[PATCH v21 04/14] media: qcom: camss: Issue stream-on REG_UPDATE from CSID

[Hangxiang Ma]

On stream-on, CAMSS starts the subdevices upstream from the video node
through their sink pads, so the VFE is started before the CSID.

Starting with CSID 680, the REG_UPDATE is issued through the CSID
rather than the VFE. However, vfe_enable_output_v2() still issues a
REG_UPDATE after queueing each initial buffer, before the CSID has
configured the stream. The VFE then never signals BUF_DONE. Therefore,
the CAMSS now issues the REG_UPDATE from configure_stream() on CSID 680
and CSID Gen3 instead. The operation happens after the RX configuration
and before the RDI path is enabled.

Skip the VFE-side stream-on REG_UPDATE only when the CSID connected to
the VFE sink pad implements the reg_update callback. Platforms whose
CSID does not provide this callback, as well as lines fed by ISPIF,
keep the existing VFE-side REG_UPDATE.

Signed-off-by: Hangxiang Ma <hangxiang.ma at oss.qualcomm.com>
---
 drivers/media/platform/qcom/camss/camss-csid-680.c |  3 ++
 .../media/platform/qcom/camss/camss-csid-gen3.c    |  3 ++
 drivers/media/platform/qcom/camss/camss-vfe.c      | 37 +++++++++++++++++++++-
 3 files changed, 42 insertions(+), 1 deletion(-)

diff --git a/drivers/media/platform/qcom/camss/camss-csid-680.c b/drivers/media/platform/qcom/camss/camss-csid-680.c
index 345a67c8fb94..556cdfef6207 100644
--- a/drivers/media/platform/qcom/camss/camss-csid-680.c
+++ b/drivers/media/platform/qcom/camss/camss-csid-680.c
@@ -296,6 +296,8 @@ static void __csid_configure_rdi_stream(struct csid_device *csid, u8 enable, u8
 	writel(val, csid->base + CSID_RDI_CFG0(port));
 }
 
+static void csid_subdev_reg_update(struct csid_device *csid, int port_id, bool is_clear);
+
 static void csid_configure_stream(struct csid_device *csid, u8 enable)
 {
 	int i;
@@ -307,6 +309,7 @@ static void csid_configure_stream(struct csid_device *csid, u8 enable)
 		if (csid->phy.en_vc & BIT(i)) {
 			__csid_configure_rdi_stream(csid, enable, i, 0);
 			__csid_configure_rx(csid, &csid->phy, 0);
+			csid_subdev_reg_update(csid, i, false);
 			__csid_ctrl_rdi(csid, enable, i);
 		}
 	}
diff --git a/drivers/media/platform/qcom/camss/camss-csid-gen3.c b/drivers/media/platform/qcom/camss/camss-csid-gen3.c
index 0fdbf75fb27d..830c9c818d3d 100644
--- a/drivers/media/platform/qcom/camss/camss-csid-gen3.c
+++ b/drivers/media/platform/qcom/camss/camss-csid-gen3.c
@@ -219,6 +219,8 @@ static void __csid_configure_rdi_stream(struct csid_device *csid, u8 enable, u8
 	writel(val, csid->base + CSID_RDI_CFG0(port));
 }
 
+static void csid_subdev_reg_update(struct csid_device *csid, int port_id, bool is_clear);
+
 static void csid_configure_stream(struct csid_device *csid, u8 enable)
 {
 	u8 i;
@@ -230,6 +232,7 @@ static void csid_configure_stream(struct csid_device *csid, u8 enable)
 		if (csid->phy.en_vc & BIT(i)) {
 			__csid_configure_rdi_stream(csid, enable, i, 0);
 			__csid_configure_rx(csid, &csid->phy, 0);
+			csid_subdev_reg_update(csid, i, false);
 			__csid_ctrl_rdi(csid, enable, i);
 		}
 }
diff --git a/drivers/media/platform/qcom/camss/camss-vfe.c b/drivers/media/platform/qcom/camss/camss-vfe.c
index 2680a9914765..16a0b5663fe2 100644
--- a/drivers/media/platform/qcom/camss/camss-vfe.c
+++ b/drivers/media/platform/qcom/camss/camss-vfe.c
@@ -502,6 +502,37 @@ void vfe_buf_done(struct vfe_device *vfe, int wm)
 	spin_unlock_irqrestore(&vfe->output_lock, flags);
 }
 
+/*
+ * vfe_upstream_csid_has_reg_update - Check whether the CSID feeding this line
+ * issues its own streamon RUP (i.e. its configure_stream does the RUP).
+ *
+ * The CSID->VFE link is created in camss.c for all CSIDs and VFEs, so the
+ * upstream entity of the sink pad is either a CSID (possibly with RUP) or an
+ * ISPIF (no RUP). Only enabled links are considered.
+ */
+static bool vfe_upstream_csid_has_reg_update(struct vfe_line *line)
+{
+	struct vfe_device *vfe = to_vfe(line);
+	struct camss *camss = vfe->camss;
+	struct media_pad *remote;
+	unsigned int i;
+
+	remote = media_pad_remote_pad_first(&line->pads[MSM_VFE_PAD_SINK]);
+	if (!remote || !is_media_entity_v4l2_subdev(remote->entity))
+		return false;
+
+	for (i = 0; i < camss->res->csid_num; i++) {
+		struct csid_device *csid = &camss->csid[i];
+
+		if (&csid->subdev.entity != remote->entity)
+			continue;
+
+		return !!csid->res->hw_ops->reg_update;
+	}
+
+	return false;
+}
+
 int vfe_enable_output_v2(struct vfe_line *line)
 {
 	struct vfe_device *vfe = to_vfe(line);
@@ -511,6 +542,7 @@ int vfe_enable_output_v2(struct vfe_line *line)
 	unsigned long flags;
 	unsigned int frame_skip = 0;
 	unsigned int i;
+	bool rup_in_csid;
 
 	sensor_pad = camss_find_sensor_pad(&line->subdev.entity);
 	if (sensor_pad) {
@@ -523,6 +555,8 @@ int vfe_enable_output_v2(struct vfe_line *line)
 			frame_skip = VFE_FRAME_DROP_VAL - 1;
 	}
 
+	rup_in_csid = vfe_upstream_csid_has_reg_update(line);
+
 	spin_lock_irqsave(&vfe->output_lock, flags);
 
 	ops->reg_update_clear(vfe, line->id);
@@ -552,7 +586,8 @@ int vfe_enable_output_v2(struct vfe_line *line)
 		output->gen2.active_num++;
 		ops->vfe_wm_update(vfe, output->wm_idx[0],
 				   output->buf[i]->addr[0], line);
-		ops->reg_update(vfe, line->id);
+		if (!rup_in_csid)
+			ops->reg_update(vfe, line->id);
 	}
 
 	spin_unlock_irqrestore(&vfe->output_lock, flags);

-- 
2.34.1