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
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40 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
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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.
50 /* GUID for HFI1 variables in EFI */
51 #define HFI1_EFIVAR_GUID EFI_GUID(0xc50a953e, 0xa8b2, 0x42a6, \
52 0xbf, 0x89, 0xd3, 0x33, 0xa6, 0xe9, 0xe6, 0xd4)
53 /* largest EFI data size we expect */
54 #define EFI_DATA_SIZE 4096
57 * Read the named EFI variable. Return the size of the actual data in *size
58 * and a kmalloc'ed buffer in *return_data. The caller must free the
59 * data. It is guaranteed that *return_data will be NULL and *size = 0
60 * if this routine fails.
62 * Return 0 on success, -errno on failure.
64 static int read_efi_var(const char *name
, unsigned long *size
,
68 efi_char16_t
*uni_name
;
70 unsigned long temp_size
;
76 /* set failure return values */
80 if (!efi_enabled(EFI_RUNTIME_SERVICES
))
83 uni_name
= kcalloc(strlen(name
) + 1, sizeof(efi_char16_t
), GFP_KERNEL
);
84 temp_buffer
= kzalloc(EFI_DATA_SIZE
, GFP_KERNEL
);
86 if (!uni_name
|| !temp_buffer
) {
91 /* input: the size of the buffer */
92 temp_size
= EFI_DATA_SIZE
;
94 /* convert ASCII to unicode - it is a 1:1 mapping */
95 for (i
= 0; name
[i
]; i
++)
96 uni_name
[i
] = name
[i
];
98 /* need a variable for our GUID */
99 guid
= HFI1_EFIVAR_GUID
;
101 /* call into EFI runtime services */
102 status
= efi
.get_variable(
110 * It would be nice to call efi_status_to_err() here, but that
111 * is in the EFIVAR_FS code and may not be compiled in.
112 * However, even that is insufficient since it does not cover
113 * EFI_BUFFER_TOO_SMALL which could be an important return.
114 * For now, just split out succces or not found.
116 ret
= status
== EFI_SUCCESS
? 0 :
117 status
== EFI_NOT_FOUND
? -ENOENT
:
123 * We have successfully read the EFI variable into our
124 * temporary buffer. Now allocate a correctly sized
127 data
= kmemdup(temp_buffer
, temp_size
, GFP_KERNEL
);
144 * Read an HFI1 EFI variable of the form:
145 * <PCIe address>-<kind>
146 * Return an kalloc'ed array and size of the data.
148 * Returns 0 on success, -errno on failure.
150 int read_hfi1_efi_var(struct hfi1_devdata
*dd
, const char *kind
,
151 unsigned long *size
, void **return_data
)
155 /* create a common prefix */
156 snprintf(name
, sizeof(name
), "%04x:%02x:%02x.%x-%s",
157 pci_domain_nr(dd
->pcidev
->bus
),
158 dd
->pcidev
->bus
->number
,
159 PCI_SLOT(dd
->pcidev
->devfn
),
160 PCI_FUNC(dd
->pcidev
->devfn
),
163 return read_efi_var(name
, size
, return_data
);
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