Something went wrong. Try again.
Linux kernel mirror (for testing) git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git
Something went wrong. Try again.
123456789101112131415161718192021222324252627282930313233343536373839404142434445464748495051525354555657585960616263646566676869707172737475767778798081828384858687888990919293949596979899100101102103104105106107108109110111112113114115116117118119120121122123124125126127128129130131132133134135136137138139140141142143144145146147148149150151152153154155156157158159160161162163164165166167168169170171172173174175176177178179180181182// SPDX-License-Identifier: GPL-2.0/* * dev-path-parser.c - EFI Device Path parser * Copyright (C) 2016 Lukas Wunner <lukas@wunner.de> * * This program is free software; you can redistribute it and/or modify * it under the terms of the GNU General Public License (version 2) as * published by the Free Software Foundation. */
#include <linux/acpi.h>#include <linux/efi.h>#include <linux/pci.h>
static long __init parse_acpi_path(const struct efi_dev_path *node, struct device *parent, struct device **child){ struct acpi_device *adev; struct device *phys_dev; char hid[ACPI_ID_LEN];
if (node->header.length != 12) return -EINVAL;
sprintf(hid, "%c%c%c%04X", 'A' + ((node->acpi.hid >> 10) & 0x1f) - 1, 'A' + ((node->acpi.hid >> 5) & 0x1f) - 1, 'A' + ((node->acpi.hid >> 0) & 0x1f) - 1, node->acpi.hid >> 16);
for_each_acpi_dev_match(adev, hid, NULL, -1) { if (acpi_dev_uid_match(adev, node->acpi.uid)) break; if (!acpi_device_uid(adev) && node->acpi.uid == 0) break; } if (!adev) return -ENODEV;
phys_dev = acpi_get_first_physical_node(adev); if (phys_dev) { *child = get_device(phys_dev); acpi_dev_put(adev); } else *child = &adev->dev;
return 0;}
static int __init match_pci_dev(struct device *dev, const void *data){ unsigned int devfn = *(const unsigned int *)data;
return dev_is_pci(dev) && to_pci_dev(dev)->devfn == devfn;}
static long __init parse_pci_path(const struct efi_dev_path *node, struct device *parent, struct device **child){ unsigned int devfn;
if (node->header.length != 6) return -EINVAL; if (!parent) return -EINVAL;
devfn = PCI_DEVFN(node->pci.dev, node->pci.fn);
*child = device_find_child(parent, &devfn, match_pci_dev); if (!*child) return -ENODEV;
return 0;}
/* * Insert parsers for further node types here. * * Each parser takes a pointer to the @node and to the @parent (will be NULL * for the first device path node). If a device corresponding to @node was * found below @parent, its reference count should be incremented and the * device returned in @child. * * The return value should be 0 on success or a negative int on failure. * The special return values 0x01 (EFI_DEV_END_INSTANCE) and 0xFF * (EFI_DEV_END_ENTIRE) signal the end of the device path, only * parse_end_path() is supposed to return this. * * Be sure to validate the node length and contents before commencing the * search for a device. */
static long __init parse_end_path(const struct efi_dev_path *node, struct device *parent, struct device **child){ if (node->header.length != 4) return -EINVAL; if (node->header.sub_type != EFI_DEV_END_INSTANCE && node->header.sub_type != EFI_DEV_END_ENTIRE) return -EINVAL; if (!parent) return -ENODEV;
*child = get_device(parent); return node->header.sub_type;}
/** * efi_get_device_by_path - find device by EFI Device Path * @node: EFI Device Path * @len: maximum length of EFI Device Path in bytes * * Parse a series of EFI Device Path nodes at @node and find the corresponding * device. If the device was found, its reference count is incremented and a * pointer to it is returned. The caller needs to drop the reference with * put_device() after use. The @node pointer is updated to point to the * location immediately after the "End of Hardware Device Path" node. * * If another Device Path instance follows, @len is decremented by the number * of bytes consumed. Otherwise @len is set to %0. * * If a Device Path node is malformed or its corresponding device is not found, * @node is updated to point to this offending node and an ERR_PTR is returned. * * If @len is initially %0, the function returns %NULL. Thus, to iterate over * all instances in a path, the following idiom may be used: * * while (!IS_ERR_OR_NULL(dev = efi_get_device_by_path(&node, &len))) { * // do something with dev * put_device(dev); * } * if (IS_ERR(dev)) * // report error * * Devices can only be found if they're already instantiated. Most buses * instantiate devices in the "subsys" initcall level, hence the earliest * initcall level in which this function should be called is "fs". * * Returns the device on success or * %ERR_PTR(-ENODEV) if no device was found, * %ERR_PTR(-EINVAL) if a node is malformed or exceeds @len, * %ERR_PTR(-ENOTSUPP) if support for a node type is not yet implemented. */struct device * __init efi_get_device_by_path(const struct efi_dev_path **node, size_t *len){ struct device *parent = NULL, *child; long ret = 0;
if (!*len) return NULL;
while (!ret) { if (*len < 4 || *len < (*node)->header.length) ret = -EINVAL; else if ((*node)->header.type == EFI_DEV_ACPI && (*node)->header.sub_type == EFI_DEV_BASIC_ACPI) ret = parse_acpi_path(*node, parent, &child); else if ((*node)->header.type == EFI_DEV_HW && (*node)->header.sub_type == EFI_DEV_PCI) ret = parse_pci_path(*node, parent, &child); else if (((*node)->header.type == EFI_DEV_END_PATH || (*node)->header.type == EFI_DEV_END_PATH2)) ret = parse_end_path(*node, parent, &child); else ret = -ENOTSUPP;
put_device(parent); if (ret < 0) return ERR_PTR(ret);
parent = child; *node = (void *)*node + (*node)->header.length; *len -= (*node)->header.length; }
if (ret == EFI_DEV_END_ENTIRE) *len = 0;
return child;}