drm/msm/dsi: switch to DRM_PANEL_BRIDGE
authorDmitry Baryshkov <dmitry.baryshkov@linaro.org>
Tue, 12 Jul 2022 13:22:58 +0000 (16:22 +0300)
committerRob Clark <robdclark@chromium.org>
Sun, 18 Sep 2022 16:38:06 +0000 (09:38 -0700)
Currently the DSI driver has two separate paths: one if the next device
in a chain is a bridge and another one if the panel is connected
directly to the DSI host. Simplify the code path by using panel-bridge
driver (already selected in Kconfig) and dropping support for
handling the panel directly.

Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Reviewed-by: Abhinav Kumar <quic_abhinavk@quicinc.com>
Patchwork: https://patchwork.freedesktop.org/patch/493608/
Link: https://lore.kernel.org/r/20220712132258.671263-1-dmitry.baryshkov@linaro.org
Signed-off-by: Dmitry Baryshkov <dmitry.baryshkov@linaro.org>
Signed-off-by: Rob Clark <robdclark@chromium.org>
drivers/gpu/drm/msm/dsi/dsi.c
drivers/gpu/drm/msm/dsi/dsi.h
drivers/gpu/drm/msm/dsi/dsi_host.c
drivers/gpu/drm/msm/dsi/dsi_manager.c

index 8f1ed31..39bbabb 100644 (file)
@@ -6,14 +6,6 @@
 #include "dsi.h"
 #include "dsi_cfg.h"
 
-struct drm_encoder *msm_dsi_get_encoder(struct msm_dsi *msm_dsi)
-{
-       if (!msm_dsi || !msm_dsi_device_connected(msm_dsi))
-               return NULL;
-
-       return msm_dsi->encoder;
-}
-
 bool msm_dsi_is_cmd_mode(struct msm_dsi *msm_dsi)
 {
        unsigned long host_flags = msm_dsi_host_get_mode_flags(msm_dsi->host);
@@ -220,7 +212,6 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
                         struct drm_encoder *encoder)
 {
        struct msm_drm_private *priv;
-       struct drm_bridge *ext_bridge;
        int ret;
 
        if (WARN_ON(!encoder) || WARN_ON(!msm_dsi) || WARN_ON(!dev))
@@ -254,26 +245,10 @@ int msm_dsi_modeset_init(struct msm_dsi *msm_dsi, struct drm_device *dev,
                goto fail;
        }
 
-       /*
-        * check if the dsi encoder output is connected to a panel or an
-        * external bridge. We create a connector only if we're connected to a
-        * drm_panel device. When we're connected to an external bridge, we
-        * assume that the drm_bridge driver will create the connector itself.
-        */
-       ext_bridge = msm_dsi_host_get_bridge(msm_dsi->host);
-
-       if (ext_bridge)
-               msm_dsi->connector =
-                       msm_dsi_manager_ext_bridge_init(msm_dsi->id);
-       else
-               msm_dsi->connector =
-                       msm_dsi_manager_connector_init(msm_dsi->id);
-
-       if (IS_ERR(msm_dsi->connector)) {
-               ret = PTR_ERR(msm_dsi->connector);
+       ret = msm_dsi_manager_ext_bridge_init(msm_dsi->id);
+       if (ret) {
                DRM_DEV_ERROR(dev->dev,
                        "failed to create dsi connector: %d\n", ret);
-               msm_dsi->connector = NULL;
                goto fail;
        }
 
@@ -287,12 +262,6 @@ fail:
                msm_dsi->bridge = NULL;
        }
 
-       /* don't destroy connector if we didn't make it */
-       if (msm_dsi->connector && !msm_dsi->external_bridge)
-               msm_dsi->connector->funcs->destroy(msm_dsi->connector);
-
-       msm_dsi->connector = NULL;
-
        return ret;
 }
 
index 8058831..2a96b4f 100644 (file)
@@ -12,7 +12,6 @@
 #include <drm/drm_bridge.h>
 #include <drm/drm_crtc.h>
 #include <drm/drm_mipi_dsi.h>
-#include <drm/drm_panel.h>
 
