[PATCH v7 0/6] Exynos-pmu: Generalise cpu{hotplug,idle},PMU intr gen and add Exynos850 CPU hotplug

[PATCH v7 0/6] Exynos-pmu: Generalise cpu{hotplug,idle},PMU intr gen and add Exynos850 CPU hotplug

[Alexey Klimov]

Series generalises the GS101-specific cpuhotplug, cpuidle and PMU interrupt
generation block support, which is currently implemented specifically for
the google GS101 SoC, to make it reusable by other Samsung Exynos SoCs.

The PMU interrupt generation IP block introduced for google GS101 is a
standard Samsung Exynos block found in other SoCs, including Exynos850,
and it is not strictly exclusive to google Exynos-based platforms.
Access to this block is required to implement and enable cpuhotplug
on Exynos850-based boards.

As a next steps it will be possible to enable idle states on top of it
(if we get our hands on correct firmware).

First patches work on DT bindings to reflect that Exynos850 SoC predates
gs101 one and adding mandatory property 'google,pmu-intr-gen-syscon'
for exynos850-pmu.
Then series generalises ("Exynosizes") cpuhotplug/cpuidle routines by
deferring platform-specific PMU and PMU-intr-gen updates to platform-
specific callbacks and then finally introduces new file exynos850-pmu.c
where such callbacks are implemented for Exynos850. Last commit adds
pmu_intr_gen DT node to exynos850.dtsi.

This series depends on
[PATCH v3] soc: samsung: exynos-pmu: fix error paths in cpuhotplug/idle states setup
https://lore.kernel.org/linux-samsung-soc/20260930-exynos-pmu-cpuhp-idle-fixes-v3-1-4269d8425978@linaro.org/

Sashiko bot reported issues here:
https://sashiko.dev/#/patchset/20260513-exynos850-cpuhotplug-v4-0-54fec5f65362@linaro.org?part=4

The are basically no updates in this v7 series, just a rebase on top of
an dependency patch.

This series was again re-tested on Exynos850 WinLink E850-96 board:
-- by spinning "chcpu -d 1-7; chcpu -e 1-7" in a loop for a few hours;
-- by running script [1] that randomly offlines or onlines random cpus
   for a few hours.

Thanks to Peter for testing!

Thanks,
Alexey

[1]: https://github.com/laklimov/xlam/blob/main/e850_cpuhotplug_random.sh

Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
---
Changes in v7:
- rebased on top of -next and patch (it is dependency):
  [PATCH v3] soc: samsung: exynos-pmu: fix error paths in cpuhotplug/idle states setup;
- retested;
- Link to v6: https://lore.kernel.org/r/20260902-exynos850-cpuhotplug-v6-0-a85bb55bb118@linaro.org

Changes in v6:
- rebase on top -next and "fixes" series, basically no other updates;
- Link to v5: https://lore.kernel.org/r/20260609-exynos850-cpuhotplug-v5-0-8422cf80d43b@linaro.org

Changes in v5:
- updated the commit message of ("soc: samsung: exynos-pmu: add Exynos850
  CPU hotplug support");
- the if-check for the presense of pmu_data->cpu_pmu_{offline,online}
  callbacks in setup_cpuhp_and_cpuidle() was moved to before acquiring ref
  counter to intr_gen_node (the initial issue was reported by Sashiko);
- added pr_fmt to exynos850-pmu.c to have more meaningful error
  messages;
- added parentheses around the `cl` in `EXYNOS850_CLUSTER_CPU_OFFSET` macro
  (as suggested by Sashiko bot);
- custom syscon regmap with raw_spinlocks for pmu offline/online callbacks
  (the initial issue was reported by Sashiko);
- using topology_cluster_id() and topology_core_id() in exynos850-pmu.c
  (the initial issue was reported by Sashiko);
- removed smp_processor_id() usage fomr pmu offline/online callbacks
  (the initial issue was reported by Sashiko);
- added/resorted headers in exynos850-pmu.c;
- Link to v4: https://lore.kernel.org/r/20260513-exynos850-cpuhotplug-v4-0-54fec5f65362@linaro.org

