Samsung SoC drivers for v6.16, part two

Add CPU hotplug support on Google GS101 by toggling respective bits in
 secondary PMU intr block (Power Management Unit (PMU) Interrupt
 Generation) from the main PMU driver.
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Merge tag 'samsung-drivers-6.16-2' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux into soc/drivers

Samsung SoC drivers for v6.16, part two

Add CPU hotplug support on Google GS101 by toggling respective bits in
secondary PMU intr block (Power Management Unit (PMU) Interrupt
Generation) from the main PMU driver.

* tag 'samsung-drivers-6.16-2' of https://git.kernel.org/pub/scm/linux/kernel/git/krzk/linux:
  soc: samsung: exynos-pmu: enable CPU hotplug support for gs101
  MAINTAINERS: Add google,gs101-pmu-intr-gen.yaml binding file
  dt-bindings: soc: samsung: exynos-pmu: gs101: add google,pmu-intr-gen phandle
  dt-bindings: soc: google: Add gs101-pmu-intr-gen binding documentation

Link: https://lore.kernel.org/r/20250516082037.7248-2-krzysztof.kozlowski@linaro.org
Signed-off-by: Arnd Bergmann <arnd@arndb.de>

Documentation/devicetree/bindings/soc/google/google,gs101-pmu-intr-gen.yaml

@@ -0,0 +1,35 @@
+# SPDX-License-Identifier: (GPL-2.0 OR BSD-2-Clause)
+%YAML 1.2
+---
+$id: http://devicetree.org/schemas/soc/google/google,gs101-pmu-intr-gen.yaml#
+$schema: http://devicetree.org/meta-schemas/core.yaml#
+
+title: Google Power Management Unit (PMU) Interrupt Generation
+
+description: |
+  PMU interrupt generator for handshaking between PMU through interrupts.
+
+maintainers:
+  - Peter Griffin <peter.griffin@linaro.org>
+
+properties:
+  compatible:
+    items:
+      - const: google,gs101-pmu-intr-gen
+      - const: syscon
+
+  reg:
+    maxItems: 1
+
+required:
+  - compatible
+  - reg
+
+additionalProperties: false
+
+examples:
+  - |
+    pmu_intr_gen: syscon@17470000 {
+      compatible = "google,gs101-pmu-intr-gen", "syscon";
+      reg = <0x17470000 0x10000>;
+    };

Documentation/devicetree/bindings/soc/samsung/exynos-pmu.yaml

@@ -129,6 +129,11 @@ properties:
     description:
       Node for reboot method
 
+  google,pmu-intr-gen-syscon:
+    $ref: /schemas/types.yaml#/definitions/phandle
+    description:
+      Phandle to PMU interrupt generation interface.
+
 required:
   - compatible
   - reg
@@ -189,6 +194,16 @@ allOf:
       properties:
         dp-phy: false
 
+  - if:
+      properties:
+        compatible:
+          contains:
+            enum:
+              - google,gs101-pmu
+    then:
+      required:
+        - google,pmu-intr-gen-syscon
+
 examples:
   - |
     #include <dt-bindings/clock/exynos5250.h>

MAINTAINERS

@@ -10085,6 +10085,7 @@ L:	linux-samsung-soc@vger.kernel.org
 S:	Maintained
 C:	irc://irc.oftc.net/pixel6-kernel-dev
 F:	Documentation/devicetree/bindings/clock/google,gs101-clock.yaml
+F:	Documentation/devicetree/bindings/soc/google/google,gs101-pmu-intr-gen.yaml
 F:	arch/arm64/boot/dts/exynos/google/
 F:	drivers/clk/samsung/clk-gs101.c
 F:	drivers/phy/samsung/phy-gs101-ufs.c

