summaryrefslogtreecommitdiffstats
path: root/drivers/infiniband/hw/hfi1/efivar.c
blob: 106349fc1fb9bf5777284e15cfc83e9393ae380c (plain)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
/*
 * Copyright(c) 2015, 2016 Intel Corporation.
 *
 * This file is provided under a dual BSD/GPLv2 license.  When using or
 * redistributing this file, you may do so under either license.
 *
 * GPL LICENSE SUMMARY
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of version 2 of the GNU General Public License as
 * published by the Free Software Foundation.
 *
 * This program is distributed in the hope that it will be useful, but
 * WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 * General Public License for more details.
 *
 * BSD LICENSE
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 *  - Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 *  - Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 *  - Neither the name of Intel Corporation nor the names of its
 *    contributors may be used to endorse or promote products derived
 *    from this software without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS FOR
 * A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE COPYRIGHT
 * OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT, INCIDENTAL,
 * SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT NOT
 * LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE,
 * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY
 * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT
 * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE
 * OF THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE.
 *
 */

#include "efivar.h"

/* GUID for HFI1 variables in EFI */
#define HFI1_EFIVAR_GUID EFI_GUID(0xc50a953e, 0xa8b2, 0x42a6, \
		0xbf, 0x89, 0xd3, 0x33, 0xa6, 0xe9, 0xe6, 0xd4)
/* largest EFI data size we expect */
#define EFI_DATA_SIZE 4096

/*
 * Read the named EFI variable.  Return the size of the actual data in *size
 * and a kmalloc'ed buffer in *return_data.  The caller must free the
 * data.  It is guaranteed that *return_data will be NULL and *size = 0
 * if this routine fails.
 *
 * Return 0 on success, -errno on failure.
 */
static int read_efi_var(const char *name, unsigned long *size,
			void **return_data)
{
	efi_status_t status;
	efi_char16_t *uni_name;
	efi_guid_t guid;
	unsigned long temp_size;
	void *temp_buffer;
	void *data;
	int i;
	int ret;

	/* set failure return values */
	*size = 0;
	*return_data = NULL;

	if (!efi_enabled(EFI_RUNTIME_SERVICES))
		return -EOPNOTSUPP;

	uni_name = kcalloc(strlen(name) + 1, sizeof(efi_char16_t), GFP_KERNEL);
	temp_buffer = kzalloc(EFI_DATA_SIZE, GFP_KERNEL);

	if (!uni_name || !temp_buffer) {
		ret = -ENOMEM;
		goto fail;
	}

	/* input: the size of the buffer */
	temp_size = EFI_DATA_SIZE;

	/* convert ASCII to unicode - it is a 1:1 mapping */
	for (i = 0; name[i]; i++)
		uni_name[i] = name[i];

	/* need a variable for our GUID */
	guid = HFI1_EFIVAR_GUID;

	/* call into EFI runtime services */
	status = efi.get_variable(
			uni_name,
			&guid,
			NULL,
			&temp_size,
			temp_buffer);

	/*
	 * It would be nice to call efi_status_to_err() here, but that
	 * is in the EFIVAR_FS code and may not be compiled in.
	 * However, even that is insufficient since it does not cover
	 * EFI_BUFFER_TOO_SMALL which could be an important return.
	 * For now, just split out succces or not found.
	 */
	ret = status == EFI_SUCCESS   ? 0 :
	      status == EFI_NOT_FOUND ? -ENOENT :
					-EINVAL;
	if (ret)
		goto fail;

	/*
	 * We have successfully read the EFI variable into our
	 * temporary buffer.  Now allocate a correctly sized
	 * buffer.
	 */
	data = kmemdup(temp_buffer, temp_size, GFP_KERNEL);
	if (!data) {
		ret = -ENOMEM;
		goto fail;
	}

	*size = temp_size;
	*return_data = data;

fail:
	kfree(uni_name);
	kfree(temp_buffer);

	return ret;
}

/*
 * Read an HFI1 EFI variable of the form:
 *	<PCIe address>-<kind>
 * Return an kalloc'ed array and size of the data.
 *
 * Returns 0 on success, -errno on failure.
 */
int read_hfi1_efi_var(struct hfi1_devdata *dd, const char *kind,
		      unsigned long *size, void **return_data)
{
	char name[64];

	/* create a common prefix */
	snprintf(name, sizeof(name), "%04x:%02x:%02x.%x-%s",
		 pci_domain_nr(dd->pcidev->bus),
		 dd->pcidev->bus->number,
		 PCI_SLOT(dd->pcidev->devfn),
		 PCI_FUNC(dd->pcidev->devfn),
		 kind);

	return read_efi_var(name, size, return_data);
}