Changes in v4:
- remove blank line in file exynos850-pmu.c, commit (as suggested by Krzysztof);
- only update trailers/tags in commit messages;
- Link to v3: https://lore.kernel.org/r/20260430-exynos850-cpuhotplug-v3-0-fd6251d02a17@linaro.org

Changes in v3:
- dropped two commits where samsung,pmu-intr-gen phandle is introduced and
  where google,pmu-intr-gen-syscon is deprecated (as suggested by Rob Herring);
- addtion to maintainers file was moved to separate entry, change commit message;
- commit message in "generalise gs101-specific cpu{idle,hotplug} for Exynos SoCs"
  was updated since it no longer touches samsung,pmu-intr-gen-syscon;
- added missing asm/cputype.h header to exynos850-pmu.h
  (reported by Henrik Grimler);
- new commit "dt-bindings: soc: samsung: exynos-pmu: Require
  pmu-intr-gen-syscon for Exynos850";
- Link to v2: https://lore.kernel.org/r/20260401-exynos850-cpuhotplug-v2-0-c5a760a3e259@linaro.org

Changes in v2:
- moved gs101 cpu {offline,online} callbacks to gs101-pmu.c, updated MAINTAINERS;
- added new file exynos850-pmu.c with cpu {offline,online} callbacks and
  exynos850 pmu data;
- new patch that adds exynos850-pmu.c to MAINTAINERS;
- moved pmu_intr_gen to right after pmu_system_controller@11860000;
- merged two patches that update google,gs101-pmu-intr-gen.yaml together,
  now rename and adding exynos850 entry goes in a single patch;
- commits 5 and 6 from RFC series are merged together and reworked,
  cpu_pmu_{offline,online} callbacks are moved into pmu_data struct, and
  callbacks now need pmu_context as an argument, exynos_pmu_context and
  CPU_INFORM defines are moved to exynos-pmu.h, gs101 callbacks
  renamed. It is really better to check commit description.
- Link to RFC (v1 from b4 point of view):
  https://lore.kernel.org/r/20260226-exynos850-cpuhotplug-v1-0-71d7c4063382@linaro.org

---
Alexey Klimov (6):
      dt-bindings: soc: move,rename google,gs101-pmu-intr-gen and add exynos850
      dt-bindings: soc: samsung: exynos-pmu: Require pmu-intr-gen-syscon for Exynos850
      soc: samsung: exynos-pmu: generalise gs101-specific cpu{idle,hotplug} for Exynos SoCs
      soc: samsung: exynos-pmu: add Exynos850 CPU hotplug support
      MAINTAINERS: add Exynos850 PMU entry
      arm64: dts: exynos850: add PMU interrupt generation node

 .../bindings/soc/samsung/exynos-pmu.yaml           |   1 +
 .../samsung,exynos850-pmu-intr-gen.yaml}           |   8 +-
 MAINTAINERS                                        |   9 +-
 arch/arm64/boot/dts/exynos/exynos850.dtsi          |   6 +
 drivers/soc/samsung/Makefile                       |   2 +-
 drivers/soc/samsung/exynos-pmu.c                   | 149 +++++++--------------
 drivers/soc/samsung/exynos-pmu.h                   |  34 +++++
 drivers/soc/samsung/exynos850-pmu.c                |  95 +++++++++++++
 drivers/soc/samsung/gs101-pmu.c                    |  51 +++++++
 include/linux/soc/samsung/exynos-regs-pmu.h        |  15 ++-
 10 files changed, 260 insertions(+), 110 deletions(-)
---
base-commit: 6375e61c01e93e35ee7acd336a689ac1fae4b509
change-id: 20260226-exynos850-cpuhotplug-69f1976eefa8
prerequisite-message-id: 20260930-exynos-pmu-cpuhp-idle-fixes-v3-1-4269d8425978@linaro.org
prerequisite-patch-id: d9ac215f16060e07e9cfe193e7c9af7c8913bdae

Best regards,
-- 
Alexey Klimov <alexey.klimov@linaro.org>

[PATCH v7 1/6] dt-bindings: soc: move,rename google,gs101-pmu-intr-gen and add exynos850

[Alexey Klimov]

The PMU interrupt generation block introduced for the Google GS101 is
actually a standard Samsung Exynos IP block found in older SoCs, such
as the Exynos850, and is not exclusive to Google SoCs. To accurately
reflect its origin, move the schema file to under soc/samsung/
directory and rename it.
Concurrently, add the new "samsung,exynos850-pmu-intr-gen" compatible
string to the bindings. Support for this block is required to enable
power management features like CPU hotplug and idle states on Exynos850
platforms.
Also, move this file under Exynos850 SoC in MAINTAINERS entry.

