[PATCH 1/7] drm/mediatek: fix atomic_state reference counting
Bibby Hsieh
bibby.hsieh at mediatek.com
Tue Nov 26 06:29:26 UTC 2019
The DRM core takes care of all atomic state refcounting.
However, mediatek drm defers some work that accesses planes
and plane_states in drm_atomic_state, and must therefore
keep its own atomic state references until this work complete.
We take the atomic_state reference in atomic_fulsh() and ensure all the
information in atomic_state already was updated in hardware for
showing on screen and then schedules unreference_work to drop references
on atomic_state.
Fixes: 119f5173628a ("drm/mediatek: Add DRM Driver for Mediatek SoC MT8173.")
Signed-off-by: Bibby Hsieh <bibby.hsieh at mediatek.com>
---
drivers/gpu/drm/mediatek/mtk_drm_crtc.c | 11 +++-
drivers/gpu/drm/mediatek/mtk_drm_drv.c | 79 +++++++++++++++++++++++++
drivers/gpu/drm/mediatek/mtk_drm_drv.h | 9 +++
3 files changed, 97 insertions(+), 2 deletions(-)
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
index 29d0582e90e9..68b92adc96bb 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_crtc.c
@@ -7,7 +7,7 @@
#include <linux/pm_runtime.h>
#include <asm/barrier.h>
-
+#include <drm/drm_atomic.h>
#include <drm/drm_atomic_helper.h>
#include <drm/drm_plane_helper.h>
#include <drm/drm_probe_helper.h>
@@ -47,6 +47,7 @@ struct mtk_drm_crtc {
struct mtk_disp_mutex *mutex;
unsigned int ddp_comp_nr;
struct mtk_ddp_comp **ddp_comp;
+ struct drm_crtc_state *old_crtc_state;
};
struct mtk_crtc_state {
@@ -362,6 +363,7 @@ static void mtk_crtc_ddp_hw_fini(struct mtk_drm_crtc *mtk_crtc)
static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
{
struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
+ struct drm_atomic_state *atomic_state = mtk_crtc->old_crtc_state->state;
struct mtk_crtc_state *state = to_mtk_crtc_state(mtk_crtc->base.state);
struct mtk_ddp_comp *comp = mtk_crtc->ddp_comp[0];
unsigned int i;
@@ -399,6 +401,7 @@ static void mtk_crtc_ddp_config(struct drm_crtc *crtc)
plane_state->pending.config = false;
}
mtk_crtc->pending_planes = false;
+ mtk_atomic_state_put_queue(atomic_state);
}
}
@@ -494,6 +497,7 @@ static void mtk_drm_crtc_atomic_begin(struct drm_crtc *crtc,
static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
struct drm_crtc_state *old_crtc_state)
{
+ struct drm_atomic_state *old_atomic_state = old_crtc_state->state;
struct mtk_drm_crtc *mtk_crtc = to_mtk_crtc(crtc);
struct mtk_drm_private *priv = crtc->dev->dev_private;
unsigned int pending_planes = 0;
@@ -512,8 +516,11 @@ static void mtk_drm_crtc_atomic_flush(struct drm_crtc *crtc,
pending_planes |= BIT(i);
}
}
- if (pending_planes)
+ if (pending_planes) {
mtk_crtc->pending_planes = true;
+ drm_atomic_state_get(old_atomic_state);
+ mtk_crtc->old_crtc_state = old_crtc_state;
+ }
if (crtc->state->color_mgmt_changed)
for (i = 0; i < mtk_crtc->ddp_comp_nr; i++)
mtk_ddp_gamma_set(mtk_crtc->ddp_comp[i], crtc->state);
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.c b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
index 6588dc6dd5e3..6c68283b6124 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.c
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.c
@@ -115,10 +115,85 @@ static int mtk_atomic_commit(struct drm_device *drm,
return 0;
}
+struct mtk_atomic_state {
+ struct drm_atomic_state base;
+ struct list_head list;
+};
+
+static inline struct mtk_atomic_state *to_mtk_state(struct drm_atomic_state *s)
+{
+ return container_of(s, struct mtk_atomic_state, base);
+}
+
+void mtk_atomic_state_put_queue(struct drm_atomic_state *state)
+{
+ struct drm_device *drm = state->dev;
+ struct mtk_drm_private *mtk_drm = drm->dev_private;
+ struct mtk_atomic_state *mtk_state = to_mtk_state(state);
+ unsigned long flags;
+
+ spin_lock_irqsave(&mtk_drm->unreference.lock, flags);
+ list_add_tail(&mtk_state->list, &mtk_drm->unreference.list);
+ spin_unlock_irqrestore(&mtk_drm->unreference.lock, flags);
+
+ schedule_work(&mtk_drm->unreference.work);
+}
+
+static void mtk_unreference_work(struct work_struct *work)
+{
+ struct mtk_drm_private *mtk_drm = container_of(work,
+ struct mtk_drm_private, unreference.work);
+ unsigned long flags;
+ struct mtk_atomic_state *state, *tmp;
+
+ /*
+ * framebuffers cannot be unreferenced in atomic context.
