[RFC] usbnet: use eth%d name for known ethernet devices

The documentation for the USB ethernet devices suggests that
only some devices are supposed to use usb0 as the network interface
name instead of eth0. The logic used there, and documented in
Kconfig for CDC is that eth0 will be used when the mac address
is a globally assigned one, but usb0 is used for the locally
managed range that is typically used on point-to-point links.

Unfortunately, this has caused a lot of pain on the smsc95xx
device that is used on the popular pandaboard without an
EEPROM to store the MAC address, which causes the driver to
call random_ether_address().

Obviously, there should be a proper MAC addressed assigned to
the device, and discussions are ongoing about how to solve
this, but this patch at least makes sure that the default
interface naming gets a little saner and matches what the
user can expect based on the documentation, including for
new devices.

The approach taken here is to flag whether a device might be a 
point-to-point link with the new FLAG_PTP setting in the usbnet
driver_info. A driver can set both FLAG_PTP and FLAG_ETHER if
it is not sure (e.g. cdc_ether), or just one of the two.
The usbnet framework only looks at the MAC address for device
naming if both flags are set, otherwise it trusts the flag.

Signed-off-by: Arnd Bergmann <redacted>
Cc: Andy Green <redacted>
---
 drivers/net/usb/cdc_eem.c     |    2 +-
 drivers/net/usb/cdc_ether.c   |    2 +-
 drivers/net/usb/cdc_ncm.c     |    2 +-
 drivers/net/usb/cdc_subset.c  |    8 ++++++++
 drivers/net/usb/gl620a.c      |    2 +-
 drivers/net/usb/net1080.c     |    2 +-
 drivers/net/usb/plusb.c       |    2 +-
 drivers/net/usb/rndis_host.c  |    2 +-
 drivers/net/usb/smsc75xx.c    |    2 +-
 drivers/net/usb/smsc95xx.c    |    2 +-
 drivers/net/usb/usbnet.c      |    3 ++-
 drivers/net/usb/zaurus.c      |    8 ++++----
 drivers/usb/serial/usb_wwan.c |    2 +-
 include/linux/usb/usbnet.h    |    2 ++

Not tested yet, could someone try this out on a panda board
and ideally on a CDC device as well?

diff --git a/drivers/net/usb/cdc_eem.c b/drivers/net/usb/cdc_eem.c
index 5f3b976..4d6bcb8 100644
--- a/drivers/net/usb/cdc_eem.c
+++ b/drivers/net/usb/cdc_eem.c

@@ -340,7 +340,7 @@ next:
 
 static const struct driver_info eem_info = {
 	.description =	"CDC EEM Device",
-	.flags =	FLAG_ETHER,
+	.flags =	FLAG_ETHER | FLAG_PTP,
 	.bind =		eem_bind,
 	.rx_fixup =	eem_rx_fixup,
 	.tx_fixup =	eem_tx_fixup,

diff --git a/drivers/net/usb/cdc_ether.c b/drivers/net/usb/cdc_ether.c
index 9a60e41..6dc89d0 100644
--- a/drivers/net/usb/cdc_ether.c
+++ b/drivers/net/usb/cdc_ether.c

@@ -450,7 +450,7 @@ static int cdc_manage_power(struct usbnet *dev, int on)
 
 static const struct driver_info	cdc_info = {
 	.description =	"CDC Ethernet Device",
-	.flags =	FLAG_ETHER,
+	.flags =	FLAG_ETHER | FLAG_PTP,
 	// .check_connect = cdc_check_connect,
 	.bind =		cdc_bind,
 	.unbind =	usbnet_cdc_unbind,

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index 7113168..a6a026a 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c

@@ -1237,7 +1237,7 @@ static int cdc_ncm_manage_power(struct usbnet *dev, int status)
 
 static const struct driver_info cdc_ncm_info = {
 	.description = "CDC NCM",
-	.flags = FLAG_NO_SETINT | FLAG_MULTI_PACKET,
+	.flags = FLAG_PTP | FLAG_NO_SETINT | FLAG_MULTI_PACKET,
 	.bind = cdc_ncm_bind,
 	.unbind = cdc_ncm_unbind,
 	.check_connect = cdc_ncm_check_connect,

diff --git a/drivers/net/usb/cdc_subset.c b/drivers/net/usb/cdc_subset.c
index ca39ace..fbe2b1b 100644
--- a/drivers/net/usb/cdc_subset.c
+++ b/drivers/net/usb/cdc_subset.c

@@ -89,6 +89,7 @@ static int always_connected (struct usbnet *dev)
 
 static const struct driver_info	ali_m5632_info = {
 	.description =	"ALi M5632",
+	.flags       = FLAG_PTP,
 };
 
 #endif

@@ -110,6 +111,7 @@ static const struct driver_info	ali_m5632_info = {
 
 static const struct driver_info	an2720_info = {
 	.description =	"AnchorChips/Cypress 2720",
+	.flags       = FLAG_PTP,
 	// no reset available!
 	// no check_connect available!
 

