[PATCH v9 05/10] coresight: syscfg: Add API to activate and enable configurations
Mike Leach
mike.leach at linaro.org
Wed Jul 28 09:41:41 PDT 2021
Hi Mathieu,
On Wed, 28 Jul 2021 at 17:24, Mathieu Poirier
<mathieu.poirier at linaro.org> wrote:
>
> On Fri, Jul 23, 2021 at 05:54:39PM +0100, Mike Leach wrote:
> > Configurations are first activated, then when any coresight device is
> > enabled, the active configurations are checked and any matching
> > one is enabled.
> >
> > This patch provides the activation / enable API.
> >
> > Signed-off-by: Mike Leach <mike.leach at linaro.org>
> > ---
> > .../hwtracing/coresight/coresight-config.h | 2 +
> > .../hwtracing/coresight/coresight-syscfg.c | 212 ++++++++++++++++++
> > .../hwtracing/coresight/coresight-syscfg.h | 8 +
> > include/linux/coresight.h | 2 +
> > 4 files changed, 224 insertions(+)
> >
> > diff --git a/drivers/hwtracing/coresight/coresight-config.h b/drivers/hwtracing/coresight/coresight-config.h
> > index 0667581822c1..25eb6c632692 100644
> > --- a/drivers/hwtracing/coresight/coresight-config.h
> > +++ b/drivers/hwtracing/coresight/coresight-config.h
> > @@ -127,6 +127,7 @@ struct cscfg_feature_desc {
> > * @nr_total_params: Sum of all parameters declared by used features
> > * @presets: Array of preset values.
> > * @event_ea: Extended attribute for perf event value
> > + * @active_cnt: ref count for activate on this configuration.
> > *
> > */
> > struct cscfg_config_desc {
> > @@ -139,6 +140,7 @@ struct cscfg_config_desc {
> > int nr_total_params;
> > const u64 *presets; /* nr_presets * nr_total_params */
> > struct dev_ext_attribute *event_ea;
> > + atomic_t active_cnt;
> > };
> >
> > /**
> > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.c b/drivers/hwtracing/coresight/coresight-syscfg.c
> > index b93f2b4a777e..8903aab36c51 100644
> > --- a/drivers/hwtracing/coresight/coresight-syscfg.c
> > +++ b/drivers/hwtracing/coresight/coresight-syscfg.c
> > @@ -282,6 +282,7 @@ static int cscfg_load_config(struct cscfg_config_desc *config_desc)
> > return err;
> >
> > list_add(&config_desc->item, &cscfg_mgr->config_desc_list);
> > + atomic_set(&config_desc->active_cnt, 0);
> > return 0;
> > }
> >
> > @@ -468,6 +469,216 @@ void cscfg_unregister_csdev(struct coresight_device *csdev)
> > }
> > EXPORT_SYMBOL_GPL(cscfg_unregister_csdev);
> >
> > +/**
> > + * cscfg_csdev_reset_feats - reset features for a CoreSight device.
> > + *
> > + * Resets all parameters and register values for any features loaded
> > + * into @csdev to their default values.
> > + *
> > + * @csdev: The CoreSight device.
> > + */
> > +void cscfg_csdev_reset_feats(struct coresight_device *csdev)
> > +{
> > + struct cscfg_feature_csdev *feat_csdev;
> > + unsigned long flags;
> > +
> > + spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> > + if (list_empty(&csdev->feature_csdev_list))
> > + goto unlock_exit;
> > +
> > + list_for_each_entry(feat_csdev, &csdev->feature_csdev_list, node)
> > + cscfg_reset_feat(feat_csdev);
> > +
> > +unlock_exit:
> > + spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> > +}
> > +EXPORT_SYMBOL_GPL(cscfg_csdev_reset_feats);
> > +
> > +/**
> > + * cscfg_activate_config - Mark a configuration descriptor as active.
> > + *
> > + * This will be seen when csdev devices are enabled in the system.
> > + * Only activated configurations can be enabled on individual devices.
> > + * Activation protects the configuration from alteration or removal while
> > + * active.
> > + *
> > + * Selection by hash value - generated from the configuration name when it
> > + * was loaded and added to the cs_etm/configurations file system for selection
> > + * by perf.
> > + *
> > + * Increments the configuration descriptor active count and the global active
> > + * count.
> > + *
> > + * @cfg_hash: Hash value of the selected configuration name.
> > + */
> > +int cscfg_activate_config(unsigned long cfg_hash)
> > +{
> > + struct cscfg_config_desc *config_desc;
> > + int err = -EINVAL;
> > +
> > + mutex_lock(&cscfg_mutex);
> > +
> > + list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
> > + if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
> > + /*
> > + * increment the global active count - control changes to
> > + * active configurations
> > + */
> > + atomic_inc(&cscfg_mgr->sys_active_cnt);
> > +
> > + /*
> > + * mark the descriptor as active so enable config on a
> > + * device instance will use it
> > + */
> > + atomic_inc(&config_desc->active_cnt);
> > +
> > + err = 0;
> > + dev_dbg(cscfg_device(), "Activate config %s.\n", config_desc->name);
> > + break;
> > + }
> > + }
> > + mutex_unlock(&cscfg_mutex);
> > +
> > + return err;
> > +}
> > +EXPORT_SYMBOL_GPL(cscfg_activate_config);
> > +
> > +/**
> > + * cscfg_deactivate_config - Mark a config descriptor as inactive.
