gpu: drm: apple: Wait for iomfb initialization

Avoids "[drm] Cannot find any crtc or sizes" during fbdev initialization
if a display is connected.

Signed-off-by: Janne Grunau <j@jannau.net>

Author: jannau

drivers/gpu/drm/apple/apple_drv.c

@@ -9,6 +9,7 @@
 
 #include <linux/component.h>
 #include <linux/dma-mapping.h>
+#include <linux/jiffies.h>
 #include <linux/module.h>
 #include <linux/of_address.h>
 #include <linux/of_device.h>
@@ -401,7 +402,8 @@ static int apple_drm_init_dcp(struct device *dev)
 	struct apple_drm_private *apple = dev_get_drvdata(dev);
 	struct platform_device *dcp[MAX_COPROCESSORS];
 	struct device_node *np;
-	int ret, num_dcp = 0;
+	u64 timeout;
+	int i, ret, num_dcp = 0;
 
 	for_each_matching_node(np, apple_dcp_id_tbl) {
 		if (!of_device_is_available(np)) {
@@ -429,6 +431,21 @@ static int apple_drm_init_dcp(struct device *dev)
 	if (num_dcp < 1)
 		return -ENODEV;
 
+	timeout = get_jiffies_64() + msecs_to_jiffies(500);
+
+	for (i = 0; i < num_dcp; ++i) {
+		u64 jiffies = get_jiffies_64();
+		u64 wait = time_after_eq64(jiffies, timeout) ?
+				   0 :
+				   timeout - jiffies;
+		ret = dcp_wait_ready(dcp[i], wait);
+		/* There is nothing we can do if a dcp/dcpext does not boot
+		 * (successfully). Ignoring it should not do any harm now.
+		 * Needs to reevaluated whenn adding dcpext support.
+		 */
+		if (ret)
+			dev_warn(dev, "DCP[%d] not ready: %d\n", i, ret);
+	}
 
 	return 0;
 }

drivers/gpu/drm/apple/dcp-internal.h

@@ -134,6 +134,9 @@ struct apple_dcp {
 	bool valid_mode;
 	struct dcp_set_digital_out_mode_req mode;
 
+	/* completion for active turning true */
+	struct completion start_done;
+
 	/* Is the DCP booted? */
 	bool active;
 

drivers/gpu/drm/apple/dcp.c

@@ -117,6 +117,7 @@ static void dcp_rtk_crashed(void *cookie)
 		dcp->connector->connected = 0;
 		schedule_work(&dcp->connector->hotplug_wq);
 	}
+	complete(&dcp->start_done);
 }
 
 static int dcp_rtk_shmem_setup(void *cookie, struct apple_rtkit_shmem *bfr)
@@ -248,6 +249,8 @@ int dcp_start(struct platform_device *pdev)
 	struct apple_dcp *dcp = platform_get_drvdata(pdev);
 	int ret;
 
+	init_completion(&dcp->start_done);
+
 	/* start RTKit endpoints */
 	ret = iomfb_start_rtkit(dcp);
 	if (ret)
@@ -257,6 +260,29 @@ int dcp_start(struct platform_device *pdev)
 }
 EXPORT_SYMBOL(dcp_start);
 
+int dcp_wait_ready(struct platform_device *pdev, u64 timeout)
+{
+	struct apple_dcp *dcp = platform_get_drvdata(pdev);
+	int ret;
+
+	if (dcp->crashed)
+		return -ENODEV;
+	if (dcp->active)
+		return 0;
+	if (timeout <= 0)
+		return -ETIMEDOUT;
+
+	ret = wait_for_completion_timeout(&dcp->start_done, timeout);
+	if (ret < 0)
+		return ret;
+
+	if (dcp->crashed)
+		return -ENODEV;
+
+	return dcp->active ? 0 : -ETIMEDOUT;
+}
+EXPORT_SYMBOL(dcp_wait_ready);
+
 static void dcp_work_register_backlight(struct work_struct *work)
 {
 	int ret;

drivers/gpu/drm/apple/dcp.h

@@ -49,6 +49,7 @@ int dcp_get_connector_type(struct platform_device *pdev);
 void dcp_link(struct platform_device *pdev, struct apple_crtc *apple,
 	      struct apple_connector *connector);
 int dcp_start(struct platform_device *pdev);
+int dcp_wait_ready(struct platform_device *pdev, u64 timeout);
 void dcp_flush(struct drm_crtc *crtc, struct drm_atomic_state *state);
 bool dcp_is_initialized(struct platform_device *pdev);
 void apple_crtc_vblank(struct apple_crtc *apple);

drivers/gpu/drm/apple/iomfb.c

@@ -1810,13 +1810,14 @@ static void res_is_main_display(struct apple_dcp *dcp, void *out, void *cookie)
 
 	dcp->main_display = result != 0;
 
-	dcp->active = true;
-
 	connector = dcp->connector;
 	if (connector) {
 		connector->connected = dcp->nr_modes > 0;
 		schedule_work(&connector->hotplug_wq);
 	}
+
+	dcp->active = true;
+	complete(&dcp->start_done);
 }
 
 static void init_3(struct apple_dcp *dcp, void *out, void *cookie)