Dell systems with Type-C ports have support for a persistent system specific MAC address when used with Dell Type-C docks and dongles. This means a dock plugged into two different systems will show different (but persistent) MAC addresses. Dell Type-C docks and dongles use the r8152 driver.
This information for the system's persistent MAC address is burned in when the HW is built and available under _SB\AMAC in the DSDT at runtime. More information about the technology is available here: http://www.dell.com/support/article/us/en/04/SLN301147 Signed-off-by: Mario Limonciello <mario_limoncie...@dell.com> --- drivers/net/usb/r8152.c | 53 +++++++++++++++++++++++++++++++++++++++++++++++++ 1 file changed, 53 insertions(+) diff --git a/drivers/net/usb/r8152.c b/drivers/net/usb/r8152.c index 3f9f6ed..6dea542 100644 --- a/drivers/net/usb/r8152.c +++ b/drivers/net/usb/r8152.c @@ -26,6 +26,8 @@ #include <linux/mdio.h> #include <linux/usb/cdc.h> #include <linux/suspend.h> +#include <linux/acpi.h> +#include <linux/dmi.h> /* Information for net-next */ #define NETNEXT_VERSION "08" @@ -500,6 +502,7 @@ enum rtl8152_flags { SELECTIVE_SUSPEND, PHY_RESET, SCHEDULE_NAPI, + MAC_PASSTHRU = 0, }; /* Define these values to match your device */ @@ -653,6 +656,7 @@ enum tx_csum_stat { */ static const int multicast_filter_limit = 32; static unsigned int agg_buf_sz = 16384; +static bool mac_passthru_active; #define RTL_LIMITED_TSO_SIZE (agg_buf_sz - sizeof(struct tx_desc) - \ VLAN_ETH_HLEN - VLAN_HLEN) @@ -1030,6 +1034,49 @@ out1: return ret; } +static int get_auxiliary_addr(struct r8152 *tp, struct sockaddr *sa) +{ + acpi_status status; + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + union acpi_object *obj; + int ret = -1; + unsigned char buf[6]; + + if (!dmi_name_in_vendors("Dell Inc.") || mac_passthru_active) + return -1; + + /* 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) { + pr_warn("r8152: get_auxiliary_addr: Invalid buffer"); + goto amacout; + } + if (strncmp(obj->string.pointer, "_AUXMAC_#", 9) != 0) { + pr_warn("r8152: get_auxiliary_addr: Invalid header"); + goto amacout; + } + ret = hex2bin(buf, obj->string.pointer + 9, 6); + if (ret < 0) { + pr_warn("r8152: get_auxiliary_addr: Invalid MAC"); + goto amacout; + } + memcpy(sa->sa_data, buf, 6); + ether_addr_copy(tp->netdev->dev_addr, sa->sa_data); + netdev_info(tp->netdev, "Using system MAC address %pM\n", + sa->sa_data); + set_bit(MAC_PASSTHRU, &tp->flags); + mac_passthru_active = true; + ret = 1; + } + +amacout: + kfree(obj); + return ret; +} + static int set_ethernet_addr(struct r8152 *tp) { struct net_device *dev = tp->netdev; @@ -1041,6 +1088,10 @@ static int set_ethernet_addr(struct r8152 *tp) else ret = pla_ocp_read(tp, PLA_BACKUP, 8, sa.sa_data); + /* if system provides auxiliary MAC address */ + if (get_auxiliary_addr(tp, &sa)) + ret = 0; + if (ret < 0) { netif_err(tp, probe, dev, "Get ether addr fail\n"); } else if (!is_valid_ether_addr(sa.sa_data)) { @@ -4268,6 +4319,8 @@ static void rtl8152_disconnect(struct usb_interface *intf) if (udev->state == USB_STATE_NOTATTACHED) set_bit(RTL8152_UNPLUG, &tp->flags); + if (test_bit(MAC_PASSTHRU, &tp->flags)) + mac_passthru_active = false; netif_napi_del(&tp->napi); unregister_netdev(tp->netdev); tp->rtl_ops.unload(tp); -- 2.7.4
