coresight: etm4x: add CPU hotplug support for probing
etm4x devices cannot be successfully probed when their CPU is offline. For example, when booting with maxcpus=n, ETM probing will fail on CPUs >n, and the probing won't be reattempted once the CPUs come online. This will leave those CPUs unable to make use of ETM. This change adds a mechanism to delay the probing if the corresponding CPU is offline, and to try it again when the CPU comes online. Signed-off-by: Tamas Zsoldos <tamas.zsoldos@arm.com> Signed-off-by: Suzuki K Poulose <suzuki.poulose@arm.com> Link: https://lore.kernel.org/r/20220705145935.24679-1-tamas.zsoldos@arm.com
This commit is contained in:
Tamas Zsoldos
Suzuki K Poulose
parent
30a0b95b13
commit
3c728e079d
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@ -66,10 +66,13 @@ static enum cpuhp_state hp_online;
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struct etm4_init_arg {
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unsigned int pid;
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struct etmv4_drvdata *drvdata;
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struct device *dev;
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struct csdev_access *csa;
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};
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static DEFINE_PER_CPU(struct etm4_init_arg *, delayed_probe);
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static int etm4_probe_cpu(unsigned int cpu);
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/*
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* Check if TRCSSPCICRn(i) is implemented for a given instance.
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*
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@ -1085,7 +1088,7 @@ static void etm4_init_arch_data(void *info)
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struct csdev_access *csa;
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int i;
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drvdata = init_arg->drvdata;
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drvdata = dev_get_drvdata(init_arg->dev);
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csa = init_arg->csa;
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/*
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@ -1528,7 +1531,7 @@ void etm4_config_trace_mode(struct etmv4_config *config)
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static int etm4_online_cpu(unsigned int cpu)
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{
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if (!etmdrvdata[cpu])
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return 0;
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return etm4_probe_cpu(cpu);
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if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
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coresight_enable(etmdrvdata[cpu]->csdev);
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@ -1904,48 +1907,20 @@ static void etm4_pm_clear(void)
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}
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}
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static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
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static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
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{
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int ret;
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struct coresight_platform_data *pdata = NULL;
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struct etmv4_drvdata *drvdata;
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struct device *dev = init_arg->dev;
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struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
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struct coresight_desc desc = { 0 };
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struct etm4_init_arg init_arg = { 0 };
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u8 major, minor;
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char *type_name;
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drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
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if (!drvdata)
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return -ENOMEM;
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return -EINVAL;
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dev_set_drvdata(dev, drvdata);
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if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE)
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pm_save_enable = coresight_loses_context_with_cpu(dev) ?
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PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER;
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if (pm_save_enable != PARAM_PM_SAVE_NEVER) {
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drvdata->save_state = devm_kmalloc(dev,
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sizeof(struct etmv4_save_state), GFP_KERNEL);
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if (!drvdata->save_state)
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return -ENOMEM;
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}
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drvdata->base = base;
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spin_lock_init(&drvdata->spinlock);
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drvdata->cpu = coresight_get_cpu(dev);
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if (drvdata->cpu < 0)
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return drvdata->cpu;
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init_arg.drvdata = drvdata;
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init_arg.csa = &desc.access;
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init_arg.pid = etm_pid;
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if (smp_call_function_single(drvdata->cpu,
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etm4_init_arch_data, &init_arg, 1))
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dev_err(dev, "ETM arch init failed\n");
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desc.access = *init_arg->csa;
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if (!drvdata->arch)
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return -EINVAL;
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@ -2016,6 +1991,68 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
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return 0;
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}
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static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
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{
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struct etmv4_drvdata *drvdata;
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struct csdev_access access = { 0 };
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struct etm4_init_arg init_arg = { 0 };
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struct etm4_init_arg *delayed;
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drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
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if (!drvdata)
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return -ENOMEM;
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dev_set_drvdata(dev, drvdata);
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if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE)
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pm_save_enable = coresight_loses_context_with_cpu(dev) ?
