hwtracing/coresight-etm4x: 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: Sebastian Andrzej Siewior <bigeasy@linutronix.de>
Signed-off-by: Anna-Maria Gleixner <anna-maria@linutronix.de>
Acked-by: Mathieu 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/20160713153337.228918408@linutronix.de
Signed-off-by: Ingo Molnar <mingo@kernel.org>

diff --git a/drivers/hwtracing/coresight/coresight-etm4x.c b/drivers/hwtracing/coresight/coresight-etm4x.c
index 462f0dc..1a5e0d1 100644 (file)
--- a/drivers/hwtracing/coresight/coresight-etm4x.c
+++ b/drivers/hwtracing/coresight/coresight-etm4x.c
@@ -48,6 +48,8 @@ static int etm4_count;
 static struct etmv4_drvdata *etmdrvdata[NR_CPUS];
 static void etm4_set_default(struct etmv4_config *config);
 
+static enum cpuhp_state hp_online;
+
 static void etm4_os_unlock(struct etmv4_drvdata *drvdata)
 {
        /* Writing any value to ETMOSLAR unlocks the trace registers */
@@ -673,47 +675,44 @@ void etm4_config_trace_mode(struct etmv4_config *config)
        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])
-               goto out;
-
-       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;
+               return 0;
 
-       case CPU_ONLINE:
-               if (etmdrvdata[cpu]->boot_enable &&
-                       !etmdrvdata[cpu]->sticky_enable)
-                       coresight_enable(etmdrvdata[cpu]->csdev);
-               break;
+       if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
+               coresight_enable(etmdrvdata[cpu]->csdev);
+       return 0;
+}
 
-       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;
+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;
        }
-out:
-       return NOTIFY_OK;
+
+       if (local_read(&etmdrvdata[cpu]->mode))
+               etm4_enable_hw(etmdrvdata[cpu]);
+       spin_unlock(&etmdrvdata[cpu]->spinlock);
+       return 0;
 }
 
-static struct notifier_block etm4_cpu_notifier = {
-       .notifier_call = etm4_cpu_callback,
-};
+static int etm4_dying_cpu(unsigned int cpu)
+{
+       if (!etmdrvdata[cpu])
+               return 0;
+
+       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)
 {
@@ -767,8 +766,17 @@ static int etm4_probe(struct amba_device *adev, const struct amba_id *id)
                                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 *adev, const struct amba_id *id)
        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;
 }
 

diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 576ad23..6cede62 100644 (file)
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -50,6 +50,7 @@ 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,