Merge tag 'arm-soc/for-4.19/drivers' of https://github.com/Broadcom/stblinux into next/drivers

This pull request contains Broadcom ARM/ARM64/MIPS SoCs drivers changes
for 4.19, please pull the following:

- Doug updates the low-level suspend/resume code for ARM SoCs to support
  the latest rev B3.0 memory controllers found on newer chips with an
  appropriate match structure to perform the correct entry sequencing

- Florian updates the Device Tree binding document for these memory
  controllers to list all possible compatible strings that exist given
   the supported memory controllers.

- Stefan adds the GET_THROTTLED firmware property value that is required
  for the Rasperry Pi voltage monitoring driver and updates the
  Raspberry Pi firmware driver accordingly to register such a device
  using the HWMON subsystem. Finally he adds support for reporting under
  voltage conditions using a specialized HWMON driver.

* tag 'arm-soc/for-4.19/drivers' of https://github.com/Broadcom/stblinux:
  firmware: raspberrypi: Remove VLA usage
  firmware: raspberrypi: Register hwmon driver
  hwmon: Add support for RPi voltage sensor
  soc: bcm: brcmstb: Add missing DDR MEMC compatible strings
  soc: bcm: brcmstb: pm: Add support for newer rev B3.0 controllers
  ARM: bcm2835: Add GET_THROTTLED firmware property

Signed-off-by: Olof Johansson <olof@lixom.net>

drivers/firmware/raspberrypi.c

@@ -21,6 +21,10 @@
 #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;
+
 struct rpi_firmware {
 	struct mbox_client cl;
 	struct mbox_chan *chan; /* The property channel. */
@@ -143,18 +147,22 @@ int rpi_firmware_property(struct rpi_firmware *fw,
 	/* Single tags are very small (generally 8 bytes), so the
 	 * stack should be safe.
 	 */
-	u8 data[buf_size + sizeof(struct rpi_firmware_property_tag_header)];
+	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;
 	int ret;
 
+	if (WARN_ON(buf_size > sizeof(data) - sizeof(*header)))
+		return -EINVAL;
+
 	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);
 
-	ret = rpi_firmware_property_list(fw, &data, sizeof(data));
+	ret = rpi_firmware_property_list(fw, &data, buf_size + sizeof(*header));
 	memcpy(tag_data,
 	       data + sizeof(struct rpi_firmware_property_tag_header),
 	       buf_size);
@@ -183,6 +191,20 @@ rpi_firmware_print_firmware_revision(struct rpi_firmware *fw)
 	}
 }
 
+static void
+rpi_register_hwmon_driver(struct device *dev, struct rpi_firmware *fw)
+{
+	u32 packet;
+	int ret = rpi_firmware_property(fw, RPI_FIRMWARE_GET_THROTTLED,
+					&packet, sizeof(packet));
+
+	if (ret)
+		return;
+
+	rpi_hwmon = platform_device_register_data(dev, "raspberrypi-hwmon",
+						  -1, NULL, 0);
+}
+
 static int rpi_firmware_probe(struct platform_device *pdev)
 {
 	struct device *dev = &pdev->dev;
@@ -209,6 +231,7 @@ static int rpi_firmware_probe(struct platform_device *pdev)
 	platform_set_drvdata(pdev, fw);
 
 	rpi_firmware_print_firmware_revision(fw);
+	rpi_register_hwmon_driver(dev, fw);
 
 	return 0;
 }
@@ -217,6 +240,8 @@ 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;
 	mbox_free_channel(fw->chan);
 
 	return 0;