[QUEUED v20160630 2/4] intel_th: Add runtime power management handling

From: Alexander Shishkin
Date: Thu Jun 30 2016 - 08:57:32 EST

Currently, an Intel TH (pci) device will be always active, because the
devices on the 'intel_th' bus don't implement runtime pm to track their
usage.

To address this, this patch adds runtime pm support to the 'intel_th'
bus and some additional bits for the hub. The 'output' type device is
in use while a capture is active; the 'source' type device (STH) relies
on its child stm class device for runtime pm tracking.

Signed-off-by: Alexander Shishkin <alexander.shishkin@xxxxxxxxxxxxxxx>
---
drivers/hwtracing/intel_th/core.c | 54 ++++++++++++++++++++++++++++++++-------
drivers/hwtracing/intel_th/gth.c | 16 +++++++++++-
2 files changed, 60 insertions(+), 10 deletions(-)

diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
index 0b112ae689..6f0a51a2c6 100644
--- a/drivers/hwtracing/intel_th/core.c
+++ b/drivers/hwtracing/intel_th/core.c
@@ -23,6 +23,7 @@
#include <linux/debugfs.h>
#include <linux/idr.h>
#include <linux/pci.h>
+#include <linux/pm_runtime.h>
#include <linux/dma-mapping.h>

#include "intel_th.h"
@@ -67,23 +68,33 @@ static int intel_th_probe(struct device *dev)

hubdrv = to_intel_th_driver(hub->dev.driver);

+ pm_runtime_set_active(dev);
+ pm_runtime_no_callbacks(dev);
+ pm_runtime_enable(dev);
+
ret = thdrv->probe(to_intel_th_device(dev));
if (ret)
- return ret;
+ goto out_pm;

if (thdrv->attr_group) {
ret = sysfs_create_group(&thdev->dev.kobj, thdrv->attr_group);
- if (ret) {
- thdrv->remove(thdev);
-
- return ret;
- }
+ if (ret)
+ goto out;
}

if (thdev->type == INTEL_TH_OUTPUT &&
!intel_th_output_assigned(thdev))
+ /* does not talk to hardware */
ret = hubdrv->assign(hub, thdev);

+out:
+ if (ret)
+ thdrv->remove(thdev);
+
+out_pm:
+ if (ret)
+ pm_runtime_disable(dev);
+
return ret;
}

@@ -103,6 +114,8 @@ static int intel_th_remove(struct device *dev)
if (thdrv->attr_group)
sysfs_remove_group(&thdev->dev.kobj, thdrv->attr_group);

+ pm_runtime_get_sync(dev);
+
thdrv->remove(thdev);

if (intel_th_output_assigned(thdev)) {
@@ -110,9 +123,14 @@ static int intel_th_remove(struct device *dev)
to_intel_th_driver(dev->parent->driver);

if (hub->dev.driver)
+ /* does not talk to hardware */
hubdrv->unassign(hub, thdev);
}

+ pm_runtime_disable(dev);
+ pm_runtime_set_active(dev);
+ pm_runtime_enable(dev);
+
return 0;
}

@@ -185,6 +203,7 @@ static int intel_th_output_activate(struct intel_th_device *thdev)
{
struct intel_th_driver *thdrv =
to_intel_th_driver_or_null(thdev->dev.driver);
+ int ret = 0;

if (!thdrv)
return -ENODEV;
@@ -192,12 +211,17 @@ static int intel_th_output_activate(struct intel_th_device *thdev)
if (!try_module_get(thdrv->driver.owner))
return -ENODEV;

+ pm_runtime_get_sync(&thdev->dev);
+
if (thdrv->activate)
- return thdrv->activate(thdev);
+ ret = thdrv->activate(thdev);
+ else
+ intel_th_trace_enable(thdev);

- intel_th_trace_enable(thdev);
+ if (ret)
+ pm_runtime_put(&thdev->dev);

- return 0;
+ return ret;
}

static void intel_th_output_deactivate(struct intel_th_device *thdev)
@@ -213,6 +237,7 @@ static void intel_th_output_deactivate(struct intel_th_device *thdev)
else
intel_th_trace_disable(thdev);

