intel_th: Add runtime power management handling

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@linux.intel.com>

diff --git a/drivers/hwtracing/intel_th/core.c b/drivers/hwtracing/intel_th/core.c
index 1be543e..fdd1763 100644 (file)
--- 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);
 }
 
@@ -628,6 +653,10 @@ 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;
@@ -635,6 +664,8 @@ 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");
 
@@ -658,6 +689,9 @@ 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");
 
@@ -682,6 +716,7 @@ 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;
@@ -702,6 +737,7 @@ 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 9beea0b..4106eaf 100644 (file)
--- 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;
 }