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1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.02/*******************************************************************************3 *4 * Module Name: hwpci - Obtain PCI bus, device, and function numbers5 *6 ******************************************************************************/7 8#include <acpi/acpi.h>9#include "accommon.h"10 11#define _COMPONENT ACPI_NAMESPACE12ACPI_MODULE_NAME("hwpci")13 14/* PCI configuration space values */15#define PCI_CFG_HEADER_TYPE_REG 0x0E16#define PCI_CFG_PRIMARY_BUS_NUMBER_REG 0x1817#define PCI_CFG_SECONDARY_BUS_NUMBER_REG 0x1918/* PCI header values */19#define PCI_HEADER_TYPE_MASK 0x7F20#define PCI_TYPE_BRIDGE 0x0121#define PCI_TYPE_CARDBUS_BRIDGE 0x0222typedef struct acpi_pci_device {23 acpi_handle device;24 struct acpi_pci_device *next;25 26} acpi_pci_device;27 28/* Local prototypes */29 30static acpi_status31acpi_hw_build_pci_list(acpi_handle root_pci_device,32 acpi_handle pci_region,33 struct acpi_pci_device **return_list_head);34 35static acpi_status36acpi_hw_process_pci_list(struct acpi_pci_id *pci_id,37 struct acpi_pci_device *list_head);38 39static void acpi_hw_delete_pci_list(struct acpi_pci_device *list_head);40 41static acpi_status42acpi_hw_get_pci_device_info(struct acpi_pci_id *pci_id,43 acpi_handle pci_device,44 u16 *bus_number, u8 *is_bridge);45 46/*******************************************************************************47 *48 * FUNCTION: acpi_hw_derive_pci_id49 *50 * PARAMETERS: pci_id - Initial values for the PCI ID. May be51 * modified by this function.52 * root_pci_device - A handle to a PCI device object. This53 * object must be a PCI Root Bridge having a54 * _HID value of either PNP0A03 or PNP0A0855 * pci_region - A handle to a PCI configuration space56 * Operation Region being initialized57 *58 * RETURN: Status59 *60 * DESCRIPTION: This function derives a full PCI ID for a PCI device,61 * consisting of a Segment number, Bus number, Device number,62 * and function code.63 *64 * The PCI hardware dynamically configures PCI bus numbers65 * depending on the bus topology discovered during system66 * initialization. This function is invoked during configuration67 * of a PCI_Config Operation Region in order to (possibly) update68 * the Bus/Device/Function numbers in the pci_id with the actual69 * values as determined by the hardware and operating system70 * configuration.71 *72 * The pci_id parameter is initially populated during the Operation73 * Region initialization. This function is then called, and is74 * will make any necessary modifications to the Bus, Device, or75 * Function number PCI ID subfields as appropriate for the76 * current hardware and OS configuration.77 *78 * NOTE: Created 08/2010. Replaces the previous OSL acpi_os_derive_pci_id79 * interface since this feature is OS-independent. This module80 * specifically avoids any use of recursion by building a local81 * temporary device list.82 *83 ******************************************************************************/84 85acpi_status86acpi_hw_derive_pci_id(struct acpi_pci_id *pci_id,87 acpi_handle root_pci_device, acpi_handle pci_region)88{89 acpi_status status;90 struct acpi_pci_device *list_head;91 92 ACPI_FUNCTION_TRACE(hw_derive_pci_id);93 94 if (!pci_id) {95 return_ACPI_STATUS(AE_BAD_PARAMETER);96 }97 98 /* Build a list of PCI devices, from pci_region up to root_pci_device */99 100 status =101 acpi_hw_build_pci_list(root_pci_device, pci_region, &list_head);102 if (ACPI_SUCCESS(status)) {103 104 /* Walk the list, updating the PCI device/function/bus numbers */105 106 status = acpi_hw_process_pci_list(pci_id, list_head);107 108 /* Delete the list */109 110 acpi_hw_delete_pci_list(list_head);111 }112 113 return_ACPI_STATUS(status);114}115 