[PATCH v4] r8152: Add support for setting pass through MAC address on RTL8153-AD

[PATCH v4] r8152: Add support for setting pass through MAC address on RTL8153-AD

[Mario Limonciello]

The RTL8153-AD supports a persistent system specific MAC address.
This means a device plugged into two different systems with host side
support will show different (but persistent) MAC addresses.

This information for the system's persistent MAC address is burned in when
the system HW is built and available under _SB\AMAC in the DSDT at runtime.

This technology is currently implemented in the Dell TB15 and WD15 Type-C
docks.  More information is available here:
http://www.dell.com/support/article/us/en/04/SLN301147

Signed-off-by: Mario Limonciello <mario_limonciello@dell.com>
---
Changes from v3:
 * Add additional comments about functions and what they're doing
 * Adjust warning calls to use netif instead
 * Rename function

 drivers/net/usb/r8152.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++--
 1 file changed, 68 insertions(+), 2 deletions(-)

diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
index 3f9f6ed..b2339d3 100644
--- a/drivers/net/usb/r8152.c
+++ b/drivers/net/usb/r8152.c
@@ -26,6 +26,7 @@
 #include <linux/mdio.h>
 #include <linux/usb/cdc.h>
 #include <linux/suspend.h>
+#include <linux/acpi.h>
 
 /* Information for net-next */
 #define NETNEXT_VERSION		"08"
@@ -455,6 +456,11 @@
 /* SRAM_IMPEDANCE */
 #define RX_DRIVING_MASK		0x6000
 
+/* MAC PASSTHRU */
+#define AD_MASK			0xfee0
+#define EFUSE			0xcfdb
+#define PASS_THRU_MASK		0x1
+
 enum rtl_register_content {
 	_1000bps	= 0x10,
 	_100bps		= 0x08,
@@ -1030,6 +1036,59 @@ out1:
 	return ret;
 }
 
+/* Devices containing RTL8153-AD can support a persistent
+ * host system provided MAC address.
+ * Examples of this are Dell TB15 and Dell WD15 docks
+ */
+static int get_vendor_mac_passthru_addr(struct r8152 *tp, struct sockaddr *sa)
+{
+	acpi_status status;
+	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
+	union acpi_object *obj;
+	int ret = -EINVAL;
+	u32 ocp_data;
+	unsigned char buf[6];
+
+	/* test for -AD variant of RTL8153 */
+	ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_MISC_0);
+	if ((ocp_data & AD_MASK) != 0x1000)
+		return -ENODEV;
+
+	/* test for MAC address pass-through bit */
+	ocp_data = ocp_read_byte(tp, MCU_TYPE_USB, EFUSE);
+	if ((ocp_data & PASS_THRU_MASK) != 1)
+		return -ENODEV;
+
+	/* returns _AUXMAC_#AABBCCDDEEFF# */
+	status = acpi_evaluate_object(NULL, "\\_SB.AMAC", NULL, &buffer);
+	obj = (union acpi_object *)buffer.pointer;
+	if (ACPI_SUCCESS(status)) {
+		if (obj->type != ACPI_TYPE_BUFFER ||
+		    obj->string.length != 0x17) {
+			netif_warn(tp, probe, tp->netdev, "Invalid buffer\n");
+			goto amacout;
+		}
+		if (strncmp(obj->string.pointer, "_AUXMAC_#", 9) != 0) {
+			netif_warn(tp, probe, tp->netdev, "Invalid header\n");
+			goto amacout;
+		}
+		ret = hex2bin(buf, obj->string.pointer + 9, 6);
+		if (ret < 0 || !is_valid_ether_addr(buf)) {
+			netif_warn(tp, probe, tp->netdev, "Invalid MAC\n");
+			goto amacout;
+		}
+		memcpy(sa->sa_data, buf, 6);
+		ether_addr_copy(tp->netdev->dev_addr, sa->sa_data);
+		netif_info(tp, probe, tp->netdev,
+			   "Using pass-through MAC addr %pM\n", sa->sa_data);
+		ret = 0;
+	}
+
+amacout:
+	kfree(obj);
+	return ret;
+}
+
 static int set_ethernet_addr(struct r8152 *tp)
 {
 	struct net_device *dev = tp->netdev;
@@ -1038,8 +1097,15 @@ static int set_ethernet_addr(struct r8152 *tp)
 