> > + *
> > + * Decrement the configuration and global active counts.
> > + *
> > + * @cfg_hash: Hash value of the selected configuration name.
> > + */
> > +void cscfg_deactivate_config(unsigned long cfg_hash)
> > +{
> > + struct cscfg_config_desc *config_desc;
> > +
> > + mutex_lock(&cscfg_mutex);
> > +
> > + list_for_each_entry(config_desc, &cscfg_mgr->config_desc_list, item) {
> > + if ((unsigned long)config_desc->event_ea->var == cfg_hash) {
> > + atomic_dec(&config_desc->active_cnt);
> > + atomic_dec(&cscfg_mgr->sys_active_cnt);
> > + dev_dbg(cscfg_device(), "Deactivate config %s.\n", config_desc->name);
> > + break;
> > + }
> > + }
> > + mutex_unlock(&cscfg_mutex);
> > +}
> > +EXPORT_SYMBOL_GPL(cscfg_deactivate_config);
> > +
> > +/**
> > + * cscfg_csdev_enable_active_config - Enable matching active configuration for device.
> > + *
> > + * Enables the configuration selected by @cfg_hash if the configuration is supported
> > + * on the device and has been activated.
> > + *
> > + * If active and supported the CoreSight device @csdev will be programmed with the
> > + * configuration, using @preset parameters.
> > + *
> > + * Should be called before driver hardware enable for the requested device, prior to
> > + * programming and enabling the physical hardware.
> > + *
> > + * @csdev: CoreSight device to program.
> > + * @cfg_hash: Selector for the configuration.
> > + * @preset: Preset parameter values to use, 0 for current / default values.
> > + */
> > +int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
> > + unsigned long cfg_hash, int preset)
> > +{
> > + struct cscfg_config_csdev *config_csdev_active = NULL, *config_csdev_item;
> > + const struct cscfg_config_desc *config_desc;
> > + unsigned long flags;
> > + int err = 0;
> > +
> > + /* quickly check global count */
> > + if (!atomic_read(&cscfg_mgr->sys_active_cnt))
> > + return 0;
> > +
> > + /* look for matching config - set in_enable flag if found */
>
> The second part of this comment no longer applies.
>
You are right - sorry missed that!
> > + spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> > + list_for_each_entry(config_csdev_item, &csdev->config_csdev_list, node) {
> > + config_desc = config_csdev_item->config_desc;
> > + if ((atomic_read(&config_desc->active_cnt)) &&
> > + ((unsigned long)config_desc->event_ea->var == cfg_hash)) {
> > + config_csdev_active = config_csdev_item;
> > + csdev->active_cscfg_ctxt = (void *)config_csdev_active;
> > + break;
> > + }
> > + }
> > + spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> > +
> > + /*
> > + * If found, attempt to enable
> > + */
> > + if (config_csdev_active) {
> > + /*
> > + * Call the generic routine that will program up the internal
> > + * driver structures prior to programming up the hardware.
> > + * This routine takes the driver spinlock saved in the configs.
> > + */
> > + err = cscfg_csdev_enable_config(config_csdev_active, preset);
> > + if (!err) {
> > + /*
> > + * Successful programming. Check the active_cscfg_ctxt
> > + * pointer to ensure no pre-emption disabled it via
> > + * cscfg_csdev_disable_active_config() before
> > + * we could start.
> > + *
> > + * Set enabled if OK, err if not.
> > + */
> > + spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> > + if (csdev->active_cscfg_ctxt)
> > + config_csdev_active->enabled = true;
> > + else
> > + err = -EBUSY;
> > + spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> > + }
>
> This is much better. I spent some time trying to break the heuristic and I
> can't. I intend to re-apply this set to give it as much exposure as possible but
> want to see the above comment fixed. I will do that locally though to avoid
> having to deal with another revision. What do you think of:
>
> /*
> * Look for a matching configuration - set the active configuration
> * context if found.
> */
>
That looks fin to me
Thanks
Mike
> Thanks,
> Mathieu
>
> > + }
> > + return err;
> > +}
> > +EXPORT_SYMBOL_GPL(cscfg_csdev_enable_active_config);
> > +
> > +/**
> > + * cscfg_csdev_disable_active_config - disable an active config on the device.
> > + *
> > + * Disables the active configuration on the CoreSight device @csdev.
> > + * Disable will save the values of any registers marked in the configurations
> > + * as save on disable.
