1 /** @file
2 Temporarily enable IO and MMIO decoding for all PCI devices while QEMU
3 regenerates the ACPI tables.
4
5 Copyright (C) 2016, Red Hat, Inc.
6
7 This program and the accompanying materials are licensed and made available
8 under the terms and conditions of the BSD License which accompanies this
9 distribution. The full text of the license may be found at
10 http://opensource.org/licenses/bsd-license.php
11
12 THE PROGRAM IS DISTRIBUTED UNDER THE BSD LICENSE ON AN "AS IS" BASIS, WITHOUT
13 WARRANTIES OR REPRESENTATIONS OF ANY KIND, EITHER EXPRESS OR IMPLIED.
14 **/
15
16 #include <Library/MemoryAllocationLib.h>
17
18 #include "AcpiPlatform.h"
19
20
21 /**
22 Collect all PciIo protocol instances in the system. Save their original
23 attributes, and enable IO and MMIO decoding for each.
24
25 This is a best effort function; it doesn't return status codes. Its
26 caller is supposed to proceed even if this function fails.
27
28 @param[out] OriginalAttributes On output, a dynamically allocated array of
29 ORIGINAL_ATTRIBUTES elements. The array lists
30 the PciIo protocol instances found in the
31 system at the time of the call, plus the
32 original PCI attributes for each.
33
34 Before returning, the function enables IO and
35 MMIO decoding for each PciIo instance it
36 finds.
37
38 On error, or when no such instances are
39 found, OriginalAttributes is set to NULL.
40
41 @param[out] Count On output, the number of elements in
42 OriginalAttributes. On error it is set to
43 zero.
44 **/
45 VOID
EnablePciDecoding(OUT ORIGINAL_ATTRIBUTES ** OriginalAttributes,OUT UINTN * Count)46 EnablePciDecoding (
47 OUT ORIGINAL_ATTRIBUTES **OriginalAttributes,
48 OUT UINTN *Count
49 )
50 {
51 EFI_STATUS Status;
52 UINTN NoHandles;
53 EFI_HANDLE *Handles;
54 ORIGINAL_ATTRIBUTES *OrigAttrs;
55 UINTN Idx;
56
57 *OriginalAttributes = NULL;
58 *Count = 0;
59
60 if (PcdGetBool (PcdPciDisableBusEnumeration)) {
61 //
62 // The platform downloads ACPI tables from QEMU in general, but there are
63 // no root bridges in this execution. We're done.
64 //
65 return;
66 }
67
68 Status = gBS->LocateHandleBuffer (ByProtocol, &gEfiPciIoProtocolGuid,
69 NULL /* SearchKey */, &NoHandles, &Handles);
70 if (Status == EFI_NOT_FOUND) {
71 //
72 // No PCI devices were found on either of the root bridges. We're done.
73 //
74 return;
75 }
76
77 if (EFI_ERROR (Status)) {
78 DEBUG ((EFI_D_WARN, "%a: LocateHandleBuffer(): %r\n", __FUNCTION__,
79 Status));
80 return;
81 }
82
83 OrigAttrs = AllocatePool (NoHandles * sizeof *OrigAttrs);
84 if (OrigAttrs == NULL) {
85 DEBUG ((EFI_D_WARN, "%a: AllocatePool(): out of resources\n",
86 __FUNCTION__));
87 goto FreeHandles;
88 }
89
90 for (Idx = 0; Idx < NoHandles; ++Idx) {
91 EFI_PCI_IO_PROTOCOL *PciIo;
92 UINT64 Attributes;
93
94 //
95 // Look up PciIo on the handle and stash it
96 //
97 Status = gBS->HandleProtocol (Handles[Idx], &gEfiPciIoProtocolGuid,
98 (VOID**)&PciIo);
99 ASSERT_EFI_ERROR (Status);
100 OrigAttrs[Idx].PciIo = PciIo;
101
102 //
103 // Stash the current attributes
104 //
105 Status = PciIo->Attributes (PciIo, EfiPciIoAttributeOperationGet, 0,
106 &OrigAttrs[Idx].PciAttributes);
107 if (EFI_ERROR (Status)) {
108 DEBUG ((EFI_D_WARN, "%a: EfiPciIoAttributeOperationGet: %r\n",
109 __FUNCTION__, Status));
110 goto RestoreAttributes;
111 }
112
113 //
114 // Retrieve supported attributes
115 //
116 Status = PciIo->Attributes (PciIo, EfiPciIoAttributeOperationSupported, 0,
117 &Attributes);
118 if (EFI_ERROR (Status)) {
119 DEBUG ((EFI_D_WARN, "%a: EfiPciIoAttributeOperationSupported: %r\n",
120 __FUNCTION__, Status));
121 goto RestoreAttributes;
122 }
123
124 //
125 // Enable IO and MMIO decoding
126 //
127 Attributes &= EFI_PCI_IO_ATTRIBUTE_IO | EFI_PCI_IO_ATTRIBUTE_MEMORY;
128 Status = PciIo->Attributes (PciIo, EfiPciIoAttributeOperationEnable,
129 Attributes, NULL);
130 if (EFI_ERROR (Status)) {
131 DEBUG ((EFI_D_WARN, "%a: EfiPciIoAttributeOperationEnable: %r\n",
132 __FUNCTION__, Status));
133 goto RestoreAttributes;
134 }
135 }
136
137 //
138 // Success
139 //
140 FreePool (Handles);
141 *OriginalAttributes = OrigAttrs;
142 *Count = NoHandles;
143 return;
144
145 RestoreAttributes:
146 while (Idx > 0) {
147 --Idx;
148 OrigAttrs[Idx].PciIo->Attributes (OrigAttrs[Idx].PciIo,
149 EfiPciIoAttributeOperationSet,
150 OrigAttrs[Idx].PciAttributes,
151 NULL
152 );
153 }
154 FreePool (OrigAttrs);
155
156 FreeHandles:
157 FreePool (Handles);
158 }
159
160
161 /**
162 Restore the original PCI attributes saved with EnablePciDecoding().
163
164 @param[in] OriginalAttributes The array allocated and populated by
165 EnablePciDecoding(). This parameter may be
166 NULL. If OriginalAttributes is NULL, then the
167 function is a no-op; otherwise the PciIo
168 attributes will be restored, and the
169 OriginalAttributes array will be freed.
170
171 @param[in] Count The Count value stored by EnablePciDecoding(),
172 the number of elements in OriginalAttributes.
173 Count may be zero if and only if
174 OriginalAttributes is NULL.
175 **/
176 VOID
RestorePciDecoding(IN ORIGINAL_ATTRIBUTES * OriginalAttributes,IN UINTN Count)177 RestorePciDecoding (
178 IN ORIGINAL_ATTRIBUTES *OriginalAttributes,
179 IN UINTN Count
180 )
181 {
182 UINTN Idx;
183
184 ASSERT ((OriginalAttributes == NULL) == (Count == 0));
185 if (OriginalAttributes == NULL) {
186 return;
187 }
188
189 for (Idx = 0; Idx < Count; ++Idx) {
190 OriginalAttributes[Idx].PciIo->Attributes (
191 OriginalAttributes[Idx].PciIo,
192 EfiPciIoAttributeOperationSet,
193 OriginalAttributes[Idx].PciAttributes,
194 NULL
195 );
196 }
197 FreePool (OriginalAttributes);
198 }
199