[RFC PATCH v2 3/5] clk: qcom: gdsc: Avoid actual power off until sync state

From: Abel Vesa <abel.vesa@linaro.org>
To: "Rafael J. Wysocki" <rafael@kernel.org>,
	Kevin Hilman <khilman@kernel.org>,
	Ulf Hansson <ulf.hansson@linaro.org>, Pavel Machek <pavel@ucw.cz>,
	Len Brown <len.brown@intel.com>,
	Greg Kroah-Hartman <gregkh@linuxfoundation.org>,
	Bjorn Andersson <andersson@kernel.org>,
	Andy Gross <agross@kernel.org>,
	Konrad Dybcio <konrad.dybcio@linaro.org>,
	Mike Turquette <mturquette@baylibre.com>,
	Stephen Boyd <sboyd@kernel.org>,
	Saravana Kannan <saravanak@google.com>
Cc: linux-pm@vger.kernel.org,
	Linux Kernel Mailing List <linux-kernel@vger.kernel.org>,
	linux-arm-msm@vger.kernel.org, linux-clk@vger.kernel.org,
	Doug Anderson <dianders@chromium.org>,
	Matthias Kaehlcke <mka@chromium.org>
Subject: [RFC PATCH v2 3/5] clk: qcom: gdsc: Avoid actual power off until sync state
Date: Mon, 20 Mar 2023 15:42:15 +0200	[thread overview]
Message-ID: <20230320134217.1685781-4-abel.vesa@linaro.org> (raw)
In-Reply-To: <20230320134217.1685781-1-abel.vesa@linaro.org>

In case there is a sync state callback registered for a provider,
do not actually power off any gdsc for that provider until sync state
has been reached and return busy instead. Since the qcom_cc is
private, add a helper that returns the gdsc_desc based on the device of
the provider. Finally, add the generic gdsc sync state callback to be
used by the platform specific providers.

Signed-off-by: Abel Vesa <abel.vesa@linaro.org>
---
 drivers/clk/qcom/common.c | 19 +++++++++++++++++++
 drivers/clk/qcom/common.h |  2 ++
 drivers/clk/qcom/gdsc.c   | 26 ++++++++++++++++++++++++++
 drivers/clk/qcom/gdsc.h   |  6 ++++++
 4 files changed, 53 insertions(+)

diff --git a/drivers/clk/qcom/common.c b/drivers/clk/qcom/common.c
index 75f09e6e057e..d7fd1b170c1c 100644
--- a/drivers/clk/qcom/common.c
+++ b/drivers/clk/qcom/common.c
@@ -20,6 +20,7 @@
 struct qcom_cc {
 	struct qcom_reset_controller reset;
 	struct clk_regmap **rclks;
+	struct gdsc_desc *scd;
 	size_t num_rclks;
 };
 
@@ -234,6 +235,13 @@ static struct clk_hw *qcom_cc_clk_hw_get(struct of_phandle_args *clkspec,
 	return cc->rclks[idx] ? &cc->rclks[idx]->hw : NULL;
 }
 
+struct gdsc_desc *qcom_cc_get_gdsc_desc(struct device *dev)
+{
+	struct qcom_cc *cc = dev_get_drvdata(dev);
+
+	return cc->scd;
+}
+
 int qcom_cc_really_probe(struct platform_device *pdev,
 			 const struct qcom_cc_desc *desc, struct regmap *regmap)
 {
@@ -251,6 +259,8 @@ int qcom_cc_really_probe(struct platform_device *pdev,
 	if (!cc)
 		return -ENOMEM;
 
+	dev_set_drvdata(dev, cc);
+
 	reset = &cc->reset;
 	reset->rcdev.of_node = dev->of_node;
 	reset->rcdev.ops = &qcom_reset_ops;
@@ -267,6 +277,9 @@ int qcom_cc_really_probe(struct platform_device *pdev,
 		scd = devm_kzalloc(dev, sizeof(*scd), GFP_KERNEL);
 		if (!scd)
 			return -ENOMEM;
+
+		cc->scd = scd;
+
 		scd->dev = dev;
 		scd->scs = desc->gdscs;
 		scd->num = desc->num_gdscs;
@@ -319,6 +332,12 @@ int qcom_cc_probe(struct platform_device *pdev, const struct qcom_cc_desc *desc)
 }
 EXPORT_SYMBOL_GPL(qcom_cc_probe);
 
+void qcom_cc_sync_state(struct device *dev)
+{
+	gdsc_sync_state(dev);
+}
+EXPORT_SYMBOL_GPL(qcom_cc_sync_state);
+
 int qcom_cc_probe_by_index(struct platform_device *pdev, int index,
 			   const struct qcom_cc_desc *desc)
 {
diff --git a/drivers/clk/qcom/common.h b/drivers/clk/qcom/common.h
index 9c8f7b798d9f..1bea04da0a00 100644
--- a/drivers/clk/qcom/common.h
+++ b/drivers/clk/qcom/common.h
@@ -61,9 +61,11 @@ extern struct regmap *qcom_cc_map(struct platform_device *pdev,
 extern int qcom_cc_really_probe(struct platform_device *pdev,
 				const struct qcom_cc_desc *desc,
 				struct regmap *regmap);
+extern struct gdsc_desc *qcom_cc_get_gdsc_desc(struct device *dev);
 extern int qcom_cc_probe(struct platform_device *pdev,
 			 const struct qcom_cc_desc *desc);
 extern int qcom_cc_probe_by_index(struct platform_device *pdev, int index,
 				  const struct qcom_cc_desc *desc);
+extern void qcom_cc_sync_state(struct device *dev);
 
