Newer Thinkpads have a feature called Mac Address Passthrough.
This patch provides a sysfs interface that userspace can use
to get this auxiliary mac address.
Signed-off-by: Fernando Eckhardt Valle <fevalle@xxxxxx>
---
drivers/platform/x86/thinkpad_acpi.c | 77 ++++++++++++++++++++++++++++
1 file changed, 77 insertions(+)
diff --git a/drivers/platform/x86/thinkpad_acpi.c b/drivers/platform/x86/thinkpad_acpi.c
index d70c89d32..0b1c36b0d 100644
--- a/drivers/platform/x86/thinkpad_acpi.c
+++ b/drivers/platform/x86/thinkpad_acpi.c
@@ -10785,6 +10785,78 @@ static struct ibm_struct dprc_driver_data = {
.name = "dprc",
};
+/*
+ * Auxmac
+ *
+ * This auxiliary mac address is enabled in the bios through the
+ * Mac Address Passthrough 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
+static char auxmac[AUXMAC_LEN];
+
+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 = (union acpi_object *)buffer.pointer;
+
+ if (obj->type != ACPI_TYPE_STRING || obj->string.length != AUXMAC_STRLEN) {
+ pr_info("Invalid buffer for mac addr passthrough.\n");
+ goto auxmacinvalid;
+ }
+
+ if (strncmp(obj->string.pointer + 0x8, "#", 1) != 0 ||
+ strncmp(obj->string.pointer + 0x15, "#", 1) != 0) {
+ pr_info("Invalid header for mac addr passthrough.\n");
+ goto auxmacinvalid;
+ }
+
+ memcpy(auxmac, obj->string.pointer + AUXMAC_START, AUXMAC_LEN);
+ kfree(obj);
+ return 0;
+
+auxmacinvalid:
+ kfree(obj);
+ memcpy(auxmac, "unavailable", 11);
+ return 0;
+}
+
+static struct ibm_struct auxmac_data = {
+ .name = "auxmac",
+};
+
+static ssize_t auxmac_show(struct device *dev,
+ struct device_attribute *attr,
+ char *buf)
+{
+ if (strncmp(auxmac, "XXXXXXXXXXXX", AUXMAC_LEN) == 0)
+ memcpy(auxmac, "disabled", 9);
+
+ 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 +10915,7 @@ static const struct attribute_group *tpacpi_groups[] = {
&proxsensor_attr_group,
&kbdlang_attr_group,
&dprc_attr_group,
+ &auxmac_attr_group,
NULL,
};
@@ -11414,6 +11487,10 @@ 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