 #include "msm_drv.h"
 #include "disp/msm_disp_snapshot.h"
@@ -36,8 +35,6 @@ struct msm_dsi {
        struct drm_device *dev;
        struct platform_device *pdev;
 
-       /* connector managed by us when we're connected to a drm_panel */
-       struct drm_connector *connector;
        /* internal dsi bridge attached to MDP interface */
        struct drm_bridge *bridge;
 
@@ -45,10 +42,8 @@ struct msm_dsi {
        struct msm_dsi_phy *phy;
 
        /*
-        * panel/external_bridge connected to dsi bridge output, only one of the
-        * two can be valid at a time
+        * external_bridge connected to dsi bridge output
         */
-       struct drm_panel *panel;
        struct drm_bridge *external_bridge;
 
        struct device *phy_dev;
@@ -63,8 +58,7 @@ struct msm_dsi {
 /* dsi manager */
 struct drm_bridge *msm_dsi_manager_bridge_init(u8 id);
 void msm_dsi_manager_bridge_destroy(struct drm_bridge *bridge);
-struct drm_connector *msm_dsi_manager_connector_init(u8 id);
-struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id);
+int msm_dsi_manager_ext_bridge_init(u8 id);
 int msm_dsi_manager_cmd_xfer(int id, const struct mipi_dsi_msg *msg);
 bool msm_dsi_manager_cmd_xfer_trigger(int id, u32 dma_base, u32 len);
 int msm_dsi_manager_register(struct msm_dsi *msm_dsi);
@@ -74,11 +68,9 @@ void msm_dsi_manager_tpg_enable(void);
 /* msm dsi */
 static inline bool msm_dsi_device_connected(struct msm_dsi *msm_dsi)
 {
-       return msm_dsi->panel || msm_dsi->external_bridge;
+       return msm_dsi->external_bridge;
 }
 
-struct drm_encoder *msm_dsi_get_encoder(struct msm_dsi *msm_dsi);
-
 /* dsi host */
 struct msm_dsi_host;
 int msm_dsi_host_xfer_prepare(struct mipi_dsi_host *host,
@@ -103,9 +95,7 @@ int msm_dsi_host_set_display_mode(struct mipi_dsi_host *host,
                                  const struct drm_display_mode *mode);
 enum drm_mode_status msm_dsi_host_check_dsc(struct mipi_dsi_host *host,
                                            const struct drm_display_mode *mode);
-struct drm_panel *msm_dsi_host_get_panel(struct mipi_dsi_host *host);
 unsigned long msm_dsi_host_get_mode_flags(struct mipi_dsi_host *host);
-struct drm_bridge *msm_dsi_host_get_bridge(struct mipi_dsi_host *host);
 int msm_dsi_host_register(struct mipi_dsi_host *host);
 void msm_dsi_host_unregister(struct mipi_dsi_host *host);
 void msm_dsi_host_set_phy_mode(struct mipi_dsi_host *host,
index 9bb124c..57a4c0f 100644 (file)
@@ -163,7 +163,6 @@ struct msm_dsi_host {
        struct drm_dsc_config *dsc;
 
        /* connected device info */
-       struct device_node *device_node;
        unsigned int channel;
        unsigned int lanes;
        enum mipi_dsi_pixel_format format;
@@ -1628,8 +1627,6 @@ static int dsi_host_detach(struct mipi_dsi_host *host,
 
        dsi_dev_detach(msm_host->pdev);
 
-       msm_host->device_node = NULL;
-
        DBG("id=%d", msm_host->id);
 
        return 0;
@@ -1893,16 +1890,6 @@ static int dsi_host_parse_dt(struct msm_dsi_host *msm_host)
                goto err;
        }
 
-       /* Get panel node from the output port's endpoint data */
-       device_node = of_graph_get_remote_node(np, 1, 0);
-       if (!device_node) {
-               DRM_DEV_DEBUG(dev, "%s: no valid device\n", __func__);
-               ret = -ENODEV;
-               goto err;
-       }
-
-       msm_host->device_node = device_node;
-
        if (of_property_read_bool(np, "syscon-sfpb")) {
                msm_host->sfpb = syscon_regmap_lookup_by_phandle(np,
                                        "syscon-sfpb");
@@ -2587,23 +2574,11 @@ enum drm_mode_status msm_dsi_host_check_dsc(struct mipi_dsi_host *host,
        return MODE_OK;
 }
 