@@ -132,6 +134,7 @@ static const struct driver_info	an2720_info = {
 
 static const struct driver_info	belkin_info = {
 	.description =	"Belkin, eTEK, or compatible",
+	.flags       = FLAG_PTP,
 };
 
 #endif	/* CONFIG_USB_BELKIN */

@@ -157,6 +160,7 @@ static const struct driver_info	belkin_info = {
 static const struct driver_info	epson2888_info = {
 	.description =	"Epson USB Device",
 	.check_connect = always_connected,
+	.flags = FLAG_PTP,
 
 	.in = 4, .out = 3,
 };

@@ -173,6 +177,7 @@ static const struct driver_info	epson2888_info = {
 #define HAVE_HARDWARE
 static const struct driver_info kc2190_info = {
 	.description =  "KC Technology KC-190",
+	.flags = FLAG_PTP,
 };
 #endif /* CONFIG_USB_KC2190 */
 

@@ -200,16 +205,19 @@ static const struct driver_info kc2190_info = {
 static const struct driver_info	linuxdev_info = {
 	.description =	"Linux Device",
 	.check_connect = always_connected,
+	.flags = FLAG_PTP,
 };
 
 static const struct driver_info	yopy_info = {
 	.description =	"Yopy",
 	.check_connect = always_connected,
+	.flags = FLAG_PTP,
 };
 
 static const struct driver_info	blob_info = {
 	.description =	"Boot Loader OBject",
 	.check_connect = always_connected,
+	.flags = FLAG_PTP,
 };
 
 #endif	/* CONFIG_USB_ARMLINUX */

diff --git a/drivers/net/usb/gl620a.c b/drivers/net/usb/gl620a.c
index dcd57c3..972ee83 100644
--- a/drivers/net/usb/gl620a.c
+++ b/drivers/net/usb/gl620a.c

@@ -193,7 +193,7 @@ static int genelink_bind(struct usbnet *dev, struct usb_interface *intf)
 
 static const struct driver_info	genelink_info = {
 	.description =	"Genesys GeneLink",
-	.flags =	FLAG_FRAMING_GL | FLAG_NO_SETINT,
+	.flags =	FLAG_PTP | FLAG_FRAMING_GL | FLAG_NO_SETINT,
 	.bind =		genelink_bind,
 	.rx_fixup =	genelink_rx_fixup,
 	.tx_fixup =	genelink_tx_fixup,

diff --git a/drivers/net/usb/net1080.c b/drivers/net/usb/net1080.c
index ba72a72..f8a294e 100644
--- a/drivers/net/usb/net1080.c
+++ b/drivers/net/usb/net1080.c

@@ -560,7 +560,7 @@ static int net1080_bind(struct usbnet *dev, struct usb_interface *intf)
 
 static const struct driver_info	net1080_info = {
 	.description =	"NetChip TurboCONNECT",
-	.flags =	FLAG_FRAMING_NC,
+	.flags =	FLAG_PTP | FLAG_FRAMING_NC,
 	.bind =		net1080_bind,
 	.reset =	net1080_reset,
 	.check_connect = net1080_check_connect,

diff --git a/drivers/net/usb/plusb.c b/drivers/net/usb/plusb.c
index 08ad269..0ac7845 100644
--- a/drivers/net/usb/plusb.c
+++ b/drivers/net/usb/plusb.c

@@ -96,7 +96,7 @@ static int pl_reset(struct usbnet *dev)
 
 static const struct driver_info	prolific_info = {
 	.description =	"Prolific PL-2301/PL-2302",
-	.flags =	FLAG_NO_SETINT,
+	.flags =	FLAG_PTP | FLAG_NO_SETINT,
 		/* some PL-2302 versions seem to fail usb_set_interface() */
 	.reset =	pl_reset,
 };

diff --git a/drivers/net/usb/rndis_host.c b/drivers/net/usb/rndis_host.c
index dd8a4ad..bf2ab6e 100644
--- a/drivers/net/usb/rndis_host.c
+++ b/drivers/net/usb/rndis_host.c