Reviewed-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
---
 .../samsung,exynos850-pmu-intr-gen.yaml}                          | 8 +++++---
 MAINTAINERS                                                       | 2 +-
 2 files changed, 6 insertions(+), 4 deletions(-)

diff --git a/Documentation/devicetree/bindings/soc/google/google,gs101-pmu-intr-gen.yaml b/Documentation/devicetree/bindings/soc/samsung/samsung,exynos850-pmu-intr-gen.yaml
similarity index 70%
rename from Documentation/devicetree/bindings/soc/google/google,gs101-pmu-intr-gen.yaml
rename to Documentation/devicetree/bindings/soc/samsung/samsung,exynos850-pmu-intr-gen.yaml
index 2be022ca6a7d..df23467d0e0e 100644
--- a/Documentation/devicetree/bindings/soc/google/google,gs101-pmu-intr-gen.yaml
+++ b/Documentation/devicetree/bindings/soc/samsung/samsung,exynos850-pmu-intr-gen.yaml
@@ -1,10 +1,10 @@
 # SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
 %YAML 1.2
 ---
-$id: http://devicetree.org/schemas/soc/google/google,gs101-pmu-intr-gen.yaml#
+$id: http://devicetree.org/schemas/soc/samsung/samsung,exynos850-pmu-intr-gen.yaml#
 $schema: http://devicetree.org/meta-schemas/core.yaml#
 
-title: Google Power Management Unit (PMU) Interrupt Generation
+title: Samsung Power Management Unit (PMU) Interrupt Generation
 
 description: |
   PMU interrupt generator for handshaking between PMU through interrupts.
@@ -15,7 +15,9 @@ maintainers:
 properties:
   compatible:
     items:
-      - const: google,gs101-pmu-intr-gen
+      - enum:
+          - google,gs101-pmu-intr-gen
+          - samsung,exynos850-pmu-intr-gen
       - const: syscon
 
   reg:
diff --git a/MAINTAINERS b/MAINTAINERS
index 1c02b919d6ae..137297bf508b 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -11298,7 +11298,6 @@ P:	Documentation/process/maintainer-soc-clean-dts.rst
 C:	irc://irc.oftc.net/pixel6-kernel-dev
 F:	Documentation/devicetree/bindings/clock/google,gs101-clock.yaml
 F:	Documentation/devicetree/bindings/phy/google,lga-usb-phy.yaml
-F:	Documentation/devicetree/bindings/soc/google/google,gs101-pmu-intr-gen.yaml
 F:	Documentation/devicetree/bindings/usb/google,lga-dwc3.yaml
 F:	arch/arm64/boot/dts/exynos/google/
 F:	drivers/clk/samsung/clk-gs101.c
@@ -24629,6 +24628,7 @@ L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
 L:	linux-samsung-soc@vger.kernel.org
 S:	Maintained
 F:	Documentation/devicetree/bindings/clock/samsung,exynos850-clock.yaml
+F:	Documentation/devicetree/bindings/soc/samsung/samsung,exynos850-pmu-intr-gen.yaml
 F:	arch/arm64/boot/dts/exynos/exynos850*
 F:	drivers/clk/samsung/clk-exynos850.c
 F:	include/dt-bindings/clock/exynos850.h

-- 
2.51.0

[PATCH v7 2/6] dt-bindings: soc: samsung: exynos-pmu: Require pmu-intr-gen-syscon for Exynos850

[Alexey Klimov]

Update the Exynos PMU schema to mandate the 'google,pmu-intr-gen-syscon'
property for the 'samsung,exynos850-pmu' compatible so the driver can
obtain the necessary syscon regmap.