-struct drm_panel *msm_dsi_host_get_panel(struct mipi_dsi_host *host)
-{
-       return of_drm_find_panel(to_msm_dsi_host(host)->device_node);
-}
-
 unsigned long msm_dsi_host_get_mode_flags(struct mipi_dsi_host *host)
 {
        return to_msm_dsi_host(host)->mode_flags;
 }
 
-struct drm_bridge *msm_dsi_host_get_bridge(struct mipi_dsi_host *host)
-{
-       struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
-
-       return of_drm_find_bridge(msm_host->device_node);
-}
-
 void msm_dsi_host_snapshot(struct msm_disp_state *disp_state, struct mipi_dsi_host *host)
 {
        struct msm_dsi_host *msm_host = to_msm_dsi_host(host);
index 0b516a0..3a14173 100644 (file)
@@ -211,39 +211,26 @@ static void dsi_mgr_phy_disable(int id)
        }
 }
 
-struct dsi_connector {
-       struct drm_connector base;
-       int id;
-};
-
 struct dsi_bridge {
        struct drm_bridge base;
        int id;
 };
 
-#define to_dsi_connector(x) container_of(x, struct dsi_connector, base)
 #define to_dsi_bridge(x) container_of(x, struct dsi_bridge, base)
 
-static inline int dsi_mgr_connector_get_id(struct drm_connector *connector)
-{
-       struct dsi_connector *dsi_connector = to_dsi_connector(connector);
-       return dsi_connector->id;
-}
-
 static int dsi_mgr_bridge_get_id(struct drm_bridge *bridge)
 {
        struct dsi_bridge *dsi_bridge = to_dsi_bridge(bridge);
        return dsi_bridge->id;
 }
 
-static int msm_dsi_manager_panel_init(struct drm_connector *conn, u8 id)
+static void msm_dsi_manager_set_split_display(u8 id)
 {
-       struct msm_drm_private *priv = conn->dev->dev_private;
-       struct msm_kms *kms = priv->kms;
        struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
        struct msm_dsi *other_dsi = dsi_mgr_get_other_dsi(id);
+       struct msm_drm_private *priv = msm_dsi->dev->dev_private;
+       struct msm_kms *kms = priv->kms;
        struct msm_dsi *master_dsi, *slave_dsi;
-       struct drm_panel *panel;
 
        if (IS_BONDED_DSI() && !IS_MASTER_DSI_LINK(id)) {
                master_dsi = other_dsi;
@@ -253,89 +240,18 @@ static int msm_dsi_manager_panel_init(struct drm_connector *conn, u8 id)
                slave_dsi = other_dsi;
        }
 
-       /*
-        * There is only 1 panel in the global panel list for bonded DSI mode.
-        * Therefore slave dsi should get the drm_panel instance from master
-        * dsi.
-        */
-       panel = msm_dsi_host_get_panel(master_dsi->host);
-       if (IS_ERR(panel)) {
-               DRM_ERROR("Could not find panel for %u (%ld)\n", msm_dsi->id,
-                         PTR_ERR(panel));
-               return PTR_ERR(panel);
-       }
-
-       if (!panel || !IS_BONDED_DSI())
-               goto out;
-
-       drm_object_attach_property(&conn->base,
-                                  conn->dev->mode_config.tile_property, 0);
+       if (!msm_dsi->external_bridge || !IS_BONDED_DSI())
+               return;
 