@@ -573,7 +573,7 @@ EXPORT_SYMBOL_GPL(rndis_tx_fixup);
 
 static const struct driver_info	rndis_info = {
 	.description =	"RNDIS device",
-	.flags =	FLAG_ETHER | FLAG_FRAMING_RN | FLAG_NO_SETINT,
+	.flags =	FLAG_ETHER | FLAG_PTP | FLAG_FRAMING_RN | FLAG_NO_SETINT,
 	.bind =		rndis_bind,
 	.unbind =	rndis_unbind,
 	.status =	rndis_status,

diff --git a/drivers/net/usb/smsc75xx.c b/drivers/net/usb/smsc75xx.c
index 753ee6e..404a475 100644
--- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c

@@ -1244,7 +1244,7 @@ static const struct driver_info smsc75xx_info = {
 	.rx_fixup	= smsc75xx_rx_fixup,
 	.tx_fixup	= smsc75xx_tx_fixup,
 	.status		= smsc75xx_status,
-	.flags		= FLAG_ETHER | FLAG_SEND_ZLP,
+	.flags		= FLAG_ETHER | FLAG_SEND_ZLP | FLAG_REALLY_ETHER,
 };
 
 static const struct usb_device_id products[] = {

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index bc86f4b..c98d3a7 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c

@@ -1231,7 +1231,7 @@ static const struct driver_info smsc95xx_info = {
 	.rx_fixup	= smsc95xx_rx_fixup,
 	.tx_fixup	= smsc95xx_tx_fixup,
 	.status		= smsc95xx_status,
-	.flags		= FLAG_ETHER | FLAG_SEND_ZLP,
+	.flags		= FLAG_ETHER | FLAG_SEND_ZLP | FLAG_REALLY_ETHER,
 };
 
 static const struct usb_device_id products[] = {

diff --git a/drivers/net/usb/usbnet.c b/drivers/net/usb/usbnet.c
index 95c41d5..b339d3f 100644
--- a/drivers/net/usb/usbnet.c
+++ b/drivers/net/usb/usbnet.c

@@ -1376,7 +1376,8 @@ usbnet_probe (struct usb_interface *udev, const struct usb_device_id *prod)
 		// else "eth%d" when there's reasonable doubt.  userspace
 		// can rename the link if it knows better.
 		if ((dev->driver_info->flags & FLAG_ETHER) != 0 &&
-		    (net->dev_addr [0] & 0x02) == 0)
+		    ((dev->driver_info->flags & FLAG_PTP) == 0 ||
+		     (net->dev_addr [0] & 0x02) == 0))
 			strcpy (net->name, "eth%d");
 		/* WLAN devices should always be named "wlan%d" */
 		if ((dev->driver_info->flags & FLAG_WLAN) != 0)

diff --git a/drivers/net/usb/zaurus.c b/drivers/net/usb/zaurus.c
index 3eb0b16..e906700 100644
--- a/drivers/net/usb/zaurus.c
+++ b/drivers/net/usb/zaurus.c

@@ -102,7 +102,7 @@ static int always_connected (struct usbnet *dev)
 
 static const struct driver_info	zaurus_sl5x00_info = {
 	.description =	"Sharp Zaurus SL-5x00",
-	.flags =	FLAG_FRAMING_Z,
+	.flags =	FLAG_PTP | FLAG_FRAMING_Z,
 	.check_connect = always_connected,
 	.bind =		zaurus_bind,
 	.unbind =	usbnet_cdc_unbind,

@@ -112,7 +112,7 @@ static const struct driver_info	zaurus_sl5x00_info = {
 
 static const struct driver_info	zaurus_pxa_info = {
 	.description =	"Sharp Zaurus, PXA-2xx based",
-	.flags =	FLAG_FRAMING_Z,
+	.flags =	FLAG_PTP | FLAG_FRAMING_Z,
 	.check_connect = always_connected,
 	.bind =		zaurus_bind,
 	.unbind =	usbnet_cdc_unbind,

