[PATCH v6 3/6] soc: samsung: exynos-pmu: generalise gs101-specific cpu{idle,hotplug} for Exynos SoCs

From: Alexey Klimov <alexey.klimov@linaro.org>
Date: 2026-09-02 04:06:11
Also in: linux-devicetree, linux-samsung-soc, lkml
Subsystem: arm/samsung s3c, s5p and exynos arm architectures, google tensor soc support, the rest · Maintainers: Krzysztof Kozlowski, Peter Griffin, Linus Torvalds

The cpuhotplug and cpuidle support for GS101-based SoCs which
utilizes GS101 PMU interrupts generation block can be generalised
to be (re)used for other Exynos-based SoCs. Also, the GS101 PMU
interrupts generation block is not exclusive to Google GS101 SoCs
and should be made more Exynos-generic.

Specifically, apply the following changes:
- rename gs101-specific calls, structs, names to be exynos-prefixed;
- move exynos_pmu_context and CPU_INFORM_* defines into exynos-pmu.h;
- introduce cpu_pmu_{offline,online} callbacks in driver-specific
  exynos_pmu_data which can be used to hold PMU and PMU intr gen
  update routines for different platforms and update cpuidle and cpuhotplug
  support to use them;
- add checks for the presense of cpu_pmu_{offline,online} callbacks;
- move and rename gs101-specific cpu{offline,online} PMU updates
  routines into gs101-pmu.c file, also removing underscore prefix;
- update gs101_pmu_data to use newly introduced callbacks;
- rename PMU interrupts generation GS101_INTR_* regs to EXYNOS_INTR_*.

This allows other platforms to add cpuhotplug and cpuidle support in
a similar manner, using their own platform-specific PMU and
PMU intr gen update routines.

Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Tested-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
---
 drivers/soc/samsung/exynos-pmu.c            | 125 ++++++----------------------
 drivers/soc/samsung/exynos-pmu.h            |  33 ++++++++
 drivers/soc/samsung/gs101-pmu.c             |  51 ++++++++++++
 include/linux/soc/samsung/exynos-regs-pmu.h |  10 +--
 4 files changed, 114 insertions(+), 105 deletions(-)

diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c
index fce922d5ab92..02076148c53d 100644
--- a/drivers/soc/samsung/exynos-pmu.c
+++ b/drivers/soc/samsung/exynos-pmu.c

@@ -24,24 +24,6 @@
 
 #include "exynos-pmu.h"
 
-struct exynos_pmu_context {
-	struct device *dev;
-	const struct exynos_pmu_data *pmu_data;
-	struct regmap *pmureg;
-	struct regmap *pmuintrgen;
-	/*
-	 * Serialization lock for CPU hot plug and cpuidle ACPM hint
-	 * programming. Also protects in_cpuhp, sys_insuspend & sys_inreboot
-	 * flags.
-	 */
-	raw_spinlock_t cpupm_lock;
-	unsigned long *in_cpuhp;
-	bool sys_insuspend;
-	bool sys_inreboot;
-	int cpuhp_prepare_state;
-	int cpuhp_online_state;
-};
-
 void __iomem *pmu_base_addr;
 static struct exynos_pmu_context *pmu_context;
 /* forward declaration */

@@ -221,44 +203,8 @@ struct regmap *exynos_get_pmu_regmap_by_phandle(struct device_node *np,
 }
 EXPORT_SYMBOL_GPL(exynos_get_pmu_regmap_by_phandle);
 