        /*
         * Set split display info to kms once bonded DSI panel is connected to
         * both hosts.
         */
-       if (other_dsi && other_dsi->panel && kms->funcs->set_split_display) {
+       if (other_dsi && other_dsi->external_bridge && kms->funcs->set_split_display) {
                kms->funcs->set_split_display(kms, master_dsi->encoder,
                                              slave_dsi->encoder,
                                              msm_dsi_is_cmd_mode(msm_dsi));
        }
-
-out:
-       msm_dsi->panel = panel;
-       return 0;
-}
-
-static enum drm_connector_status dsi_mgr_connector_detect(
-               struct drm_connector *connector, bool force)
-{
-       int id = dsi_mgr_connector_get_id(connector);
-       struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
-
-       return msm_dsi->panel ? connector_status_connected :
-               connector_status_disconnected;
-}
-
-static void dsi_mgr_connector_destroy(struct drm_connector *connector)
-{
-       struct dsi_connector *dsi_connector = to_dsi_connector(connector);
-
-       DBG("");
-
-       drm_connector_cleanup(connector);
-
-       kfree(dsi_connector);
-}
-
-static int dsi_mgr_connector_get_modes(struct drm_connector *connector)
-{
-       int id = dsi_mgr_connector_get_id(connector);
-       struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
-       struct drm_panel *panel = msm_dsi->panel;
-       int num;
-
-       if (!panel)
-               return 0;
-
-       /*
-        * In bonded DSI mode, we have one connector that can be
-        * attached to the drm_panel.
-        */
-       num = drm_panel_get_modes(panel, connector);
-       if (!num)
-               return 0;
-
-       return num;
-}
-
-static struct drm_encoder *
-dsi_mgr_connector_best_encoder(struct drm_connector *connector)
-{
-       int id = dsi_mgr_connector_get_id(connector);
-       struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
-
-       DBG("");
-       return msm_dsi_get_encoder(msm_dsi);
 }
 
 static void dsi_mgr_bridge_power_on(struct drm_bridge *bridge)
@@ -400,7 +316,6 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
        struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
        struct msm_dsi *msm_dsi1 = dsi_mgr_get_dsi(DSI_1);
        struct mipi_dsi_host *host = msm_dsi->host;
-       struct drm_panel *panel = msm_dsi->panel;
        bool is_bonded_dsi = IS_BONDED_DSI();
        int ret;
 
@@ -415,18 +330,6 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
        if (!dsi_mgr_power_on_early(bridge))
                dsi_mgr_bridge_power_on(bridge);
 
-       /* Always call panel functions once, because even for dual panels,
-        * there is only one drm_panel instance.
-        */
-       if (panel) {
-               ret = drm_panel_prepare(panel);
-               if (ret) {
-                       pr_err("%s: prepare panel %d failed, %d\n", __func__,
-                                                               id, ret);
-                       goto panel_prep_fail;
-               }
-       }
-
        ret = msm_dsi_host_enable(host);
        if (ret) {
                pr_err("%s: enable host %d failed, %d\n", __func__, id, ret);
@@ -446,9 +349,6 @@ static void dsi_mgr_bridge_pre_enable(struct drm_bridge *bridge)
 host1_en_fail:
        msm_dsi_host_disable(host);
 host_en_fail:
-       if (panel)
-               drm_panel_unprepare(panel);
-panel_prep_fail:
 
        return;
 }
@@ -466,62 +366,12 @@ void msm_dsi_manager_tpg_enable(void)
        }
 }
 
