From 6a0953ce7de918b06f7fed561754ad114fd964c1 Mon Sep 17 00:00:00 2001 From: Mike Leach Date: Mon, 18 May 2020 12:02:42 -0600 Subject: coresight: cti: Add CPU idle pm notifer to CTI devices Adds a notify callback for CPU PM events to the CTI driver - for CPU bound CTI devices. Signed-off-by: Mike Leach Signed-off-by: Mathieu Poirier Link: https://lore.kernel.org/r/20200518180242.7916-24-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman --- drivers/hwtracing/coresight/coresight-cti.c | 69 +++++++++++++++++++++++++++++ 1 file changed, 69 insertions(+) (limited to 'drivers/hwtracing') diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c index 7e7ec6dd93c0..40387d58c8e7 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 @@ -656,6 +657,70 @@ static void cti_remove_conn_xrefs(struct cti_drvdata *drvdata) } } +/** cti PM callbacks **/ +static int cti_cpu_pm_notify(struct notifier_block *nb, unsigned long cmd, + void *v) +{ + struct cti_drvdata *drvdata; + unsigned int cpu = smp_processor_id(); + int notify_res = NOTIFY_OK; + + if (!cti_cpu_drvdata[cpu]) + return NOTIFY_OK; + + drvdata = cti_cpu_drvdata[cpu]; + + if (WARN_ON_ONCE(drvdata->ctidev.cpu != cpu)) + return NOTIFY_BAD; + + spin_lock(&drvdata->spinlock); + + switch (cmd) { + case CPU_PM_ENTER: + /* CTI regs all static - we have a copy & nothing to save */ + drvdata->config.hw_powered = false; + if (drvdata->config.hw_enabled) + coresight_disclaim_device(drvdata->base); + break; + + case CPU_PM_ENTER_FAILED: + drvdata->config.hw_powered = true; + if (drvdata->config.hw_enabled) { + if (coresight_claim_device(drvdata->base)) + drvdata->config.hw_enabled = false; + } + break; + + case CPU_PM_EXIT: + /* write hardware registers to re-enable. */ + drvdata->config.hw_powered = true; + drvdata->config.hw_enabled = false; + + /* check enable reference count to enable HW */ + if (atomic_read(&drvdata->config.enable_req_count)) { + /* check we can claim the device as we re-power */ + if (coresight_claim_device(drvdata->base)) + goto cti_notify_exit; + + drvdata->config.hw_enabled = true; + cti_write_all_hw_regs(drvdata); + } + break; + + default: + notify_res = NOTIFY_DONE; + break; + } + +cti_notify_exit: + spin_unlock(&drvdata->spinlock); + return notify_res; +} + +static struct notifier_block cti_cpu_pm_nb = { + .notifier_call = cti_cpu_pm_notify, +}; + /* CPU HP handlers */ static int cti_starting_cpu(unsigned int cpu) { @@ -687,6 +752,8 @@ static void cti_pm_release(struct cti_drvdata *drvdata) { if (drvdata->ctidev.cpu >= 0) { if (--nr_cti_cpu == 0) { + cpu_pm_unregister_notifier(&cti_cpu_pm_nb); + cpuhp_remove_state_nocalls( CPUHP_AP_ARM_CORESIGHT_CTI_STARTING); } @@ -815,6 +882,8 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id) "arm/coresight_cti:starting", cti_starting_cpu, cti_dying_cpu); + if (!ret) + ret = cpu_pm_register_notifier(&cti_cpu_pm_nb); cpus_read_unlock(); if (ret) goto err_out; -- cgit