[efi] Generalise EFI entropy generation to non-x86 CPUs
[ipxe.git] / src / interface / efi / efi_utils.c
1 /*
2 * Copyright (C) 2011 Michael Brown <mbrown@fensystems.co.uk>.
3 *
4 * This program is free software; you can redistribute it and/or
5 * modify it under the terms of the GNU General Public License as
6 * published by the Free Software Foundation; either version 2 of the
7 * License, or any later version.
8 *
9 * This program is distributed in the hope that it will be useful, but
10 * WITHOUT ANY WARRANTY; without even the implied warranty of
11 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU
12 * General Public License for more details.
13 *
14 * You should have received a copy of the GNU General Public License
15 * along with this program; if not, write to the Free Software
16 * Foundation, Inc., 51 Franklin Street, Fifth Floor, Boston, MA
17 * 02110-1301, USA.
18 */
19
20 FILE_LICENCE ( GPL2_OR_LATER );
21
22 #include <stdio.h>
23 #include <string.h>
24 #include <errno.h>
25 #include <ipxe/efi/efi.h>
26 #include <ipxe/efi/efi_pci.h>
27 #include <ipxe/efi/efi_utils.h>
28
29 /** @file
30 *
31 * EFI utilities
32 *
33 */
34
35 /**
36 * Find end of device path
37 *
38 * @v path Path to device
39 * @ret path_end End of device path
40 */
41 EFI_DEVICE_PATH_PROTOCOL * efi_devpath_end ( EFI_DEVICE_PATH_PROTOCOL *path ) {
42
43 while ( path->Type != END_DEVICE_PATH_TYPE ) {
44 path = ( ( ( void * ) path ) +
45 /* There's this amazing new-fangled thing known as
46 * a UINT16, but who wants to use one of those? */
47 ( ( path->Length[1] << 8 ) | path->Length[0] ) );
48 }
49
50 return path;
51 }
52
53 /**
54 * Find length of device path (excluding terminator)
55 *
56 * @v path Path to device
57 * @ret path_len Length of device path
58 */
59 size_t efi_devpath_len ( EFI_DEVICE_PATH_PROTOCOL *path ) {
60 EFI_DEVICE_PATH_PROTOCOL *end = efi_devpath_end ( path );
61
62 return ( ( ( void * ) end ) - ( ( void * ) path ) );
63 }
64
65 /**
66 * Locate parent device supporting a given protocol
67 *
68 * @v device EFI device handle
69 * @v protocol Protocol GUID
70 * @v parent Parent EFI device handle to fill in
71 * @ret rc Return status code
72 */
73 int efi_locate_device ( EFI_HANDLE device, EFI_GUID *protocol,
74 EFI_HANDLE *parent ) {
75 EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
76 union {
77 EFI_DEVICE_PATH_PROTOCOL *path;
78 void *interface;
79 } path;
80 EFI_DEVICE_PATH_PROTOCOL *devpath;
81 EFI_STATUS efirc;
82 int rc;
83
84 /* Get device path */
85 if ( ( efirc = bs->OpenProtocol ( device,
86 &efi_device_path_protocol_guid,
87 &path.interface,
88 efi_image_handle, device,
89 EFI_OPEN_PROTOCOL_GET_PROTOCOL ))!=0){
90 rc = -EEFI ( efirc );
91 DBGC ( device, "EFIDEV %s cannot open device path: %s\n",
92 efi_handle_name ( device ), strerror ( rc ) );
93 goto err_open_device_path;
94 }
95 devpath = path.path;
96
97 /* Check for presence of specified protocol */
98 if ( ( efirc = bs->LocateDevicePath ( protocol, &devpath,
99 parent ) ) != 0 ) {
100 rc = -EEFI ( efirc );
101 DBGC ( device, "EFIDEV %s has no parent supporting %s: %s\n",
102 efi_handle_name ( device ),
103 efi_guid_ntoa ( protocol ), strerror ( rc ) );
104 goto err_locate_protocol;
105 }
106
107 /* Success */
108 rc = 0;
109
110 err_locate_protocol:
111 bs->CloseProtocol ( device, &efi_device_path_protocol_guid,
112 efi_image_handle, device );
113 err_open_device_path:
114 return rc;
115 }
116
