,7 +736,7 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
switch (event) {
case DEVFREQ_GOV_START:
devfreq_monitor_start(devfreq);
- tegra_actmon_start(tegra);
+ ret = tegra_actmon_start(tegra);
break;
case DEVFREQ_GOV_STOP:
@@ -683,11 +751,11 @@ static int tegra_governor_event_handler(struct devfreq *devfreq,
case DEVFREQ_GOV_RESUME:
devfreq_monitor_resume(devfreq);
- tegra_actmon_start(tegra);
+ ret = tegra_actmon_start(tegra);
break;
}
- return 0;
+ return ret;
}
static struct devfreq_governor tegra_devfreq_governor = {
@@ -793,9 +861,12 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
platform_set_drvdata(pdev, tegra);
- tegra->rate_change_nb.notifier_call = tegra_actmon_rate_notify_cb;
+ tegra->cpu_rate_change_nb.notifier_call = tegra_actmon_cpu_notify_cb;
+ INIT_WORK(&tegra->update_work, tegra_actmon_delayed_update);
+
+ tegra->clk_rate_change_nb.notifier_call = tegra_actmon_clk_notify_cb;
err = clk_notifier_register(tegra->emc_clock,
- &tegra->rate_change_nb);
+ &tegra->clk_rate_change_nb);
if (err) {
dev_err(&pdev->dev,
"Failed to register rate change notifier\n");
@@ -822,7 +893,7 @@ static int tegra_devfreq_probe(struct platform_device *pdev)
devfreq_remove_governor(&tegra_devfreq_governor);
unreg_notifier:
- clk_notifier_unregister(tegra->emc_clock, &tegra->rate_change_nb);
+ clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
remove_opps:
dev_pm_opp_remove_all_dynamic(&pdev->dev);
@@ -840,7 +911,7 @@ static int tegra_devfreq_remove(struct platform_device *pdev)
devfreq_remove_device(tegra->devfreq);
devfreq_remove_governor(&tegra_devfreq_governor);
- clk_notifier_unregister(tegra->emc_clock, &tegra->rate_change_nb);
+ clk_notifier_unregister(tegra->emc_clock, &tegra->clk_rate_change_nb);
dev_pm_opp_remove_all_dynamic(&pdev->dev);
reset_control_reset(tegra->reset);
--
2.22.0
next prev parent reply other threads:[~2019-06-27 21:11 UTC|newest]
Thread overview: 25+ messages / expand[flat|nested] mbox.gz Atom feed top
2019-06-27 21:10 [PATCH v3 00/22] More improvements for Tegra30 devfreq driver Dmitry Osipenko
2019-06-27 21:10 ` [PATCH v3 01/22] PM / devfreq: tegra30: Change irq type to unsigned int Dmitry Osipenko
2019-06-27 21:10 ` [PATCH v3 02/22] PM / devfreq: tegra30: Keep interrupt disabled while governor is stopped Dmitry Osipenko
2019-06-27 21:10 ` [PATCH v3 03/22] PM / devfreq: tegra30: Handle possible round-rate error Dmitry Osipenko
2019-06-27 21:10 ` [PATCH v3 04/22] PM / devfreq: tegra30: Drop write-barrier Dmitry Osipenko
2019-06-27 21:10 ` [PATCH v3 05/22] PM / devfreq: tegra30: Set up watermarks properly Dmitry Osipenko
2019-06-27 21:10 ` [PATCH v3 06/22] PM / devfreq: tegra30: Tune up boosting thresholds Dmitry Osipenko
2019-06-27 21:11 ` Dmitry Osipenko [this message]
2019-06-27 21:11 ` [PATCH v3 08/22] PM / devfreq: tegra30: Move clk-notifier's registration to governor's start Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 09/22] PM / devfreq: tegra30: Reset boosting on startup Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 10/22] PM / devfreq: tegra30: Don't enable consecutive-down interrupt " Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 11/22] PM / devfreq: tegra30: Add debug messages Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 12/22] PM / devfreq: tegra30: Inline all one-line functions Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 13/22] PM / devfreq: tegra30: Constify structs Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 14/22] PM / devfreq: tegra30: Ensure that target freq won't overflow Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 15/22] PM / devfreq: tegra30: Fix integer overflow on CPU's freq max out Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 16/22] PM / devfreq: tegra30: Use kHz units uniformly in the code Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 17/22] PM / devfreq: tegra30: Use tracepoints for debugging Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 18/22] PM / devfreq: tegra30: Optimize CPUFreq notifier Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 19/22] PM / devfreq: tegra30: Optimize upper consecutive watermark selection Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 20/22] PM / devfreq: tegra30: Optimize upper average " Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 21/22] PM / devfreq: tegra30: Include appropriate header Dmitry Osipenko
2019-06-27 21:11 ` [PATCH v3 22/22] PM / devfreq: tegra20/30: Add Dmitry as a maintainer Dmitry Osipenko
[not found] ` <CGME20190627211230epcas5p2504c225e67a823a586768a2749248b72@epcms1p3>
2019-06-28 6:48 ` [PATCH v3 02/22] PM / devfreq: tegra30: Keep interrupt disabled while governor is stopped MyungJoo Ham
2019-06-28 7:12 ` Dmitry Osipenko
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