 	if (tp->version == RTL_VER_01)
 		ret = pla_ocp_read(tp, PLA_IDR, 8, sa.sa_data);
-	else
-		ret = pla_ocp_read(tp, PLA_BACKUP, 8, sa.sa_data);
+	else {
+		/* if this is not an RTL8153-AD, no eFuse mac pass thru set,
+		 * or system doesn't provide valid _SB.AMAC this will be
+		 * be expected to non-zero
+		 */
+		ret = get_vendor_mac_passthru_addr(tp, &sa);
+		if (ret < 0)
+			ret = pla_ocp_read(tp, PLA_BACKUP, 8, sa.sa_data);
+	}
 
 	if (ret < 0) {
 		netif_err(tp, probe, dev, "Get ether addr fail\n");
-- 
2.7.4

RE: [EXT] [PATCH v4] r8152: Add support for setting pass through MAC address on RTL8153-AD

[Konstantin Shkolnyy]

> -----Original Message-----
> From: linux-usb-owner@vger.kernel.org [mailto:linux-usb-
> owner@vger.kernel.org] On Behalf Of Mario Limonciello
> Sent: Monday, June 06, 2016 12:19
> To: hayeswang@realtek.com
> Cc: LKML; Netdev; Linux USB; pali.rohar@gmail.com;
> anthony.wong@canonical.com; Greg KH; Mario Limonciello
> Subject: [EXT] [PATCH v4] r8152: Add support for setting pass through MAC
> address on RTL8153-AD
> 
> The RTL8153-AD supports a persistent system specific MAC address.
> This means a device plugged into two different systems with host side
> support will show different (but persistent) MAC addresses.
> 
> This information for the system's persistent MAC address is burned in when
> the system HW is built and available under _SB\AMAC in the DSDT at
> runtime.
> 
> This technology is currently implemented in the Dell TB15 and WD15 Type-C
> docks.  More information is available here:
> http://www.dell.com/support/article/us/en/04/SLN301147

What is going to happen if I connect multiple dongles? Will they all get the same address?

RE: [EXT] [PATCH v4] r8152: Add support for setting pass through MAC address on RTL8153-AD

[Mario_Limonciello]

> -----Original Message-----
> From: Konstantin Shkolnyy [mailto:Konstantin.Shkolnyy@silabs.com]
> Sent: Monday, June 6, 2016 12:43 PM
> To: Limonciello, Mario <Mario_Limonciello@Dell.com>;
> hayeswang@realtek.com
> Cc: LKML <linux-kernel@vger.kernel.org>; Netdev
> <netdev@vger.kernel.org>; Linux USB <linux-usb@vger.kernel.org>;
> pali.rohar@gmail.com; anthony.wong@canonical.com; Greg KH
> <gregkh@linuxfoundation.org>
> Subject: RE: [EXT] [PATCH v4] r8152: Add support for setting pass through
> MAC address on RTL8153-AD
> 
> > -----Original Message-----
> > From: linux-usb-owner@vger.kernel.org [mailto:linux-usb-
> > owner@vger.kernel.org] On Behalf Of Mario Limonciello
> > Sent: Monday, June 06, 2016 12:19
> > To: hayeswang@realtek.com
> > Cc: LKML; Netdev; Linux USB; pali.rohar@gmail.com;
> > anthony.wong@canonical.com; Greg KH; Mario Limonciello
> > Subject: [EXT] [PATCH v4] r8152: Add support for setting pass through MAC
> > address on RTL8153-AD
> >
> > The RTL8153-AD supports a persistent system specific MAC address.
> > This means a device plugged into two different systems with host side
> > support will show different (but persistent) MAC addresses.
> >
> > This information for the system's persistent MAC address is burned in
> when
> > the system HW is built and available under _SB\AMAC in the DSDT at
> > runtime.
> >
> > This technology is currently implemented in the Dell TB15 and WD15 Type-C
> > docks.  More information is available here:
> > http://www.dell.com/support/article/us/en/04/SLN301147
> 
> What is going to happen if I connect multiple dongles? Will they all get the
> same address?