+ pm_runtime_put(&thdev->dev);
module_put(thdrv->driver.owner);
}

@@ -660,6 +685,10 @@ intel_th_alloc(struct device *dev, struct resource *devres,

dev_set_drvdata(dev, th);

+ pm_runtime_no_callbacks(dev);
+ pm_runtime_put(dev);
+ pm_runtime_allow(dev);
+
err = intel_th_populate(th, devres, ndevres, irq);
if (err)
goto err_chrdev;
@@ -667,6 +696,8 @@ intel_th_alloc(struct device *dev, struct resource *devres,
return th;

err_chrdev:
+ pm_runtime_forbid(dev);
+
__unregister_chrdev(th->major, 0, TH_POSSIBLE_OUTPUTS,
"intel_th/output");

@@ -691,6 +722,9 @@ void intel_th_free(struct intel_th *th)

intel_th_device_remove(th->hub);

+ pm_runtime_get_sync(th->dev);
+ pm_runtime_forbid(th->dev);
+
__unregister_chrdev(th->major, 0, TH_POSSIBLE_OUTPUTS,
"intel_th/output");

@@ -715,6 +749,7 @@ int intel_th_trace_enable(struct intel_th_device *thdev)
if (WARN_ON_ONCE(thdev->type != INTEL_TH_OUTPUT))
return -EINVAL;

+ pm_runtime_get_sync(&thdev->dev);
hubdrv->enable(hub, &thdev->output);

return 0;
@@ -735,6 +770,7 @@ int intel_th_trace_disable(struct intel_th_device *thdev)
return -EINVAL;

hubdrv->disable(hub, &thdev->output);
+ pm_runtime_put(&thdev->dev);

return 0;
}
diff --git a/drivers/hwtracing/intel_th/gth.c b/drivers/hwtracing/intel_th/gth.c
index 9beea0b542..4106eaf131 100644
--- a/drivers/hwtracing/intel_th/gth.c
+++ b/drivers/hwtracing/intel_th/gth.c
@@ -22,6 +22,7 @@
#include <linux/mm.h>
#include <linux/slab.h>
#include <linux/bitmap.h>
+#include <linux/pm_runtime.h>

#include "intel_th.h"
#include "gth.h"
@@ -190,6 +191,11 @@ static ssize_t master_attr_store(struct device *dev,
if (old_port >= 0) {
gth->master[ma->master] = -1;
clear_bit(ma->master, gth->output[old_port].master);
+
+ /*
+ * if the port is active, program this setting,
+ * implies that runtime PM is on
+ */
if (gth->output[old_port].output->active)
gth_master_set(gth, ma->master, -1);
}
@@ -204,7 +210,7 @@ static ssize_t master_attr_store(struct device *dev,

set_bit(ma->master, gth->output[port].master);

- /* if the port is active, program this setting */
+ /* if the port is active, program this setting, see above */
if (gth->output[port].output->active)
gth_master_set(gth, ma->master, port);
}
@@ -326,11 +332,15 @@ static ssize_t output_attr_show(struct device *dev,
struct gth_device *gth = oa->gth;
size_t count;

+ pm_runtime_get_sync(dev);
+
spin_lock(&gth->gth_lock);
count = snprintf(buf, PAGE_SIZE, "%x\n",
gth_output_parm_get(gth, oa->port, oa->parm));
spin_unlock(&gth->gth_lock);

+ pm_runtime_put(dev);
+
return count;
}

@@ -346,10 +356,14 @@ static ssize_t output_attr_store(struct device *dev,
if (kstrtouint(buf, 16, &config) < 0)
return -EINVAL;

+ pm_runtime_get_sync(dev);
+
spin_lock(&gth->gth_lock);
gth_output_parm_set(gth, oa->port, oa->parm, config);
spin_unlock(&gth->gth_lock);

+ pm_runtime_put(dev);
+
return count;
}

--
2.8.1