ARM: rpi_b: query internal MAC address from firmware

The built-in SMSC 95xx chip doesn't know its own MAC address. Instead,
we must query it from the VC firmware; it's probably encoded in fuses
on the BCM2835.

Signed-off-by: Stephen Warren <swarren@wwwdotorg.org>

arch/arm/include/asm/arch-bcm2835/mbox.h

@@ -119,6 +119,20 @@ struct bcm2835_mbox_tag_hdr {
  * };
  */
 
+#define BCM2835_MBOX_TAG_GET_MAC_ADDRESS	0x00010003
+
+struct bcm2835_mbox_tag_get_mac_address {
+	struct bcm2835_mbox_tag_hdr tag_hdr;
+	union {
+		struct {
+		} req;
+		struct {
+			u8 mac[6];
+			u8 pad[2];
+		} resp;
+	} body;
+};
+
 #define BCM2835_MBOX_TAG_GET_ARM_MEMORY		0x00010005
 
 struct bcm2835_mbox_tag_get_arm_mem {

board/raspberrypi/rpi_b/rpi_b.c

@@ -31,6 +31,12 @@ struct msg_get_arm_mem {
 	u32 end_tag;
 };
 
+struct msg_get_mac_address {
+	struct bcm2835_mbox_hdr hdr;
+	struct bcm2835_mbox_tag_get_mac_address get_mac_address;
+	u32 end_tag;
+};
+
 struct msg_set_power_state {
 	struct bcm2835_mbox_hdr hdr;
 	struct bcm2835_mbox_tag_set_power_state set_power_state;
@@ -62,6 +68,29 @@ int dram_init(void)
 	return 0;
 }
 
+int misc_init_r(void)
+{
+	ALLOC_ALIGN_BUFFER(struct msg_get_mac_address, msg, 1, 16);
+	int ret;
+
+	if (getenv("usbethaddr"))
+		return 0;
+
+	BCM2835_MBOX_INIT_HDR(msg);
+	BCM2835_MBOX_INIT_TAG(&msg->get_mac_address, GET_MAC_ADDRESS);
+
+	ret = bcm2835_mbox_call_prop(BCM2835_MBOX_PROP_CHAN, &msg->hdr);
+	if (ret) {
+		printf("bcm2835: Could not query MAC address\n");
+		/* Ignore error; not critical */
+		return 0;
+	}
+
+	eth_setenv_enetaddr("usbethaddr", msg->get_mac_address.body.resp.mac);
+
+	return 0;
+}
+
 static int power_on_module(u32 module)
 {
 	ALLOC_ALIGN_BUFFER(struct msg_set_power_state, msg_pwr, 1, 16);

include/configs/rpi_b.h

@@ -182,6 +182,7 @@
 #define CONFIG_USB_STORAGE
 #define CONFIG_USB_HOST_ETHER
 #define CONFIG_USB_ETHER_SMSC95XX
+#define CONFIG_MISC_INIT_R
 #endif
 
 #endif