Newer Thinkpads have a feature called MAC Address Pass-through. This patch provides a sysfs interface that userspace can use to get this auxiliary mac address. Signed-off-by: Fernando Eckhardt Valle <fevalle@xxxxxx> --- Changes in v5: - Repeated code deleted. - Adjusted offset of a strscpy(). Changes in v4: - strscpy() in all string copies. Changes in v3: - Added null terminator to auxmac string when copying auxiliary mac address value. Changes in v2: - Added documentation. - All handling of the auxmac value is done in the _init function. --- .../admin-guide/laptops/thinkpad-acpi.rst | 20 +++++ drivers/platform/x86/thinkpad_acpi.c | 81 +++++++++++++++++++ 2 files changed, 101 insertions(+) diff --git a/Documentation/admin-guide/laptops/thinkpad-acpi.rst b/Documentation/admin-guide/laptops/thinkpad-acpi.rst index e27a1c3f6..98d304010 100644 --- a/Documentation/admin-guide/laptops/thinkpad-acpi.rst +++ b/Documentation/admin-guide/laptops/thinkpad-acpi.rst @@ -53,6 +53,7 @@ detailed description): - Lap mode sensor - Setting keyboard language - WWAN Antenna type + - Auxmac A compatibility table by model and feature is maintained on the web site, http://ibm-acpi.sf.net/. I appreciate any success or failure @@ -1511,6 +1512,25 @@ Currently 2 antenna types are supported as mentioned below: The property is read-only. If the platform doesn't have support the sysfs class is not created. +Auxmac +------ + +sysfs: auxmac + +Some newer Thinkpads have a feature called MAC Address Pass-through. This +feature is implemented by the system firmware to provide a system unique MAC, +that can override a dock or USB ethernet dongle MAC, when connected to a +network. This property enables user-space to easily determine the MAC address +if the feature is enabled. + +The values of this auxiliary MAC are: + + cat /sys/devices/platform/thinkpad_acpi/auxmac + +If the feature is disabled, the value will be 'disabled'. + +This property is read-only. + Adaptive keyboard ----------------- diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c index d70c89d32..2324ebb46 100644 --- a/drivers/platform/x86/thinkpad_acpi.c +++ b/drivers/platform/x86/thinkpad_acpi.c @@ -10785,6 +10785,82 @@ static struct ibm_struct dprc_driver_data = { .name = "dprc", }; +/* + * Auxmac + * + * This auxiliary mac address is enabled in the bios through the + * MAC Address Pass-through feature. In most cases, there are three + * possibilities: Internal Mac, Second Mac, and disabled. + * + */ + +#define AUXMAC_LEN 12 +#define AUXMAC_START 9 +#define AUXMAC_STRLEN 22 +#define AUXMAC_BEGIN_MARKER 8 +#define AUXMAC_END_MARKER 21 + +static char auxmac[AUXMAC_LEN + 1]; + +static int auxmac_init(struct ibm_init_struct *iibm) +{ + acpi_status status; + struct acpi_buffer buffer = { ACPI_ALLOCATE_BUFFER, NULL }; + union acpi_object *obj; + + status = acpi_evaluate_object(NULL, "\\MACA", NULL, &buffer); + + if (ACPI_FAILURE(status)) + return -ENODEV; + + obj = buffer.pointer; + + if (obj->type != ACPI_TYPE_STRING || obj->string.length != AUXMAC_STRLEN) { + pr_info("Invalid buffer for MAC address pass-through.\n"); + goto auxmacinvalid; + } + + if (obj->string.pointer[AUXMAC_BEGIN_MARKER] != '#' || + obj->string.pointer[AUXMAC_END_MARKER] != '#') { + pr_info("Invalid header for MAC address pass-through.\n"); + goto auxmacinvalid; + } + + if (strncmp(obj->string.pointer + AUXMAC_START, "XXXXXXXXXXXX", AUXMAC_LEN) != 0) + strscpy(auxmac, obj->string.pointer + AUXMAC_START, AUXMAC_LEN + 1); + else + strscpy(auxmac, "disabled", AUXMAC_LEN); + +free: + kfree(obj); + return 0; + +auxmacinvalid: + strscpy(auxmac, "unavailable", AUXMAC_LEN); + goto free; +} + +static struct ibm_struct auxmac_data = { + .name = "auxmac", +}; + +static ssize_t auxmac_show(struct device *dev, + struct device_attribute *attr, + char *buf) +{ + return sysfs_emit(buf, "%s\n", auxmac); +} +static DEVICE_ATTR_RO(auxmac); + +static struct attribute *auxmac_attributes[] = { + &dev_attr_auxmac.attr, + NULL +}; + +static const struct attribute_group auxmac_attr_group = { + .attrs = auxmac_attributes, +}; + /* --------------------------------------------------------------------- */ static struct attribute *tpacpi_driver_attributes[] = { @@ -10843,6 +10919,7 @@ static const struct attribute_group *tpacpi_groups[] = { &proxsensor_attr_group, &kbdlang_attr_group, &dprc_attr_group, + &auxmac_attr_group, NULL, }; @@ -11414,6 +11491,10 @@ static struct ibm_init_struct ibms_init[] __initdata = { .init = tpacpi_dprc_init, .data = &dprc_driver_data, }, + { + .init = auxmac_init, + .data = &auxmac_data, + }, }; static int __init set_ibm_param(const char *val, const struct kernel_param *kp) -- 2.25.1
