1 // SPDX-License-Identifier: GPL-2.0
3  * dev-path-parser.c - EFI Device Path parser
28 	if (adev->pnp.unique_id)  in match_acpi_dev()
29 		return !strcmp(adev->pnp.unique_id, hid_uid.uid);  in match_acpi_dev()
35 				   struct device *parent, struct device **child)  in parse_acpi_path()  argument
40 	if (node->header.length != 12)  in parse_acpi_path()
41 		return -EINVAL;  in parse_acpi_path()
44 		'A' + ((node->acpi.hid >> 10) & 0x1f) - 1,  in parse_acpi_path()
45 		'A' + ((node->acpi.hid >>  5) & 0x1f) - 1,  in parse_acpi_path()
46 		'A' + ((node->acpi.hid >>  0) & 0x1f) - 1,  in parse_acpi_path()
47 			node->acpi.hid >> 16);  in parse_acpi_path()
48 	sprintf(hid_uid.uid, "%u", node->acpi.uid);  in parse_acpi_path()
50 	*child = bus_find_device(&acpi_bus_type, NULL, &hid_uid,  in parse_acpi_path()
52 	if (!*child)  in parse_acpi_path()
53 		return -ENODEV;  in parse_acpi_path()
55 	phys_dev = acpi_get_first_physical_node(to_acpi_device(*child));  in parse_acpi_path()
58 		put_device(*child);  in parse_acpi_path()
59 		*child = phys_dev;  in parse_acpi_path()
69 	return dev_is_pci(dev) && to_pci_dev(dev)->devfn == devfn;  in match_pci_dev()
73 				  struct device *parent, struct device **child)  in parse_pci_path()  argument
77 	if (node->header.length != 6)  in parse_pci_path()
78 		return -EINVAL;  in parse_pci_path()
79 	if (!parent)  in parse_pci_path()
80 		return -EINVAL;  in parse_pci_path()
82 	devfn = PCI_DEVFN(node->pci.dev, node->pci.fn);  in parse_pci_path()
84 	*child = device_find_child(parent, &devfn, match_pci_dev);  in parse_pci_path()
85 	if (!*child)  in parse_pci_path()
86 		return -ENODEV;  in parse_pci_path()
94  * Each parser takes a pointer to the @node and to the @parent (will be NULL
96  * found below @parent, its reference count should be incremented and the
97  * device returned in @child.
109 				  struct device *parent, struct device **child)  in parse_end_path()  argument
111 	if (node->header.length != 4)  in parse_end_path()
112 		return -EINVAL;  in parse_end_path()
113 	if (node->header.sub_type != EFI_DEV_END_INSTANCE &&  in parse_end_path()
114 	    node->header.sub_type != EFI_DEV_END_ENTIRE)  in parse_end_path()
115 		return -EINVAL;  in parse_end_path()
116 	if (!parent)  in parse_end_path()
117 		return -ENODEV;  in parse_end_path()
119 	*child = get_device(parent);  in parse_end_path()
120 	return node->header.sub_type;  in parse_end_path()
124  * efi_get_device_by_path - find device by EFI Device Path
155  *	%ERR_PTR(-ENODEV) if no device was found,
156  *	%ERR_PTR(-EINVAL) if a node is malformed or exceeds @len,
157  *	%ERR_PTR(-ENOTSUPP) if support for a node type is not yet implemented.
162 	struct device *parent = NULL, *child;  in efi_get_device_by_path()  local
169 		if (*len < 4 || *len < (*node)->header.length)  in efi_get_device_by_path()
170 			ret = -EINVAL;  in efi_get_device_by_path()
171 		else if ((*node)->header.type		== EFI_DEV_ACPI &&  in efi_get_device_by_path()
172 			 (*node)->header.sub_type	== EFI_DEV_BASIC_ACPI)  in efi_get_device_by_path()
173 			ret = parse_acpi_path(*node, parent, &child);  in efi_get_device_by_path()
174 		else if ((*node)->header.type		== EFI_DEV_HW &&  in efi_get_device_by_path()
175 			 (*node)->header.sub_type	== EFI_DEV_PCI)  in efi_get_device_by_path()
176 			ret = parse_pci_path(*node, parent, &child);  in efi_get_device_by_path()
177 		else if (((*node)->header.type		== EFI_DEV_END_PATH ||  in efi_get_device_by_path()
178 			  (*node)->header.type		== EFI_DEV_END_PATH2))  in efi_get_device_by_path()
179 			ret = parse_end_path(*node, parent, &child);  in efi_get_device_by_path()
181 			ret = -ENOTSUPP;  in efi_get_device_by_path()
183 		put_device(parent);  in efi_get_device_by_path()
187 		parent = child;  in efi_get_device_by_path()
188 		*node  = (void *)*node + (*node)->header.length;  in efi_get_device_by_path()
189 		*len  -= (*node)->header.length;  in efi_get_device_by_path()
195 	return child;  in efi_get_device_by_path()