2 This file declares EFI PCI Hot Plug Init Protocol.
4 This protocol provides the necessary functionality to initialize the Hot Plug
5 Controllers (HPCs) and the buses that they control. This protocol also provides
6 information regarding resource padding.
9 This protocol is required only on platforms that support one or more PCI Hot
10 Plug* slots or CardBus sockets.
12 The EFI_PCI_HOT_PLUG_INIT_PROTOCOL provides a mechanism for the PCI bus enumerator
13 to properly initialize the HPCs and CardBus sockets that require initialization.
14 The HPC initialization takes place before the PCI enumeration process is complete.
15 There cannot be more than one instance of this protocol in a system. This protocol
16 is installed on its own separate handle.
18 Because the system may include multiple HPCs, one instance of this protocol
19 should represent all of them. The protocol functions use the device path of
20 the HPC to identify the HPC. When the PCI bus enumerator finds a root HPC, it
21 will call EFI_PCI_HOT_PLUG_INIT_PROTOCOL.InitializeRootHpc(). If InitializeRootHpc()
22 is unable to initialize a root HPC, the PCI enumerator will ignore that root HPC
23 and continue the enumeration process. If the HPC is not initialized, the devices
24 that it controls may not be initialized, and no resource padding will be provided.
26 From the standpoint of the PCI bus enumerator, HPCs are divided into the following
30 These HPCs must be initialized by calling InitializeRootHpc() during the
31 enumeration process. These HPCs will also require resource padding. The
32 platform code must have a priori knowledge of these devices and must know
33 how to initialize them. There may not be any way to access their PCI
34 configuration space before the PCI enumerator programs all the upstream
35 bridges and thus enables the path to these devices. The PCI bus enumerator
36 is responsible for determining the PCI bus address of the HPC before it
37 calls InitializeRootHpc().
39 These HPCs will not need explicit initialization during enumeration process.
40 These HPCs will require resource padding. The platform code does not have
41 to have a priori knowledge of these devices.
43 Copyright (c) 2007 - 2018, Intel Corporation. All rights reserved.<BR>
44 SPDX-License-Identifier: BSD-2-Clause-Patent
46 @par Revision Reference:
47 This Protocol is defined in UEFI Platform Initialization Specification 1.2
52 #ifndef _EFI_PCI_HOT_PLUG_INIT_H_
53 #define _EFI_PCI_HOT_PLUG_INIT_H_
56 /// Global ID for the EFI_PCI_HOT_PLUG_INIT_PROTOCOL
58 #define EFI_PCI_HOT_PLUG_INIT_PROTOCOL_GUID \
60 0xaa0e8bc1, 0xdabc, 0x46b0, {0xa8, 0x44, 0x37, 0xb8, 0x16, 0x9b, 0x2b, 0xea } \
64 /// Forward declaration for EFI_PCI_HOT_PLUG_INIT_PROTOCOL
66 typedef struct _EFI_PCI_HOT_PLUG_INIT_PROTOCOL EFI_PCI_HOT_PLUG_INIT_PROTOCOL
;
69 /// Describes the current state of an HPC
71 typedef UINT16 EFI_HPC_STATE
;
74 /// The HPC initialization function was called and the HPC completed
75 /// initialization, but it was not enabled for some reason. The HPC may be
76 /// disabled in hardware, or it may be disabled due to user preferences,
77 /// hardware failure, or other reasons. No resource padding is required.
79 #define EFI_HPC_STATE_INITIALIZED 0x01
82 /// The HPC initialization function was called, the HPC completed
83 /// initialization, and it was enabled. Resource padding is required.
85 #define EFI_HPC_STATE_ENABLED 0x02
88 /// Location definition for PCI Hot Plug Controller
93 /// The device path to the root HPC. An HPC cannot control its parent buses.