If you connect a dongle without a RTL8153-AD or without that bit they'll
get the MAC that was burned into the dongle.

If you connect multiple docks that have this Realtek chip with this bit set,
yes they'll all get the same address.
I confirmed that's what happens on Windows too.

Re: [PATCH v4] r8152: Add support for setting pass through MAC address on RTL8153-AD

[Pali Rohár]

Hi! Below are my comments, all about coding style.

On Monday 06 June 2016 12:19:29 Mario Limonciello wrote:
> The RTL8153-AD supports a persistent system specific MAC address.
> This means a device plugged into two different systems with host side
> support will show different (but persistent) MAC addresses.
> 
> This information for the system's persistent MAC address is burned in when
> the system HW is built and available under _SB\AMAC in the DSDT at runtime.

For consistency it would be great to use same ACPI name in whole patch: \_SB.AMAC

> This technology is currently implemented in the Dell TB15 and WD15 Type-C
> docks.  More information is available here:
> http://www.dell.com/support/article/us/en/04/SLN301147
> 
> Signed-off-by: Mario Limonciello <mario_limonciello@dell.com>
> ---
> Changes from v3:
>  * Add additional comments about functions and what they're doing
>  * Adjust warning calls to use netif instead
>  * Rename function
> 
>  drivers/net/usb/r8152.c | 70 +++++++++++++++++++++++++++++++++++++++++++++++--
>  1 file changed, 68 insertions(+), 2 deletions(-)
> 
> diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c
> index 3f9f6ed..b2339d3 100644
> --- a/drivers/net/usb/r8152.c
> +++ b/drivers/net/usb/r8152.c
> @@ -26,6 +26,7 @@
>  #include <linux/mdio.h>
>  #include <linux/usb/cdc.h>
>  #include <linux/suspend.h>
> +#include <linux/acpi.h>
>  
>  /* Information for net-next */
>  #define NETNEXT_VERSION		"08"
> @@ -455,6 +456,11 @@
>  /* SRAM_IMPEDANCE */
>  #define RX_DRIVING_MASK		0x6000
>  
> +/* MAC PASSTHRU */
> +#define AD_MASK			0xfee0
> +#define EFUSE			0xcfdb
> +#define PASS_THRU_MASK		0x1
> +
>  enum rtl_register_content {
>  	_1000bps	= 0x10,
>  	_100bps		= 0x08,
> @@ -1030,6 +1036,59 @@ out1:
>  	return ret;
>  }
>  
> +/* Devices containing RTL8153-AD can support a persistent
> + * host system provided MAC address.
> + * Examples of this are Dell TB15 and Dell WD15 docks
> + */
> +static int get_vendor_mac_passthru_addr(struct r8152 *tp, struct sockaddr *sa)
> +{
> +	acpi_status status;
> +	struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL };
> +	union acpi_object *obj;
> +	int ret = -EINVAL;
> +	u32 ocp_data;
> +	unsigned char buf[6];
> +
> +	/* test for -AD variant of RTL8153 */
> +	ocp_data = ocp_read_word(tp, MCU_TYPE_USB, USB_MISC_0);
> +	if ((ocp_data & AD_MASK) != 0x1000)
> +		return -ENODEV;
> +
> +	/* test for MAC address pass-through bit */
> +	ocp_data = ocp_read_byte(tp, MCU_TYPE_USB, EFUSE);
> +	if ((ocp_data & PASS_THRU_MASK) != 1)
> +		return -ENODEV;
> +
> +	/* returns _AUXMAC_#AABBCCDDEEFF# */
> +	status = acpi_evaluate_object(NULL, "\\_SB.AMAC", NULL, &buffer);

What about?

	if (!ACPI_SUCCESS(status))
		return -ENODEV;

You will save one level of indentation.

