From e9b880581d555c8f7b58c7d19cc3f8f9016a1b5f Mon Sep 17 00:00:00 2001 From: Mike Leach Date: Mon, 18 May 2020 12:02:41 -0600 Subject: coresight: cti: Add CPU Hotplug handling to CTI driver Adds registration of CPU start and stop functions to CPU hotplug mechanisms - for any CPU bound CTI. Sets CTI powered flag according to state. Will enable CTI on CPU start if there are existing enable requests. Signed-off-by: Mike Leach Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20200518180242.7916-23-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-cti.c | 92 +++++++++++++++++++++++++++++ 1 file changed, 92 insertions(+) (limited to 'drivers/hwtracing') diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c index be61c1705916..7e7ec6dd93c0 100644 --- a/drivers/hwtracing/coresight/coresight-cti.c +++ b/drivers/hwtracing/coresight/coresight-cti.c @@ -8,6 +8,7 @@ #include #include #include +#include #include #include #include @@ -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 where * N is the CPU ID. System CTIs will have the name cti_sys 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; } -- cgit v1.2.3