media: vsp1: wpf: Add writeback support

Add support for the writeback feature of the WPF, to enable capturing
frames at the WPF output for display pipelines. To enable writeback the
vsp1_rwpf structure mem field must be set to the address of the
writeback buffer and the writeback field set to true before the WPF
.configure_stream() and .configure_partition() are called. The WPF will
enable writeback in the display list for a single frame, and writeback
will then be automatically disabled.

Signed-off-by: Laurent Pinchart <laurent.pinchart+renesas@ideasonboard.com>
Reviewed-by: Kieran Bingham <kieran.bingham+renesas@ideasonboard.com>
Reviewed-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org>

diff --git a/drivers/media/platform/vsp1/vsp1_rwpf.h b/drivers/media/platform/vsp1/vsp1_rwpf.h
index 70742ec..2f35825 100644 (file)
--- a/drivers/media/platform/vsp1/vsp1_rwpf.h
+++ b/drivers/media/platform/vsp1/vsp1_rwpf.h
@@ -61,6 +61,7 @@ struct vsp1_rwpf {
        } flip;
 
        struct vsp1_rwpf_memory mem;
+       bool writeback;
 
        struct vsp1_dl_manager *dlm;
 };

diff --git a/drivers/media/platform/vsp1/vsp1_wpf.c b/drivers/media/platform/vsp1/vsp1_wpf.c
index fc5c1b0..208498f 100644 (file)
--- a/drivers/media/platform/vsp1/vsp1_wpf.c
+++ b/drivers/media/platform/vsp1/vsp1_wpf.c
@@ -232,6 +232,27 @@ static void vsp1_wpf_destroy(struct vsp1_entity *entity)
        vsp1_dlm_destroy(wpf->dlm);
 }
 
+static int wpf_configure_writeback_chain(struct vsp1_rwpf *wpf,
+                                        struct vsp1_dl_list *dl)
+{
+       unsigned int index = wpf->entity.index;
+       struct vsp1_dl_list *dl_next;
+       struct vsp1_dl_body *dlb;
+
+       dl_next = vsp1_dl_list_get(wpf->dlm);
+       if (!dl_next) {
+               dev_err(wpf->entity.vsp1->dev,
+                       "Failed to obtain a dl list, disabling writeback\n");
+               return -ENOMEM;
+       }
+
+       dlb = vsp1_dl_list_get_body0(dl_next);
+       vsp1_dl_body_write(dlb, VI6_WPF_WRBCK_CTRL(index), 0);
+       vsp1_dl_list_add_chain(dl, dl_next);
+
+       return 0;
+}
+
 static void wpf_configure_stream(struct vsp1_entity *entity,
                                 struct vsp1_pipeline *pipe,
                                 struct vsp1_dl_list *dl,
@@ -241,9 +262,11 @@ static void wpf_configure_stream(struct vsp1_entity *entity,
        struct vsp1_device *vsp1 = wpf->entity.vsp1;
        const struct v4l2_mbus_framefmt *source_format;
        const struct v4l2_mbus_framefmt *sink_format;
+       unsigned int index = wpf->entity.index;
        unsigned int i;
        u32 outfmt = 0;
        u32 srcrpf = 0;
+       int ret;
 
        sink_format = vsp1_entity_get_pad_format(&wpf->entity,
                                                 wpf->entity.config,
@@ -251,8 +274,9 @@ static void wpf_configure_stream(struct vsp1_entity *entity,
        source_format = vsp1_entity_get_pad_format(&wpf->entity,
                                                   wpf->entity.config,
                                                   RWPF_PAD_SOURCE);
+
        /* Format */
-       if (!pipe->lif) {
+       if (!pipe->lif || wpf->writeback) {
                const struct v4l2_pix_format_mplane *format = &wpf->format;
                const struct vsp1_format_info *fmtinfo = wpf->fmtinfo;
 
@@ -277,8 +301,7 @@ static void wpf_configure_stream(struct vsp1_entity *entity,
 
                vsp1_wpf_write(wpf, dlb, VI6_WPF_DSWAP, fmtinfo->swap);
 