-/*
- * CPU_INFORM register "hint" values are required to be programmed in addition to
- * the standard PSCI calls to have functional CPU hotplug and CPU idle states.
- * This is required to workaround limitations in the el3mon/ACPM firmware.
- */
-#define CPU_INFORM_CLEAR	0
-#define CPU_INFORM_C2		1
-
-/*
- * __gs101_cpu_pmu_ prefix functions are common code shared by CPU PM notifiers
- * (CPUIdle) and CPU hotplug callbacks. Functions should be called with IRQs
- * disabled and cpupm_lock held.
- */
-static int __gs101_cpu_pmu_online(unsigned int cpu)
-	__must_hold(&pmu_context->cpupm_lock)
-{
-	unsigned int cpuhint = smp_processor_id();
-	u32 reg, mask;
-
-	/* clear cpu inform hint */
-	regmap_write(pmu_context->pmureg, GS101_CPU_INFORM(cpuhint),
-		     CPU_INFORM_CLEAR);
-
-	mask = BIT(cpu);
-
-	regmap_update_bits(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_ENABLE,
-			   mask, (0 << cpu));
-
-	regmap_read(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_UPEND, &reg);
-
-	regmap_write(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_CLEAR,
-		     reg & mask);
-
-	return 0;
-}
-
 /* Called from CPU PM notifier (CPUIdle code path) with IRQs disabled */
-static int gs101_cpu_pmu_online(void)
+static int exynos_cpu_pmu_online(void)
 {
 	int cpu;

@@ -270,20 +216,20 @@ static int gs101_cpu_pmu_online(void)
 	}
 
 	cpu = smp_processor_id();
-	__gs101_cpu_pmu_online(cpu);
+	pmu_context->pmu_data->cpu_pmu_online(pmu_context, cpu);
 	raw_spin_unlock(&pmu_context->cpupm_lock);
 
 	return NOTIFY_OK;
 }
 
 /* Called from CPU hot plug callback with IRQs enabled */
-static int gs101_cpuhp_pmu_online(unsigned int cpu)
+static int exynos_cpuhp_pmu_online(unsigned int cpu)
 {
 	unsigned long flags;
 
 	raw_spin_lock_irqsave(&pmu_context->cpupm_lock, flags);
 
-	__gs101_cpu_pmu_online(cpu);
+	pmu_context->pmu_data->cpu_pmu_online(pmu_context, cpu);
 	/*
 	 * Mark this CPU as having finished the hotplug.
 	 * This means this CPU can now enter C2 idle state.

@@ -294,35 +240,8 @@ static int gs101_cpuhp_pmu_online(unsigned int cpu)
 	return 0;
 }
 
-/* Common function shared by both CPU hot plug and CPUIdle */
-static int __gs101_cpu_pmu_offline(unsigned int cpu)
-	__must_hold(&pmu_context->cpupm_lock)
-{
-	unsigned int cpuhint = smp_processor_id();
-	u32 reg, mask;
-
-	/* set cpu inform hint */
-	regmap_write(pmu_context->pmureg, GS101_CPU_INFORM(cpuhint),
-		     CPU_INFORM_C2);
-
-	mask = BIT(cpu);
-	regmap_update_bits(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_ENABLE,
-			   mask, BIT(cpu));
-
-	regmap_read(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_UPEND, &reg);
-	regmap_write(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_CLEAR,
-		     reg & mask);
-
-	mask = (BIT(cpu + 8));
-	regmap_read(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_UPEND, &reg);
-	regmap_write(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_CLEAR,
-		     reg & mask);
-
-	return 0;
-}
-
 /* Called from CPU PM notifier (CPUIdle code path) with IRQs disabled */
-static int gs101_cpu_pmu_offline(void)
+static int exynos_cpu_pmu_offline(void)
 {
 	int cpu;

@@ -340,14 +259,14 @@ static int gs101_cpu_pmu_offline(void)
 		return NOTIFY_OK;
 	}
 
-	__gs101_cpu_pmu_offline(cpu);
+	pmu_context->pmu_data->cpu_pmu_offline(pmu_context, cpu);
 	raw_spin_unlock(&pmu_context->cpupm_lock);
 
 	return NOTIFY_OK;
 }
 
 /* Called from CPU hot plug callback with IRQs enabled */
-static int gs101_cpuhp_pmu_offline(unsigned int cpu)
+static int exynos_cpuhp_pmu_offline(unsigned int cpu)
 {
 	unsigned long flags;

