coresight: cti: Add CPU Hotplug handling to CTI driver (e9b88058) · Commits · 戴 / test

drivers/hwtracing/coresight/coresight-cti.c

+92 −0

Original line number	Diff line number	Diff line
		@@ -8,6 +8,7 @@
		#include <linux/atomic.h>
		#include <linux/bits.h>
		#include <linux/coresight.h>
		#include <linux/cpuhotplug.h>
		#include <linux/device.h>
		#include <linux/io.h>
		#include <linux/kernel.h>
		@@ -40,6 +41,12 @@ static DEFINE_MUTEX(ect_mutex);
		#define csdev_to_cti_drvdata(csdev) \
		dev_get_drvdata(csdev->dev.parent)

		/* power management handling */
		static int nr_cti_cpu;

		/* quick lookup list for CPU bound CTIs when power handling */
		static struct cti_drvdata *cti_cpu_drvdata[NR_CPUS];

		/*
		* CTI naming. CTI bound to cores will have the name cti_cpu<N> where
		* N is the CPU ID. System CTIs will have the name cti_sys<I> where I
		@@ -129,6 +136,35 @@ cti_err_not_enabled:
		return rc;
		}

		/* re-enable CTI on CPU when using CPU hotplug */
		static void cti_cpuhp_enable_hw(struct cti_drvdata *drvdata)
		{
		struct cti_config *config = &drvdata->config;
		struct device *dev = &drvdata->csdev->dev;

		pm_runtime_get_sync(dev->parent);
		spin_lock(&drvdata->spinlock);
		config->hw_powered = true;

		/* no need to do anything if no enable request */
		if (!atomic_read(&drvdata->config.enable_req_count))
		goto cti_hp_not_enabled;

		/* try to claim the device */
		if (coresight_claim_device(drvdata->base))
		goto cti_hp_not_enabled;

		cti_write_all_hw_regs(drvdata);
		config->hw_enabled = true;
		spin_unlock(&drvdata->spinlock);
		return;

		/* did not re-enable due to no claim / no request */
		cti_hp_not_enabled:
		spin_unlock(&drvdata->spinlock);
		pm_runtime_put(dev->parent);
		}

		/* disable hardware */
		static int cti_disable_hw(struct cti_drvdata *drvdata)
		{
		@@ -620,6 +656,44 @@ static void cti_remove_conn_xrefs(struct cti_drvdata *drvdata)
		}
		}

		/* CPU HP handlers */
		static int cti_starting_cpu(unsigned int cpu)
		{
		struct cti_drvdata *drvdata = cti_cpu_drvdata[cpu];

		if (!drvdata)
		return 0;

		cti_cpuhp_enable_hw(drvdata);
		return 0;
		}

		static int cti_dying_cpu(unsigned int cpu)
		{
		struct cti_drvdata *drvdata = cti_cpu_drvdata[cpu];

		if (!drvdata)
		return 0;

		spin_lock(&drvdata->spinlock);
		drvdata->config.hw_powered = false;
		coresight_disclaim_device(drvdata->base);
		spin_unlock(&drvdata->spinlock);
		return 0;
		}

		/* release PM registrations */
		static void cti_pm_release(struct cti_drvdata *drvdata)
		{
		if (drvdata->ctidev.cpu >= 0) {
		if (--nr_cti_cpu == 0) {
		cpuhp_remove_state_nocalls(
		CPUHP_AP_ARM_CORESIGHT_CTI_STARTING);
		}
		cti_cpu_drvdata[drvdata->ctidev.cpu] = NULL;
		}
		}

		/ cti ect operations /
		int cti_enable(struct coresight_device *csdev)
		{
		@@ -655,6 +729,7 @@ static void cti_device_release(struct device *dev)

		mutex_lock(&ect_mutex);
		cti_remove_conn_xrefs(drvdata);
		cti_pm_release(drvdata);

		/* remove from the list */
		list_for_each_entry_safe(ect_item, ect_tmp, &ect_net, node) {
		@@ -730,6 +805,22 @@ static int cti_probe(struct amba_device adev, const struct amba_id id)
		goto err_out;
		}

		/* setup CPU power management handling for CPU bound CTI devices. */
		if (drvdata->ctidev.cpu >= 0) {
		cti_cpu_drvdata[drvdata->ctidev.cpu] = drvdata;
		if (!nr_cti_cpu++) {
		cpus_read_lock();
		ret = cpuhp_setup_state_nocalls_cpuslocked(
		CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
		"arm/coresight_cti:starting",
		cti_starting_cpu, cti_dying_cpu);

		cpus_read_unlock();
		if (ret)
		goto err_out;
		}
		}

		/* create dynamic attributes for connections */
		ret = cti_create_cons_sysfs(dev, drvdata);
		if (ret) {
		@@ -768,6 +859,7 @@ static int cti_probe(struct amba_device adev, const struct amba_id id)
		return 0;

		err_out:
		cti_pm_release(drvdata);
		return ret;
		}

include/linux/cpuhotplug.h

+1 −0

Original line number	Diff line number	Diff line
		@@ -142,6 +142,7 @@ enum cpuhp_state {
		CPUHP_AP_ARM_XEN_STARTING,
		CPUHP_AP_ARM_KVMPV_STARTING,
		CPUHP_AP_ARM_CORESIGHT_STARTING,
		CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
		CPUHP_AP_ARM64_ISNDEP_STARTING,
		CPUHP_AP_SMPCFD_DYING,
		CPUHP_AP_X86_TBOOT_DYING,

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