[PATCH v2 05/30] drm/xe/pm: Add scope-based cleanup helper for runtime PM

[Matt Roper <matthew.d.roper@intel.com>]

Add a scope-based helpers for runtime PM that may be used to simplify
cleanup logic and potentially avoid goto-based cleanup.

For example, using

        guard(xe_pm_runtime)(xe);

will get runtime PM and cause a corresponding put to occur automatically
when the current scope is exited.  'xe_pm_runtime_noresume' can be used
as a guard replacement for the corresponding 'noresume' variant.
There's also an xe_pm_runtime_ioctl conditional guard that can be used
as a replacement for xe_runtime_ioctl():

        ACQUIRE(xe_pm_runtime_ioctl, pm)(xe);
        if ((ret = ACQUIRE_ERR(xe_pm_runtime_ioctl, &pm)) < 0)
                /* failed */

In a few rare cases (such as gt_reset_worker()) we need to ensure that
runtime PM is dropped when the function is exited by any means
(including error paths), but the function does not need to acquire
runtime PM because that has already been done earlier by a different
function.  For these special cases, an 'xe_pm_runtime_release_only'
guard can be used to handle the release without doing an acquisition.

These guards will be used in future patches to eliminate some of our
goto-based cleanup.

v2:
 - Specify success condition for xe_pm runtime_ioctl as _RET >= 0 so
   that positive values will be properly identified as success and
   trigger destructor cleanup properly.

Signed-off-by: Matt Roper <matthew.d.roper@intel.com>
---
 drivers/gpu/drm/xe/xe_pm.h | 17 +++++++++++++++++
 1 file changed, 17 insertions(+)

diff --git a/drivers/gpu/drm/xe/xe_pm.h b/drivers/gpu/drm/xe/xe_pm.h
index f7f89a18b6fc..6b27039e7b2d 100644
--- a/drivers/gpu/drm/xe/xe_pm.h
+++ b/drivers/gpu/drm/xe/xe_pm.h
@@ -6,6 +6,7 @@
 #ifndef _XE_PM_H_
 #define _XE_PM_H_
 
+#include <linux/cleanup.h>
 #include <linux/pm_runtime.h>
 
 #define DEFAULT_VRAM_THRESHOLD 300 /* in MB */
@@ -37,4 +38,20 @@ int xe_pm_block_on_suspend(struct xe_device *xe);
 void xe_pm_might_block_on_suspend(void);
 int xe_pm_module_init(void);
 
+static inline void __xe_pm_runtime_noop(struct xe_device *xe) {}
+
+DEFINE_GUARD(xe_pm_runtime, struct xe_device *,
+	     xe_pm_runtime_get(_T), xe_pm_runtime_put(_T))
+DEFINE_GUARD(xe_pm_runtime_noresume, struct xe_device *,
+	     xe_pm_runtime_get_noresume(_T), xe_pm_runtime_put(_T))
+DEFINE_GUARD_COND(xe_pm_runtime, _ioctl, xe_pm_runtime_get_ioctl(_T), _RET >= 0)
+
+/*
+ * Used when a function needs to release runtime PM in all possible cases
+ * and error paths, but the wakeref was already acquired by a different
+ * function (i.e., get() has already happened so only a put() is needed).
+ */
+DEFINE_GUARD(xe_pm_runtime_release_only, struct xe_device *,
+	     __xe_pm_runtime_noop(_T), xe_pm_runtime_put(_T));
+
 #endif
-- 
2.51.1