-static void dsi_mgr_bridge_enable(struct drm_bridge *bridge)
-{
-       int id = dsi_mgr_bridge_get_id(bridge);
-       struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
-       struct drm_panel *panel = msm_dsi->panel;
-       bool is_bonded_dsi = IS_BONDED_DSI();
-       int ret;
-
-       DBG("id=%d", id);
-       if (!msm_dsi_device_connected(msm_dsi))
-               return;
-
-       /* Do nothing with the host if it is slave-DSI in case of bonded DSI */
-       if (is_bonded_dsi && !IS_MASTER_DSI_LINK(id))
-               return;
-
-       if (panel) {
-               ret = drm_panel_enable(panel);
-               if (ret) {
-                       pr_err("%s: enable panel %d failed, %d\n", __func__, id,
-                                                                       ret);
-               }
-       }
-}
-
-static void dsi_mgr_bridge_disable(struct drm_bridge *bridge)
-{
-       int id = dsi_mgr_bridge_get_id(bridge);
-       struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
-       struct drm_panel *panel = msm_dsi->panel;
-       bool is_bonded_dsi = IS_BONDED_DSI();
-       int ret;
-
-       DBG("id=%d", id);
-       if (!msm_dsi_device_connected(msm_dsi))
-               return;
-
-       /* Do nothing with the host if it is slave-DSI in case of bonded DSI */
-       if (is_bonded_dsi && !IS_MASTER_DSI_LINK(id))
-               return;
-
-       if (panel) {
-               ret = drm_panel_disable(panel);
-               if (ret)
-                       pr_err("%s: Panel %d OFF failed, %d\n", __func__, id,
-                                                                       ret);
-       }
-}
-
 static void dsi_mgr_bridge_post_disable(struct drm_bridge *bridge)
 {
        int id = dsi_mgr_bridge_get_id(bridge);
        struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
        struct msm_dsi *msm_dsi1 = dsi_mgr_get_dsi(DSI_1);
        struct mipi_dsi_host *host = msm_dsi->host;
-       struct drm_panel *panel = msm_dsi->panel;
        bool is_bonded_dsi = IS_BONDED_DSI();
        int ret;
 
@@ -548,13 +398,6 @@ static void dsi_mgr_bridge_post_disable(struct drm_bridge *bridge)
                        pr_err("%s: host1 disable failed, %d\n", __func__, ret);
        }
 
-       if (panel) {
-               ret = drm_panel_unprepare(panel);
-               if (ret)
-                       pr_err("%s: Panel %d unprepare failed,%d\n", __func__,
-                                                               id, ret);
-       }
-
        msm_dsi_host_disable_irq(host);
        if (is_bonded_dsi && msm_dsi1)
                msm_dsi_host_disable_irq(msm_dsi1->host);
@@ -611,76 +454,13 @@ static enum drm_mode_status dsi_mgr_bridge_mode_valid(struct drm_bridge *bridge,
        return msm_dsi_host_check_dsc(host, mode);
 }
 
-static const struct drm_connector_funcs dsi_mgr_connector_funcs = {
-       .detect = dsi_mgr_connector_detect,
-       .fill_modes = drm_helper_probe_single_connector_modes,
-       .destroy = dsi_mgr_connector_destroy,
-       .reset = drm_atomic_helper_connector_reset,
-       .atomic_duplicate_state = drm_atomic_helper_connector_duplicate_state,
-       .atomic_destroy_state = drm_atomic_helper_connector_destroy_state,
-};
-
-static const struct drm_connector_helper_funcs dsi_mgr_conn_helper_funcs = {
-       .get_modes = dsi_mgr_connector_get_modes,
-       .best_encoder = dsi_mgr_connector_best_encoder,
-};
-
 static const struct drm_bridge_funcs dsi_mgr_bridge_funcs = {
        .pre_enable = dsi_mgr_bridge_pre_enable,
-       .enable = dsi_mgr_bridge_enable,
-       .disable = dsi_mgr_bridge_disable,
        .post_disable = dsi_mgr_bridge_post_disable,
        .mode_set = dsi_mgr_bridge_mode_set,
        .mode_valid = dsi_mgr_bridge_mode_valid,
 };
 
