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Message-ID: <CANLsYkzGx0Ta_+u6ECE5QwmtTJ+O+BJfAhFmbUGB8Q5d7cnUUw@mail.gmail.com>
Date: Tue, 12 Jul 2016 09:19:29 -0600
From: Mathieu Poirier <mathieu.poirier@...aro.org>
To: Anna-Maria Gleixner <anna-maria@...utronix.de>
Cc: LKML <linux-kernel@...r.kernel.org>,
Peter Zijlstra <peterz@...radead.org>,
Ingo Molnar <mingo@...nel.org>,
Richard Cochran <rcochran@...utronix.de>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [patch 54/66] hwtracing: coresight-etm3x: Convert to hotplug
state machine
On 11 July 2016 at 06:29, Anna-Maria Gleixner <anna-maria@...utronix.de> wrote:
> From: Richard Cochran <rcochran@...utronix.de>
>
> This driver has an asymmetry of ONLINE code without any corresponding tear
> down code. Otherwise, this is a straightforward conversion.
>
> Signed-off-by: Richard Cochran <rcochran@...utronix.de>
> Reviewed-by: Sebastian Andrzej Siewior <bigeasy@...utronix.de>
> Cc: Mathieu Poirier <mathieu.poirier@...aro.org>
> Cc: linux-arm-kernel@...ts.infradead.org
> Signed-off-by: Anna-Maria Gleixner <anna-maria@...utronix.de>
>
> ---
> drivers/hwtracing/coresight/coresight-etm3x.c | 90 ++++++++++++++------------
> include/linux/cpuhotplug.h | 1
> 2 files changed, 50 insertions(+), 41 deletions(-)
>
> --- a/drivers/hwtracing/coresight/coresight-etm3x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm3x.c
> @@ -481,8 +481,7 @@ static int etm_enable_sysfs(struct cores
>
> /*
> * 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,
> @@ -641,47 +640,44 @@ static const struct coresight_ops etm_cs
> .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])
> - 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]);
> - etmdrvdata[cpu]->os_unlock = true;
> - }
> -
> - if (local_read(&etmdrvdata[cpu]->mode))
> - etm_enable_hw(etmdrvdata[cpu]);
> - spin_unlock(&etmdrvdata[cpu]->spinlock);
> - break;
> + if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
> + coresight_enable(etmdrvdata[cpu]->csdev);
> + return 0;
> +}
>
> - case CPU_ONLINE:
> - if (etmdrvdata[cpu]->boot_enable &&
> - !etmdrvdata[cpu]->sticky_enable)
> - coresight_enable(etmdrvdata[cpu]->csdev);
> - break;
> +static int etm_starting_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;
> + spin_lock(&etmdrvdata[cpu]->spinlock);
> + if (!etmdrvdata[cpu]->os_unlock) {
> + etm_os_unlock(etmdrvdata[cpu]);
> + etmdrvdata[cpu]->os_unlock = true;
> }
> -out:
> - return NOTIFY_OK;
> +
> + if (local_read(&etmdrvdata[cpu]->mode))
> + etm_enable_hw(etmdrvdata[cpu]);
> + spin_unlock(&etmdrvdata[cpu]->spinlock);
> + return 0;
> }
>
> -static struct notifier_block etm_cpu_notifier = {
> - .notifier_call = etm_cpu_callback,
> -};
> +static int etm_dying_cpu(unsigned int cpu)
> +{
> + if (!etmdrvdata[cpu])
> + return 0;
> +
> + spin_lock(&etmdrvdata[cpu]->spinlock);
> + if (local_read(&etmdrvdata[cpu]->mode))
> + etm_disable_hw(etmdrvdata[cpu]);
> + spin_unlock(&etmdrvdata[cpu]->spinlock);
> + return 0;
> +}
>
> static bool etm_arch_supported(u8 arch)
> {
> @@ -750,6 +746,8 @@ static void etm_init_trace_id(struct etm
> drvdata->traceid = coresight_get_trace_id(drvdata->cpu);
> }
>
> +static enum cpuhp_state hp_online;
> +
Can we put this at the top of the file with the other global declaration?
> static int etm_probe(struct amba_device *adev, const struct amba_id *id)
> {
> int ret;
> @@ -806,9 +804,17 @@ static int etm_probe(struct amba_device
> 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
>
> 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
> 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;
> }
>
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -54,6 +54,7 @@ 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,
>
>
This looks good to me - thanks for contribution. With the above change,
Acked-by: Mathieu Poirier <mathieu.poirier@...aro.org>
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