The Exynos850 PMU relies on a separate system controller block to handle
interrupts generation, similar to the hardware design of the GS101
SoC. To ensure the hardware is correctly described, this syscon phandle
must be explicitly provided.

Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Acked-by: Rob Herring (Arm) <robh@kernel.org>
Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
---
 Documentation/devicetree/bindings/soc/samsung/exynos-pmu.yaml | 1 +
 1 file changed, 1 insertion(+)

diff --git a/Documentation/devicetree/bindings/soc/samsung/exynos-pmu.yaml b/Documentation/devicetree/bindings/soc/samsung/exynos-pmu.yaml
index 5bd39876e3b3..7d58976dccc4 100644
--- a/Documentation/devicetree/bindings/soc/samsung/exynos-pmu.yaml
+++ b/Documentation/devicetree/bindings/soc/samsung/exynos-pmu.yaml
@@ -196,6 +196,7 @@ allOf:
           contains:
             enum:
               - google,gs101-pmu
+              - samsung,exynos850-pmu
     then:
       properties:
         reboot-mode:

-- 
2.51.0

[PATCH v7 3/6] soc: samsung: exynos-pmu: generalise gs101-specific cpu{idle,hotplug} for Exynos SoCs

[Alexey Klimov]

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 c764f35fbfc2..9efaaf4696cf 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.
@@ -417,6 +336,12 @@ 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
@@ -457,28 +382,28 @@ 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_state_prepare;
 
 	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;
 
@@ -487,7 +412,7 @@ 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:
 	cpuhp_remove_state(pmu_context->cpuhp_online_state);
@@ -502,7 +427,7 @@ static int setup_cpuhp_and_cpuidle(struct device *dev)
 
 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)
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

[PATCH v7 4/6] soc: samsung: exynos-pmu: add Exynos850 CPU hotplug support

[Alexey Klimov]

Add cpuhotplug support for Exynos850 platforms. This SoC requires
its own specific set of writes/updates to PMU and PMU interrupts
generation block in order to put a CPU or a group of CPUs into
a different sleep states or prepare these entities for a CPU_OFF
or wake-up out of idle state or after CPU online.
Without these writes/updates the CPU(s) wake-up or online fails.

This also requires syscon regmap with raw spinlocks, so add
its initialisation to main exynos pmu probe() routine.

Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
---
 drivers/soc/samsung/Makefile                |  2 +-
 drivers/soc/samsung/exynos-pmu.c            | 24 ++++++++
 drivers/soc/samsung/exynos-pmu.h            |  1 +
 drivers/soc/samsung/exynos850-pmu.c         | 95 +++++++++++++++++++++++++++++
 include/linux/soc/samsung/exynos-regs-pmu.h |  5 ++
 5 files changed, 126 insertions(+), 1 deletion(-)

diff --git a/drivers/soc/samsung/Makefile b/drivers/soc/samsung/Makefile
index 636a762608c9..7f544e3c1fcc 100644
--- a/drivers/soc/samsung/Makefile
+++ b/drivers/soc/samsung/Makefile
@@ -7,7 +7,7 @@ exynos_chipid-y			+= exynos-chipid.o exynos-asv.o
 obj-$(CONFIG_EXYNOS_USI)	+= exynos-usi.o
 
 obj-$(CONFIG_EXYNOS_PMU)	+= exynos_pmu.o
-exynos_pmu-y			+= exynos-pmu.o gs101-pmu.o
+exynos_pmu-y			+= exynos-pmu.o gs101-pmu.o exynos850-pmu.o
 
 obj-$(CONFIG_EXYNOS_PMU_ARM_DRIVERS)	+= exynos3250-pmu.o exynos4-pmu.o \
 					exynos5250-pmu.o exynos5420-pmu.o
diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c
index 9efaaf4696cf..387ed149fa71 100644
--- a/drivers/soc/samsung/exynos-pmu.c
+++ b/drivers/soc/samsung/exynos-pmu.c
@@ -92,6 +92,14 @@ static const struct regmap_config regmap_smccfg = {
 	.use_raw_spinlock = true,
 };
 