 #endif
diff --git a/drivers/clk/qcom/gdsc.c b/drivers/clk/qcom/gdsc.c
index 5358e28122ab..af745907dc49 100644
--- a/drivers/clk/qcom/gdsc.c
+++ b/drivers/clk/qcom/gdsc.c
@@ -15,6 +15,8 @@
 #include <linux/regulator/consumer.h>
 #include <linux/reset-controller.h>
 #include <linux/slab.h>
+
+#include "common.h"
 #include "gdsc.h"
 
 #define PWR_ON_MASK		BIT(31)
@@ -319,6 +321,9 @@ static int gdsc_disable(struct generic_pm_domain *domain)
 	struct gdsc *sc = domain_to_gdsc(domain);
 	int ret;
 
+	if (!sc->state_synced)
+		return -EBUSY;
+
 	if (sc->pwrsts == PWRSTS_ON)
 		return gdsc_assert_reset(sc);
 
@@ -365,6 +370,7 @@ static int gdsc_disable(struct generic_pm_domain *domain)
 
 static int gdsc_init(struct gdsc *sc)
 {
+	struct device *dev = sc->dev;
 	u32 mask, val;
 	int on, ret;
 
@@ -452,6 +458,9 @@ static int gdsc_init(struct gdsc *sc)
 	if (!sc->pd.power_on)
 		sc->pd.power_on = gdsc_enable;
 
+	if (!dev_has_sync_state(dev))
+		sc->state_synced = true;
+
 	ret = pm_genpd_init(&sc->pd, NULL, !on);
 	if (ret)
 		goto err_disable_supply;
@@ -496,6 +505,7 @@ int gdsc_register(struct gdsc_desc *desc,
 	for (i = 0; i < num; i++) {
 		if (!scs[i])
 			continue;
+		scs[i]->dev = dev;
 		scs[i]->regmap = regmap;
 		scs[i]->rcdev = rcdev;
 		ret = gdsc_init(scs[i]);
@@ -536,6 +546,22 @@ void gdsc_unregister(struct gdsc_desc *desc)
 	of_genpd_del_provider(dev->of_node);
 }
 
+void gdsc_sync_state(struct device *dev)
+{
+	struct gdsc_desc *scd = qcom_cc_get_gdsc_desc(dev);
+	struct gdsc **scs = scd->scs;
+	size_t num = scd->num;
+	int i;
+
+	for (i = 0; i < num; i++) {
+		if (!scs[i])
+			continue;
+
+		scs[i]->state_synced = true;
+		genpd_queue_power_off_work(&scs[i]->pd);
+	}
+}
+
 /*
  * On SDM845+ the GPU GX domain is *almost* entirely controlled by the GMU
  * running in the CX domain so the CPU doesn't need to know anything about the
diff --git a/drivers/clk/qcom/gdsc.h b/drivers/clk/qcom/gdsc.h
index 803512688336..e1c902caecde 100644
--- a/drivers/clk/qcom/gdsc.h
+++ b/drivers/clk/qcom/gdsc.h
@@ -35,6 +35,7 @@ struct gdsc {
 	struct generic_pm_domain	pd;
 	struct generic_pm_domain	*parent;
 	struct regmap			*regmap;
+	struct device			*dev;
 	unsigned int			gdscr;
 	unsigned int			collapse_ctrl;
 	unsigned int			collapse_mask;
@@ -73,6 +74,8 @@ struct gdsc {
 
 	const char 			*supply;
 	struct regulator		*rsupply;
+
+	bool				state_synced;
 };
 
 struct gdsc_desc {
@@ -86,6 +89,7 @@ int gdsc_register(struct gdsc_desc *desc, struct reset_controller_dev *,
 		  struct regmap *);
 void gdsc_unregister(struct gdsc_desc *desc);
 int gdsc_gx_do_nothing_enable(struct generic_pm_domain *domain);
+void gdsc_sync_state(struct device *dev);
 #else
 static inline int gdsc_register(struct gdsc_desc *desc,
 				struct reset_controller_dev *rcdev,
@@ -94,6 +98,8 @@ static inline int gdsc_register(struct gdsc_desc *desc,
 	return -ENOSYS;
 }
 
+static inline void gdsc_sync_state(struct device *dev) { }
+
 static inline void gdsc_unregister(struct gdsc_desc *desc) {};
 #endif /* CONFIG_QCOM_GDSC */
 #endif /* __QCOM_GDSC_H__ */
-- 
2.34.1