116/*******************************************************************************117 *118 * FUNCTION: acpi_hw_build_pci_list119 *120 * PARAMETERS: root_pci_device - A handle to a PCI device object. This121 * object is guaranteed to be a PCI Root122 * Bridge having a _HID value of either123 * PNP0A03 or PNP0A08124 * pci_region - A handle to the PCI configuration space125 * Operation Region126 * return_list_head - Where the PCI device list is returned127 *128 * RETURN: Status129 *130 * DESCRIPTION: Builds a list of devices from the input PCI region up to the131 * Root PCI device for this namespace subtree.132 *133 ******************************************************************************/134 135static acpi_status136acpi_hw_build_pci_list(acpi_handle root_pci_device,137 acpi_handle pci_region,138 struct acpi_pci_device **return_list_head)139{140 acpi_handle current_device;141 acpi_handle parent_device;142 acpi_status status;143 struct acpi_pci_device *list_element;144 145 /*146 * Ascend namespace branch until the root_pci_device is reached, building147 * a list of device nodes. Loop will exit when either the PCI device is148 * found, or the root of the namespace is reached.149 */150 *return_list_head = NULL;151 current_device = pci_region;152 while (1) {153 status = acpi_get_parent(current_device, &parent_device);154 if (ACPI_FAILURE(status)) {155 156 /* Must delete the list before exit */157 158 acpi_hw_delete_pci_list(*return_list_head);159 return (status);160 }161 162 /* Finished when we reach the PCI root device (PNP0A03 or PNP0A08) */163 164 if (parent_device == root_pci_device) {165 return (AE_OK);166 }167 168 list_element = ACPI_ALLOCATE(sizeof(struct acpi_pci_device));169 if (!list_element) {170 171 /* Must delete the list before exit */172 173 acpi_hw_delete_pci_list(*return_list_head);174 return (AE_NO_MEMORY);175 }176 177 /* Put new element at the head of the list */178 179 list_element->next = *return_list_head;180 list_element->device = parent_device;181 *return_list_head = list_element;182 183 current_device = parent_device;184 }185}186 187/*******************************************************************************188 *189 * FUNCTION: acpi_hw_process_pci_list190 *191 * PARAMETERS: pci_id - Initial values for the PCI ID. May be192 * modified by this function.193 * list_head - Device list created by194 * acpi_hw_build_pci_list195 *196 * RETURN: Status197 *198 * DESCRIPTION: Walk downward through the PCI device list, getting the device199 * info for each, via the PCI configuration space and updating200 * the PCI ID as necessary. Deletes the list during traversal.201 *202 ******************************************************************************/203 204static acpi_status205acpi_hw_process_pci_list(struct acpi_pci_id *pci_id,206 struct acpi_pci_device *list_head)207{208 acpi_status status = AE_OK;209 struct acpi_pci_device *info;210 u16 bus_number;211 u8 is_bridge = TRUE;212 213 ACPI_FUNCTION_NAME(hw_process_pci_list);214 215 ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,216 "Input PciId: Seg %4.4X Bus %4.4X Dev %4.4X Func %4.4X\n",217 pci_id->segment, pci_id->bus, pci_id->device,218 pci_id->function));219 220 bus_number = pci_id->bus;221 222 /*223 * Descend down the namespace tree, collecting PCI device, function,224 * and bus numbers. bus_number is only important for PCI bridges.225 * Algorithm: As we descend the tree, use the last valid PCI device,226 * function, and bus numbers that are discovered, and assign them227 * to the PCI ID for the target device.228 */229 info = list_head;230 while (info) {231 status = acpi_hw_get_pci_device_info(pci_id, info->device,232 &bus_number, &is_bridge);233 if (ACPI_FAILURE(status)) {234 return (status);235 }236 237 info = info->next;238 }239 240 ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,241 "Output PciId: Seg %4.4X Bus %4.4X Dev %4.4X Func %4.4X "242 "Status %X BusNumber %X IsBridge %X\n",243 pci_id->segment, pci_id->bus, pci_id->device,244 pci_id->function, status, bus_number, is_bridge));245 246 return (AE_OK);247}248 249/*******************************************************************************250 *251 * FUNCTION: acpi_hw_delete_pci_list252 *253 * PARAMETERS: list_head - Device list created by254 * acpi_hw_build_pci_list255 *256 * RETURN: None257 *258 * DESCRIPTION: Free the entire PCI list.259 *260 ******************************************************************************/261 262static void acpi_hw_delete_pci_list(struct acpi_pci_device *list_head)263{264 struct acpi_pci_device *next;265 struct acpi_pci_device *previous;266 267 next = list_head;268 while (next) {269 previous = next;270 next = previous->next;271 ACPI_FREE(previous);272 }273}274 275/*******************************************************************************276 *277 * FUNCTION: acpi_hw_get_pci_device_info278 *279 * PARAMETERS: pci_id - Initial values for the PCI ID. May be280 * modified by this function.281 * pci_device - Handle for the PCI device object282 * bus_number - Where a PCI bridge bus number is returned283 * is_bridge - Return value, indicates if this PCI284 * device is a PCI bridge285 *286 * RETURN: Status287 *288 * DESCRIPTION: Get the device info for a single PCI device object. Get the289 * _ADR (contains PCI device and function numbers), and for PCI290 * bridge devices, get the bus number from PCI configuration291 * space.292 *293 ******************************************************************************/294 295static acpi_status296acpi_hw_get_pci_device_info(struct acpi_pci_id *pci_id,297 acpi_handle pci_device,298 u16 *bus_number, u8 *is_bridge)299{300 acpi_status status;301 acpi_object_type object_type;302 u64 return_value;303 u64 pci_value;304 305 /* We only care about objects of type Device */306 307 status = acpi_get_type(pci_device, &object_type);308 if (ACPI_FAILURE(status)) {309 return (status);310 }311 312 if (object_type != ACPI_TYPE_DEVICE) {313 return (AE_OK);314 }315 316 /* We need an _ADR. Ignore device if not present */317 318 status = acpi_ut_evaluate_numeric_object(METHOD_NAME__ADR,319 pci_device, &return_value);320 if (ACPI_FAILURE(status)) {321 return (AE_OK);322 }323 324 /*325 * From _ADR, get the PCI Device and Function and326 * update the PCI ID.327 */328 pci_id->device = ACPI_HIWORD(ACPI_LODWORD(return_value));329 pci_id->function = ACPI_LOWORD(ACPI_LODWORD(return_value));330 331 /*332 * If the previous device was a bridge, use the previous333 * device bus number334 */335 if (*is_bridge) {336 pci_id->bus = *bus_number;337 }338 339 /*340 * Get the bus numbers from PCI Config space:341 *342 * First, get the PCI header_type343 */344 *is_bridge = FALSE;345 status = acpi_os_read_pci_configuration(pci_id,346 PCI_CFG_HEADER_TYPE_REG,347 &pci_value, 8);348 if (ACPI_FAILURE(status)) {349 return (status);350 }351 352 /* We only care about bridges (1=pci_bridge, 2=card_bus_bridge) */353 354 pci_value &= PCI_HEADER_TYPE_MASK;355 356 if ((pci_value != PCI_TYPE_BRIDGE) &&357 (pci_value != PCI_TYPE_CARDBUS_BRIDGE)) {358 return (AE_OK);359 }360 361 /* Bridge: Get the Primary bus_number */362 363 status = acpi_os_read_pci_configuration(pci_id,364 PCI_CFG_PRIMARY_BUS_NUMBER_REG,365 &pci_value, 8);366 if (ACPI_FAILURE(status)) {367 return (status);368 }369 370 *is_bridge = TRUE;371 pci_id->bus = (u16)pci_value;372 373 /* Bridge: Get the Secondary bus_number */374 375 status = acpi_os_read_pci_configuration(pci_id,376 PCI_CFG_SECONDARY_BUS_NUMBER_REG,377 &pci_value, 8);378 if (ACPI_FAILURE(status)) {379 return (status);380 }381 382 *bus_number = (u16)pci_value;383 return (AE_OK);384}385