@@ -357,29 +276,29 @@ static int gs101_cpuhp_pmu_offline(unsigned int cpu)
 	 * ACPM the CPU entering hotplug should not enter C2 idle state.
 	 */
 	set_bit(cpu, pmu_context->in_cpuhp);
-	__gs101_cpu_pmu_offline(cpu);
+	pmu_context->pmu_data->cpu_pmu_offline(pmu_context, cpu);
 
 	raw_spin_unlock_irqrestore(&pmu_context->cpupm_lock, flags);
 
 	return 0;
 }
 
-static int gs101_cpu_pm_notify_callback(struct notifier_block *self,
+static int exynos_cpu_pm_notify_callback(struct notifier_block *self,
 					unsigned long action, void *v)
 {
 	switch (action) {
 	case CPU_PM_ENTER:
-		return gs101_cpu_pmu_offline();
+		return exynos_cpu_pmu_offline();
 
 	case CPU_PM_EXIT:
-		return gs101_cpu_pmu_online();
+		return exynos_cpu_pmu_online();
 	}
 
 	return NOTIFY_OK;
 }
 
-static struct notifier_block gs101_cpu_pm_notifier = {
-	.notifier_call = gs101_cpu_pm_notify_callback,
+static struct notifier_block exynos_cpu_pm_notifier = {
+	.notifier_call = exynos_cpu_pm_notify_callback,
 	/*
 	 * We want to be called first, as the ACPM hint and handshake is what
 	 * puts the CPU into C2.

@@ -411,7 +330,7 @@ static struct notifier_block exynos_cpupm_reboot_nb = {
 
 static void destroy_cpuhp_and_cpuidle(void)
 {
-	cpu_pm_unregister_notifier(&gs101_cpu_pm_notifier);
+	cpu_pm_unregister_notifier(&exynos_cpu_pm_notifier);
 	unregister_reboot_notifier(&exynos_cpupm_reboot_nb);
 
 	if (pmu_context->cpuhp_prepare_state != CPUHP_INVALID)

@@ -428,6 +347,12 @@ static int setup_cpuhp_and_cpuidle(struct device *dev)
 	void __iomem *virt_addr;
 	int ret, cpu;
 
+	if (!pmu_context->pmu_data->cpu_pmu_offline || !pmu_context->pmu_data->cpu_pmu_online) {
+		dev_warn(dev,
+			"PMU write/update sequence is not present for cpuhotplug and cpuidle\n");
+		return 0;
+	}
+
 	if (!intr_gen_node) {
 		/*
 		 * To maintain support for older DTs that didn't specify syscon

@@ -468,28 +393,28 @@ static int setup_cpuhp_and_cpuidle(struct device *dev)
 
 	/* set PMU to power on */
 	for_each_online_cpu(cpu)
-		gs101_cpuhp_pmu_online(cpu);
+		exynos_cpuhp_pmu_online(cpu);
 
 	/* register CPU hotplug callbacks */
 	pmu_context->cpuhp_prepare_state = CPUHP_INVALID;
 	pmu_context->cpuhp_online_state = CPUHP_INVALID;
 
 	ret = cpuhp_setup_state(CPUHP_BP_PREPARE_DYN, "soc/exynos-pmu:prepare",
-				gs101_cpuhp_pmu_online, NULL);
+				exynos_cpuhp_pmu_online, NULL);
 	if (ret < 0)
 		return ret;
 
 	pmu_context->cpuhp_prepare_state = ret;
 
 	ret = cpuhp_setup_state(CPUHP_AP_ONLINE_DYN, "soc/exynos-pmu:online",
-				NULL, gs101_cpuhp_pmu_offline);
+				NULL, exynos_cpuhp_pmu_offline);
 	if (ret < 0)
 		goto clean_cpuhp_states;
 
 	pmu_context->cpuhp_online_state = ret;
 
 	/* register CPU PM notifiers for cpuidle */
-	ret = cpu_pm_register_notifier(&gs101_cpu_pm_notifier);
+	ret = cpu_pm_register_notifier(&exynos_cpu_pm_notifier);
 	if (ret)
 		goto clean_cpuhp_states;

@@ -498,7 +423,7 @@ static int setup_cpuhp_and_cpuidle(struct device *dev)
 		/* Success */
 		return ret;
 
