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 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 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