@@ -122,7 +122,7 @@ static const struct driver_info	zaurus_pxa_info = {
 
 static const struct driver_info	olympus_mxl_info = {
 	.description =	"Olympus R1000",
-	.flags =	FLAG_FRAMING_Z,
+	.flags =	FLAG_PTP | FLAG_FRAMING_Z,
 	.check_connect = always_connected,
 	.bind =		zaurus_bind,
 	.unbind =	usbnet_cdc_unbind,

@@ -258,7 +258,7 @@ bad_desc:
 
 static const struct driver_info	bogus_mdlm_info = {
 	.description =	"pseudo-MDLM (BLAN) device",
-	.flags =	FLAG_FRAMING_Z,
+	.flags =	FLAG_PTP | FLAG_FRAMING_Z,
 	.check_connect = always_connected,
 	.tx_fixup =	zaurus_tx_fixup,
 	.bind =		blan_mdlm_bind,

diff --git a/include/linux/usb/usbnet.h b/include/linux/usb/usbnet.h
index 44842c8..5ecd8e7 100644
--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h

@@ -97,6 +97,8 @@ struct driver_info {
 
 #define FLAG_LINK_INTR	0x0800		/* updates link (carrier) status */
 
+#define FLAG_PTP	0x1000		/* maybe use "usb%d" names */
+
 /*
  * Indicates to usbnet, that USB driver accumulates multiple IP packets.
  * Affects statistic (counters) and short packet handling.

On 03/23/2011 04:56 PM, Somebody in the thread at some point said:

The approach taken here is to flag whether a device might be a
point-to-point link with the new FLAG_PTP setting in the usbnet
driver_info. A driver can set both FLAG_PTP and FLAG_ETHER if
it is not sure (e.g. cdc_ether), or just one of the two.
The usbnet framework only looks at the MAC address for device
naming if both flags are set, otherwise it trusts the flag.

-	.flags		= FLAG_ETHER | FLAG_SEND_ZLP,
+	.flags		= FLAG_ETHER | FLAG_SEND_ZLP | FLAG_REALLY_ETHER,

  		if ((dev->driver_info->flags&  FLAG_ETHER) != 0&&
+		    ((dev->driver_info->flags&  FLAG_PTP) == 0 ||
+		     (net->dev_addr [0]&  0x02) == 0))
  			strcpy (net->name, "eth%d");

So it just takes the approach that all smsc95xx are going to be eth%d? 
Sounds good to me.

-Andy

On Wednesday 23 March 2011, Andy Green wrote:

quoted

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index bc86f4b..c98d3a7 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c

@@ -1231,7 +1231,7 @@ static const struct driver_info smsc95xx_info = {

quoted

-     .flags          = FLAG_ETHER | FLAG_SEND_ZLP,
+     .flags          = FLAG_ETHER | FLAG_SEND_ZLP | FLAG_REALLY_ETHER,

quoted

              if ((dev->driver_info->flags&  FLAG_ETHER) != 0&&
+                 ((dev->driver_info->flags&  FLAG_PTP) == 0 ||
+                  (net->dev_addr [0]&  0x02) == 0))
                      strcpy (net->name, "eth%d");

So it just takes the approach that all smsc95xx are going to be eth%d? 

Right, and all other drivers that are obviously ethernet-only, including
future drivers.

	Arnd

On Wednesday 23 March 2011, Arnd Bergmann wrote:

These two hunks are from an earlier version of the patch and should not
be there, they break compilation. I'll wait for more comments and
then send a fixed version.

	Arnd

On 03/23/2011 12:13 PM, Arnd Bergmann wrote:

On Wednesday 23 March 2011, Arnd Bergmann wrote:
   

quoted

--- a/drivers/net/usb/smsc75xx.c
+++ b/drivers/net/usb/smsc75xx.c

@@ -1244,7 +1244,7 @@ static const struct driver_info smsc75xx_info = {
         .rx_fixup       = smsc75xx_rx_fixup,
         .tx_fixup       = smsc75xx_tx_fixup,
         .status         = smsc75xx_status,
-       .flags          = FLAG_ETHER | FLAG_SEND_ZLP,
+       .flags          = FLAG_ETHER | FLAG_SEND_ZLP | FLAG_REALLY_ETHER,
  };

  static const struct usb_device_id products[] = {

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index bc86f4b..c98d3a7 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c

@@ -1231,7 +1231,7 @@ static const struct driver_info smsc95xx_info = {
         .rx_fixup       = smsc95xx_rx_fixup,
         .tx_fixup       = smsc95xx_tx_fixup,
         .status         = smsc95xx_status,
-       .flags          = FLAG_ETHER | FLAG_SEND_ZLP,
+       .flags          = FLAG_ETHER | FLAG_SEND_ZLP | FLAG_REALLY_ETHER,
  };

     

These two hunks are from an earlier version of the patch and should not
be there, they break compilation. I'll wait for more comments and
then send a fixed version.