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PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER;
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if (pm_save_enable != PARAM_PM_SAVE_NEVER) {
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drvdata->save_state = devm_kmalloc(dev,
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sizeof(struct etmv4_save_state), GFP_KERNEL);
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if (!drvdata->save_state)
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return -ENOMEM;
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}
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drvdata->base = base;
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spin_lock_init(&drvdata->spinlock);
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drvdata->cpu = coresight_get_cpu(dev);
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if (drvdata->cpu < 0)
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return drvdata->cpu;
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init_arg.dev = dev;
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init_arg.csa = &access;
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init_arg.pid = etm_pid;
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/*
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* Serialize against CPUHP callbacks to avoid race condition
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* between the smp call and saving the delayed probe.
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*/
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cpus_read_lock();
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if (smp_call_function_single(drvdata->cpu,
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etm4_init_arch_data, &init_arg, 1)) {
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/* The CPU was offline, try again once it comes online. */
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delayed = devm_kmalloc(dev, sizeof(*delayed), GFP_KERNEL);
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if (!delayed) {
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cpus_read_unlock();
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return -ENOMEM;
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}
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*delayed = init_arg;
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per_cpu(delayed_probe, drvdata->cpu) = delayed;
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cpus_read_unlock();
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return 0;
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}
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cpus_read_unlock();
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return etm4_add_coresight_dev(&init_arg);
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}
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static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
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{
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void __iomem *base;
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@ -2054,6 +2091,35 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
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return ret;
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}
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static int etm4_probe_cpu(unsigned int cpu)
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{
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int ret;
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struct etm4_init_arg init_arg;
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struct csdev_access access = { 0 };
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struct etm4_init_arg *iap = *this_cpu_ptr(&delayed_probe);
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if (!iap)
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return 0;
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init_arg = *iap;
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devm_kfree(init_arg.dev, iap);
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*this_cpu_ptr(&delayed_probe) = NULL;
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ret = pm_runtime_resume_and_get(init_arg.dev);
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if (ret < 0) {
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dev_err(init_arg.dev, "Failed to get PM runtime!\n");
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return 0;
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}
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init_arg.csa = &access;
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etm4_init_arch_data(&init_arg);
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etm4_add_coresight_dev(&init_arg);
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pm_runtime_put(init_arg.dev);
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return 0;
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}
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static struct amba_cs_uci_id uci_id_etm4[] = {
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{
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/* ETMv4 UCI data */
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@ -2068,16 +2134,20 @@ static void clear_etmdrvdata(void *info)
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int cpu = *(int *)info;
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etmdrvdata[cpu] = NULL;
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per_cpu(delayed_probe, cpu) = NULL;
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}
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static int __exit etm4_remove_dev(struct etmv4_drvdata *drvdata)
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{
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etm_perf_symlink(drvdata->csdev, false);
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bool had_delayed_probe;
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/*
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* Taking hotplug lock here to avoid racing between etm4_remove_dev()
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* and CPU hotplug call backs.
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*/
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cpus_read_lock();
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had_delayed_probe = per_cpu(delayed_probe, drvdata->cpu);
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/*
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* The readers for etmdrvdata[] are CPU hotplug call backs
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* and PM notification call backs. Change etmdrvdata[i] on
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@ -2085,12 +2155,15 @@ static int __exit etm4_remove_dev(struct etmv4_drvdata *drvdata)
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* inside one call back function.
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*/
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if (smp_call_function_single(drvdata->cpu, clear_etmdrvdata, &drvdata->cpu, 1))
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etmdrvdata[drvdata->cpu] = NULL;
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clear_etmdrvdata(&drvdata->cpu);
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cpus_read_unlock();
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cscfg_unregister_csdev(drvdata->csdev);
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coresight_unregister(drvdata->csdev);
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if (!had_delayed_probe) {
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etm_perf_symlink(drvdata->csdev, false);
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cscfg_unregister_csdev(drvdata->csdev);
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coresight_unregister(drvdata->csdev);
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}
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return 0;
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}
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