drm/omap: dsi: drop virtual channel logic

This drops the virtual channel logic. Afterwards DSI clients
request their channel number and get the virtual channel with
the same number or -EBUSY if already in use.

The change here is not strictly speaking correct, as it combines the VC
(DSI's "configuration block") and virtual channel ID (the ID sent in the
DSI packets). But as we currently only support a single DSI command mode
panel, this works fine: we always use VC0, and VC ID 0.

This needs more work to support video mode panels, but that can be done
after moving to DRM bridge and panel model, after which we can do that
work with the proper APIs.
Signed-off-by: Sebastian Reichel <sebastian.reichel@collabora.com>
Signed-off-by: Tomi Valkeinen <tomi.valkeinen@ti.com>
Reviewed-by: Laurent Pinchart <laurent.pinchart@ideasonboard.com>
Link: https://patchwork.freedesktop.org/patch/msgid/20201215104657.802264-9-tomi.valkeinen@ti.com

drivers/gpu/drm/omapdrm/displays/panel-dsi-cm.c

@@ -768,19 +768,12 @@ static int dsicm_connect(struct omap_dss_device *src,
 	struct device *dev = &ddata->pdev->dev;
 	int r;
 
-	r = src->ops->dsi.request_vc(src, &ddata->channel);
+	r = src->ops->dsi.request_vc(src, ddata->channel);
 	if (r) {
 		dev_err(dev, "failed to get virtual channel\n");
 		return r;
 	}
 
-	r = src->ops->dsi.set_vc_id(src, ddata->channel, TCH);
-	if (r) {
-		dev_err(dev, "failed to set VC_ID\n");
-		src->ops->dsi.release_vc(src, ddata->channel);
-		return r;
-	}
-
 	ddata->src = src;
 	return 0;
 }
@@ -1215,6 +1208,8 @@ static int dsicm_probe_of(struct platform_device *pdev)
 	struct display_timing timing;
 	int err;
 
+	ddata->channel = TCH;
+
 	ddata->reset_gpio = devm_gpiod_get(&pdev->dev, "reset", GPIOD_OUT_LOW);
 	if (IS_ERR(ddata->reset_gpio)) {
 		err = PTR_ERR(ddata->reset_gpio);

drivers/gpu/drm/omapdrm/dss/dsi.c

@@ -350,7 +350,6 @@ struct dsi_data {
 		struct omap_dss_device *dssdev;
 		enum fifo_size tx_fifo_size;
 		enum fifo_size rx_fifo_size;
-		int vc_id;
 	} vc[4];
 
 	struct mutex lock;
@@ -2581,7 +2580,7 @@ static inline void dsi_vc_write_long_header(struct dsi_data *dsi, int channel,
 
 	WARN_ON(!dsi_bus_is_locked(dsi));
 
-	data_id = data_type | dsi->vc[channel].vc_id << 6;
+	data_id = data_type | channel << 6;
 
 	val = FLD_VAL(data_id, 7, 0) | FLD_VAL(len, 23, 8) |
 		FLD_VAL(ecc, 31, 24);
@@ -2685,7 +2684,7 @@ static int dsi_vc_send_short(struct dsi_data *dsi, int channel, u8 data_type,
 		return -EINVAL;
 	}
 
-	data_id = data_type | dsi->vc[channel].vc_id << 6;
+	data_id = data_type | channel << 6;
 
 	r = (data_id << 0) | (data << 8) | (ecc << 24);
 
@@ -4787,45 +4786,19 @@ static enum omap_channel dsi_get_channel(struct dsi_data *dsi)
 	}
 }
 
-static int dsi_request_vc(struct omap_dss_device *dssdev, int *channel)
+static int dsi_request_vc(struct omap_dss_device *dssdev, int channel)
 {
 	struct dsi_data *dsi = to_dsi_data(dssdev);
-	int i;
-
-	for (i = 0; i < ARRAY_SIZE(dsi->vc); i++) {
-		if (!dsi->vc[i].dssdev) {
-			dsi->vc[i].dssdev = dssdev;
-			*channel = i;
-			return 0;
-		}
-	}
 
-	DSSERR("cannot get VC for display %s", dssdev->name);
-	return -ENOSPC;
-}
-
-static int dsi_set_vc_id(struct omap_dss_device *dssdev, int channel, int vc_id)
-{
-	struct dsi_data *dsi = to_dsi_data(dssdev);
-
-	if (vc_id < 0 || vc_id > 3) {
-		DSSERR("VC ID out of range\n");
-		return -EINVAL;
-	}
-
-	if (channel < 0 || channel > 3) {
-		DSSERR("Virtual Channel out of range\n");
+	if (channel < 0 || channel > 3)
 		return -EINVAL;
-	}
 
-	if (dsi->vc[channel].dssdev != dssdev) {
-		DSSERR("Virtual Channel not allocated to display %s\n",
-			dssdev->name);
-		return -EINVAL;
+	if (dsi->vc[channel].dssdev) {
+		DSSERR("cannot get VC for display %s", dssdev->name);
+		return -EBUSY;
 	}
 
-	dsi->vc[channel].vc_id = vc_id;
-
+	dsi->vc[channel].dssdev = dssdev;
 	return 0;
 }
 
@@ -4836,7 +4809,6 @@ static void dsi_release_vc(struct omap_dss_device *dssdev, int channel)
 	if ((channel >= 0 && channel <= 3) &&
 		dsi->vc[channel].dssdev == dssdev) {
 		dsi->vc[channel].dssdev = NULL;
-		dsi->vc[channel].vc_id = 0;
 	}
 }
 
@@ -4943,7 +4915,6 @@ static const struct omap_dss_device_ops dsi_ops = {
 		.enable_te = dsi_enable_te,
 
 		.request_vc = dsi_request_vc,
-		.set_vc_id = dsi_set_vc_id,
 		.release_vc = dsi_release_vc,
 
 		.transfer = omap_dsi_transfer,
@@ -5399,7 +5370,6 @@ static int dsi_probe(struct platform_device *pdev)
 	for (i = 0; i < ARRAY_SIZE(dsi->vc); i++) {
 		dsi->vc[i].source = DSI_VC_SOURCE_L4;
 		dsi->vc[i].dssdev = NULL;
-		dsi->vc[i].vc_id = 0;
 	}
 
 	r = dsi_get_clocks(dsi);

drivers/gpu/drm/omapdrm/dss/omapdss.h

@@ -305,9 +305,7 @@ struct omapdss_dsi_ops {
 	void (*disable_video_output)(struct omap_dss_device *dssdev,
 			int channel);
 
-	int (*request_vc)(struct omap_dss_device *dssdev, int *channel);
-	int (*set_vc_id)(struct omap_dss_device *dssdev, int channel,
-			int vc_id);
+	int (*request_vc)(struct omap_dss_device *dssdev, int channel);
 	void (*release_vc)(struct omap_dss_device *dssdev, int channel);
 
 	/* data transfer */