-/* initialize connector when we're connected to a drm_panel */
-struct drm_connector *msm_dsi_manager_connector_init(u8 id)
-{
-       struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
-       struct drm_connector *connector = NULL;
-       struct dsi_connector *dsi_connector;
-       int ret;
-
-       dsi_connector = kzalloc(sizeof(*dsi_connector), GFP_KERNEL);
-       if (!dsi_connector)
-               return ERR_PTR(-ENOMEM);
-
-       dsi_connector->id = id;
-
-       connector = &dsi_connector->base;
-
-       ret = drm_connector_init(msm_dsi->dev, connector,
-                       &dsi_mgr_connector_funcs, DRM_MODE_CONNECTOR_DSI);
-       if (ret)
-               return ERR_PTR(ret);
-
-       drm_connector_helper_add(connector, &dsi_mgr_conn_helper_funcs);
-
-       /* Enable HPD to let hpd event is handled
-        * when panel is attached to the host.
-        */
-       connector->polled = DRM_CONNECTOR_POLL_HPD;
-
-       /* Display driver doesn't support interlace now. */
-       connector->interlace_allowed = 0;
-       connector->doublescan_allowed = 0;
-
-       drm_connector_attach_encoder(connector, msm_dsi->encoder);
-
-       ret = msm_dsi_manager_panel_init(connector, id);
-       if (ret) {
-               DRM_DEV_ERROR(msm_dsi->dev->dev, "init panel failed %d\n", ret);
-               goto fail;
-       }
-
-       return connector;
-
-fail:
-       connector->funcs->destroy(connector);
-       return ERR_PTR(ret);
-}
-
 /* initialize bridge */
 struct drm_bridge *msm_dsi_manager_bridge_init(u8 id)
 {
@@ -719,18 +499,21 @@ fail:
        return ERR_PTR(ret);
 }
 
-struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id)
+int msm_dsi_manager_ext_bridge_init(u8 id)
 {
        struct msm_dsi *msm_dsi = dsi_mgr_get_dsi(id);
        struct drm_device *dev = msm_dsi->dev;
-       struct drm_connector *connector;
        struct drm_encoder *encoder;
        struct drm_bridge *int_bridge, *ext_bridge;
        int ret;
 
        int_bridge = msm_dsi->bridge;
-       ext_bridge = msm_dsi->external_bridge =
-                       msm_dsi_host_get_bridge(msm_dsi->host);
+       ext_bridge = devm_drm_of_get_bridge(&msm_dsi->pdev->dev,
+                                           msm_dsi->pdev->dev.of_node, 1, 0);
+       if (IS_ERR(ext_bridge))
+               return PTR_ERR(ext_bridge);
+
+       msm_dsi->external_bridge = ext_bridge;
 
        encoder = msm_dsi->encoder;
 
@@ -742,36 +525,32 @@ struct drm_connector *msm_dsi_manager_ext_bridge_init(u8 id)
        ret = drm_bridge_attach(encoder, ext_bridge, int_bridge,
                        DRM_BRIDGE_ATTACH_NO_CONNECTOR);
        if (ret == -EINVAL) {
-               struct drm_connector *connector;
-               struct list_head *connector_list;
-
-               /* link the internal dsi bridge to the external bridge */
-               drm_bridge_attach(encoder, ext_bridge, int_bridge, 0);
-
                /*
-                * we need the drm_connector created by the external bridge
-                * driver (or someone else) to feed it to our driver's
-                * priv->connector[] list, mainly for msm_fbdev_init()
+                * link the internal dsi bridge to the external bridge,
+                * connector is created by the next bridge.
                 */
-               connector_list = &dev->mode_config.connector_list;
+               ret = drm_bridge_attach(encoder, ext_bridge, int_bridge, 0);
+               if (ret < 0)
+                       return ret;
+       } else {
+               struct drm_connector *connector;
 
-               list_for_each_entry(connector, connector_list, head) {
-                       if (drm_connector_has_possible_encoder(connector, encoder))
-                               return connector;
+               /* We are in charge of the connector, create one now. */
+               connector = drm_bridge_connector_init(dev, encoder);
+               if (IS_ERR(connector)) {
+                       DRM_ERROR("Unable to create bridge connector\n");
+                       return PTR_ERR(connector);
                }
 
-               return ERR_PTR(-ENODEV);
-       }
-
-       connector = drm_bridge_connector_init(dev, encoder);
-       if (IS_ERR(connector)) {
-               DRM_ERROR("Unable to create bridge connector\n");
-               return ERR_CAST(connector);
+               ret = drm_connector_attach_encoder(connector, encoder);
+               if (ret < 0)
+                       return ret;
        }
 
-       drm_connector_attach_encoder(connector, encoder);
+       /* The pipeline is ready, ping encoders if necessary */
+       msm_dsi_manager_set_split_display(id);
 
-       return connector;
+       return 0;
 }
 
 void msm_dsi_manager_bridge_destroy(struct drm_bridge *bridge)