memory: brcmstb: dpfe: support for deferred firmware download

We add support for deferred downloading of the DPFE firmware. It may be
necessary to do this if the root file system containing the firmware
image is not yet available at the time the driver's probe function is
being called.
Signed-off-by: Markus Mayer <mmayer@broadcom.com>
Signed-off-by: Florian Fainelli <f.fainelli@gmail.com>

drivers/memory/brcmstb_dpfe.c

@@ -614,10 +614,13 @@ static int brcmstb_dpfe_download_firmware(struct brcmstb_dpfe_priv *priv)
 	if (!priv->dpfe_api->fw_name)
 		return -ENODEV;
 
-	ret = request_firmware(&fw, priv->dpfe_api->fw_name, dev);
-	/* request_firmware() prints its own error messages. */
+	ret = firmware_request_nowarn(&fw, priv->dpfe_api->fw_name, dev);
+	/*
+	 * Defer the firmware download if the firmware file couldn't be found.
+	 * The root file system may not be available yet.
+	 */
 	if (ret)
-		return ret;
+		return (ret == -ENOENT) ? -EPROBE_DEFER : ret;
 
 	ret = __verify_firmware(&init, fw);
 	if (ret)
@@ -862,7 +865,8 @@ static int brcmstb_dpfe_probe(struct platform_device *pdev)
 
 	ret = brcmstb_dpfe_download_firmware(priv);
 	if (ret) {
-		dev_err(dev, "Couldn't download firmware -- %d\n", ret);
+		if (ret != -EPROBE_DEFER)
+			dev_err(dev, "Couldn't download firmware -- %d\n", ret);
 		return ret;
 	}