Re: [RFC PATCH v3 16/16] drivers: coresight: cti: Add CPU power event handling.

On Wed, Jun 05, 2019 at 08:03:13PM +0100, Mike Leach wrote:

CPU bound CTI's require registration with CPU power event handling to ensure we know when device power state changes alongside associated CPU.

Signed-off-by: Mike Leach mike.leach@linaro.org

drivers/hwtracing/coresight/coresight-cti.c | 59 +++++++++++++++++++++ 1 file changed, 59 insertions(+)

diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c index 6996b70f99e8..c58173d4b11b 100644 --- a/drivers/hwtracing/coresight/coresight-cti.c +++ b/drivers/hwtracing/coresight/coresight-cti.c @@ -91,6 +91,11 @@ static int cti_enable_hw(struct cti_drvdata *drvdata, bool update_refcount) if (config->hw_enabled || !config->hw_powered) goto cti_not_enabled;

• /* if not updating refcount and it is 0 then nothing to do */
• if (!update_refcount &&

•    (atomic_read(&drvdata->config.enable_req_count) == 0))
  

• goto cti_not_enabled;
  

What scenario is the above covering?

I am officially done reviewing this set.

Thanks, Mathieu

/* claim the device */ rc = coresight_claim_device(drvdata->base); if (rc) @@ -584,6 +589,40 @@ const struct coresight_ops cti_ops = { .ect_ops = &cti_ops_ect, }; +/* pm event notifiers */ +int cti_cs_cpupm_event(struct coresight_device *csdev, unsigned int cpuid,

•        enum cs_cpu_pm_events event)
  

+{

• struct cti_drvdata *drvdata = csdev_to_cti_drvdata(csdev);
• switch (event) {

• /* called on the device cpu during registration */
  

• case CS_CPUPM_SMP_ON_REG_CPU:

• drvdata->config.hw_powered = true;
  

• break;
  

• /* cpu hotplug start */
  

• case CS_CPUPM_CPUHP_CS_START:

• spin_lock(&drvdata->spinlock);
  

• drvdata->config.hw_powered = true;
  

• spin_unlock(&drvdata->spinlock);
  

• cti_enable_hw(drvdata, false);
  

• break;
  

• /* cpu hotplug stop */
  

• case CS_CPUPM_CPUHP_CS_STOP:

• cti_disable_hw(drvdata, false);
  

• spin_lock(&drvdata->spinlock);
  

• drvdata->config.hw_powered = false;
  

• spin_unlock(&drvdata->spinlock);
  

• break;
  

• default:

• break;
  

• }
• return 0;

+}

static int cti_probe(struct amba_device *adev, const struct amba_id *id) { int ret = 0; @@ -594,6 +633,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) struct coresight_platform_data *pdata = NULL; struct resource *res = &adev->res; struct ect_node *ect_nd = NULL;

• bool cpupm_registered = false;

/* node to keep track of CTI net */ ect_nd = devm_kzalloc(dev, sizeof(struct ect_node), GFP_KERNEL); @@ -676,6 +716,20 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) goto err_out; }

• /* setup cpu related CTI PM, otherwise assume powered */
• if (drvdata->ctidev.cpu >= 0) {

• drvdata->config.hw_powered = false;
  

• ret = coresight_cpupm_register(drvdata->csdev,
  

• 			       drvdata->ctidev.cpu,
  

• 			       cti_cs_cpupm_event);
  

• if (ret) {
  

• 	pr_err("%s:CS cpu pm register error\n", cti_desc.name);
  

• 	goto err_out;
  

• }
  

• cpupm_registered = true;
  

• } else

• drvdata->config.hw_powered = true;
  

• /* add to list of CTI devices */ mutex_lock(&ect_mutex); ect_nd->cti_drv = drvdata;

@@ -696,6 +750,8 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) return 0; err_out:

• if (cpupm_registered && drvdata->csdev && (drvdata->ctidev.cpu >= 0))

• coresight_cpupm_unregister(drvdata->csdev, drvdata->ctidev.cpu);
  

  return ret;

} @@ -726,6 +782,9 @@ void cti_device_release(struct device *dev) struct ect_node *ect_item, *ect_tmp; mutex_lock(&ect_mutex);

• /* free up resources associated with the cti connections */
• if (drvdata->ctidev.cpu >= 0)

• coresight_cpupm_unregister(drvdata->csdev, drvdata->ctidev.cpu);
  

/* clear the dynamic sysfs associate with connections */ cti_destroy_cons_sysfs(&drvdata->ctidev); -- 2.20.1

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