1 // SPDX-License-Identifier: GPL-2.0
3  * dev-path-parser.c - EFI Device Path parser
15 static long __init parse_acpi_path(const struct efi_dev_path *node,  in parse_acpi_path()  argument
16 				   struct device *parent, struct device **child)  in parse_acpi_path()  argument
24 	if (node->header.length != 12)  in parse_acpi_path()
25 		return -EINVAL;  in parse_acpi_path()
28 		'A' + ((node->acpi.hid >> 10) & 0x1f) - 1,  in parse_acpi_path()
29 		'A' + ((node->acpi.hid >>  5) & 0x1f) - 1,  in parse_acpi_path()
30 		'A' + ((node->acpi.hid >>  0) & 0x1f) - 1,  in parse_acpi_path()
31 			node->acpi.hid >> 16);  in parse_acpi_path()
33 	for_each_acpi_dev_match(adev, hid, NULL, -1) {  in parse_acpi_path()
35 		if (ret == 0 && node->acpi.uid == uid)  in parse_acpi_path()
37 		if (ret == -ENODATA && node->acpi.uid == 0)  in parse_acpi_path()
41 		return -ENODEV;  in parse_acpi_path()
45 		*child = get_device(phys_dev);  in parse_acpi_path()
48 		*child = &adev->dev;  in parse_acpi_path()
57 	return dev_is_pci(dev) && to_pci_dev(dev)->devfn == devfn;  in match_pci_dev()
60 static long __init parse_pci_path(const struct efi_dev_path *node,  in parse_pci_path()  argument
61 				  struct device *parent, struct device **child)  in parse_pci_path()  argument
65 	if (node->header.length != 6)  in parse_pci_path()
66 		return -EINVAL;  in parse_pci_path()
68 		return -EINVAL;  in parse_pci_path()
70 	devfn = PCI_DEVFN(node->pci.dev, node->pci.fn);  in parse_pci_path()
72 	*child = device_find_child(parent, &devfn, match_pci_dev);  in parse_pci_path()
73 	if (!*child)  in parse_pci_path()
74 		return -ENODEV;  in parse_pci_path()
80  * Insert parsers for further node types here.
82  * Each parser takes a pointer to the @node and to the @parent (will be NULL
83  * for the first device path node). If a device corresponding to @node was
85  * device returned in @child.
92  * Be sure to validate the node length and contents before commencing the
96 static long __init parse_end_path(const struct efi_dev_path *node,  in parse_end_path()  argument
97 				  struct device *parent, struct device **child)  in parse_end_path()  argument
99 	if (node->header.length != 4)  in parse_end_path()
100 		return -EINVAL;  in parse_end_path()
101 	if (node->header.sub_type != EFI_DEV_END_INSTANCE &&  in parse_end_path()
102 	    node->header.sub_type != EFI_DEV_END_ENTIRE)  in parse_end_path()
103 		return -EINVAL;  in parse_end_path()
105 		return -ENODEV;  in parse_end_path()
107 	*child = get_device(parent);  in parse_end_path()
108 	return node->header.sub_type;  in parse_end_path()
112  * efi_get_device_by_path - find device by EFI Device Path
113  * @node: EFI Device Path
116  * Parse a series of EFI Device Path nodes at @node and find the corresponding
119  * put_device() after use.  The @node pointer is updated to point to the
120  * location immediately after the "End of Hardware Device Path" node.
125  * If a Device Path node is malformed or its corresponding device is not found,
126  * @node is updated to point to this offending node and an ERR_PTR is returned.
131  *	while (!IS_ERR_OR_NULL(dev = efi_get_device_by_path(&node, &len))) {
143  *	%ERR_PTR(-ENODEV) if no device was found,
144  *	%ERR_PTR(-EINVAL) if a node is malformed or exceeds @len,
145  *	%ERR_PTR(-ENOTSUPP) if support for a node type is not yet implemented.
147 struct device * __init efi_get_device_by_path(const struct efi_dev_path **node,  in efi_get_device_by_path()  argument
150 	struct device *parent = NULL, *child;  in efi_get_device_by_path()  local
157 		if (*len < 4 || *len < (*node)->header.length)  in efi_get_device_by_path()
158 			ret = -EINVAL;  in efi_get_device_by_path()
159 		else if ((*node)->header.type		== EFI_DEV_ACPI &&  in efi_get_device_by_path()
160 			 (*node)->header.sub_type	== EFI_DEV_BASIC_ACPI)  in efi_get_device_by_path()
161 			ret = parse_acpi_path(*node, parent, &child);  in efi_get_device_by_path()
162 		else if ((*node)->header.type		== EFI_DEV_HW &&  in efi_get_device_by_path()
163 			 (*node)->header.sub_type	== EFI_DEV_PCI)  in efi_get_device_by_path()
164 			ret = parse_pci_path(*node, parent, &child);  in efi_get_device_by_path()
165 		else if (((*node)->header.type		== EFI_DEV_END_PATH ||  in efi_get_device_by_path()
166 			  (*node)->header.type		== EFI_DEV_END_PATH2))  in efi_get_device_by_path()
167 			ret = parse_end_path(*node, parent, &child);  in efi_get_device_by_path()
169 			ret = -ENOTSUPP;  in efi_get_device_by_path()
175 		parent = child;  in efi_get_device_by_path()
176 		*node  = (void *)*node + (*node)->header.length;  in efi_get_device_by_path()
177 		*len  -= (*node)->header.length;  in efi_get_device_by_path()
183 	return child;  in efi_get_device_by_path()