2 * Copyright(c) 2015, 2016 Intel Corporation.
4 * This file is provided under a dual BSD/GPLv2 license. When using or
5 * redistributing this file, you may do so under either license.
9 * This program is free software; you can redistribute it and/or modify
10 * it under the terms of version 2 of the GNU General Public License as
11 * published by the Free Software Foundation.
13 * This program is distributed in the hope that it will be useful, but
14 * WITHOUT ANY WARRANTY; without even the implied warranty of
15 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
16 * General Public License for more details.
20 * Redistribution and use in source and binary forms, with or without
21 * modification, are permitted provided that the following conditions
24 * - Redistributions of source code must retain the above copyright
25 * notice, this list of conditions and the following disclaimer.
26 * - Redistributions in binary form must reproduce the above copyright
27 * notice, this list of conditions and the following disclaimer in
28 * the documentation and/or other materials provided with the
30 * - Neither the name of Intel Corporation nor the names of its
31 * contributors may be used to endorse or promote products derived
32 * from this software without specific prior written permission.
34 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
35 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
36 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
37 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
38 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
39 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
40 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
41 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
42 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
43 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
44 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
48 #include <linux/ctype.h>
51 /* GUID for HFI1 variables in EFI */
52 #define HFI1_EFIVAR_GUID EFI_GUID(0xc50a953e, 0xa8b2, 0x42a6, \
53 0xbf, 0x89, 0xd3, 0x33, 0xa6, 0xe9, 0xe6, 0xd4)
54 /* largest EFI data size we expect */
55 #define EFI_DATA_SIZE 4096
58 * Read the named EFI variable. Return the size of the actual data in *size
59 * and a kmalloc'ed buffer in *return_data. The caller must free the
60 * data. It is guaranteed that *return_data will be NULL and *size = 0
61 * if this routine fails.
63 * Return 0 on success, -errno on failure.
65 static int read_efi_var(const char *name, unsigned long *size,
69 efi_char16_t *uni_name;
71 unsigned long temp_size;
77 /* set failure return values */
81 if (!efi_enabled(EFI_RUNTIME_SERVICES))
84 uni_name = kcalloc(strlen(name) + 1, sizeof(efi_char16_t), GFP_KERNEL);
85 temp_buffer = kzalloc(EFI_DATA_SIZE, GFP_KERNEL);
87 if (!uni_name || !temp_buffer) {
92 /* input: the size of the buffer */
93 temp_size = EFI_DATA_SIZE;
95 /* convert ASCII to unicode - it is a 1:1 mapping */
96 for (i = 0; name[i]; i++)
97 uni_name[i] = name[i];
99 /* need a variable for our GUID */
100 guid = HFI1_EFIVAR_GUID;
102 /* call into EFI runtime services */
103 status = efi.get_variable(
111 * It would be nice to call efi_status_to_err() here, but that
112 * is in the EFIVAR_FS code and may not be compiled in.
113 * However, even that is insufficient since it does not cover
114 * EFI_BUFFER_TOO_SMALL which could be an important return.
115 * For now, just split out succces or not found.
117 ret = status == EFI_SUCCESS ? 0 :
118 status == EFI_NOT_FOUND ? -ENOENT :
124 * We have successfully read the EFI variable into our
125 * temporary buffer. Now allocate a correctly sized
128 data = kmemdup(temp_buffer, temp_size, GFP_KERNEL);
145 * Read an HFI1 EFI variable of the form:
146 * <PCIe address>-<kind>
147 * Return an kalloc'ed array and size of the data.
149 * Returns 0 on success, -errno on failure.
151 int read_hfi1_efi_var(struct hfi1_devdata *dd, const char *kind,
152 unsigned long *size, void **return_data)
154 char prefix_name[64];
159 /* create a common prefix */
160 snprintf(prefix_name, sizeof(prefix_name), "%04x:%02x:%02x.%x",
161 pci_domain_nr(dd->pcidev->bus),
162 dd->pcidev->bus->number,
163 PCI_SLOT(dd->pcidev->devfn),
164 PCI_FUNC(dd->pcidev->devfn));
165 snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
166 result = read_efi_var(name, size, return_data);
169 * If reading the lowercase EFI variable fail, read the uppercase
173 /* Converting to uppercase */
174 for (i = 0; prefix_name[i]; i++)
175 if (isalpha(prefix_name[i]))
176 prefix_name[i] = toupper(prefix_name[i]);
177 snprintf(name, sizeof(name), "%s-%s", prefix_name, kind);
178 result = read_efi_var(name, size, return_data);