+static const struct regmap_config regmap_pmu = {
+	.name = "pmu_regs",
+	.reg_bits = 32,
+	.val_bits = 32,
+	.reg_stride = 4,
+	.use_raw_spinlock = true,
+};
+
 static const struct regmap_config regmap_pmu_intr = {
 	.name = "pmu_intr_gen",
 	.reg_bits = 32,
@@ -133,6 +141,7 @@ static const struct of_device_id exynos_pmu_of_device_ids[] = {
 		.compatible = "samsung,exynos7-pmu",
 	}, {
 		.compatible = "samsung,exynos850-pmu",
+		.data = &exynos850_pmu_data,
 	},
 	{ /*sentinel*/ },
 };
@@ -480,6 +489,21 @@ static int exynos_pmu_probe(struct platform_device *pdev)
 		ret = of_syscon_register_regmap(dev->of_node, regmap);
 		if (ret)
 			return ret;
+	/*
+	 * For SoCs that support cpuhotplug/cpuidle via PMU updates callbacks.
+	 * Such callbacks are executed under raw_spinlock so we need a custom
+	 * regmap too.
+	 */
+	} else if (pmu_context->pmu_data && pmu_context->pmu_data->pmu_cpuhp) {
+		regmap = devm_regmap_init_mmio(dev, pmu_base_addr, &regmap_pmu);
+		if (IS_ERR(regmap))
+			return dev_err_probe(dev, PTR_ERR(regmap),
+					     "hotplug regmap init failed\n");
+
+		ret = of_syscon_register_regmap(dev->of_node, regmap);
+		if (ret)
+			return dev_err_probe(dev, ret,
+					     "failed to register hotplug regmap with syscon\n");
 	} else {
 		/* let syscon create mmio regmap */
 		regmap = syscon_node_to_regmap(dev->of_node);
diff --git a/drivers/soc/samsung/exynos-pmu.h b/drivers/soc/samsung/exynos-pmu.h
index 733e188fa2b1..4ecbf53cd4f7 100644
--- a/drivers/soc/samsung/exynos-pmu.h
+++ b/drivers/soc/samsung/exynos-pmu.h
@@ -104,6 +104,7 @@ extern const struct exynos_pmu_data exynos5250_pmu_data;
 extern const struct exynos_pmu_data exynos5420_pmu_data;
 #endif
 extern const struct exynos_pmu_data gs101_pmu_data;
+extern const struct exynos_pmu_data exynos850_pmu_data;
 
