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coresight: cti: Add CPU idle pm notifer to CTI devices

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Adds a notify callback for CPU PM events to the CTI driver - for
CPU bound CTI devices.

Signed-off-by: Mike Leach <mike.leach@linaro.org>
Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org>
Link: https://lore.kernel.org/r/20200518180242.7916-24-mathieu.poirier@linaro.org
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mike Leach 2020-05-18 12:02:42 -06:00 committed by Greg Kroah-Hartman
parent e9b880581d
commit 6a0953ce7d
1 changed files with 69 additions and 0 deletions
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69
drivers/hwtracing/coresight/coresight-cti.c
View File

@ -8,6 +8,7 @@
#include <linux/atomic.h>
#include <linux/bits.h>
#include <linux/coresight.h>
#include <linux/cpu_pm.h>
#include <linux/cpuhotplug.h>
#include <linux/device.h>
#include <linux/io.h>
@ -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;