117 /**
118 * Add EFI device as child of another EFI device
119 *
120 * @v parent EFI parent device handle
121 * @v child EFI child device handle
122 * @ret rc Return status code
123 */
124 int efi_child_add ( EFI_HANDLE parent, EFI_HANDLE child ) {
125 EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
126 void *devpath;
127 EFI_STATUS efirc;
128 int rc;
129
130 /* Re-open the device path protocol */
131 if ( ( efirc = bs->OpenProtocol ( parent,
132 &efi_device_path_protocol_guid,
133 &devpath,
134 efi_image_handle, child,
135 EFI_OPEN_PROTOCOL_BY_CHILD_CONTROLLER
136 ) ) != 0 ) {
137 rc = -EEFI ( efirc );
138 DBGC ( parent, "EFIDEV %s could not add child",
139 efi_handle_name ( parent ) );
140 DBGC ( parent, " %s: %s\n",
141 efi_handle_name ( child ), strerror ( rc ) );
142 DBGC_EFI_OPENERS ( parent, parent,
143 &efi_device_path_protocol_guid );
144 return rc;
145 }
146
147 DBGC2 ( parent, "EFIDEV %s added child", efi_handle_name ( parent ) );
148 DBGC2 ( parent, " %s\n", efi_handle_name ( child ) );
149 return 0;
150 }
151
152 /**
153 * Remove EFI device as child of another EFI device
154 *
155 * @v parent EFI parent device handle
156 * @v child EFI child device handle
157 */
158 void efi_child_del ( EFI_HANDLE parent, EFI_HANDLE child ) {
159 EFI_BOOT_SERVICES *bs = efi_systab->BootServices;
160
161 bs->CloseProtocol ( parent, &efi_device_path_protocol_guid,
162 efi_image_handle, child );
163 DBGC2 ( parent, "EFIDEV %s removed child", efi_handle_name ( parent ) );
164 DBGC2 ( parent, " %s\n", efi_handle_name ( child ) );
165 }
166
167 /**
168 * Get underlying PCI device information
169 *
170 * @v device EFI device handle
171 * @v prefix Device name prefix
172 * @v dev Generic device to fill in
173 * @ret rc Return status code
174 */
175 static int efi_pci_info ( EFI_HANDLE device, const char *prefix,
176 struct device *dev ) {
177 EFI_HANDLE pci_device;
178 struct pci_device pci;
179 int rc;
180
181 /* Find parent PCI device */
182 if ( ( rc = efi_locate_device ( device, &efi_pci_io_protocol_guid,
183 &pci_device ) ) != 0 ) {
184 DBGC ( device, "EFIDEV %s is not a PCI device: %s\n",
185 efi_handle_name ( device ), strerror ( rc ) );
186 return rc;
187 }
188
189 /* Get PCI device information */
190 if ( ( rc = efipci_info ( pci_device, &pci ) ) != 0 ) {
191 DBGC ( device, "EFIDEV %s could not get PCI information: %s\n",
192 efi_handle_name ( device ), strerror ( rc ) );
193 return rc;
194 }
195
196 /* Populate device information */
197 memcpy ( &dev->desc, &pci.dev.desc, sizeof ( dev->desc ) );
198 snprintf ( dev->name, sizeof ( dev->name ), "%s-%s",
199 prefix, pci.dev.name );
200
201 return 0;
202 }
203
204 /**
205 * Get underlying device information
206 *
207 * @v device EFI device handle
208 * @v prefix Device name prefix
209 * @v dev Generic device to fill in
210 */
211 void efi_device_info ( EFI_HANDLE device, const char *prefix,
212 struct device *dev ) {
213 int rc;
214
215 /* Try getting underlying PCI device information */
216 if ( ( rc = efi_pci_info ( device, prefix, dev ) ) == 0 )
217 return;
218
219 /* If we cannot get any underlying device information, fall
220 * back to providing information about the EFI handle.
221 */
222 DBGC ( device, "EFIDEV %s could not get underlying device "
223 "information\n", efi_handle_name ( device ) );
224 dev->desc.bus_type = BUS_TYPE_EFI;
225 snprintf ( dev->name, sizeof ( dev->name ), "%s-%p", prefix, device );
226 }