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, 65 insertions, 1 deletions

diff --git a/drivers/firmware/iscsi_ibft.c b/drivers/firmware/iscsi_ibft.c
index 81037e5fe301..14042a64bdd5 100644
--- a/drivers/firmware/iscsi_ibft.c
+++ b/drivers/firmware/iscsi_ibft.c
@@ -418,6 +418,31 @@ static ssize_t ibft_attr_show_target(void *data, int type, char *buf)
 	return str - buf;
 }
 
+static ssize_t ibft_attr_show_acpitbl(void *data, int type, char *buf)
+{
+	struct ibft_kobject *entry = data;
+	char *str = buf;
+
+	switch (type) {
+	case ISCSI_BOOT_ACPITBL_SIGNATURE:
+		str += sprintf_string(str, ACPI_NAME_SIZE,
+				      entry->header->header.signature);
+		break;
+	case ISCSI_BOOT_ACPITBL_OEM_ID:
+		str += sprintf_string(str, ACPI_OEM_ID_SIZE,
+				      entry->header->header.oem_id);
+		break;
+	case ISCSI_BOOT_ACPITBL_OEM_TABLE_ID:
+		str += sprintf_string(str, ACPI_OEM_TABLE_ID_SIZE,
+				      entry->header->header.oem_table_id);
+		break;
+	default:
+		break;
+	}
+
+	return str - buf;
+}
+
 static int __init ibft_check_device(void)
 {
 	int len;
@@ -576,6 +601,24 @@ static umode_t __init ibft_check_initiator_for(void *data, int type)
 	return rc;
 }
 
+static umode_t __init ibft_check_acpitbl_for(void *data, int type)
+{
+
+	umode_t rc = 0;
+
+	switch (type) {
+	case ISCSI_BOOT_ACPITBL_SIGNATURE:
+	case ISCSI_BOOT_ACPITBL_OEM_ID:
+	case ISCSI_BOOT_ACPITBL_OEM_TABLE_ID:
+		rc = S_IRUGO;
+		break;
+	default:
+		break;
+	}
+
+	return rc;
+}
+
 static void ibft_kobj_release(void *data)
 {
 	kfree(data);
@@ -699,6 +742,8 @@ free_ibft_obj:
 static int __init ibft_register_kobjects(struct acpi_table_ibft *header)
 {
 	struct ibft_control *control = NULL;
+	struct iscsi_boot_kobj *boot_kobj;
+	struct ibft_kobject *ibft_kobj;
 	void *ptr, *end;
 	int rc = 0;
 	u16 offset;
@@ -726,6 +771,25 @@ static int __init ibft_register_kobjects(struct acpi_table_ibft *header)
 				break;
 		}
 	}
+	if (rc)
+		return rc;
+
+	ibft_kobj = kzalloc(sizeof(*ibft_kobj), GFP_KERNEL);
+	if (!ibft_kobj)
+		return -ENOMEM;
+
+	ibft_kobj->header = header;
+	ibft_kobj->hdr = NULL; /*for ibft_unregister*/
+
+	boot_kobj = iscsi_boot_create_acpitbl(boot_kset, 0,
+					ibft_kobj,
+					ibft_attr_show_acpitbl,
+					ibft_check_acpitbl_for,
+					ibft_kobj_release);
+	if (!boot_kobj)  {
+		kfree(ibft_kobj);
+		rc = -ENOMEM;
+	}
 
 	return rc;
 }
@@ -738,7 +802,7 @@ static void ibft_unregister(void)
 	list_for_each_entry_safe(boot_kobj, tmp_kobj,
 				 &boot_kset->kobj_list, list) {
 		ibft_kobj = boot_kobj->data;
-		if (ibft_kobj->hdr->id == id_nic)
+		if (ibft_kobj->hdr && ibft_kobj->hdr->id == id_nic)
 			sysfs_remove_link(&boot_kobj->kobj, "device");
 	};
 }