+ * Therefore, only hold the spinlock when iterating unreference_list,
+ * and drop it when doing the unreference.
+ */
+ spin_lock_irqsave(&mtk_drm->unreference.lock, flags);
+ list_for_each_entry_safe(state, tmp, &mtk_drm->unreference.list, list) {
+ list_del(&state->list);
+ spin_unlock_irqrestore(&mtk_drm->unreference.lock, flags);
+ drm_atomic_state_put(&state->base);
+ spin_lock_irqsave(&mtk_drm->unreference.lock, flags);
+ }
+ spin_unlock_irqrestore(&mtk_drm->unreference.lock, flags);
+}
+
+static struct drm_atomic_state *
+ mtk_drm_atomic_state_alloc(struct drm_device *dev)
+{
+ struct mtk_atomic_state *mtk_state;
+
+ mtk_state = kzalloc(sizeof(*mtk_state), GFP_KERNEL);
+ if (!mtk_state)
+ return NULL;
+
+ if (drm_atomic_state_init(dev, &mtk_state->base) < 0) {
+ kfree(mtk_state);
+ return NULL;
+ }
+
+ INIT_LIST_HEAD(&mtk_state->list);
+
+ return &mtk_state->base;
+}
+
+static void mtk_drm_atomic_state_free(struct drm_atomic_state *state)
+{
+ struct mtk_atomic_state *mtk_state = to_mtk_state(state);
+
+ drm_atomic_state_default_release(state);
+ kfree(mtk_state);
+}
+
static const struct drm_mode_config_funcs mtk_drm_mode_config_funcs = {
.fb_create = mtk_drm_mode_fb_create,
.atomic_check = drm_atomic_helper_check,
.atomic_commit = mtk_atomic_commit,
+ .atomic_state_alloc = mtk_drm_atomic_state_alloc,
+ .atomic_state_free = mtk_drm_atomic_state_free
};
static const enum mtk_ddp_comp_id mt2701_mtk_ddp_main[] = {
@@ -337,6 +412,10 @@ static int mtk_drm_kms_init(struct drm_device *drm)
drm_kms_helper_poll_init(drm);
drm_mode_config_reset(drm);
+ INIT_WORK(&private->unreference.work, mtk_unreference_work);
+ INIT_LIST_HEAD(&private->unreference.list);
+ spin_lock_init(&private->unreference.lock);
+
return 0;
err_unset_dma_parms:
diff --git a/drivers/gpu/drm/mediatek/mtk_drm_drv.h b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
index b6a82728d563..c37d835cf949 100644
--- a/drivers/gpu/drm/mediatek/mtk_drm_drv.h
+++ b/drivers/gpu/drm/mediatek/mtk_drm_drv.h
@@ -55,6 +55,13 @@ struct mtk_drm_private {
struct drm_atomic_state *suspend_state;
+ struct {
+ struct work_struct work;
+ struct list_head list;
+ /* lock for unreference list */
+ spinlock_t lock;
+ } unreference;
+
bool dma_parms_allocated;
};
@@ -66,4 +73,6 @@ extern struct platform_driver mtk_dpi_driver;
extern struct platform_driver mtk_dsi_driver;
extern struct platform_driver mtk_mipi_tx_driver;
+void mtk_atomic_state_put_queue(struct drm_atomic_state *state);
+
#endif /* MTK_DRM_DRV_H */
--
2.18.0
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