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154 lines
4.8 KiB
Diff
154 lines
4.8 KiB
Diff
From: Sylwester Nawrocki <s.nawrocki@samsung.com>
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To: krzk@kernel.org, vireshk@kernel.org, robh+dt@kernel.org
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Cc: sboyd@kernel.org, roger.lu@mediatek.com,
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linux-pm@vger.kernel.org, linux-arm-kernel@lists.infradead.org,
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linux-samsung-soc@vger.kernel.org, devicetree@vger.kernel.org,
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b.zolnierkie@samsung.com, m.szyprowski@samsung.com,
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Stephen Boyd <sboyd@codeaurora.org>,
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Sylwester Nawrocki <s.nawrocki@samsung.com>
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Subject: [PATCH v5 1/4] PM / OPP: Support adjusting OPP voltages at runtime
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Date: Wed, 16 Oct 2019 16:57:53 +0200
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Message-ID: <20191016145756.16004-2-s.nawrocki@samsung.com> (raw)
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In-Reply-To: <20191016145756.16004-1-s.nawrocki@samsung.com>
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From: Stephen Boyd <sboyd@codeaurora.org>
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On some SoCs the Adaptive Voltage Scaling (AVS) technique is
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employed to optimize the operating voltage of a device. At a
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given frequency, the hardware monitors dynamic factors and either
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makes a suggestion for how much to adjust a voltage for the
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current frequency, or it automatically adjusts the voltage
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without software intervention. Add an API to the OPP library for
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the former case, so that AVS type devices can update the voltages
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for an OPP when the hardware determines the voltage should
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change. The assumption is that drivers like CPUfreq or devfreq
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will register for the OPP notifiers and adjust the voltage
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according to suggestions that AVS makes.
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This patch is derived from [1] submitted by Stephen.
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[1] https://lore.kernel.org/patchwork/patch/599279/
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Signed-off-by: Stephen Boyd <sboyd@codeaurora.org>
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Signed-off-by: Roger Lu <roger.lu@mediatek.com>
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[s.nawrocki@samsung.com: added handling of OPP min/max voltage]
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Signed-off-by: Sylwester Nawrocki <s.nawrocki@samsung.com>
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---
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drivers/opp/core.c | 69 ++++++++++++++++++++++++++++++++++++++++++
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include/linux/pm_opp.h | 13 ++++++++
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2 files changed, 82 insertions(+)
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--- a/drivers/opp/core.c
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+++ b/drivers/opp/core.c
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@@ -1629,6 +1629,75 @@ put_table:
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}
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/**
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+ * dev_pm_opp_adjust_voltage() - helper to change the voltage of an OPP
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+ * @dev: device for which we do this operation
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+ * @freq: OPP frequency to adjust voltage of
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+ * @u_volt: new OPP target voltage
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+ * @u_volt_min: new OPP min voltage
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+ * @u_volt_max: new OPP max voltage
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+ *
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+ * Return: -EINVAL for bad pointers, -ENOMEM if no memory available for the
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+ * copy operation, returns 0 if no modifcation was done OR modification was
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+ * successful.
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+ */
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+int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
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+ unsigned long u_volt, unsigned long u_volt_min,
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+ unsigned long u_volt_max)
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+
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+{
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+ struct opp_table *opp_table;
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+ struct dev_pm_opp *tmp_opp, *opp = ERR_PTR(-ENODEV);
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+ int r = 0;
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+
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+ /* Find the opp_table */
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+ opp_table = _find_opp_table(dev);
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+ if (IS_ERR(opp_table)) {
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+ r = PTR_ERR(opp_table);
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+ dev_warn(dev, "%s: Device OPP not found (%d)\n", __func__, r);
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+ return r;
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+ }
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+
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+ mutex_lock(&opp_table->lock);
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+
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+ /* Do we have the frequency? */
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+ list_for_each_entry(tmp_opp, &opp_table->opp_list, node) {
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+ if (tmp_opp->rate == freq) {
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+ opp = tmp_opp;
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+ break;
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+ }
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+ }
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+
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+ if (IS_ERR(opp)) {
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+ r = PTR_ERR(opp);
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+ goto adjust_unlock;
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+ }
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+
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+ /* Is update really needed? */
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+ if (opp->supplies->u_volt == u_volt)
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+ goto adjust_unlock;
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+
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+ opp->supplies->u_volt = u_volt;
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+ opp->supplies->u_volt_min = u_volt_min;
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+ opp->supplies->u_volt_max = u_volt_max;
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+
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+ dev_pm_opp_get(opp);
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+ mutex_unlock(&opp_table->lock);
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+
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+ /* Notify the voltage change of the OPP */
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+ blocking_notifier_call_chain(&opp_table->head, OPP_EVENT_ADJUST_VOLTAGE,
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+ opp);
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+
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+ dev_pm_opp_put(opp);
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+ goto adjust_put_table;
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+
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+adjust_unlock:
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+ mutex_unlock(&opp_table->lock);
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+adjust_put_table:
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+ dev_pm_opp_put_opp_table(opp_table);
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+ return r;
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+}
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+
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+/**
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* dev_pm_opp_enable() - Enable a specific OPP
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* @dev: device for which we do this operation
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* @freq: OPP frequency to enable
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--- a/include/linux/pm_opp.h
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+++ b/include/linux/pm_opp.h
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@@ -25,6 +25,7 @@ struct opp_table;
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enum dev_pm_opp_event {
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OPP_EVENT_ADD, OPP_EVENT_REMOVE, OPP_EVENT_ENABLE, OPP_EVENT_DISABLE,
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+ OPP_EVENT_ADJUST_VOLTAGE,
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};
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/**
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@@ -108,6 +109,10 @@ int dev_pm_opp_add(struct device *dev, u
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unsigned long u_volt);
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void dev_pm_opp_remove(struct device *dev, unsigned long freq);
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+int dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
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+ unsigned long u_volt, unsigned long u_volt_min,
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+ unsigned long u_volt_max);
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+
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int dev_pm_opp_enable(struct device *dev, unsigned long freq);
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int dev_pm_opp_disable(struct device *dev, unsigned long freq);
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@@ -208,6 +213,14 @@ static inline void dev_pm_opp_remove(str
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{
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}
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+static inline int
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+dev_pm_opp_adjust_voltage(struct device *dev, unsigned long freq,
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+ unsigned long u_volt, unsigned long u_volt_min,
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+ unsigned long u_volt_max)
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+{
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+ return 0;
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+}
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+
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static inline int dev_pm_opp_enable(struct device *dev, unsigned long freq)
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{
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return 0;
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