From 2c3c1048746a4622d8c89a29670120dc8fab93c4 Mon Sep 17 00:00:00 2001 From: Daniel Baumann Date: Sun, 7 Apr 2024 20:49:45 +0200 Subject: Adding upstream version 6.1.76. Signed-off-by: Daniel Baumann --- drivers/firmware/efi/dev-path-parser.c | 184 +++++++++++++++++++++++++++++++++ 1 file changed, 184 insertions(+) create mode 100644 drivers/firmware/efi/dev-path-parser.c (limited to 'drivers/firmware/efi/dev-path-parser.c') diff --git a/drivers/firmware/efi/dev-path-parser.c b/drivers/firmware/efi/dev-path-parser.c new file mode 100644 index 000000000..f80d87c19 --- /dev/null +++ b/drivers/firmware/efi/dev-path-parser.c @@ -0,0 +1,184 @@ +// SPDX-License-Identifier: GPL-2.0 +/* + * dev-path-parser.c - EFI Device Path parser + * Copyright (C) 2016 Lukas Wunner + * + * 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 +#include +#include + +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]; + u64 uid; + int ret; + + 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) { + ret = acpi_dev_uid_to_integer(adev, &uid); + if (ret == 0 && node->acpi.uid == uid) + break; + if (ret == -ENODATA && 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, void *data) +{ + unsigned int devfn = *(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; +} -- cgit v1.2.3