[RFC PATCH 2/2] OMAP2+: PANDA: Fix up random or missing MAC addresses for eth0 and wlan0

[mailto:linux-omap-owner at vger.kernel.org] On Behalf Of Andy Green
Sent: Friday, March 25, 2011 2:58 AM
To: linux-arm-kernel at lists.infradead.org; linux-omap at vger.kernel.org
Cc: patches at linaro.org; nicolas.pitre at linaro.org;
arnd at arndb.de; x0132446 at ti.com; s-jan at ti.com;
tony at atomide.com; Alan Cox; Andy Green
Subject: [RFC PATCH 2/2] OMAP2+: PANDA: Fix up random or
missing MAC addresses for eth0 and wlan0

This patch registers a network device notifier callback to set the mac
addresses for the onboard network assets of Panda correctly,
despite the
drivers involved have used a random or all-zeros MAC address.

The technique was suggested by Alan Cox on lkml.

It works by device path so it corrects the MAC addresses even if the
drivers are in modules loaded in an order that changes their interface
name from usual (eg, the onboard module might be "wlan1" if there is a
USB wireless stick plugged in and its module is inserted first.)

Cc: Alan Cox <redacted>
Signed-off-by: Andy Green <redacted>
---

arch/arm/mach-omap2/board-omap4panda.c |   91
++++++++++++++++++++++++++++++++
1 files changed, 91 insertions(+), 0 deletions(-)

diff --git a/arch/arm/mach-omap2/board-omap4panda.c

b/arch/arm/mach-omap2/board-omap4panda.c
index 80b8860..0b92873 100644

--- a/arch/arm/mach-omap2/board-omap4panda.c
+++ b/arch/arm/mach-omap2/board-omap4panda.c

@@ -28,9 +28,12 @@

#include <linux/regulator/machine.h>
#include <linux/regulator/fixed.h>
#include <linux/wl12xx.h>
+#include <linux/netdevice.h>
+#include <linux/if_ether.h>

#include <mach/hardware.h>
#include <mach/omap4-common.h>
+#include <mach/id.h>
#include <asm/mach-types.h>
#include <asm/mach/arch.h>
#include <asm/mach/map.h>

@@ -506,6 +509,92 @@ static inline void board_serial_init(void)

}
#endif

+/*
+ * These device paths represent the onboard USB <-> Ethernet
bridge, and
+ * the WLAN module on Panda, both of which need their random
or all-zeros
+ * mac address replacing with a per-cpu stable generated one
+ */
+
+static const char * const panda_fixup_mac_device_paths[] = {
+	"usb1/1-1/1-1.1/1-1.1:1.0",
+	"mmc1:0001:2",
+};
+
+static int panda_device_path_need_mac(struct device *dev)
+{
+	const char **try = panda_fixup_mac_device_paths;
+	const char *path;
+	int count = ARRAY_SIZE(panda_fixup_mac_device_paths);
+	const char *p;
+	int len;
+	struct device *devn;
+
+	while (count--) {
+
+		p = *try + strlen(*try);
+		devn = dev;
+
+		while (devn) {
+
+			path = dev_name(devn);
+			len = strlen(path);
+
+			if ((p - *try) < len) {
+				devn = NULL;
+				continue;
+			}
+
+			p -= len;
+
+			if (strncmp(path, p, len)) {
+				devn = NULL;
+				continue;
+			}
+
+			devn = devn->parent;
+			if (p == *try)
+				return count;
+
+			if (devn != NULL && (p - *try) < 2)
+				devn = NULL;
+
+			p--;
+			if (devn != NULL && *p != '/')
+				devn = NULL;
+		}
+
+		try++;
+	}
+
+	return -ENOENT;
+}
+
+static int omap_panda_netdev_event(struct notifier_block *this,
+						 unsigned long
event, void *ptr)
+{
+	struct net_device *dev = ptr;
+	struct sockaddr sa;
+	int n;
+
+	if (event != NETDEV_REGISTER)
+		return NOTIFY_DONE;
+
+	n = panda_device_path_need_mac(dev->dev.parent);
+	if (n >= 0) {
+		sa.sa_family = dev->type;
+		omap2_die_id_to_ethernet_mac(sa.sa_data, n);
+		dev->netdev_ops->ndo_set_mac_address(dev, &sa);
+	}
+
+	return NOTIFY_DONE;
+}
+
+static struct notifier_block omap_panda_netdev_notifier = {
+	.notifier_call = omap_panda_netdev_event,
+	.priority = 1,
+};
+
+

static void __init omap4_panda_init(void)
{
	int package = OMAP_PACKAGE_CBS;

@@ -517,6 +606,8 @@ static void __init omap4_panda_init(void)

	if (wl12xx_set_platform_data(&omap_panda_wlan_data))
		pr_err("error setting wl12xx data\n");

+	register_netdevice_notifier(&omap_panda_netdev_notifier);
+
	omap4_panda_i2c_init();
	platform_add_devices(panda_devices, ARRAY_SIZE(panda_devices));
	platform_device_register(&omap_vwlan_device);

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