korg/linux
0
0
Fork 0
mirror of https://mirrors.bfsu.edu.cn/git/linux.git synced 2024-12-02 08:34:20 +08:00
Code Issues Packages Projects Releases Wiki Activity

coresight: etm4x: add CPU hotplug support for probing

Browse Source 
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 2022-07-05 16:59:35 +02:00 committed by Suzuki K Poulose
parent 30a0b95b13
commit 3c728e079d
1 changed files with 113 additions and 40 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

153
drivers/hwtracing/coresight/coresight-etm4x-core.c
View File

@ -66,10 +66,13 @@ static enum cpuhp_state hp_online;
struct etm4_init_arg {
unsigned int pid;
struct etmv4_drvdata *drvdata;
struct device *dev;
struct csdev_access *csa;
};
static DEFINE_PER_CPU(struct etm4_init_arg *, delayed_probe);
static int etm4_probe_cpu(unsigned int cpu);
/*
* Check if TRCSSPCICRn(i) is implemented for a given instance.
*
@ -1085,7 +1088,7 @@ static void etm4_init_arch_data(void *info)
struct csdev_access *csa;
int i;
drvdata = init_arg->drvdata;
drvdata = dev_get_drvdata(init_arg->dev);
csa = init_arg->csa;
/*
@ -1528,7 +1531,7 @@ void etm4_config_trace_mode(struct etmv4_config *config)
static int etm4_online_cpu(unsigned int cpu)
{
if (!etmdrvdata[cpu])
return 0;
return etm4_probe_cpu(cpu);
if (etmdrvdata[cpu]->boot_enable && !etmdrvdata[cpu]->sticky_enable)
coresight_enable(etmdrvdata[cpu]->csdev);
@ -1904,48 +1907,20 @@ static void etm4_pm_clear(void)
}
}
static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
static int etm4_add_coresight_dev(struct etm4_init_arg *init_arg)
{
int ret;
struct coresight_platform_data *pdata = NULL;
struct etmv4_drvdata *drvdata;
struct device *dev = init_arg->dev;
struct etmv4_drvdata *drvdata = dev_get_drvdata(dev);
struct coresight_desc desc = { 0 };
struct etm4_init_arg init_arg = { 0 };
u8 major, minor;
char *type_name;
drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
if (!drvdata)
return -ENOMEM;
return -EINVAL;
dev_set_drvdata(dev, drvdata);
if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE)
pm_save_enable = coresight_loses_context_with_cpu(dev) ?
PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER;
if (pm_save_enable != PARAM_PM_SAVE_NEVER) {
drvdata->save_state = devm_kmalloc(dev,
sizeof(struct etmv4_save_state), GFP_KERNEL);
if (!drvdata->save_state)
return -ENOMEM;
}
drvdata->base = base;
spin_lock_init(&drvdata->spinlock);
drvdata->cpu = coresight_get_cpu(dev);
if (drvdata->cpu < 0)
return drvdata->cpu;
init_arg.drvdata = drvdata;
init_arg.csa = &desc.access;
init_arg.pid = etm_pid;
if (smp_call_function_single(drvdata->cpu,
etm4_init_arch_data, &init_arg, 1))
dev_err(dev, "ETM arch init failed\n");
desc.access = *init_arg->csa;
if (!drvdata->arch)
return -EINVAL;
@ -2016,6 +1991,68 @@ static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
return 0;
}
static int etm4_probe(struct device *dev, void __iomem *base, u32 etm_pid)
{
struct etmv4_drvdata *drvdata;
struct csdev_access access = { 0 };
struct etm4_init_arg init_arg = { 0 };
struct etm4_init_arg *delayed;
drvdata = devm_kzalloc(dev, sizeof(*drvdata), GFP_KERNEL);