 extern void pmu_raw_writel(u32 val, u32 offset);
 extern u32 pmu_raw_readl(u32 offset);
diff --git a/drivers/soc/samsung/exynos850-pmu.c b/drivers/soc/samsung/exynos850-pmu.c
new file mode 100644
index 000000000000..0503c54d6363
--- /dev/null
+++ b/drivers/soc/samsung/exynos850-pmu.c
@@ -0,0 +1,95 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright 2026 Linaro Ltd.
+ *
+ * Exynos850 PMU support
+ */
+
+#define pr_fmt(fmt)	KBUILD_MODNAME ": " fmt
+
+#include <linux/bits.h>
+#include <linux/printk.h>
+#include <linux/regmap.h>
+#include <linux/soc/samsung/exynos-pmu.h>
+#include <linux/soc/samsung/exynos-regs-pmu.h>
+#include <linux/topology.h>
+#include <asm/cputype.h>
+
+#include "exynos-pmu.h"
+
+static int exynos850_cpu_pmu_offline(struct exynos_pmu_context *pmu_context, unsigned int cpu)
+	__must_hold(&pmu_context->cpupm_lock)
+{
+	int cluster_id, core_id;
+	u32 reg, mask;
+
+	cluster_id = topology_cluster_id(cpu);
+	if (cluster_id < 0) {
+		pr_err_ratelimited("invalid cluster ID for cpu: %u\n", cpu);
+		return -EINVAL;
+	}
+
+	core_id = topology_core_id(cpu);
+	if (core_id < 0) {
+		pr_err_ratelimited("invalid core ID for cpu: %u\n", cpu);
+		return -EINVAL;
+	}
+
+	/* set cpu inform hint */
+	regmap_write(pmu_context->pmureg, EXYNOS850_CPU_INFORM(cpu), 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);
+
+	regmap_update_bits(pmu_context->pmureg,
+			   EXYNOS850_CLUSTER_CPU_INT_EN(cluster_id, core_id), 1 << 3, 1 << 3);
+	return 0;
+}
+
+static int exynos850_cpu_pmu_online(struct exynos_pmu_context *pmu_context, unsigned int cpu)
+	__must_hold(&pmu_context->cpupm_lock)
+{
+	int cluster_id, core_id;
+	u32 reg, mask;
+
+	cluster_id = topology_cluster_id(cpu);
+	if (cluster_id < 0) {
+		pr_err_ratelimited("invalid cluster ID for cpu: %u\n", cpu);
+		return -EINVAL;
+	}
+
+	core_id = topology_core_id(cpu);
+	if (core_id < 0) {
+		pr_err_ratelimited("invalid core ID for cpu: %u\n", cpu);
+		return -EINVAL;
+	}
+
+	/* clear cpu inform hint */
+	regmap_write(pmu_context->pmureg, EXYNOS850_CPU_INFORM(cpu), 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);
+
+	regmap_update_bits(pmu_context->pmureg,
+			   EXYNOS850_CLUSTER_CPU_INT_EN(cluster_id, core_id), 1 << 3, 0 << 3);
+	return 0;
+}
+
+const struct exynos_pmu_data exynos850_pmu_data = {
+	.pmu_cpuhp = true,
+	.cpu_pmu_offline = exynos850_cpu_pmu_offline,
+	.cpu_pmu_online = exynos850_cpu_pmu_online,
+};
diff --git a/include/linux/soc/samsung/exynos-regs-pmu.h b/include/linux/soc/samsung/exynos-regs-pmu.h
index 9c4d3da41dbf..c7a82635fc36 100644
--- a/include/linux/soc/samsung/exynos-regs-pmu.h
+++ b/include/linux/soc/samsung/exynos-regs-pmu.h
@@ -1015,6 +1015,11 @@
 #define EXYNOS_GRP2_INTR_BID_UPEND				(0x0208)
 #define EXYNOS_GRP2_INTR_BID_CLEAR				(0x020c)
 
+/* Exynos850 PMU Alive */
+#define EXYNOS850_CPU_INFORM(cpu)		(0x0860 + ((cpu) & 7) * 4)
+#define EXYNOS850_CLUSTER_CPU_OFFSET(cl, cpu)	(0x1000 + (((cl) * 0x400) + ((cpu) * 0x80)))
+#define EXYNOS850_CLUSTER_CPU_INT_EN(cl, cpu)	(EXYNOS850_CLUSTER_CPU_OFFSET(cl, cpu) + 0x44)
+
 /* exynosautov920 */
 #define EXYNOSAUTOV920_PHY_CTRL_USB20				(0x0710)
 #define EXYNOSAUTOV920_PHY_CTRL_USB31				(0x0714)

-- 
2.51.0

[PATCH v7 5/6] MAINTAINERS: add Exynos850 PMU entry

[Alexey Klimov]

Add Exynos850 PMU entry describing new file
drivers/soc/samsung/exynos850-pmu.c.
Add myself as M there since I contributed Exynos850
PMU support and intend to maintain that.

Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
---
 MAINTAINERS | 7 +++++++
 1 file changed, 7 insertions(+)

diff --git a/MAINTAINERS b/MAINTAINERS
index 137297bf508b..810111c83478 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -24622,6 +24622,13 @@ F:	arch/arm64/boot/dts/exynos/exynos2200*
 F:	drivers/clk/samsung/clk-exynos2200.c
 F:	include/dt-bindings/clock/samsung,exynos2200-cmu.h
 