-	cpu_pm_unregister_notifier(&gs101_cpu_pm_notifier);
+	cpu_pm_unregister_notifier(&exynos_cpu_pm_notifier);
 
 clean_cpuhp_states:
 	if (pmu_context->cpuhp_prepare_state != CPUHP_INVALID) {

diff --git a/drivers/soc/samsung/exynos-pmu.h b/drivers/soc/samsung/exynos-pmu.h
index fbe381e2a2e1..733e188fa2b1 100644
--- a/drivers/soc/samsung/exynos-pmu.h
+++ b/drivers/soc/samsung/exynos-pmu.h

@@ -13,6 +13,14 @@
 
 #define PMU_TABLE_END	(-1U)
 
+/*
+ * CPU_INFORM register "hint" values are required to be programmed in addition to
+ * the standard PSCI calls to have functional CPU hotplug and CPU idle states.
+ * This is required to workaround limitations in the el3mon/ACPM firmware.
+ */
+#define CPU_INFORM_CLEAR	0
+#define CPU_INFORM_C2		1
+
 struct regmap_access_table;
 
 struct exynos_pmu_conf {

@@ -20,6 +28,24 @@ struct exynos_pmu_conf {
 	u8 val[NUM_SYS_POWERDOWN];
 };
 
+struct exynos_pmu_context {
+	struct device *dev;
+	const struct exynos_pmu_data *pmu_data;
+	struct regmap *pmureg;
+	struct regmap *pmuintrgen;
+	/*
+	 * Serialization lock for CPU hot plug and cpuidle ACPM hint
+	 * programming. Also protects in_cpuhp, sys_insuspend & sys_inreboot
+	 * flags.
+	 */
+	raw_spinlock_t cpupm_lock;
+	unsigned long *in_cpuhp;
+	bool sys_insuspend;
+	bool sys_inreboot;
+	int cpuhp_prepare_state;
+	int cpuhp_online_state;
+};
+
 /**
  * struct exynos_pmu_data - of_device_id (match) data
  *

@@ -44,6 +70,10 @@ struct exynos_pmu_conf {
  *            used (i.e. when @pmu_secure is @true).
  * @wr_table: A table of writable register ranges in case a custom regmap is
  *            used (i.e. when @pmu_secure is @true).
+ * @cpu_pmu_offline: Optional callback to be called before entering CPU offline
+ *                   or idle state. Only valid when pmu_cpuhp set to true.
+ * @cpu_pmu_online: Optional callback to be called after CPU onlined or after
+ *                  exiting idle state. Only valid when pmu_cpuhp set to true.
  */
 struct exynos_pmu_data {
 	const struct exynos_pmu_conf *pmu_config;

@@ -57,6 +87,9 @@ struct exynos_pmu_data {
 
 	const struct regmap_access_table *rd_table;
 	const struct regmap_access_table *wr_table;
+
+	int (*cpu_pmu_offline)(struct exynos_pmu_context *pmu_context, unsigned int cpu);
+	int (*cpu_pmu_online)(struct exynos_pmu_context *pmu_context, unsigned int cpu);
 };
 
 extern void __iomem *pmu_base_addr;

diff --git a/drivers/soc/samsung/gs101-pmu.c b/drivers/soc/samsung/gs101-pmu.c
index 17dadc1b9c6e..ee7897eed20a 100644
--- a/drivers/soc/samsung/gs101-pmu.c
+++ b/drivers/soc/samsung/gs101-pmu.c

@@ -322,11 +322,62 @@ static const struct regmap_access_table gs101_pmu_wr_table = {
 	.n_no_ranges = ARRAY_SIZE(gs101_pmu_ro_registers),
 };
 
