OMAP4 Panda: Generate a unique usbethaddr

The panda board has a usb nic but the nic has no
rom.  Use the die-id to generate a unique address.
This is derived from an RFC kernel patch by Andy Green
that does the same thing:
	https://patchwork.kernel.org/patch/660541/

	[RFC PATCH 1/2] OMAP2+: add cpu id register to MAC address helper

Signed-off-by: John Rigby <john.rigby@linaro.org>

4 files changed, 72 insertions, 0 deletions

diff --git a/arch/arm/cpu/armv7/omap-common/hwinit-common.c b/arch/arm/cpu/armv7/omap-common/hwinit-common.c
index 9ef10bdf2..42b14edc6 100644
--- a/arch/arm/cpu/armv7/omap-common/hwinit-common.c
+++ b/arch/arm/cpu/armv7/omap-common/hwinit-common.c
@@ -29,6 +29,7 @@
  */
 #include <common.h>
 #include <spl.h>
+#include <asm/io.h>
 #include <asm/arch/sys_proto.h>
 #include <asm/sizes.h>
 #include <asm/emif.h>
@@ -252,6 +253,46 @@ int print_cpuinfo(void)
 
 	return 0;
 }
+
+/*
+ * this uses the unique per-cpu info from the cpu fuses set at factory to
+ * generate a 6-byte MAC address.  Two bits in the generated code are used
+ * to elaborate the generated address into four, so it can be used on multiple
+ * network interfaces.
+ */
+void omap4_die_id_to_ethernet_mac(u8 *mac, int subtype)
+{
+	struct ctrl_id *id_base = (struct ctrl_id *)(CTRL_BASE + 0x200);
+	u32 idcode;
+	u32 id[4];
+
+	idcode = readl(&id_base->idcode);
+	id[0] = readl(&id_base->die_id_0);
+	id[1] = readl(&id_base->die_id_1);
+	id[2] = readl(&id_base->die_id_2);
+	id[3] = readl(&id_base->die_id_3);
+
+	mac[0] = id[2];
+	mac[1] = id[2] >> 8;
+	mac[2] = id[1];
+	mac[3] = id[1] >> 8;
+	mac[4] = id[1] >> 16;
+	mac[5] = id[1] >> 24;
+	/* XOR other chip-specific data with ID */
+	idcode ^= id[3];
+
+	mac[0] ^= idcode;
+	mac[1] ^= idcode >> 8;
+	mac[2] ^= idcode >> 16;
+	mac[3] ^= idcode >> 24;
+
+	/* allow four MACs from this same basic data */
+	mac[1] = (mac[1] & ~0xc0) | ((subtype & 3) << 6);
+
+	/* mark it as not multicast and outside official 80211 MAC namespace */
+	mac[0] = (mac[0] & ~1) | 2;
+}
+
 #ifndef CONFIG_SYS_DCACHE_OFF
 void enable_caches(void)
 {
diff --git a/arch/arm/include/asm/arch-omap4/cpu.h b/arch/arm/include/asm/arch-omap4/cpu.h
index 3a0bfbf0c..4258f3448 100644
--- a/arch/arm/include/asm/arch-omap4/cpu.h
+++ b/arch/arm/include/asm/arch-omap4/cpu.h
@@ -94,6 +94,17 @@ struct gptimer {
 	u32 tcicr;		/* 0x40 rw */
 	u32 tcar2;		/* 0x44 r */
 };
+
+struct ctrl_id {
+	u32 die_id_0;		/* 0x00 */
+	u32 idcode;		/* 0x04 */
+	u32 die_id_1;		/* 0x08 */
+	u32 die_id_2;		/* 0x0c */
+	u32 die_id_3;		/* 0x10 */
+	u32 prod_id_0;		/* 0x14 */
+	u32 prod_id_1;		/* 0x18 */
+};
+
 #endif /* __ASSEMBLY__ */
 #endif /* __KERNEL_STRICT_NAMES */
 
diff --git a/arch/arm/include/asm/arch-omap4/sys_proto.h b/arch/arm/include/asm/arch-omap4/sys_proto.h
index b48f81dc3..77f2cf7ab 100644
--- a/arch/arm/include/asm/arch-omap4/sys_proto.h
+++ b/arch/arm/include/asm/arch-omap4/sys_proto.h
@@ -58,6 +58,7 @@ void omap_vc_init(u16 speed_khz);
 int omap_vc_bypass_send_value(u8 sa, u8 reg_addr, u8 reg_data);
 u32 warm_reset(void);
 void force_emif_self_refresh(void);
+void omap4_die_id_to_ethernet_mac(u8 *, int);
 /*
  * This is used to verify if the configuration header
  * was executed by Romcode prior to control of transfer
diff --git a/board/ti/panda/panda.c b/board/ti/panda/panda.c
index 4feef78ef..20be81c7a 100644
--- a/board/ti/panda/panda.c
+++ b/board/ti/panda/panda.c
@@ -61,8 +61,27 @@ int board_init(void)
 	return 0;
 }
 
+/*
+ * Panda has a usb nic with no ethernet rom so generate a macaddr
+ * from the SOC die-id and set the usbethaddr env var to that
+ * value.
+ */
 int board_eth_init(bd_t *bis)
 {
+	u8 macaddr[6];
+	char usbethaddr[20];
+
+	/*
+	 * NB: The 1 here has been found to generate an address
+	 * consistent with the kernel.
+	 */
+	omap4_die_id_to_ethernet_mac(macaddr, 1);
+	sprintf (usbethaddr, "%02X:%02X:%02X:%02X:%02X:%02X",
+		 macaddr[0], macaddr[1],
+		 macaddr[2], macaddr[3],
+		 macaddr[4], macaddr[5]) ;
+	setenv ("usbethaddr", usbethaddr);
+
 	return 0;
 }