* [PATCH v3 1/2] coresight: cti: Add CPU Hotplug handling to CTI driver.
2020-05-11 20:48 [PATCH v3 0/2] Add CPU power management for CPU bound CTI devices Mike Leach
@ 2020-05-11 20:48 ` Mike Leach
2020-05-11 20:48 ` [PATCH v3 2/2] coresight: cti: Add CPU idle pm notifer to CTI devices Mike Leach
2020-05-14 17:12 ` [PATCH v3 0/2] Add CPU power management for CPU bound " Mathieu Poirier
2 siblings, 0 replies; 4+ messages in thread
From: Mike Leach @ 2020-05-11 20:48 UTC (permalink / raw)
To: linux-arm-kernel, coresight, mathieu.poirier
Cc: tglx, Mike Leach, suzuki.poulose
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>
---
drivers/hwtracing/coresight/coresight-cti.c | 91 +++++++++++++++++++++
include/linux/cpuhotplug.h | 1 +
2 files changed, 92 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
index be61c1705916..716cd5a45d12 100644
--- a/drivers/hwtracing/coresight/coresight-cti.c
+++ b/drivers/hwtracing/coresight/coresight-cti.c
@@ -40,6 +40,12 @@ static DEFINE_MUTEX(ect_mutex);
#define csdev_to_cti_drvdata(csdev) \
dev_get_drvdata(csdev->dev.parent)
+/* power management handling */
+static int nr_cti_cpu;
+
+/* quick lookup list for CPU bound CTIs when power handling */
+static struct cti_drvdata *cti_cpu_drvdata[NR_CPUS];
+
/*
* CTI naming. CTI bound to cores will have the name cti_cpu<N> where
* N is the CPU ID. System CTIs will have the name cti_sys<I> where I
@@ -129,6 +135,35 @@ static int cti_enable_hw(struct cti_drvdata *drvdata)
return rc;
}
+/* re-enable CTI on CPU when using CPU hotplug */
+static void cti_cpuhp_enable_hw(struct cti_drvdata *drvdata)
+{
+ struct cti_config *config = &drvdata->config;
+ struct device *dev = &drvdata->csdev->dev;
+
+ pm_runtime_get_sync(dev->parent);
+ spin_lock(&drvdata->spinlock);
+ config->hw_powered = true;
+
+ /* no need to do anything if no enable request */
+ if (!atomic_read(&drvdata->config.enable_req_count))
+ goto cti_hp_not_enabled;
+
+ /* try to claim the device */
+ if (coresight_claim_device(drvdata->base))
+ goto cti_hp_not_enabled;
+
+ cti_write_all_hw_regs(drvdata);
+ config->hw_enabled = true;
+ spin_unlock(&drvdata->spinlock);
+ return;
+
+ /* did not re-enable due to no claim / no request */
+cti_hp_not_enabled:
+ spin_unlock(&drvdata->spinlock);
+ pm_runtime_put(dev->parent);
+}
+
/* disable hardware */
static int cti_disable_hw(struct cti_drvdata *drvdata)
{
@@ -620,6 +655,44 @@ static void cti_remove_conn_xrefs(struct cti_drvdata *drvdata)
}
}
+/* CPU HP handlers */
+static int cti_starting_cpu(unsigned int cpu)
+{
+ struct cti_drvdata *drvdata = cti_cpu_drvdata[cpu];
+
+ if (!drvdata)
+ return 0;
+
+ cti_cpuhp_enable_hw(drvdata);
+ return 0;
+}
+
+static int cti_dying_cpu(unsigned int cpu)
+{
+ struct cti_drvdata *drvdata = cti_cpu_drvdata[cpu];
+
+ if (!drvdata)
+ return 0;
+
+ spin_lock(&drvdata->spinlock);
+ drvdata->config.hw_powered = false;
+ coresight_disclaim_device(drvdata->base);
+ spin_unlock(&drvdata->spinlock);
+ return 0;
+}
+
+/* release PM registrations */
+static void cti_pm_release(struct cti_drvdata *drvdata)
+{
+ if (drvdata->ctidev.cpu >= 0) {
+ if (--nr_cti_cpu == 0) {
+ cpuhp_remove_state_nocalls(
+ CPUHP_AP_ARM_CORESIGHT_CTI_STARTING);
+ }
+ cti_cpu_drvdata[drvdata->ctidev.cpu] = NULL;
+ }
+}
+
/** cti ect operations **/
int cti_enable(struct coresight_device *csdev)
{
@@ -655,6 +728,7 @@ static void cti_device_release(struct device *dev)
mutex_lock(&ect_mutex);
cti_remove_conn_xrefs(drvdata);
+ cti_pm_release(drvdata);
/* remove from the list */
list_for_each_entry_safe(ect_item, ect_tmp, &ect_net, node) {
@@ -730,6 +804,22 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
goto err_out;
}
+ /* setup CPU power management handling for CPU bound CTI devices. */
+ if (drvdata->ctidev.cpu >= 0) {
+ cti_cpu_drvdata[drvdata->ctidev.cpu] = drvdata;
+ if (!nr_cti_cpu++) {
+ cpus_read_lock();
+ ret = cpuhp_setup_state_nocalls_cpuslocked(
+ CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
+ "arm/coresight_cti:starting",
+ cti_starting_cpu, cti_dying_cpu);
+
+ cpus_read_unlock();
+ if (ret)
+ goto err_out;
+ }
+ }
+
/* create dynamic attributes for connections */
ret = cti_create_cons_sysfs(dev, drvdata);
if (ret) {
@@ -768,6 +858,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
return 0;
err_out:
+ cti_pm_release(drvdata);
return ret;
}
diff --git a/include/linux/cpuhotplug.h b/include/linux/cpuhotplug.h
index 77d70b633531..6dc7332307ca 100644
--- a/include/linux/cpuhotplug.h
+++ b/include/linux/cpuhotplug.h
@@ -142,6 +142,7 @@ enum cpuhp_state {
CPUHP_AP_ARM_XEN_STARTING,
CPUHP_AP_ARM_KVMPV_STARTING,
CPUHP_AP_ARM_CORESIGHT_STARTING,
+ CPUHP_AP_ARM_CORESIGHT_CTI_STARTING,
CPUHP_AP_ARM64_ISNDEP_STARTING,
CPUHP_AP_SMPCFD_DYING,
CPUHP_AP_X86_TBOOT_DYING,
--
2.17.1
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^ permalink raw reply related [flat|nested] 4+ messages in thread* [PATCH v3 2/2] coresight: cti: Add CPU idle pm notifer to CTI devices.
