Re: [PATCH 1/3] OMAP2+: add cpu id register to MAC address helper

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On 06/29/12 17:05, the mail apparently from Tony Lindgren included:
* Andy Green <andy.green@xxxxxxxxxx> [120628 22:59]:

Introduce a generic helper function that can generate a valid MAC
address using data from the OMAP unique CPU ID register.
...

--- a/arch/arm/mach-omap2/id.c
+++ b/arch/arm/mach-omap2/id.c
@@ -530,3 +530,42 @@ void __init omap2_set_globals_tap(struct omap_globals *omap2_globals)
  	else
  		tap_prod_id = 0x0208;
  }
+
+/*
+ * 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 omap2_die_id_to_ethernet_mac(u8 *mac, int subtype)
+{
+	struct omap_die_id odi;
+	u32 tap = read_tap_reg(OMAP_TAP_IDCODE);
+
+	omap_get_die_id(&odi);
+
+	mac[0] = odi.id_2;
+	mac[1] = odi.id_2 >> 8;
+	mac[2] = odi.id_1;
+	mac[3] = odi.id_1 >> 8;
+	mac[4] = odi.id_1 >> 16;
+	mac[5] = odi.id_1 >> 24;
+
+	/* XOR other chip-specific data with ID */
+
+	tap ^= odi.id_3;
+
+	mac[0] ^= tap;
+	mac[1] ^= tap >> 8;
+	mac[2] ^= tap >> 16;
+	mac[3] ^= tap >> 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;
+}

Let's just make this omap_die_id_to_ethernet_mac, no need to keep the
omap2 naming there as this should not conflict with any omap1 stuff.

Okay, will do thanks.

-Andy

--
Andy Green | TI Landing Team Leader
Linaro.org │ Open source software for ARM SoCs | Follow Linaro
http://facebook.com/pages/Linaro/155974581091106 - http://twitter.com/#!/linaroorg - http://linaro.org/linaro-blog


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