diff --git a/drivers/firmware/raspberrypi.c b/drivers/firmware/raspberrypi.c
index a200a21..da26a58 100644
--- a/drivers/firmware/raspberrypi.c
+++ b/drivers/firmware/raspberrypi.c
@@ -1,12 +1,9 @@
+// SPDX-License-Identifier: GPL-2.0
 /*
  * Defines interfaces for interacting wtih the Raspberry Pi firmware's
  * property channel.
  *
  * Copyright © 2015 Broadcom
- *
- * This program is free software; you can redistribute it and/or modify
- * it under the terms of the GNU General Public License version 2 as
- * published by the Free Software Foundation.
  */
 
 #include <linux/dma-mapping.h>
@@ -14,6 +11,7 @@
 #include <linux/module.h>
 #include <linux/of_platform.h>
 #include <linux/platform_device.h>
+#include <linux/slab.h>
 #include <soc/bcm2835/raspberrypi-firmware.h>
 
 #define MBOX_MSG(chan, data28)		(((data28) & ~0xf) | ((chan) & 0xf))
@@ -21,9 +19,8 @@
 #define MBOX_DATA28(msg)		((msg) & ~0xf)
 #define MBOX_CHAN_PROPERTY		8
 
-#define MAX_RPI_FW_PROP_BUF_SIZE	32
-
 static struct platform_device *rpi_hwmon;
+static struct platform_device *rpi_clk;
 
 struct rpi_firmware {
 	struct mbox_client cl;
@@ -56,8 +53,12 @@
 	reinit_completion(&fw->c);
 	ret = mbox_send_message(fw->chan, &message);
 	if (ret >= 0) {
-		wait_for_completion(&fw->c);
-		ret = 0;
+		if (wait_for_completion_timeout(&fw->c, HZ)) {
+			ret = 0;
+		} else {
+			ret = -ETIMEDOUT;
+			WARN_ONCE(1, "Firmware transaction timeout");
+		}
 	} else {
 		dev_err(fw->cl.dev, "mbox_send_message returned %d\n", ret);
 	}
@@ -144,28 +145,30 @@
 int rpi_firmware_property(struct rpi_firmware *fw,
 			  u32 tag, void *tag_data, size_t buf_size)
 {
-	/* Single tags are very small (generally 8 bytes), so the
-	 * stack should be safe.
-	 */
-	u8 data[sizeof(struct rpi_firmware_property_tag_header) +
-		MAX_RPI_FW_PROP_BUF_SIZE];
-	struct rpi_firmware_property_tag_header *header =
-		(struct rpi_firmware_property_tag_header *)data;
+	struct rpi_firmware_property_tag_header *header;
 	int ret;
 
-	if (WARN_ON(buf_size > sizeof(data) - sizeof(*header)))
-		return -EINVAL;
+	/* Some mailboxes can use over 1k bytes. Rather than checking
+	 * size and using stack or kmalloc depending on requirements,
+	 * just use kmalloc. Mailboxes don't get called enough to worry
+	 * too much about the time taken in the allocation.
+	 */
+	void *data = kmalloc(sizeof(*header) + buf_size, GFP_KERNEL);
 
+	if (!data)
+		return -ENOMEM;
+
+	header = data;
 	header->tag = tag;
 	header->buf_size = buf_size;
 	header->req_resp_size = 0;
-	memcpy(data + sizeof(struct rpi_firmware_property_tag_header),
-	       tag_data, buf_size);
+	memcpy(data + sizeof(*header), tag_data, buf_size);
 
-	ret = rpi_firmware_property_list(fw, &data, buf_size + sizeof(*header));
-	memcpy(tag_data,
-	       data + sizeof(struct rpi_firmware_property_tag_header),
-	       buf_size);
+	ret = rpi_firmware_property_list(fw, data, buf_size + sizeof(*header));
+
+	memcpy(tag_data, data + sizeof(*header), buf_size);
+
+	kfree(data);
 
 	return ret;
 }
@@ -205,6 +208,12 @@
 						  -1, NULL, 0);
 }
 
+static void rpi_register_clk_driver(struct device *dev)
+{
+	rpi_clk = platform_device_register_data(dev, "raspberrypi-clk",
+						-1, NULL, 0);
+}
+
 static int rpi_firmware_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -232,16 +241,29 @@
 
 	rpi_firmware_print_firmware_revision(fw);
 	rpi_register_hwmon_driver(dev, fw);
+	rpi_register_clk_driver(dev);
 
 	return 0;
 }
 
+static void rpi_firmware_shutdown(struct platform_device *pdev)
+{
+	struct rpi_firmware *fw = platform_get_drvdata(pdev);
+
+	if (!fw)
+		return;
+
+	rpi_firmware_property(fw, RPI_FIRMWARE_NOTIFY_REBOOT, NULL, 0);
+}
+
 static int rpi_firmware_remove(struct platform_device *pdev)
 {
 	struct rpi_firmware *fw = platform_get_drvdata(pdev);
 
 	platform_device_unregister(rpi_hwmon);
 	rpi_hwmon = NULL;
+	platform_device_unregister(rpi_clk);
+	rpi_clk = NULL;
 	mbox_free_channel(fw->chan);
 
 	return 0;
@@ -276,6 +298,7 @@
 		.of_match_table = rpi_firmware_of_match,
 	},
 	.probe		= rpi_firmware_probe,
+	.shutdown	= rpi_firmware_shutdown,
 	.remove		= rpi_firmware_remove,
 };
 module_platform_driver(rpi_firmware_driver);