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Message-Id: <20250429-contrib-pg-cpu-hotplug-suspend2ram-fixes-v1-v3-5-1bcc44fb1d55@linaro.org>
Date: Tue, 29 Apr 2025 07:19:41 +0100
From: Peter Griffin <peter.griffin@...aro.org>
To: Rob Herring <robh@...nel.org>, Krzysztof Kozlowski <krzk@...nel.org>,
Conor Dooley <conor+dt@...nel.org>, Alim Akhtar <alim.akhtar@...sung.com>
Cc: devicetree@...r.kernel.org, linux-arm-kernel@...ts.infradead.org,
linux-samsung-soc@...r.kernel.org, linux-kernel@...r.kernel.org,
tudor.ambarus@...aro.org, andre.draszik@...aro.org, willmcvicker@...gle.com,
kernel-team@...roid.com, Peter Griffin <peter.griffin@...aro.org>
Subject: [PATCH v3 5/5] soc: samsung: exynos-pmu: enable CPU hotplug
support for gs101
Some additional register writes are required when hotplugging CPUs
on gs101, without these the system hangs when hotplugging.
Specifically a CPU_INFORM register needs to be programmed with
a hint value which is used by the EL3 firmware (el3mon) and the
pmu-intr-gen registers need to be programmed.
With this patch applied, and corresponding DT update CPU hotplug
now works as expected. e.g.
echo 0 > /sys/devices/system/cpu/cpu6/online
echo 1 > /sys/devices/system/cpu/cpu6/online
Note: to maintain compatibility with older DTs that didn't specify
pmu-intr-gen phandle only a warning is issued if the syscon can't
be obtained.
Signed-off-by: Peter Griffin <peter.griffin@...aro.org>
---
Changes since v1:
* Use BIT macro (Kryzstof)
* Use gs101_ prefix for cpuhp functions (Kryzstof)
* Model pmuintrgen SFR region as it's own syscon (Kryzstof)
* Use regmap_update_bits() API (Kryzstof)
* Program hint on current processor number (Peter)
---
drivers/soc/samsung/exynos-pmu.c | 80 ++++++++++++++++++++++++++++-
drivers/soc/samsung/exynos-pmu.h | 1 +
include/linux/soc/samsung/exynos-regs-pmu.h | 11 ++++
3 files changed, 91 insertions(+), 1 deletion(-)
diff --git a/drivers/soc/samsung/exynos-pmu.c b/drivers/soc/samsung/exynos-pmu.c
index c40313886a012304b3f345d5d7369f15713eb857..41955ec2ccdb955b2d0b969651fad1a344628f1b 100644
--- a/drivers/soc/samsung/exynos-pmu.c
+++ b/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 +329,60 @@ 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, ®);
+
+ 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, ®);
+ regmap_write(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_CLEAR,
+ reg & mask);
+
+ mask = (BIT(cpu+8));
+ regmap_read(pmu_context->pmuintrgen, GS101_GRP1_INTR_BID_UPEND, ®);
+ regmap_write(pmu_context->pmuintrgen, GS101_GRP2_INTR_BID_CLEAR,
+ reg & mask);
+ return 0;
+}
+
static int exynos_pmu_probe(struct platform_device *pdev)
{
struct device *dev = &pdev->dev;
@@ -378,6 +435,27 @@ 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();
diff --git a/drivers/soc/samsung/exynos-pmu.h b/drivers/soc/samsung/exynos-pmu.h
index 0a49a2c9a08ef5bc75670551bdbf6d0a2d3e8ae9..0938bb4fe15f439e2d8bddeec51b6077e79a7e84 100644
--- a/drivers/soc/samsung/exynos-pmu.h
+++ b/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);
diff --git a/include/linux/soc/samsung/exynos-regs-pmu.h b/include/linux/soc/samsung/exynos-regs-pmu.h
index cde299a85384a70d04dae49ee9a4e2daa88fbbf6..c82b40035e9fa8fe6a673b829a75a50a707afb1b 100644
--- a/include/linux/soc/samsung/exynos-regs-pmu.h
+++ b/include/linux/soc/samsung/exynos-regs-pmu.h
@@ -660,9 +660,20 @@
#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 */
--
2.49.0.901.g37484f566f-goog
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