94 /// The PCI bus driver requires this information so that it can pass the
95 /// correct HpcPciAddress to the InitializeRootHpc() and GetResourcePadding()
98 EFI_DEVICE_PATH_PROTOCOL
*HpcDevicePath
;
100 /// The device path to the Hot Plug Bus (HPB) that is controlled by the root
101 /// HPC. The PCI bus driver uses this information to check if a particular PCI
102 /// bus has hot-plug slots. The device path of a PCI bus is the same as the
103 /// device path of its parent. For Standard(PCI) Hot Plug Controllers (SHPCs)
104 /// and PCI Express*, HpbDevicePath is the same as HpcDevicePath.
106 EFI_DEVICE_PATH_PROTOCOL
*HpbDevicePath
;
110 /// Describes how resource padding should be applied
114 /// Apply the padding at a PCI bus level. In other words, the resources
115 /// that are allocated to the bus containing hot-plug slots are padded by
116 /// the specified amount. If the hot-plug bus is behind a PCI-to-PCI
117 /// bridge, the PCI-to-PCI bridge apertures will indicate the padding
121 /// Apply the padding at a PCI root bridge level. If a PCI root bridge
122 /// includes more than one hot-plug bus, the resource padding requests
123 /// for these buses are added together and the resources that are
124 /// allocated to the root bridge are padded by the specified amount. This
125 /// strategy may reduce the total amount of padding, but requires
126 /// reprogramming of PCI-to-PCI bridges in a hot-add event. If the hotplug
127 /// bus is behind a PCI-to-PCI bridge, the PCI-to-PCI bridge
128 /// apertures do not indicate the padding for that bus.
130 EfiPaddingPciRootBridge
131 } EFI_HPC_PADDING_ATTRIBUTES
;
134 Returns a list of root Hot Plug Controllers (HPCs) that require initialization
135 during the boot process.
137 This procedure returns a list of root HPCs. The PCI bus driver must initialize
138 these controllers during the boot process. The PCI bus driver may or may not be
139 able to detect these HPCs. If the platform includes a PCI-to-CardBus bridge, it
140 can be included in this list if it requires initialization. The HpcList must be
141 self consistent. An HPC cannot control any of its parent buses. Only one HPC can
142 control a PCI bus. Because this list includes only root HPCs, no HPC in the list
143 can be a child of another HPC. This policy must be enforced by the
144 EFI_PCI_HOT_PLUG_INIT_PROTOCOL. The PCI bus driver may not check for such
145 invalid conditions. The callee allocates the buffer HpcList
147 @param[in] This Pointer to the EFI_PCI_HOT_PLUG_INIT_PROTOCOL instance.
148 @param[out] HpcCount The number of root HPCs that were returned.
149 @param[out] HpcList The list of root HPCs. HpcCount defines the number of
150 elements in this list.
152 @retval EFI_SUCCESS HpcList was returned.
153 @retval EFI_OUT_OF_RESOURCES HpcList was not returned due to insufficient
155 @retval EFI_INVALID_PARAMETER HpcCount is NULL or HpcList is NULL.
160 (EFIAPI
*EFI_GET_ROOT_HPC_LIST
)(
161 IN EFI_PCI_HOT_PLUG_INIT_PROTOCOL
*This
,
163 OUT EFI_HPC_LOCATION
**HpcList
167 Initializes one root Hot Plug Controller (HPC). This process may causes
168 initialization of its subordinate buses.
170 This function initializes the specified HPC. At the end of initialization,
171 the hot-plug slots or sockets (controlled by this HPC) are powered and are
172 connected to the bus. All the necessary registers in the HPC are set up. For
173 a Standard (PCI) Hot Plug Controller (SHPC), the registers that must be set
174 up are defined in the PCI Standard Hot Plug Controller and Subsystem
177 @param[in] This Pointer to the EFI_PCI_HOT_PLUG_INIT_PROTOCOL instance.
178 @param[in] HpcDevicePath The device path to the HPC that is being initialized.
179 @param[in] HpcPciAddress The address of the HPC function on the PCI bus.
