[PATCH i-g-t 07/10] lib/xe: Add xe_wa_from_cache()

An upcoming change will need to check if a workaround is enabled
during the creation of the xe_device struct, i.e., during the
execution of xe_device_get().  It is not possible to call xe_wa() in
that context because the struct is not yet cached and xe_wa() calling
xe_device_get() will cause an infinite recursion.

Add the function xe_wa_from_cache() to allow checking for workarounds
in that specific scenario and make a note in the function's
documentation about its purpose.

Signed-off-by: Gustavo Sousa <[email protected]>
---
 lib/xe/xe_wa.c | 34 ++++++++++++++++++++++++++++------
 lib/xe/xe_wa.h |  1 +
 2 files changed, 29 insertions(+), 6 deletions(-)

diff --git a/lib/xe/xe_wa.c b/lib/xe/xe_wa.c
index 8c8f7156c21f..ac3dcf6ef1c1 100644
--- a/lib/xe/xe_wa.c
+++ b/lib/xe/xe_wa.c
@@ -105,19 +105,28 @@ static bool debugfs_dump_has_wa(char *dump, const char *wa)
 
 /**
  * xe_wa: Check if a workaround is enabled for the device.
- * @fd: A drm file descriptor.
+ * @xe_dev: Xe device where the cached data is stashed.
  * @wa: Name of the workaround to be checked.
  *
- * Return a boolean indicating whether the workaround is enabled.
- * On error, returns false and a warning is printed.
+ * This function is like xe_wa(), but it receives the "incomplete"
+ * (see next paragraph) xe_device struct directly instead of a drm
+ * file descriptor.
+ *
+ * This function is only expected to be used in specific paths during
+ * the initialization of a xe_device struct (i.e. during execution of
+ * xe_device_get()), where the workaround cache is ready
+ * (i.e. xe_wa_build_cache()), but the xe_device struct is not yet
+ * fully built and cached (which is a requirement for xe_wa()).
  */
-bool xe_wa(int fd, const char *wa)
+bool xe_wa_from_cache(struct xe_device *xe_dev, const char *wa)
 {
-	char **dumps = xe_device_get(fd)->wa_cache;
+	char **dumps;
 
-	if (igt_warn_on(!dumps))
+	if (igt_warn_on(!xe_dev->wa_cache))
 		return false;
 
+	dumps = xe_dev->wa_cache;
+
 	for (char **dump = dumps; *dump; dump++)
 		if (debugfs_dump_has_wa(*dump, wa))
 			return true;
@@ -125,6 +134,19 @@ bool xe_wa(int fd, const char *wa)
 	return false;
 }
 
+/**
+ * xe_wa: Check if a workaround is enabled for the device.
+ * @fd: A drm file descriptor.
+ * @wa: Name of the workaround to be checked.
+ *
+ * Return a boolean indicating whether the workaround is enabled.
+ * On error, returns false and a warning is printed.
+ */
+bool xe_wa(int fd, const char *wa)
+{
+	return xe_wa_from_cache(xe_device_get(fd), wa);
+}
+
 /**
  * xe_wa_build_cache: Build cached data for xe_wa().
  * @xe_dev: Xe device where the cache will be stashed.
diff --git a/lib/xe/xe_wa.h b/lib/xe/xe_wa.h
index aa1c50c0f9c9..2f141ae15016 100644
--- a/lib/xe/xe_wa.h
+++ b/lib/xe/xe_wa.h
@@ -14,5 +14,6 @@ bool xe_wa(int fd, const char *wa);
 
 void xe_wa_build_cache(struct xe_device *xe_dev);
 void xe_wa_free_cache(struct xe_device *xe_dev);
+bool xe_wa_from_cache(struct xe_device *xe_dev, const char *wa);
 
 #endif /* XE_WA_H */

-- 
2.55.0