+SAMSUNG EXYNOS850 PMU SUPPORT
+M:	Alexey Klimov <alexey.klimov@linaro.org>
+L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)
+L:	linux-samsung-soc@vger.kernel.org
+S:	Maintained
+F:	drivers/soc/samsung/exynos850-pmu.c
+
 SAMSUNG EXYNOS850 SoC SUPPORT
 M:	Sam Protsenko <semen.protsenko@linaro.org>
 L:	linux-arm-kernel@lists.infradead.org (moderated for non-subscribers)

-- 
2.51.0

[PATCH v7 6/6] arm64: dts: exynos850: add PMU interrupt generation node

[Alexey Klimov]

Add pmu_intr_gen node for Exynos850. This hw block is required
for different power management routines like CPU hotplug and
different sleep and idle states.
Also reference this node from main PMU node.

Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
---
 arch/arm64/boot/dts/exynos/exynos850.dtsi | 6 ++++++
 1 file changed, 6 insertions(+)

diff --git a/arch/arm64/boot/dts/exynos/exynos850.dtsi b/arch/arm64/boot/dts/exynos/exynos850.dtsi
index 8a4771899a8e..803fc127d895 100644
--- a/arch/arm64/boot/dts/exynos/exynos850.dtsi
+++ b/arch/arm64/boot/dts/exynos/exynos850.dtsi
@@ -231,6 +231,7 @@ gic: interrupt-controller@12a01000 {
 		pmu_system_controller: system-controller@11860000 {
 			compatible = "samsung,exynos850-pmu", "syscon";
 			reg = <0x11860000 0x10000>;
+			google,pmu-intr-gen-syscon = <&pmu_intr_gen>;
 
 			poweroff: syscon-poweroff {
 				compatible = "syscon-poweroff";
@@ -248,6 +249,11 @@ reboot: syscon-reboot {
 			};
 		};
 
+		pmu_intr_gen: syscon@11870000 {
+			compatible = "samsung,exynos850-pmu-intr-gen", "syscon";
+			reg = <0x11870000 0x10000>;
+		};
+
 		watchdog_cl0: watchdog@10050000 {
 			compatible = "samsung,exynos850-wdt";
 			reg = <0x10050000 0x100>;

-- 
2.51.0

Re: [PATCH v7 6/6] arm64: dts: exynos850: add PMU interrupt generation node

[Peter Griffin]

Hi Alexey,

On Wed, 30 Sept 2026 at 01:13, Alexey Klimov <alexey.klimov@linaro.org> wrote:
>
> Add pmu_intr_gen node for Exynos850. This hw block is required
> for different power management routines like CPU hotplug and
> different sleep and idle states.
> Also reference this node from main PMU node.
>
> Reviewed-by: Peter Griffin <peter.griffin@linaro.org>
> Signed-off-by: Alexey Klimov <alexey.klimov@linaro.org>
> ---
>  arch/arm64/boot/dts/exynos/exynos850.dtsi | 6 ++++++
>  1 file changed, 6 insertions(+)
>
> diff --git a/arch/arm64/boot/dts/exynos/exynos850.dtsi b/arch/arm64/boot/dts/exynos/exynos850.dtsi
> index 8a4771899a8e..803fc127d895 100644
> --- a/arch/arm64/boot/dts/exynos/exynos850.dtsi
> +++ b/arch/arm64/boot/dts/exynos/exynos850.dtsi
> @@ -231,6 +231,7 @@ gic: interrupt-controller@12a01000 {
>                 pmu_system_controller: system-controller@11860000 {
>                         compatible = "samsung,exynos850-pmu", "syscon";
>                         reg = <0x11860000 0x10000>;
> +                       google,pmu-intr-gen-syscon = <&pmu_intr_gen>;
>
>                         poweroff: syscon-poweroff {
>                                 compatible = "syscon-poweroff";
> @@ -248,6 +249,11 @@ reboot: syscon-reboot {
>                         };
>                 };
>
> +               pmu_intr_gen: syscon@11870000 {
> +                       compatible = "samsung,exynos850-pmu-intr-gen", "syscon";
> +                       reg = <0x11870000 0x10000>;
> +               };
> +

Since you are now creating your own custom regmap in exynos-pmu you
should drop the syscon compatible here. That should avoid syscon.c
ever creating an MMIO regmap (with the wrong spinlock). I've copied
some of the commit text from my commit
a21d38b5e209c60e73f81e467cc53ad57b5d4080 below for the rationale
behind this.

   arm64: dts: exynos: gs101: remove syscon compatible from pmu node

    Since commit ba5095ebbc7a ("mfd: syscon: Allow syscon nodes without a
    "syscon" compatible") it is possible to register a regmap without the
    syscon compatible in the node.

