[RFC 4/4] net: cdc_ncm: Add ACPI MAC address pass through functionality

[RFC 4/4] net: cdc_ncm: Add ACPI MAC address pass through functionality

[Charles.Hyde]

This change adds support to cdc_ncm for ACPI MAC address pass through
functionality that also exists in the Realtek r8152 driver.  This is in
support of Dell's Universal Dock D6000, to give it the same feature
capability as is currently available in Windows and advertized on Dell's
product web site.

Signed-off-by: Charles Hyde <charles.hyde@dellteam.com>
Cc: Mario Limonciello <mario.limonciello@dell.com>
Cc: Oliver Neukum <oliver@neukum.org>
Cc: linux-usb@vger.kernel.org
---
 drivers/net/usb/cdc_ncm.c | 8 ++++++++
 1 file changed, 8 insertions(+)

diff --git a/drivers/net/usb/cdc_ncm.c b/drivers/net/usb/cdc_ncm.c
index f77c8672f972..1f046acca6fc 100644
--- a/drivers/net/usb/cdc_ncm.c
+++ b/drivers/net/usb/cdc_ncm.c
@@ -52,6 +52,7 @@
 #include <linux/usb/usbnet.h>
 #include <linux/usb/cdc.h>
 #include <linux/usb/cdc_ncm.h>
+#include <acpi/acpi_mac_passthru.h>
 
 #if IS_ENABLED(CONFIG_USB_NET_CDC_MBIM)
 static bool prefer_mbim = true;
@@ -930,11 +931,18 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
 	usb_set_intfdata(ctx->control, dev);
 
 	if (ctx->ether_desc) {
+		struct sockaddr sa;
+
 		temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
 		if (temp) {
 			dev_dbg(&intf->dev, "failed to get mac address\n");
 			goto error2;
 		}
+		if (get_acpi_mac_passthru(&intf->dev, &sa) == 0) {
+			memcpy(dev->net->dev_addr, sa.sa_data, ETH_ALEN);
+			if (usbnet_set_ethernet_addr(dev) < 0)
+				usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
+		}
 		dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
 	}
 
-- 
2.20.1

Re: [RFC 4/4] net: cdc_ncm: Add ACPI MAC address pass through functionality

[Bjørn Mork]

<Charles.Hyde@dellteam.com> writes:

> @@ -930,11 +931,18 @@ int cdc_ncm_bind_common(struct usbnet *dev, struct usb_interface *intf, u8 data_
>  	usb_set_intfdata(ctx->control, dev);
>  
>  	if (ctx->ether_desc) {
> +		struct sockaddr sa;
> +
>  		temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
>  		if (temp) {
>  			dev_dbg(&intf->dev, "failed to get mac address\n");
>  			goto error2;
>  		}
> +		if (get_acpi_mac_passthru(&intf->dev, &sa) == 0) {
> +			memcpy(dev->net->dev_addr, sa.sa_data, ETH_ALEN);
> +			if (usbnet_set_ethernet_addr(dev) < 0)
> +				usbnet_get_ethernet_addr(dev, ctx->ether_desc->iMACAddress);
> +		}
>  		dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net->dev_addr);
>  	}

So you want to run a Dell specific ACPI method every time anyone plugs
some NCM class device into a host supporing ACPI?  That's going to annoy
the hell out of 99.9997% of the x86, ia64 and arm64 users of this
driver.

Call ACPI once when the driver loads, and only if running on an actual
Dell system where this method is supported.  There must be some ACPI
device ID you can match on to know if this method is supported or not?


Bjørn

RE: [RFC 4/4] net: cdc_ncm: Add ACPI MAC address pass through functionality

[Mario.Limonciello]

> -----Original Message-----
> From: Bjørn Mork <bjorn@mork.no>
> Sent: Saturday, August 24, 2019 5:44 AM
> To: Hyde, Charles - Dell Team
> Cc: linux-usb@vger.kernel.org; linux-acpi@vger.kernel.org;
> gregkh@linuxfoundation.org; Limonciello, Mario; oliver@neukum.org;
> netdev@vger.kernel.org; nic_swsd@realtek.com
> Subject: Re: [RFC 4/4] net: cdc_ncm: Add ACPI MAC address pass through
> functionality
> 
> 
> [EXTERNAL EMAIL]
> 
> <Charles.Hyde@dellteam.com> writes:
> 
> > @@ -930,11 +931,18 @@ int cdc_ncm_bind_common(struct usbnet *dev,
> struct usb_interface *intf, u8 data_
> >  	usb_set_intfdata(ctx->control, dev);
> >
> >  	if (ctx->ether_desc) {
> > +		struct sockaddr sa;
> > +
> >  		temp = usbnet_get_ethernet_addr(dev, ctx->ether_desc-
> >iMACAddress);
> >  		if (temp) {
> >  			dev_dbg(&intf->dev, "failed to get mac address\n");
> >  			goto error2;
> >  		}
> > +		if (get_acpi_mac_passthru(&intf->dev, &sa) == 0) {
> > +			memcpy(dev->net->dev_addr, sa.sa_data, ETH_ALEN);
> > +			if (usbnet_set_ethernet_addr(dev) < 0)
> > +				usbnet_get_ethernet_addr(dev, ctx-
> >ether_desc->iMACAddress);
> > +		}
> >  		dev_info(&intf->dev, "MAC-Address: %pM\n", dev->net-
> >dev_addr);
> >  	}
> 
> So you want to run a Dell specific ACPI method every time anyone plugs some
> NCM class device into a host supporing ACPI?  That's going to annoy the hell out
> of 99.9997% of the x86, ia64 and arm64 users of this driver.
> 
> Call ACPI once when the driver loads, and only if running on an actual Dell
> system where this method is supported.  There must be some ACPI device ID you
> can match on to know if this method is supported or not?
> 
> 
> Bjørn

I have to agree - this is missing an identifying factor of the D6000.  It shouldn't be
running on "just any" cdc_ncm device.

The code that is in get_acpi_mac_passthrough checks for a properly built ACPI method
though.