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Commit 2b5283d1 authored by Richard Cochran's avatar Richard Cochran Committed by Ingo Molnar
Browse files

hwtracing/coresight-etm3x: Convert to hotplug state machine 



This driver has an asymmetry of ONLINE code without any corresponding tear
down code. Otherwise, this is a straightforward conversion.

Signed-off-by: default avatarRichard Cochran <rcochran@linutronix.de>
Signed-off-by: default avatarAnna-Maria Gleixner <anna-maria@linutronix.de>
Reviewed-by: default avatarSebastian Andrzej Siewior <bigeasy@linutronix.de>
Acked-by: default avatarMathieu Poirier <mathieu.poirier@linaro.org>
Cc: Linus Torvalds <torvalds@linux-foundation.org>
Cc: Peter Zijlstra <peterz@infradead.org>
Cc: Thomas Gleixner <tglx@linutronix.de>
Cc: linux-arm-kernel@lists.infradead.org
Cc: rt@linutronix.de
Link: http://lkml.kernel.org/r/20160713153337.147128995@linutronix.de


Signed-off-by: default avatarIngo Molnar <mingo@kernel.org>
parent 65264e3b

drivers/hwtracing/coresight/coresight-etm3x.c

+49 −41
Original line number Diff line number Diff line
@@ -51,6 +51,8 @@ module_param_named(boot_enable, boot_enable, int, S_IRUGO); 
static int etm_count;

static struct etm_drvdata *etmdrvdata[NR_CPUS];



static enum cpuhp_state hp_online;



/*

 * Memory mapped writes to clear os lock are not supported on some processors

 * and OS lock must be unlocked before any memory mapped access on such
@@ -481,8 +483,7 @@ static int etm_enable_sysfs(struct coresight_device *csdev) 


	/*

	 * Configure the ETM only if the CPU is online.  If it isn't online

	 * hw configuration will take place when 'CPU_STARTING' is received

	 * in @etm_cpu_callback.

	 * hw configuration will take place on the local CPU during bring up.

	 */

	if (cpu_online(drvdata->cpu)) {

		ret = smp_call_function_single(drvdata->cpu,
@@ -641,16 +642,21 @@ static const struct coresight_ops etm_cs_ops = { 
	.source_ops	= &etm_source_ops,

};



static int etm_cpu_callback(struct notifier_block *nfb, unsigned long action,

			    void *hcpu)

static int etm_online_cpu(unsigned int cpu)

{

	unsigned int cpu = (unsigned long)hcpu;

	if (!etmdrvdata[cpu])

		return 0;



	if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)

		coresight_enable(etmdrvdata[cpu]->csdev);

	return 0;

}



static int etm_starting_cpu(unsigned int cpu)

{

	if (!etmdrvdata[cpu])

		goto out;

		return 0;



	switch (action & (~CPU_TASKS_FROZEN)) {

	case CPU_STARTING:

	spin_lock(&etmdrvdata[cpu]->spinlock);

	if (!etmdrvdata[cpu]->os_unlock) {

		etm_os_unlock(etmdrvdata[cpu]);
@@ -660,29 +666,21 @@ static int etm_cpu_callback(struct notifier_block *nfb, unsigned long action, 
	if (local_read(&etmdrvdata[cpu]->mode))

		etm_enable_hw(etmdrvdata[cpu]);

	spin_unlock(&etmdrvdata[cpu]->spinlock);

		break;

	return 0;

}



	case CPU_ONLINE:

		if (etmdrvdata[cpu]->boot_enable &&

		    !etmdrvdata[cpu]->sticky_enable)

			coresight_enable(etmdrvdata[cpu]->csdev);

		break;

static int etm_dying_cpu(unsigned int cpu)

{

	if (!etmdrvdata[cpu])

		return 0;



	case CPU_DYING:

	spin_lock(&etmdrvdata[cpu]->spinlock);

	if (local_read(&etmdrvdata[cpu]->mode))

		etm_disable_hw(etmdrvdata[cpu]);

	spin_unlock(&etmdrvdata[cpu]->spinlock);

		break;

	}

out:

	return NOTIFY_OK;

	return 0;

}



static struct notifier_block etm_cpu_notifier = {

	.notifier_call = etm_cpu_callback,

};



static bool etm_arch_supported(u8 arch)

{

	switch (arch) {
@@ -806,9 +804,17 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id) 
				     etm_init_arch_data,  drvdata, 1))

		dev_err(dev, "ETM arch init failed\n");



	if (!etm_count++)

		register_hotcpu_notifier(&etm_cpu_notifier);



	if (!etm_count++) {

		cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING,

					  "AP_ARM_CORESIGHT_STARTING",

					  etm_starting_cpu, etm_dying_cpu);

		ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,

						"AP_ARM_CORESIGHT_ONLINE",

						etm_online_cpu, NULL);

		if (ret < 0)

			goto err_arch_supported;

		hp_online = ret;

	}

	put_online_cpus();



	if (etm_arch_supported(drvdata->arch) == false) {
@@ -839,7 +845,6 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id) 


	pm_runtime_put(&adev->dev);

	dev_info(dev, "%s initialized\n", (char *)id->data);



	if (boot_enable) {

		coresight_enable(drvdata->csdev);

		drvdata->boot_enable = true;
@@ -848,8 +853,11 @@ static int etm_probe(struct amba_device *adev, const struct amba_id *id) 
	return 0;



err_arch_supported:

	if (--etm_count == 0)

		unregister_hotcpu_notifier(&etm_cpu_notifier);

	if (--etm_count == 0) {

		cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT_STARTING);

		if (hp_online)

			cpuhp_remove_state_nocalls(hp_online);

	}

	return ret;

}

include/linux/cpuhotplug.h

+1 −0
Original line number Diff line number Diff line
@@ -49,6 +49,7 @@ enum cpuhp_state { 
	CPUHP_AP_KVM_ARM_VGIC_STARTING,

	CPUHP_AP_KVM_ARM_TIMER_STARTING,

	CPUHP_AP_ARM_XEN_STARTING,

	CPUHP_AP_ARM_CORESIGHT_STARTING,

	CPUHP_AP_LEDTRIG_STARTING,

	CPUHP_AP_NOTIFY_STARTING,

	CPUHP_AP_ONLINE,