    As mentioned in that commit, it's not correct to claim we are compatible
    with syscon, as a MMIO regmap created by syscon won't work. Removing the
    syscon compatible means syscon driver won't ever create a mmio regmap.

    Note this isn't usually an issue today as exynos-pmu runs at an early
    initcall so the custom regmap will have been registered first. However
    changes proposed in [1] will bring -EPROBE_DEFER support to syscon allowing
    this mechanism to be more robust, especially in highly modularized systems.

    Technically this is a ABI break but no other platforms are
    affected. Additionally (with the benefit of hindsight) a MMIO syscon has
    never worked for PMU register writes, thus the ABI break is justified.

    Link: https://lore.kernel.org/lkml/aQdHmrchkmOr34r3@stanley.mountain/ [1]

Thanks,

Peter

Re: [PATCH v7 6/6] arm64: dts: exynos850: add PMU interrupt generation node

[Krzysztof Kozlowski]

On 02/10/2026 14:41, Peter Griffin wrote:
>>
>> +               pmu_intr_gen: syscon@11870000 {
>> +                       compatible = "samsung,exynos850-pmu-intr-gen", "syscon";
>> +                       reg = <0x11870000 0x10000>;
>> +               };
>> +
> 
> Since you are now creating your own custom regmap in exynos-pmu you
> should drop the syscon compatible here. That should avoid syscon.c
> ever creating an MMIO regmap (with the wrong spinlock). I've copied
> some of the commit text from my commit

Yes, there should be no syscon fallback.

Best regards,
Krzysztof

Re: [PATCH v7 6/6] arm64: dts: exynos850: add PMU interrupt generation node

[Krzysztof Kozlowski]

On 03/10/2026 16:13, Krzysztof Kozlowski wrote:
> On 02/10/2026 14:41, Peter Griffin wrote:
>>>
>>> +               pmu_intr_gen: syscon@11870000 {
>>> +                       compatible = "samsung,exynos850-pmu-intr-gen", "syscon";
>>> +                       reg = <0x11870000 0x10000>;
>>> +               };
>>> +
>>
>> Since you are now creating your own custom regmap in exynos-pmu you
>> should drop the syscon compatible here. That should avoid syscon.c
>> ever creating an MMIO regmap (with the wrong spinlock). I've copied
>> some of the commit text from my commit
> 
> Yes, there should be no syscon fallback.

... although not here, but for existing PMU node.

Best regards,
Krzysztof

Re: [PATCH v7 4/6] soc: samsung: exynos-pmu: add Exynos850 CPU hotplug support

[Krzysztof Kozlowski]

On 30/09/2026 02:12, Alexey Klimov wrote:
> Add cpuhotplug support for Exynos850 platforms. This SoC requires

Since I expect v8 due to DTS change, one nit below.


>  		/* let syscon create mmio regmap */
>  		regmap = syscon_node_to_regmap(dev->of_node);
> diff --git a/drivers/soc/samsung/exynos-pmu.h b/drivers/soc/samsung/exynos-pmu.h
> index 733e188fa2b1..4ecbf53cd4f7 100644
> --- a/drivers/soc/samsung/exynos-pmu.h
> +++ b/drivers/soc/samsung/exynos-pmu.h
> @@ -104,6 +104,7 @@ extern const struct exynos_pmu_data exynos5250_pmu_data;
>  extern const struct exynos_pmu_data exynos5420_pmu_data;
>  #endif
>  extern const struct exynos_pmu_data gs101_pmu_data;
> +extern const struct exynos_pmu_data exynos850_pmu_data;

Before gs101. Don't add to the end of such lists.


Best regards,
Krzysztof