> > + *
> > + * Should be called after driver hardware disable for the requested device,
> > + * after disabling the physical hardware and reading back registers.
> > + *
> > + * @csdev: The CoreSight device.
> > + */
> > +void cscfg_csdev_disable_active_config(struct coresight_device *csdev)
> > +{
> > + struct cscfg_config_csdev *config_csdev;
> > + unsigned long flags;
> > +
> > + /*
> > + * Check if we have an active config, and that it was successfully enabled.
> > + * If it was not enabled, we have no work to do, otherwise mark as disabled.
> > + * Clear the active config pointer.
> > + */
> > + spin_lock_irqsave(&csdev->cscfg_csdev_lock, flags);
> > + config_csdev = (struct cscfg_config_csdev *)csdev->active_cscfg_ctxt;
> > + if (config_csdev) {
> > + if (!config_csdev->enabled)
> > + config_csdev = NULL;
> > + else
> > + config_csdev->enabled = false;
> > + }
> > + csdev->active_cscfg_ctxt = NULL;
> > + spin_unlock_irqrestore(&csdev->cscfg_csdev_lock, flags);
> > +
> > + /* true if there was an enabled active config */
> > + if (config_csdev)
> > + cscfg_csdev_disable_config(config_csdev);
> > +}
> > +EXPORT_SYMBOL_GPL(cscfg_csdev_disable_active_config);
> > +
> > /* Initialise system configuration management device. */
> >
> > struct device *cscfg_device(void)
> > @@ -536,6 +747,7 @@ int __init cscfg_init(void)
> > INIT_LIST_HEAD(&cscfg_mgr->csdev_desc_list);
> > INIT_LIST_HEAD(&cscfg_mgr->feat_desc_list);
> > INIT_LIST_HEAD(&cscfg_mgr->config_desc_list);
> > + atomic_set(&cscfg_mgr->sys_active_cnt, 0);
> >
> > dev_info(cscfg_device(), "CoreSight Configuration manager initialised");
> > return 0;
> > diff --git a/drivers/hwtracing/coresight/coresight-syscfg.h b/drivers/hwtracing/coresight/coresight-syscfg.h
> > index 5bcae3b374c6..a52775890670 100644
> > --- a/drivers/hwtracing/coresight/coresight-syscfg.h
> > +++ b/drivers/hwtracing/coresight/coresight-syscfg.h
> > @@ -24,12 +24,14 @@
> > * @csdev_desc_list: List of coresight devices registered with the configuration manager.
> > * @feat_desc_list: List of feature descriptors to load into registered devices.
> > * @config_desc_list: List of system configuration descriptors to load into registered devices.
> > + * @sys_active_cnt: Total number of active config descriptor references.
> > */
> > struct cscfg_manager {
> > struct device dev;
> > struct list_head csdev_desc_list;
> > struct list_head feat_desc_list;
> > struct list_head config_desc_list;
> > + atomic_t sys_active_cnt;
> > };
> >
> > /* get reference to dev in cscfg_manager */
> > @@ -61,5 +63,11 @@ int cscfg_load_config_sets(struct cscfg_config_desc **cfg_descs,
> > int cscfg_register_csdev(struct coresight_device *csdev, u32 match_flags,
> > struct cscfg_csdev_feat_ops *ops);
> > void cscfg_unregister_csdev(struct coresight_device *csdev);
> > +int cscfg_activate_config(unsigned long cfg_hash);
> > +void cscfg_deactivate_config(unsigned long cfg_hash);
> > +void cscfg_csdev_reset_feats(struct coresight_device *csdev);
> > +int cscfg_csdev_enable_active_config(struct coresight_device *csdev,
> > + unsigned long cfg_hash, int preset);
> > +void cscfg_csdev_disable_active_config(struct coresight_device *csdev);
> >
> > #endif /* CORESIGHT_SYSCFG_H */
> > diff --git a/include/linux/coresight.h b/include/linux/coresight.h
> > index 16544ae2b532..93a2922b7653 100644
> > --- a/include/linux/coresight.h
> > +++ b/include/linux/coresight.h
> > @@ -223,6 +223,7 @@ struct coresight_sysfs_link {
> > * @feature_csdev_list: List of complex feature programming added to the device.
> > * @config_csdev_list: List of system configurations added to the device.
> > * @cscfg_csdev_lock: Protect the lists of configurations and features.
> > + * @active_cscfg_ctxt: Context information for current active system configuration.
> > */
> > struct coresight_device {
> > struct coresight_platform_data *pdata;
> > @@ -248,6 +249,7 @@ struct coresight_device {
> > struct list_head feature_csdev_list;
> > struct list_head config_csdev_list;
> > spinlock_t cscfg_csdev_lock;
> > + void *active_cscfg_ctxt;
> > };
> >
> > /*
> > --
> > 2.17.1
> >
--
Mike Leach
Principal Engineer, ARM Ltd.
Manchester Design Centre. UK
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