brcmfmac: fix P2P_DEVICE ethernet address generation

The firmware has a requirement that the P2P_DEVICE address should
be different from the address of the primary interface. When not
specified by user-space, the driver generates the MAC address for
the P2P_DEVICE interface using the MAC address of the primary
interface and setting the locally administered bit. However, the MAC
address of the primary interface may already have that bit set causing
the creation of the P2P_DEVICE interface to fail with -EBUSY. Fix this
by using a random address instead to determine the P2P_DEVICE address.

Cc: stable@vger.kernel.org # 3.10.y
Reported-by: NHans de Goede <hdegoede@redhat.com>
Reviewed-by: NHante Meuleman <hante.meuleman@broadcom.com>
Reviewed-by: NPieter-Paul Giesberts <pieter-paul.giesberts@broadcom.com>
Reviewed-by: NFranky Lin <franky.lin@broadcom.com>
Signed-off-by: NArend van Spriel <arend.vanspriel@broadcom.com>
Signed-off-by: NKalle Valo <kvalo@codeaurora.org>

drivers/net/wireless/broadcom/brcm80211/brcmfmac/p2p.c

@@ -462,25 +462,23 @@ static int brcmf_p2p_set_firmware(struct brcmf_if *ifp, u8 *p2p_mac)
  * @dev_addr: optional device address.
  *
  * P2P needs mac addresses for P2P device and interface. If no device
- * address it specified, these are derived from the primary net device, ie.
- * the permanent ethernet address of the device.
+ * address it specified, these are derived from a random ethernet
+ * address.
  */
 static void brcmf_p2p_generate_bss_mac(struct brcmf_p2p_info *p2p, u8 *dev_addr)
 {
-	struct brcmf_if *pri_ifp = p2p->bss_idx[P2PAPI_BSSCFG_PRIMARY].vif->ifp;
-	bool local_admin = false;
+	bool random_addr = false;
 
-	if (!dev_addr || is_zero_ether_addr(dev_addr)) {
-		dev_addr = pri_ifp->mac_addr;
-		local_admin = true;
-	}
+	if (!dev_addr || is_zero_ether_addr(dev_addr))
+		random_addr = true;
 
-	/* Generate the P2P Device Address.  This consists of the device's
-	 * primary MAC address with the locally administered bit set.
+	/* Generate the P2P Device Address obtaining a random ethernet
+	 * address with the locally administered bit set.
 	 */
-	memcpy(p2p->dev_addr, dev_addr, ETH_ALEN);
-	if (local_admin)
-		p2p->dev_addr[0] |= 0x02;
+	if (random_addr)
+		eth_random_addr(p2p->dev_addr);
+	else
+		memcpy(p2p->dev_addr, dev_addr, ETH_ALEN);
 
 	/* Generate the P2P Interface Address.  If the discovery and connection
 	 * BSSCFGs need to simultaneously co-exist, then this address must be