-               if (vsp1_feature(vsp1, VSP1_HAS_WPF_HFLIP) &&
-                   wpf->entity.index == 0)
+               if (vsp1_feature(vsp1, VSP1_HAS_WPF_HFLIP) && index == 0)
                        vsp1_wpf_write(wpf, dlb, VI6_WPF_ROT_CTRL,
                                       VI6_WPF_ROT_CTRL_LN16 |
                                       (256 << VI6_WPF_ROT_CTRL_LMEM_WD_SHIFT));
@@ -289,11 +312,9 @@ static void wpf_configure_stream(struct vsp1_entity *entity,
 
        wpf->outfmt = outfmt;
 
-       vsp1_dl_body_write(dlb, VI6_DPR_WPF_FPORCH(wpf->entity.index),
+       vsp1_dl_body_write(dlb, VI6_DPR_WPF_FPORCH(index),
                           VI6_DPR_WPF_FPORCH_FP_WPFN);
 
-       vsp1_dl_body_write(dlb, VI6_WPF_WRBCK_CTRL(wpf->entity.index), 0);
-
        /*
         * Sources. If the pipeline has a single input and BRx is not used,
         * configure it as the master layer. Otherwise configure all
@@ -319,9 +340,26 @@ static void wpf_configure_stream(struct vsp1_entity *entity,
        vsp1_wpf_write(wpf, dlb, VI6_WPF_SRCRPF, srcrpf);
 
        /* Enable interrupts. */
-       vsp1_dl_body_write(dlb, VI6_WPF_IRQ_STA(wpf->entity.index), 0);
-       vsp1_dl_body_write(dlb, VI6_WPF_IRQ_ENB(wpf->entity.index),
+       vsp1_dl_body_write(dlb, VI6_WPF_IRQ_STA(index), 0);
+       vsp1_dl_body_write(dlb, VI6_WPF_IRQ_ENB(index),
                           VI6_WFP_IRQ_ENB_DFEE);
+
+       /*
+        * Configure writeback for display pipelines (the wpf writeback flag is
+        * never set for memory-to-memory pipelines). Start by adding a chained
+        * display list to disable writeback after a single frame, and process
+        * to enable writeback. If the display list allocation fails don't
+        * enable writeback as we wouldn't be able to safely disable it,
+        * resulting in possible memory corruption.
+        */
+       if (wpf->writeback) {
+               ret = wpf_configure_writeback_chain(wpf, dl);
+               if (ret < 0)
+                       wpf->writeback = false;
+       }
+
+       vsp1_dl_body_write(dlb, VI6_WPF_WRBCK_CTRL(index),
+                          wpf->writeback ? VI6_WPF_WRBCK_CTRL_WBMD : 0);
 }
 
 static void wpf_configure_frame(struct vsp1_entity *entity,
@@ -391,7 +429,11 @@ static void wpf_configure_partition(struct vsp1_entity *entity,
                       (0 << VI6_WPF_SZCLIP_OFST_SHIFT) |
                       (height << VI6_WPF_SZCLIP_SIZE_SHIFT));
 
-       if (pipe->lif)
+       /*
+        * For display pipelines without writeback enabled there's no memory
+        * address to configure, return now.
+        */
+       if (pipe->lif && !wpf->writeback)
                return;
 
        /*
@@ -480,6 +522,12 @@ static void wpf_configure_partition(struct vsp1_entity *entity,
        vsp1_wpf_write(wpf, dlb, VI6_WPF_DSTM_ADDR_Y, mem.addr[0]);
        vsp1_wpf_write(wpf, dlb, VI6_WPF_DSTM_ADDR_C0, mem.addr[1]);
        vsp1_wpf_write(wpf, dlb, VI6_WPF_DSTM_ADDR_C1, mem.addr[2]);
+
+       /*
+        * Writeback operates in single-shot mode and lasts for a single frame,
+        * reset the writeback flag to false for the next frame.
+        */
+       wpf->writeback = false;
 }
 
 static unsigned int wpf_max_width(struct vsp1_entity *entity,