180 @param[in] Event The event that should be signaled when the HPC
181 initialization is complete. Set to NULL if the
182 caller wants to wait until the entire initialization
184 @param[out] HpcState The state of the HPC hardware. The state is
185 EFI_HPC_STATE_INITIALIZED or EFI_HPC_STATE_ENABLED.
187 @retval EFI_SUCCESS If Event is NULL, the specific HPC was successfully
188 initialized. If Event is not NULL, Event will be
189 signaled at a later time when initialization is complete.
190 @retval EFI_UNSUPPORTED This instance of EFI_PCI_HOT_PLUG_INIT_PROTOCOL
191 does not support the specified HPC.
192 @retval EFI_OUT_OF_RESOURCES Initialization failed due to insufficient
194 @retval EFI_INVALID_PARAMETER HpcState is NULL.
199 (EFIAPI
*EFI_INITIALIZE_ROOT_HPC
)(
200 IN EFI_PCI_HOT_PLUG_INIT_PROTOCOL
*This
,
201 IN EFI_DEVICE_PATH_PROTOCOL
*HpcDevicePath
,
202 IN UINT64 HpcPciAddress
,
203 IN EFI_EVENT Event
, OPTIONAL
204 OUT EFI_HPC_STATE
*HpcState
208 Returns the resource padding that is required by the PCI bus that is controlled
209 by the specified Hot Plug Controller (HPC).
211 This function returns the resource padding that is required by the PCI bus that
212 is controlled by the specified HPC. This member function is called for all the
213 root HPCs and nonroot HPCs that are detected by the PCI bus enumerator. This
214 function will be called before PCI resource allocation is completed. This function
215 must be called after all the root HPCs, with the possible exception of a
216 PCI-to-CardBus bridge, have completed initialization.
218 @param[in] This Pointer to the EFI_PCI_HOT_PLUG_INIT_PROTOCOL instance.
219 @param[in] HpcDevicePath The device path to the HPC.
220 @param[in] HpcPciAddress The address of the HPC function on the PCI bus.
221 @param[in] HpcState The state of the HPC hardware.
222 @param[out] Padding The amount of resource padding that is required by the
223 PCI bus under the control of the specified HPC.
224 @param[out] Attributes Describes how padding is accounted for. The padding
225 is returned in the form of ACPI 2.0 resource descriptors.
227 @retval EFI_SUCCESS The resource padding was successfully returned.
228 @retval EFI_UNSUPPORTED This instance of the EFI_PCI_HOT_PLUG_INIT_PROTOCOL
229 does not support the specified HPC.
230 @retval EFI_NOT_READY This function was called before HPC initialization
232 @retval EFI_INVALID_PARAMETER HpcState or Padding or Attributes is NULL.
233 @retval EFI_OUT_OF_RESOURCES ACPI 2.0 resource descriptors for Padding
234 cannot be allocated due to insufficient resources.
239 (EFIAPI
*EFI_GET_HOT_PLUG_PADDING
)(
240 IN EFI_PCI_HOT_PLUG_INIT_PROTOCOL
*This
,
241 IN EFI_DEVICE_PATH_PROTOCOL
*HpcDevicePath
,
242 IN UINT64 HpcPciAddress
,
243 OUT EFI_HPC_STATE
*HpcState
,
245 OUT EFI_HPC_PADDING_ATTRIBUTES
*Attributes
249 /// This protocol provides the necessary functionality to initialize the
250 /// Hot Plug Controllers (HPCs) and the buses that they control. This protocol
251 /// also provides information regarding resource padding.
253 struct _EFI_PCI_HOT_PLUG_INIT_PROTOCOL
{
255 /// Returns a list of root HPCs and the buses that they control.
257 EFI_GET_ROOT_HPC_LIST GetRootHpcList
;
260 /// Initializes the specified root HPC.
262 EFI_INITIALIZE_ROOT_HPC InitializeRootHpc
;
265 /// Returns the resource padding that is required by the HPC.
267 EFI_GET_HOT_PLUG_PADDING GetResourcePadding
;
270 extern EFI_GUID gEfiPciHotPlugInitProtocolGuid
;