> +	obj = (union acpi_object *)buffer.pointer;
> +	if (ACPI_SUCCESS(status)) {
> +		if (obj->type != ACPI_TYPE_BUFFER ||
> +		    obj->string.length != 0x17) {
> +			netif_warn(tp, probe, tp->netdev, "Invalid buffer\n");

I would suggest more specific warning messages. These are very general
and if I would see them in dmesg log I would have no idea what that
means.

> +			goto amacout;
> +		}
> +		if (strncmp(obj->string.pointer, "_AUXMAC_#", 9) != 0) {
> +			netif_warn(tp, probe, tp->netdev, "Invalid header\n");
> +			goto amacout;
> +		}

If your specification state that last character is '#' then I think you
should check it too.

> +		ret = hex2bin(buf, obj->string.pointer + 9, 6);
> +		if (ret < 0 || !is_valid_ether_addr(buf)) {
> +			netif_warn(tp, probe, tp->netdev, "Invalid MAC\n");
> +			goto amacout;
> +		}
> +		memcpy(sa->sa_data, buf, 6);
> +		ether_addr_copy(tp->netdev->dev_addr, sa->sa_data);
> +		netif_info(tp, probe, tp->netdev,
> +			   "Using pass-through MAC addr %pM\n", sa->sa_data);
> +		ret = 0;
> +	}
> +
> +amacout:
> +	kfree(obj);
> +	return ret;
> +}
> +
>  static int set_ethernet_addr(struct r8152 *tp)
>  {
>  	struct net_device *dev = tp->netdev;
> @@ -1038,8 +1097,15 @@ static int set_ethernet_addr(struct r8152 *tp)
>  
>  	if (tp->version == RTL_VER_01)
>  		ret = pla_ocp_read(tp, PLA_IDR, 8, sa.sa_data);
> -	else
> -		ret = pla_ocp_read(tp, PLA_BACKUP, 8, sa.sa_data);
> +	else {
> +		/* if this is not an RTL8153-AD, no eFuse mac pass thru set,
> +		 * or system doesn't provide valid _SB.AMAC this will be
> +		 * be expected to non-zero
> +		 */
> +		ret = get_vendor_mac_passthru_addr(tp, &sa);

You do not "get" (return) any mac address. Personally I would use "read"
word in function name (like above pla_ocp_read). What about?

ret = vendor_mac_passthru_addr_read(tp, sa.sa_data);

Or something similar... "Get" looks like function "get" something, but
instead it set address in &sa structure.

> +		if (ret < 0)
> +			ret = pla_ocp_read(tp, PLA_BACKUP, 8, sa.sa_data);
> +	}
>  
>  	if (ret < 0) {
>  		netif_err(tp, probe, dev, "Get ether addr fail\n");

-- 
Pali Rohár
pali.rohar@gmail.com

RE: [PATCH v4] r8152: Add support for setting pass through MAC address on RTL8153-AD

[Hayes Wang]

Mario Limonciello [mailto:mario_limonciello@dell.com]
[...]
> +		ret = hex2bin(buf, obj->string.pointer + 9, 6);
> +		if (ret < 0 || !is_valid_ether_addr(buf)) {
> +			netif_warn(tp, probe, tp->netdev, "Invalid MAC\n");
> +			goto amacout;
> +		}

If hex2bin() is success, the ret would be 0.
And you would return 0 when !is_valid_ether_addr(buf) occurs.
I don't think it is what you wants.

Best Regards,
Hayes