2020-05-11 20:48 [PATCH v3 0/2] Add CPU power management for CPU bound CTI devices Mike Leach
2020-05-11 20:48 ` [PATCH v3 1/2] coresight: cti: Add CPU Hotplug handling to CTI driver Mike Leach
@ 2020-05-11 20:48 ` Mike Leach
2020-05-14 17:12 ` [PATCH v3 0/2] Add CPU power management for CPU bound " Mathieu Poirier
2 siblings, 0 replies; 4+ messages in thread
From: Mike Leach @ 2020-05-11 20:48 UTC (permalink / raw)
To: linux-arm-kernel, coresight, mathieu.poirier
Cc: tglx, Mike Leach, suzuki.poulose
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>
---
drivers/hwtracing/coresight/coresight-cti.c | 69 +++++++++++++++++++++
1 file changed, 69 insertions(+)
diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
index 716cd5a45d12..5886663a641d 100644
--- a/drivers/hwtracing/coresight/coresight-cti.c
+++ b/drivers/hwtracing/coresight/coresight-cti.c
@@ -8,6 +8,7 @@
#include <linux/atomic.h>
#include <linux/bits.h>
#include <linux/coresight.h>
+#include <linux/cpu_pm.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kernel.h>
@@ -655,6 +656,70 @@ 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)
{
@@ -686,6 +751,8 @@ 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);
}
@@ -814,6 +881,8 @@ 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;
--
2.17.1
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^ permalink raw reply related [flat|nested] 4+ messages in thread* Re: [PATCH v3 0/2] Add CPU power management for CPU bound CTI devices.
2020-05-11 20:48 [PATCH v3 0/2] Add CPU power management for CPU bound CTI devices Mike Leach
2020-05-11 20:48 ` [PATCH v3 1/2] coresight: cti: Add CPU Hotplug handling to CTI driver Mike Leach
2020-05-11 20:48 ` [PATCH v3 2/2] coresight: cti: Add CPU idle pm notifer to CTI devices Mike Leach
@ 2020-05-14 17:12 ` Mathieu Poirier
2 siblings, 0 replies; 4+ messages in thread
From: Mathieu Poirier @ 2020-05-14 17:12 UTC (permalink / raw)
To: Mike Leach; +Cc: coresight, tglx, linux-arm-kernel, suzuki.poulose
On Mon, May 11, 2020 at 09:48:34PM +0100, Mike Leach wrote:
> Adds in power management for CPU bound CTI devices:
> i) CPU Hotplug - registers a new notifier for CPU start and stop events.
> ii) CPU idle PM event notifier to handle PM_ENTER, PM_ENTER_FAILED and
> PM_EXIT events.
>
> Tested with DB410c on coresight/next tree (Linux 5.7-rc1)
>
> Changes since v2:
> 1) removed helper functions filtering on CONFIG_CPU_PM to call cpu_pm
> fns directly.
> 2) add check for return value from cpuhp_remove_state_nocalls().
>
> Changes since V1: (requested by Mathieu).
> 1) Split into separate patches for CPU pm and CPU hotplug handling.
> 2) Enable on hotplug has a specific function to enable the hardware,
> while leaving the enable reference counts unchanged.
>
> Mike Leach (2):
> coresight: cti: Add CPU Hotplug handling to CTI driver.
> coresight: cti: Add CPU idle pm notifer to CTI devices.
I have applied this set.
Thanks,
Mathieu
>
> drivers/hwtracing/coresight/coresight-cti.c | 160 ++++++++++++++++++++
> include/linux/cpuhotplug.h | 1 +
> 2 files changed, 161 insertions(+)
>
> --
> 2.17.1
>
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^ permalink raw reply [flat|nested] 4+ messages in thread