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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 <mike.leach@linaro.org> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20200518180242.7916-23-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
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2 changed files with 93 additions and 0 deletions
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@ -8,6 +8,7 @@
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#include <linux/atomic.h>
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#include <linux/bits.h>
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#include <linux/coresight.h>
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#include <linux/cpuhotplug.h>
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#include <linux/device.h>
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#include <linux/io.h>
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#include <linux/kernel.h>
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@ -40,6 +41,12 @@ static DEFINE_MUTEX(ect_mutex);
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#define csdev_to_cti_drvdata(csdev) \
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dev_get_drvdata(csdev->dev.parent)
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/* power management handling */
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static int nr_cti_cpu;
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/* quick lookup list for CPU bound CTIs when power handling */
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static struct cti_drvdata *cti_cpu_drvdata[NR_CPUS];
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/*
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* CTI naming. CTI bound to cores will have the name cti_cpu<N> where
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* N is the CPU ID. System CTIs will have the name cti_sys<I> where I
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@ -129,6 +136,35 @@ static int cti_enable_hw(struct cti_drvdata *drvdata)
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return rc;
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}
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/* re-enable CTI on CPU when using CPU hotplug */
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static void cti_cpuhp_enable_hw(struct cti_drvdata *drvdata)
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{
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struct cti_config *config = &drvdata->config;
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struct device *dev = &drvdata->csdev->dev;
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pm_runtime_get_sync(dev->parent);
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spin_lock(&drvdata->spinlock);
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config->hw_powered = true;
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/* no need to do anything if no enable request */
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if (!atomic_read(&drvdata->config.enable_req_count))
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goto cti_hp_not_enabled;
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/* try to claim the device */
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if (coresight_claim_device(drvdata->base))
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goto cti_hp_not_enabled;
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cti_write_all_hw_regs(drvdata);
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config->hw_enabled = true;
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spin_unlock(&drvdata->spinlock);
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return;
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/* did not re-enable due to no claim / no request */
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cti_hp_not_enabled:
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spin_unlock(&drvdata->spinlock);
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pm_runtime_put(dev->parent);
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}
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/* disable hardware */
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static int cti_disable_hw(struct cti_drvdata *drvdata)
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{
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@ -620,6 +656,44 @@ static void cti_remove_conn_xrefs(struct cti_drvdata *drvdata)
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}
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}
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/* CPU HP handlers */
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static int cti_starting_cpu(unsigned int cpu)
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{
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struct cti_drvdata *drvdata = cti_cpu_drvdata[cpu];
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if (!drvdata)
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return 0;
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cti_cpuhp_enable_hw(drvdata);
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return 0;
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}
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static int cti_dying_cpu(unsigned int cpu)
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{
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struct cti_drvdata *drvdata = cti_cpu_drvdata[cpu];
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if (!drvdata)
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return 0;
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spin_lock(&drvdata->spinlock);
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drvdata->config.hw_powered = false;
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coresight_disclaim_device(drvdata->base);
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spin_unlock(&drvdata->spinlock);
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return 0;
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}
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/* release PM registrations */
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static void cti_pm_release(struct cti_drvdata *drvdata)
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{
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if (drvdata->ctidev.cpu >= 0) {
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if (--nr_cti_cpu == 0) {
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cpuhp_remove_state_nocalls(
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CPUHP_AP_ARM_CORESIGHT_CTI_STARTING);
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}
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cti_cpu_drvdata[drvdata->ctidev.cpu] = NULL;
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}
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}
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/** cti ect operations **/
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int cti_enable(struct coresight_device *csdev)
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{
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@ -655,6 +729,7 @@ static void cti_device_release(struct device *dev)
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mutex_lock(&ect_mutex);
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cti_remove_conn_xrefs(drvdata);
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cti_pm_release(drvdata);
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/* remove from the list */
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list_for_each_entry_safe(ect_item, ect_tmp, &ect_net, node) {
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@ -730,6 +805,22 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
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goto err_out;
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}
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/* setup CPU power management handling for CPU bound CTI devices. */
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if (drvdata->ctidev.cpu >= 0) {
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cti_cpu_drvdata[drvdata->ctidev.cpu] = drvdata;
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if (!nr_cti_cpu++) {
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cpus_read_lock();
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ret = cpuhp_setup_state_nocalls_cpuslocked(
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CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
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"arm/coresight_cti:starting",
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cti_starting_cpu, cti_dying_cpu);
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cpus_read_unlock();
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if (ret)
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goto err_out;
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}
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}
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/* create dynamic attributes for connections */
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ret = cti_create_cons_sysfs(dev, drvdata);
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if (ret) {
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@ -768,6 +859,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
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return 0;
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err_out:
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cti_pm_release(drvdata);
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return ret;
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}
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@ -142,6 +142,7 @@ enum cpuhp_state {
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CPUHP_AP_ARM_XEN_STARTING,
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CPUHP_AP_ARM_KVMPV_STARTING,
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CPUHP_AP_ARM_CORESIGHT_STARTING,
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CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
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CPUHP_AP_ARM64_ISNDEP_STARTING,
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CPUHP_AP_SMPCFD_DYING,
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CPUHP_AP_X86_TBOOT_DYING,
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