drivers/soc/samsung/exynos-pmu.c

@@ -7,6 +7,7 @@
 
 #include <linux/array_size.h>
 #include <linux/arm-smccc.h>
+#include <linux/cpuhotplug.h>
 #include <linux/of.h>
 #include <linux/of_address.h>
 #include <linux/mfd/core.h>
@@ -33,6 +34,7 @@ struct exynos_pmu_context {
 	struct device *dev;
 	const struct exynos_pmu_data *pmu_data;
 	struct regmap *pmureg;
+	struct regmap *pmuintrgen;
 };
 
 void __iomem *pmu_base_addr;
@@ -222,7 +224,8 @@ static const struct regmap_config regmap_smccfg = {
 };
 
 static const struct exynos_pmu_data gs101_pmu_data = {
-	.pmu_secure = true
+	.pmu_secure = true,
+	.pmu_cpuhp = true,
 };
 
 /*
@@ -326,6 +329,59 @@ 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 which are used by
+ * EL3 firmware (el3mon).
+ */
+#define CPU_INFORM_CLEAR	0
+#define CPU_INFORM_C2		1
+
+static int gs101_cpuhp_pmu_online(unsigned int cpu)
+{
+	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;
+}
+
+static int gs101_cpuhp_pmu_offline(unsigned int cpu)
+{
+	u32 reg, mask;
+	unsigned int cpuhint = smp_processor_id();
+
+	/* 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;
+}
+
 static int exynos_pmu_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -378,6 +434,26 @@ static int exynos_pmu_probe(struct platform_device *pdev)
 	pmu_context->pmureg = regmap;
 	pmu_context->dev = dev;
 
+	if (pmu_context->pmu_data && pmu_context->pmu_data->pmu_cpuhp) {
+		pmu_context->pmuintrgen = syscon_regmap_lookup_by_phandle(dev->of_node,
+							"google,pmu-intr-gen-syscon");
+		if (IS_ERR(pmu_context->pmuintrgen)) {
+			/*
+			 * To maintain support for older DTs that didn't specify syscon phandle
+			 * just issue a warning rather than fail to probe.
+			 */
+			dev_warn(&pdev->dev, "pmu-intr-gen syscon unavailable\n");
+		} else {
+			cpuhp_setup_state(CPUHP_BP_PREPARE_DYN,
+					  "soc/exynos-pmu:prepare",
+					  gs101_cpuhp_pmu_online, NULL);
+
+			cpuhp_setup_state(CPUHP_AP_ONLINE_DYN,
+					  "soc/exynos-pmu:online",
+					  NULL, gs101_cpuhp_pmu_offline);
+		}
+	}
+
 	if (pmu_context->pmu_data && pmu_context->pmu_data->pmu_init)
 		pmu_context->pmu_data->pmu_init();
 

drivers/soc/samsung/exynos-pmu.h

@@ -22,6 +22,7 @@ struct exynos_pmu_data {
 	const struct exynos_pmu_conf *pmu_config;
 	const struct exynos_pmu_conf *pmu_config_extra;
 	bool pmu_secure;
+	bool pmu_cpuhp;
 
 	void (*pmu_init)(void);
 	void (*powerdown_conf)(enum sys_powerdown);

include/linux/soc/samsung/exynos-regs-pmu.h

@@ -658,9 +658,20 @@
 #define EXYNOS5433_PAD_RETENTION_FSYSGENIO_OPTION		(0x32A8)
 
 /* For Tensor GS101 */
+/* PMU ALIVE */
 #define GS101_SYSIP_DAT0					(0x810)
+#define GS101_CPU0_INFORM					(0x860)
+#define GS101_CPU_INFORM(cpu)	\
+			(GS101_CPU0_INFORM + (cpu*4))
 #define GS101_SYSTEM_CONFIGURATION				(0x3A00)
 #define GS101_PHY_CTRL_USB20					(0x3EB0)
 #define GS101_PHY_CTRL_USBDP					(0x3EB4)
 
+/* 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)
+
 #endif /* __LINUX_SOC_EXYNOS_REGS_PMU_H */