if (!drvdata)
return -ENOMEM;
dev_set_drvdata(dev, drvdata);
if (pm_save_enable == PARAM_PM_SAVE_FIRMWARE)
pm_save_enable = coresight_loses_context_with_cpu(dev) ?
PARAM_PM_SAVE_SELF_HOSTED : PARAM_PM_SAVE_NEVER;
if (pm_save_enable != PARAM_PM_SAVE_NEVER) {
drvdata->save_state = devm_kmalloc(dev,
sizeof(struct etmv4_save_state), GFP_KERNEL);
if (!drvdata->save_state)
return -ENOMEM;
}
drvdata->base = base;
spin_lock_init(&drvdata->spinlock);
drvdata->cpu = coresight_get_cpu(dev);
if (drvdata->cpu < 0)
return drvdata->cpu;
init_arg.dev = dev;
init_arg.csa = &access;
init_arg.pid = etm_pid;
/*
* Serialize against CPUHP callbacks to avoid race condition
* between the smp call and saving the delayed probe.
*/
cpus_read_lock();
if (smp_call_function_single(drvdata->cpu,
etm4_init_arch_data, &init_arg, 1)) {
/* The CPU was offline, try again once it comes online. */
delayed = devm_kmalloc(dev, sizeof(*delayed), GFP_KERNEL);
if (!delayed) {
cpus_read_unlock();
return -ENOMEM;
}
*delayed = init_arg;
per_cpu(delayed_probe, drvdata->cpu) = delayed;
cpus_read_unlock();
return 0;
}
cpus_read_unlock();
return etm4_add_coresight_dev(&init_arg);
}
static int etm4_probe_amba(struct amba_device *adev, const struct amba_id *id)
{
void __iomem *base;
@ -2054,6 +2091,35 @@ static int etm4_probe_platform_dev(struct platform_device *pdev)
return ret;
}
static int etm4_probe_cpu(unsigned int cpu)
{
int ret;
struct etm4_init_arg init_arg;
struct csdev_access access = { 0 };
struct etm4_init_arg *iap = *this_cpu_ptr(&delayed_probe);
if (!iap)
return 0;
init_arg = *iap;
devm_kfree(init_arg.dev, iap);
*this_cpu_ptr(&delayed_probe) = NULL;
ret = pm_runtime_resume_and_get(init_arg.dev);
if (ret < 0) {
dev_err(init_arg.dev, "Failed to get PM runtime!\n");
return 0;
}
init_arg.csa = &access;
etm4_init_arch_data(&init_arg);
etm4_add_coresight_dev(&init_arg);
pm_runtime_put(init_arg.dev);
return 0;
}
static struct amba_cs_uci_id uci_id_etm4[] = {
{
/* ETMv4 UCI data */
@ -2068,16 +2134,20 @@ static void clear_etmdrvdata(void *info)
int cpu = *(int *)info;
etmdrvdata[cpu] = NULL;
per_cpu(delayed_probe, cpu) = NULL;
}
static int __exit etm4_remove_dev(struct etmv4_drvdata *drvdata)
{
etm_perf_symlink(drvdata->csdev, false);
bool had_delayed_probe;
/*
* Taking hotplug lock here to avoid racing between etm4_remove_dev()
* and CPU hotplug call backs.
*/
cpus_read_lock();
had_delayed_probe = per_cpu(delayed_probe, drvdata->cpu);
/*
* The readers for etmdrvdata[] are CPU hotplug call backs
* and PM notification call backs. Change etmdrvdata[i] on
@ -2085,12 +2155,15 @@ static int __exit etm4_remove_dev(struct etmv4_drvdata *drvdata)
* inside one call back function.
*/
if (smp_call_function_single(drvdata->cpu, clear_etmdrvdata, &drvdata->cpu, 1))
etmdrvdata[drvdata->cpu] = NULL;
clear_etmdrvdata(&drvdata->cpu);
cpus_read_unlock();
cscfg_unregister_csdev(drvdata->csdev);
coresight_unregister(drvdata->csdev);
if (!had_delayed_probe) {
etm_perf_symlink(drvdata->csdev, false);
cscfg_unregister_csdev(drvdata->csdev);
coresight_unregister(drvdata->csdev);
}
return 0;
}