ibft: Expose iBFT acpi header via sysfs

Some ethernet adapter vendors are supplying products which support optional
(payed license) features. On some adapters this includes a hardware iscsi
initiator.  The same adapters in a normal (no extra licenses) mode of
operation can be used as a software iscsi initiator.  In addition, software
iscsi boot initiators are becoming a standard part of many vendors uefi
implementations.  This is creating difficulties during early boot/install
determining the proper configuration method for these adapters when they
are used as a boot device.

The attached patch creates sysfs entries to expose information from the
acpi header of the ibft table.  This information allows for a method to
easily determining if an ibft table was created by a ethernet card's
firmware or the system uefi/bios.  In the case of a hardware initiator this
information in combination with the pci vendor and device id can be used
to ascertain any vendor specific behaviors that need to be accommodated.

Reviewed-by: Lee Duncan <lduncan@suse.com>
Signed-off-by: David Bond <dbond@suse.com>
Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>

1 files changed, 62 insertions, 0 deletions

diff --git a/drivers/scsi/iscsi_boot_sysfs.c b/drivers/scsi/iscsi_boot_sysfs.c
index 8f0ea97cf31f..d453667612f8 100644
--- a/drivers/scsi/iscsi_boot_sysfs.c
+++ b/drivers/scsi/iscsi_boot_sysfs.c
@@ -306,6 +306,42 @@ static struct attribute_group iscsi_boot_initiator_attr_group = {
 	.is_visible = iscsi_boot_ini_attr_is_visible,
 };
 
+/* iBFT ACPI Table attributes */
+iscsi_boot_rd_attr(acpitbl_signature, signature, ISCSI_BOOT_ACPITBL_SIGNATURE);
+iscsi_boot_rd_attr(acpitbl_oem_id, oem_id, ISCSI_BOOT_ACPITBL_OEM_ID);
+iscsi_boot_rd_attr(acpitbl_oem_table_id, oem_table_id,
+		   ISCSI_BOOT_ACPITBL_OEM_TABLE_ID);
+
+static struct attribute *acpitbl_attrs[] = {
+	&iscsi_boot_attr_acpitbl_signature.attr,
+	&iscsi_boot_attr_acpitbl_oem_id.attr,
+	&iscsi_boot_attr_acpitbl_oem_table_id.attr,
+	NULL
+};
+
+static umode_t iscsi_boot_acpitbl_attr_is_visible(struct kobject *kobj,
+					     struct attribute *attr, int i)
+{
+	struct iscsi_boot_kobj *boot_kobj =
+			container_of(kobj, struct iscsi_boot_kobj, kobj);
+
+	if (attr ==  &iscsi_boot_attr_acpitbl_signature.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ACPITBL_SIGNATURE);
+	if (attr ==  &iscsi_boot_attr_acpitbl_oem_id.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ACPITBL_OEM_ID);
+	if (attr ==  &iscsi_boot_attr_acpitbl_oem_table_id.attr)
+		return boot_kobj->is_visible(boot_kobj->data,
+					     ISCSI_BOOT_ACPITBL_OEM_TABLE_ID);
+	return 0;
+}
+
+static struct attribute_group iscsi_boot_acpitbl_attr_group = {
+	.attrs = acpitbl_attrs,
+	.is_visible = iscsi_boot_acpitbl_attr_is_visible,
+};
+
 static struct iscsi_boot_kobj *
 iscsi_boot_create_kobj(struct iscsi_boot_kset *boot_kset,
 		       struct attribute_group *attr_group,
@@ -436,6 +472,32 @@ iscsi_boot_create_ethernet(struct iscsi_boot_kset *boot_kset, int index,
 EXPORT_SYMBOL_GPL(iscsi_boot_create_ethernet);
 
 /**
+ * iscsi_boot_create_acpitbl() - create boot acpi table sysfs dir
+ * @boot_kset: boot kset
+ * @index: not used
+ * @data: driver specific data
+ * @show: attr show function
+ * @is_visible: attr visibility function
+ * @release: release function
+ *
+ * Note: The boot sysfs lib will free the data passed in for the caller
+ * when all refs to the acpitbl kobject have been released.
+ */
+struct iscsi_boot_kobj *
+iscsi_boot_create_acpitbl(struct iscsi_boot_kset *boot_kset, int index,
+			   void *data,
+			   ssize_t (*show)(void *data, int type, char *buf),
+			   umode_t (*is_visible)(void *data, int type),
+			   void (*release)(void *data))
+{
+	return iscsi_boot_create_kobj(boot_kset,
+				      &iscsi_boot_acpitbl_attr_group,
+				      "acpi_header", index, data, show,
+				      is_visible, release);
+}
+EXPORT_SYMBOL_GPL(iscsi_boot_create_acpitbl);
+
+/**
  * iscsi_boot_create_kset() - creates root sysfs tree
  * @set_name: name of root dir
  */