+/*
+ * gs101_cpu_pmu_ prefix functions are common code shared by CPU PM notifiers
+ * (CPUIdle) and CPU hotplug callbacks. Functions should be called with IRQs
+ * disabled and cpupm_lock held.
+ */
+static int gs101_cpu_pmu_online(struct exynos_pmu_context *pmu_context, unsigned int cpu)
+	__must_hold(&pmu_context->cpupm_lock)
+{
+	unsigned int cpuhint = smp_processor_id();
+	u32 reg, mask;
+
+	/* clear cpu inform hint */
+	regmap_write(pmu_context->pmureg, GS101_CPU_INFORM(cpuhint), CPU_INFORM_CLEAR);
+
+	mask = BIT(cpu);
+	regmap_update_bits(pmu_context->pmuintrgen, EXYNOS_GRP2_INTR_BID_ENABLE,
+			   mask, (0 << cpu));
+
+	regmap_read(pmu_context->pmuintrgen, EXYNOS_GRP2_INTR_BID_UPEND, &reg);
+
+	regmap_write(pmu_context->pmuintrgen, EXYNOS_GRP2_INTR_BID_CLEAR, reg & mask);
+
+	return 0;
+}
+
+/* Common function shared by both CPU hot plug and CPUIdle */
+static int gs101_cpu_pmu_offline(struct exynos_pmu_context *pmu_context, unsigned int cpu)
+	__must_hold(&pmu_context->cpupm_lock)
+{
+	unsigned int cpuhint = smp_processor_id();
+	u32 reg, mask;
+
+	/* set cpu inform hint */
+	regmap_write(pmu_context->pmureg, GS101_CPU_INFORM(cpuhint), CPU_INFORM_C2);
+
+	mask = BIT(cpu);
+	regmap_update_bits(pmu_context->pmuintrgen, EXYNOS_GRP2_INTR_BID_ENABLE,
+			   mask, BIT(cpu));
+
+	regmap_read(pmu_context->pmuintrgen, EXYNOS_GRP1_INTR_BID_UPEND, &reg);
+	regmap_write(pmu_context->pmuintrgen, EXYNOS_GRP1_INTR_BID_CLEAR, reg & mask);
+
+	mask = (BIT(cpu + 8));
+	regmap_read(pmu_context->pmuintrgen, EXYNOS_GRP1_INTR_BID_UPEND, &reg);
+	regmap_write(pmu_context->pmuintrgen, EXYNOS_GRP1_INTR_BID_CLEAR, reg & mask);
+
+	return 0;
+}
+
 const struct exynos_pmu_data gs101_pmu_data = {
 	.pmu_secure = true,
 	.pmu_cpuhp = true,
 	.rd_table = &gs101_pmu_rd_table,
 	.wr_table = &gs101_pmu_wr_table,
+	.cpu_pmu_offline = gs101_cpu_pmu_offline,
+	.cpu_pmu_online = gs101_cpu_pmu_online,
 };
 
 /*

diff --git a/include/linux/soc/samsung/exynos-regs-pmu.h b/include/linux/soc/samsung/exynos-regs-pmu.h
index db8a7ca81080..9c4d3da41dbf 100644
--- a/include/linux/soc/samsung/exynos-regs-pmu.h
+++ b/include/linux/soc/samsung/exynos-regs-pmu.h

@@ -1009,11 +1009,11 @@
 #define GS101_PHY_CTRL_UFS                      0x3ec8
 
 /* PMU INTR GEN */
-#define GS101_GRP1_INTR_BID_UPEND				(0x0108)
-#define GS101_GRP1_INTR_BID_CLEAR				(0x010c)
-#define GS101_GRP2_INTR_BID_ENABLE				(0x0200)
-#define GS101_GRP2_INTR_BID_UPEND				(0x0208)
-#define GS101_GRP2_INTR_BID_CLEAR				(0x020c)
+#define EXYNOS_GRP1_INTR_BID_UPEND				(0x0108)
+#define EXYNOS_GRP1_INTR_BID_CLEAR				(0x010c)
+#define EXYNOS_GRP2_INTR_BID_ENABLE				(0x0200)
+#define EXYNOS_GRP2_INTR_BID_UPEND				(0x0208)
+#define EXYNOS_GRP2_INTR_BID_CLEAR				(0x020c)
 
 /* exynosautov920 */
 #define EXYNOSAUTOV920_PHY_CTRL_USB20				(0x0710)

-- 
2.51.0

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