	Arnd
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tested with 2.6.38 using omap2plus_defconfig with EHCI and smsc95xx 
turned on minus the FLAG_REALLY_ETHER. appears to work properly, assigns 
as eth0.

i ran some basic net tests with no issues.


Dave Anders

On Wed, Mar 23, 2011 at 05:56:39PM +0100, Arnd Bergmann wrote:

The documentation for the USB ethernet devices suggests that
only some devices are supposed to use usb0 as the network interface
name instead of eth0. The logic used there, and documented in
Kconfig for CDC is that eth0 will be used when the mac address
is a globally assigned one, but usb0 is used for the locally
managed range that is typically used on point-to-point links.

Unfortunately, this has caused a lot of pain on the smsc95xx
device that is used on the popular pandaboard without an
EEPROM to store the MAC address, which causes the driver to
call random_ether_address().

Obviously, there should be a proper MAC addressed assigned to
the device, and discussions are ongoing about how to solve
this, but this patch at least makes sure that the default
interface naming gets a little saner and matches what the
user can expect based on the documentation, including for
new devices.

The approach taken here is to flag whether a device might be a 
point-to-point link with the new FLAG_PTP setting in the usbnet
driver_info. A driver can set both FLAG_PTP and FLAG_ETHER if
it is not sure (e.g. cdc_ether), or just one of the two.
The usbnet framework only looks at the MAC address for device
naming if both flags are set, otherwise it trusts the flag.

Signed-off-by: Arnd Bergmann <redacted>
Cc: Andy Green <redacted>

Looks good to me, but some questions:

 drivers/usb/serial/usb_wwan.c |    2 +-

You don't modify this file in the diff, what caused this to show up in
the diffstat?

"PTP"?  What does that stand for?

curious,

greg k-h

On Wednesday 23 March 2011 19:46:50 Greg KH wrote:

Looks good to me, but some questions:

quoted

 drivers/usb/serial/usb_wwan.c |    2 +-

You don't modify this file in the diff, what caused this to show up in
the diffstat?

A stale change I had to do to get the kernel to build on my
machine. The original problem seems fixed now. I had removed
this hunk from the patch but forgot to remove it from the diffstat.

quoted

--- a/include/linux/usb/usbnet.h
+++ b/include/linux/usb/usbnet.h

@@ -97,6 +97,8 @@ struct driver_info {
 
 #define FLAG_LINK_INTR       0x0800          /* updates link (carrier) status */
 
+#define FLAG_PTP     0x1000          /* maybe use "usb%d" names */

"PTP"?  What does that stand for?

point-to-point, I'll improve the comment to spell it out when I send the
fixed version.

	Arnd

On 03/23/2011 05:11 PM, Somebody in the thread at some point said:

On Wednesday 23 March 2011, Andy Green wrote:

quoted

quoted

diff --git a/drivers/net/usb/smsc95xx.c b/drivers/net/usb/smsc95xx.c
index bc86f4b..c98d3a7 100644
--- a/drivers/net/usb/smsc95xx.c
+++ b/drivers/net/usb/smsc95xx.c

@@ -1231,7 +1231,7 @@ static const struct driver_info smsc95xx_info = {

quoted

-     .flags          = FLAG_ETHER | FLAG_SEND_ZLP,
+     .flags          = FLAG_ETHER | FLAG_SEND_ZLP | FLAG_REALLY_ETHER,

quoted

               if ((dev->driver_info->flags&   FLAG_ETHER) != 0&&
+                 ((dev->driver_info->flags&   FLAG_PTP) == 0 ||
+                  (net->dev_addr [0]&   0x02) == 0))
                       strcpy (net->name, "eth%d");

So it just takes the approach that all smsc95xx are going to be eth%d?

Right, and all other drivers that are obviously ethernet-only, including
future drivers.

I moved my tree over to using this patch now, it's working fine on Panda 
/ smsc95xx as one would expect.  Guys with pluggable smsc95xx are going 
to find their device comes as eth%d not usb%d but that seems perfectly 
defensible as how it always should have been.

So, nice job.

-Andy
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