Freeing a fragment requires freeing DMA coherent memory, which can't be
performed with interrupts disabled as per the DMA mapping API contract.
The fragments can't thus be freed synchronously when a display list is
recycled. Instead, move the fragments to a garbage list and use a work
queue to run the garbage collection.
Signed-off-by: Laurent Pinchart <laurent.pinchart+rene...@ideasonboard.com>
---
drivers/media/platform/vsp1/vsp1_dl.c | 72 ++++++++++++++++++++++++++++-------
1 file changed, 58 insertions(+), 14 deletions(-)
diff --git a/drivers/media/platform/vsp1/vsp1_dl.c
b/drivers/media/platform/vsp1/vsp1_dl.c
index e238d9b9376b..37c3518aa2a8 100644
--- a/drivers/media/platform/vsp1/vsp1_dl.c
+++ b/drivers/media/platform/vsp1/vsp1_dl.c
@@ -15,6 +15,7 @@
#include <linux/dma-mapping.h>
#include <linux/gfp.h>
#include <linux/slab.h>
+#include <linux/workqueue.h>
#include "vsp1.h"
#include "vsp1_dl.h"
@@ -92,11 +93,13 @@ enum vsp1_dl_mode {
* @index: index of the related WPF
* @mode: display list operation mode (header or headerless)
* @vsp1: the VSP1 device
- * @lock: protects the active, queued and pending lists
+ * @lock: protects the free, active, queued, pending and gc_fragments lists
* @free: array of all free display lists
* @active: list currently being processed (loaded) by hardware
* @queued: list queued to the hardware (written to the DL registers)
* @pending: list waiting to be queued to the hardware
+ * @gc_work: fragments garbage collector work struct
+ * @gc_fragments: array of display list fragments waiting to be freed
*/
struct vsp1_dl_manager {
unsigned int index;
@@ -108,6 +111,9 @@ struct vsp1_dl_manager {
struct vsp1_dl_list *active;
struct vsp1_dl_list *queued;
struct vsp1_dl_list *pending;
+
+ struct work_struct gc_work;
+ struct list_head gc_fragments;
};
/*
-----------------------------------------------------------------------------
@@ -262,21 +268,10 @@ static struct vsp1_dl_list *vsp1_dl_list_alloc(struct
vsp1_dl_manager *dlm)
return dl;
}
-static void vsp1_dl_list_free_fragments(struct vsp1_dl_list *dl)
-{
- struct vsp1_dl_body *dlb, *next;
-
- list_for_each_entry_safe(dlb, next, &dl->fragments, list) {
- list_del(&dlb->list);
- vsp1_dl_body_cleanup(dlb);
- kfree(dlb);
- }
-}
-
static void vsp1_dl_list_free(struct vsp1_dl_list *dl)
{
vsp1_dl_body_cleanup(&dl->body0);
- vsp1_dl_list_free_fragments(dl);
+ list_splice_init(&dl->fragments, &dl->dlm->gc_fragments);
kfree(dl);
}
@@ -311,7 +306,16 @@ static void __vsp1_dl_list_put(struct vsp1_dl_list *dl)
if (!dl)
return;
- vsp1_dl_list_free_fragments(dl);
+ /* We can't free fragments here as DMA memory can only be freed in
+ * interruptible context. Move all fragments to the display list
+ * manager's list of fragments to be freed, they will be
+ * garbage-collected by the work queue.
+ */
+ if (!list_empty(&dl->fragments)) {
+ list_splice_init(&dl->fragments, &dl->dlm->gc_fragments);
+ schedule_work(&dl->dlm->gc_work);
+ }
+
dl->body0.num_entries = 0;
list_add_tail(&dl->list, &dl->dlm->free);
@@ -550,6 +554,40 @@ void vsp1_dlm_reset(struct vsp1_dl_manager *dlm)
dlm->pending = NULL;
}
+/*
+ * Free all fragments awaiting to be garbage-collected.
+ *
+ * This function must be called without the display list manager lock held.
+ */
+static void vsp1_dlm_fragments_free(struct vsp1_dl_manager *dlm)
+{
+ unsigned long flags;
+
+ spin_lock_irqsave(&dlm->lock, flags);
+
+ while (!list_empty(&dlm->gc_fragments)) {
+ struct vsp1_dl_body *dlb;
+
+ dlb = list_first_entry(&dlm->gc_fragments, struct vsp1_dl_body,
+ list);
+ list_del(&dlb->list);
+
+ spin_unlock_irqrestore(&dlm->lock, flags);
+ vsp1_dl_fragment_free(dlb);
+ spin_lock_irqsave(&dlm->lock, flags);
+ }
+
+ spin_unlock_irqrestore(&dlm->lock, flags);
+}
+
+static void vsp1_dlm_garbage_collect(struct work_struct *work)
+{
+ struct vsp1_dl_manager *dlm =
+ container_of(work, struct vsp1_dl_manager, gc_work);
+
+ vsp1_dlm_fragments_free(dlm);
+}
+
struct vsp1_dl_manager *vsp1_dlm_create(struct vsp1_device *vsp1,
unsigned int index,
unsigned int prealloc)
@@ -568,6 +606,8 @@ struct vsp1_dl_manager *vsp1_dlm_create(struct vsp1_device
*vsp1,
spin_lock_init(&dlm->lock);
INIT_LIST_HEAD(&dlm->free);
+ INIT_LIST_HEAD(&dlm->gc_fragments);
+ INIT_WORK(&dlm->gc_work, vsp1_dlm_garbage_collect);
for (i = 0; i < prealloc; ++i) {
struct vsp1_dl_list *dl;
@@ -589,8 +629,12 @@ void vsp1_dlm_destroy(struct vsp1_dl_manager *dlm)
if (!dlm)
return;
+ cancel_work_sync(&dlm->gc_work);
+
list_for_each_entry_safe(dl, next, &dlm->free, list) {
list_del(&dl->list);
vsp1_dl_list_free(dl);
}
+
+ vsp1_dlm_fragments_free(dlm);
}
--
Regards,
Laurent Pinchart
