[PATCH 2/5] ARM: rpi: add serial number readout

["Daniel Brát" <danek.brat@gmail.com>]

Remove querying for serial-number node from vc fdt, since it's not
guaranteed to always be there (older firmwares dont provide it).
Instead, retrieve board's serial number via the mbox api.

Signed-off-by: Daniel Brát <danek.brat@gmail.com>
---
 arch/arm/boards/raspberry-pi/lowlevel.h     |  1 +
 arch/arm/boards/raspberry-pi/mbox-helpers.c | 27 +++++++++++++++++++++
 arch/arm/boards/raspberry-pi/rpi-common.c   | 21 +++++++++++-----
 arch/arm/mach-bcm283x/include/mach/mbox.h   | 13 ++++++++++
 4 files changed, 56 insertions(+), 6 deletions(-)

diff --git a/arch/arm/boards/raspberry-pi/lowlevel.h b/arch/arm/boards/raspberry-pi/lowlevel.h
index 260f96c714..d2699b9b08 100644
--- a/arch/arm/boards/raspberry-pi/lowlevel.h
+++ b/arch/arm/boards/raspberry-pi/lowlevel.h
@@ -12,5 +12,6 @@
 ssize_t rpi_get_arm_mem(void);
 int rpi_get_ethaddr(u8 mac[6]);
 int rpi_get_board_rev(void);
+int rpi_get_board_serial(u64 *serial);
 
 #endif /* __ARCH_ARM_BOARDS_LOWLEVEL_H__ */
diff --git a/arch/arm/boards/raspberry-pi/mbox-helpers.c b/arch/arm/boards/raspberry-pi/mbox-helpers.c
index 50fc1c5b45..62c65d1267 100644
--- a/arch/arm/boards/raspberry-pi/mbox-helpers.c
+++ b/arch/arm/boards/raspberry-pi/mbox-helpers.c
@@ -16,6 +16,12 @@ struct msg_get_board_rev {
 	u32 end_tag;
 };
 
+struct msg_get_board_serial {
+	struct bcm2835_mbox_hdr hdr;
+	struct bcm2835_mbox_tag_get_board_serial get_board_serial;
+	u32 end_tag;
+};
+
 struct msg_get_mac_address {
 	struct bcm2835_mbox_hdr hdr;
 	struct bcm2835_mbox_tag_get_mac_address get_mac_address;
@@ -71,3 +77,24 @@ int rpi_get_board_rev(void)
 
 	return msg->get_board_rev.body.resp.rev;
 }
+
+int rpi_get_board_serial(u64 *serial)
+{
+	int ret;
+
+	BCM2835_MBOX_STACK_ALIGN(struct msg_get_board_serial, msg);
+	BCM2835_MBOX_INIT_HDR(msg);
+	BCM2835_MBOX_INIT_TAG(&msg->get_board_serial, GET_BOARD_SERIAL);
+
+	if (!serial)
+		return -EINVAL;
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &msg->hdr);
+	if (ret) {
+		pr_err("Could not query board serial\n");
+		return ret;
+	}
+
+	*serial = msg->get_board_serial.body.resp.serial;
+	return 0;
+}
diff --git a/arch/arm/boards/raspberry-pi/rpi-common.c b/arch/arm/boards/raspberry-pi/rpi-common.c
index 8d1e74acab..a8f180ae92 100644
--- a/arch/arm/boards/raspberry-pi/rpi-common.c
+++ b/arch/arm/boards/raspberry-pi/rpi-common.c
@@ -60,6 +60,19 @@ struct rpi_priv {
 	const char *name;
 };
 
+static void rpi_set_serial_number(void)
+{
+	u64 serial;
+	char *serial_str;
+
+	if (rpi_get_board_serial(&serial))
+		return;
+
+	serial_str = basprintf("%016llx", serial);
+	barebox_set_serial_number(serial_str);
+	free(serial_str);
+}
+
 static void rpi_set_ethaddr(void)
 {
 	u8 mac[ETH_ALEN];
@@ -265,12 +278,6 @@ static void rpi_vc_fdt_parse(void *fdt)
 	if (IS_ERR(root))
 		return;
 
-	str = of_read_vc_string(root, "serial-number");
-	if (str) {
-		barebox_set_serial_number(str);
-		free(str);
-	}
-
 	str = of_read_vc_string(root, "model");
 	if (str) {
 		barebox_set_model(str);
@@ -446,6 +453,8 @@ static int rpi_devices_probe(struct device *dev)
 	if (IS_ERR(dcfg))
 		goto free_priv;
 
+	rpi_set_serial_number();
+
 	/* construct short recognizable host name */
 	name = of_device_get_match_compatible(priv->dev);
 	ptr = strchr(name, ',');
diff --git a/arch/arm/mach-bcm283x/include/mach/mbox.h b/arch/arm/mach-bcm283x/include/mach/mbox.h
index 92cadba62c..008ea2e614 100644
--- a/arch/arm/mach-bcm283x/include/mach/mbox.h
+++ b/arch/arm/mach-bcm283x/include/mach/mbox.h
@@ -201,6 +201,19 @@ struct bcm2835_mbox_tag_get_mac_address {
 	} body;
 };
 
+#define BCM2835_MBOX_TAG_GET_BOARD_SERIAL	0x00010004
+
+struct bcm2835_mbox_tag_get_board_serial {
+	struct bcm2835_mbox_tag_hdr tag_hdr;
+	union {
+		struct {
+		} req;
+		struct __packed {
+			u64 serial;
+		} resp;
+	} body;
+};
+
 #define BCM2835_MBOX_TAG_GET_ARM_MEMORY		0x00010005
 
 struct bcm2835_mbox_tag_get_arm_mem {
-- 
2.34.1