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authorMike Leach <mike.leach@linaro.org>2020-05-18 12:02:41 -0600
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2020-05-19 16:34:15 +0200
commite9b880581d555c8f7b58c7d19cc3f8f9016a1b5f (patch)
treefb10d0dee85d3f6e42cebfa3d0aaa47b7faf97ef /drivers/hwtracing
parent3f4943d422c5febbb3c764670011a00eb2a86238 (diff)
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coresight: cti: Add CPU Hotplug handling to CTI driver
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> Signed-off-by: Mathieu Poirier <mathieu.poirier@linaro.org> Link: https://lore.kernel.org/r/20200518180242.7916-23-mathieu.poirier@linaro.org Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/hwtracing')
-rw-r--r--drivers/hwtracing/coresight/coresight-cti.c92
1 files changed, 92 insertions, 0 deletions
diff --git a/drivers/hwtracing/coresight/coresight-cti.c b/drivers/hwtracing/coresight/coresight-cti.c
index be61c1705916..7e7ec6dd93c0 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/cpuhotplug.h>
#include <linux/device.h>
#include <linux/io.h>
#include <linux/kernel.h>
@@ -40,6 +41,12 @@ 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 +136,35 @@ cti_err_not_enabled:
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 +656,44 @@ 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 +729,7 @@ 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 +805,22 @@ 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 +859,7 @@ static int cti_probe(struct amba_device *adev, const struct amba_id *id)
return 0;
err_out:
+ cti_pm_release(drvdata);
return ret;
}