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Message-ID: <CANLsYky2f5TC2-iXCmfNAd-hv65YxBCp5FgcupoKdOYh+-fDYA@mail.gmail.com>
Date: Tue, 12 Jul 2016 09:21:44 -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>,
Sebastian Andrzej Siewior <bigeasy@...utronix.de>,
"linux-arm-kernel@...ts.infradead.org"
<linux-arm-kernel@...ts.infradead.org>
Subject: Re: [patch 55/66] hwtracing: coresight-etm4x: Convert to hotplug
state machine
On 11 July 2016 at 06:29, Anna-Maria Gleixner <anna-maria@...utronix.de> wrote:
> From: Sebastian Andrzej Siewior <bigeasy@...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: 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-etm4x.c | 93 ++++++++++++++------------
> include/linux/cpuhotplug.h | 1
> 2 files changed, 53 insertions(+), 41 deletions(-)
>
> --- a/drivers/hwtracing/coresight/coresight-etm4x.c
> +++ b/drivers/hwtracing/coresight/coresight-etm4x.c
> @@ -673,53 +673,52 @@ void etm4_config_trace_mode(struct etmv4
> config->addr_acc[ETM_DEFAULT_ADDR_COMP + 1] = addr_acc;
> }
>
> -static int etm4_cpu_callback(struct notifier_block *nfb, unsigned long action,
> - void *hcpu)
> +static int etm4_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 etm4_starting_cpu(unsigned int cpu)
> +{
> + if (!etmdrvdata[cpu])
> + return 0;
> +
> + spin_lock(&etmdrvdata[cpu]->spinlock);
> + if (!etmdrvdata[cpu]->os_unlock) {
> + etm4_os_unlock(etmdrvdata[cpu]);
> + etmdrvdata[cpu]->os_unlock = true;
> + }
>
> + if (local_read(&etmdrvdata[cpu]->mode))
> + etm4_enable_hw(etmdrvdata[cpu]);
> + spin_unlock(&etmdrvdata[cpu]->spinlock);
> + return 0;
> +}
> +
> +static int etm4_dying_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) {
> - etm4_os_unlock(etmdrvdata[cpu]);
> - etmdrvdata[cpu]->os_unlock = true;
> - }
> -
> - if (local_read(&etmdrvdata[cpu]->mode))
> - etm4_enable_hw(etmdrvdata[cpu]);
> - spin_unlock(&etmdrvdata[cpu]->spinlock);
> - break;
> -
> - case CPU_ONLINE:
> - if (etmdrvdata[cpu]->boot_enable &&
> - !etmdrvdata[cpu]->sticky_enable)
> - coresight_enable(etmdrvdata[cpu]->csdev);
> - break;
> -
> - case CPU_DYING:
> - spin_lock(&etmdrvdata[cpu]->spinlock);
> - if (local_read(&etmdrvdata[cpu]->mode))
> - etm4_disable_hw(etmdrvdata[cpu]);
> - spin_unlock(&etmdrvdata[cpu]->spinlock);
> - break;
> - }
> -out:
> - return NOTIFY_OK;
> -}
> -
> -static struct notifier_block etm4_cpu_notifier = {
> - .notifier_call = etm4_cpu_callback,
> -};
> + spin_lock(&etmdrvdata[cpu]->spinlock);
> + if (local_read(&etmdrvdata[cpu]->mode))
> + etm4_disable_hw(etmdrvdata[cpu]);
> + spin_unlock(&etmdrvdata[cpu]->spinlock);
> + return 0;
> +}
>
> static void etm4_init_trace_id(struct etmv4_drvdata *drvdata)
> {
> drvdata->trcid = coresight_get_trace_id(drvdata->cpu);
> }
>
> +static enum cpuhp_state hp_online;
> +
Same comment as with ETMv3 - I'd like to see this at the top of the
file with the rest of the global declaration.
> static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
> {
> int ret;
> @@ -767,8 +766,17 @@ static int etm4_probe(struct amba_device
> etm4_init_arch_data, drvdata, 1))
> dev_err(dev, "ETM arch init failed\n");
>
> - if (!etm4_count++)
> - register_hotcpu_notifier(&etm4_cpu_notifier);
> + if (!etm4_count++) {
> + cpuhp_setup_state_nocalls(CPUHP_AP_ARM_CORESIGHT4_STARTING,
> + "AP_ARM_CORESIGHT4_STARTING",
> + etm4_starting_cpu, etm4_dying_cpu);
> + ret = cpuhp_setup_state_nocalls(CPUHP_AP_ONLINE_DYN,
> + "AP_ARM_CORESIGHT4_ONLINE",
> + etm4_online_cpu, NULL);
> + if (ret < 0)
> + goto err_arch_supported;
> + hp_online = ret;
> + }
>
> put_online_cpus();
>
> @@ -809,8 +817,11 @@ static int etm4_probe(struct amba_device
> return 0;
>
> err_arch_supported:
> - if (--etm4_count == 0)
> - unregister_hotcpu_notifier(&etm4_cpu_notifier);
> + if (--etm4_count == 0) {
> + cpuhp_remove_state_nocalls(CPUHP_AP_ARM_CORESIGHT4_STARTING);
> + if (hp_online)
> + cpuhp_remove_state_nocalls(hp_online);
> + }
> return ret;
> }
>
> --- a/include/linux/cpuhotplug.h
> +++ b/include/linux/cpuhotplug.h
> @@ -55,6 +55,7 @@ enum cpuhp_state {
> CPUHP_AP_KVM_ARM_TIMER_STARTING,
> CPUHP_AP_ARM_XEN_STARTING,
> CPUHP_AP_ARM_CORESIGHT_STARTING,
> + CPUHP_AP_ARM_CORESIGHT4_STARTING,
> CPUHP_AP_LEDTRIG_STARTING,
> CPUHP_AP_NOTIFY_STARTING,
> CPUHP_AP_ONLINE,
>
>
With the above change,
Acked-by: Mathieu Poirier <mathieu.poirier@...aro.org>
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