1// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
2/*******************************************************************************
3 *
4 * Module Name: hwpci - Obtain PCI bus, device, and function numbers
5 *
6 ******************************************************************************/
7
8#include <acpi/acpi.h>
9#include "accommon.h"
10
11#define _COMPONENT ACPI_NAMESPACE
12ACPI_MODULE_NAME("hwpci")
13
14/* PCI configuration space values */
15#define PCI_CFG_HEADER_TYPE_REG 0x0E
16#define PCI_CFG_PRIMARY_BUS_NUMBER_REG 0x18
17#define PCI_CFG_SECONDARY_BUS_NUMBER_REG 0x19
18/* PCI header values */
19#define PCI_HEADER_TYPE_MASK 0x7F
20#define PCI_TYPE_BRIDGE 0x01
21#define PCI_TYPE_CARDBUS_BRIDGE 0x02
22typedef 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_status
31acpi_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_status
36acpi_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_status
42acpi_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_id
49 *
50 * PARAMETERS: pci_id - Initial values for the PCI ID. May be
51 * modified by this function.
52 * root_pci_device - A handle to a PCI device object. This
53 * object must be a PCI Root Bridge having a
54 * _HID value of either PNP0A03 or PNP0A08
55 * pci_region - A handle to a PCI configuration space
56 * Operation Region being initialized
57 *
58 * RETURN: Status
59 *
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 numbers
65 * depending on the bus topology discovered during system
66 * initialization. This function is invoked during configuration
67 * of a PCI_Config Operation Region in order to (possibly) update
68 * the Bus/Device/Function numbers in the pci_id with the actual
69 * values as determined by the hardware and operating system
70 * configuration.
71 *
72 * The pci_id parameter is initially populated during the Operation
73 * Region initialization. This function is then called, and is
74 * will make any necessary modifications to the Bus, Device, or
75 * Function number PCI ID subfields as appropriate for the
76 * current hardware and OS configuration.
77 *
78 * NOTE: Created 08/2010. Replaces the previous OSL acpi_os_derive_pci_id
79 * interface since this feature is OS-independent. This module
80 * specifically avoids any use of recursion by building a local
81 * temporary device list.
82 *
83 ******************************************************************************/
84
85acpi_status
86acpi_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, return_list_head: &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_list
119 *
120 * PARAMETERS: root_pci_device - A handle to a PCI device object. This
121 * object is guaranteed to be a PCI Root
122 * Bridge having a _HID value of either
123 * PNP0A03 or PNP0A08
124 * pci_region - A handle to the PCI configuration space
125 * Operation Region
126 * return_list_head - Where the PCI device list is returned
127 *
128 * RETURN: Status
129 *
130 * DESCRIPTION: Builds a list of devices from the input PCI region up to the
131 * Root PCI device for this namespace subtree.
132 *
133 ******************************************************************************/
134
135static acpi_status
136acpi_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, building
147 * a list of device nodes. Loop will exit when either the PCI device is
148 * 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(object: current_device, out_handle: &parent_device);
154 if (ACPI_FAILURE(status)) {
155
156 /* Must delete the list before exit */
157
158 acpi_hw_delete_pci_list(list_head: *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(list_head: *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_list
190 *
191 * PARAMETERS: pci_id - Initial values for the PCI ID. May be
192 * modified by this function.
193 * list_head - Device list created by
194 * acpi_hw_build_pci_list
195 *
196 * RETURN: Status
197 *
198 * DESCRIPTION: Walk downward through the PCI device list, getting the device
199 * info for each, via the PCI configuration space and updating
200 * the PCI ID as necessary. Deletes the list during traversal.
201 *
202 ******************************************************************************/
203
204static acpi_status
205acpi_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 them
227 * 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, pci_device: info->device,
232 bus_number: &bus_number, is_bridge: &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_list
252 *
253 * PARAMETERS: list_head - Device list created by
254 * acpi_hw_build_pci_list
255 *
256 * RETURN: None
257 *
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_info
278 *
279 * PARAMETERS: pci_id - Initial values for the PCI ID. May be
280 * modified by this function.
281 * pci_device - Handle for the PCI device object
282 * bus_number - Where a PCI bridge bus number is returned
283 * is_bridge - Return value, indicates if this PCI
284 * device is a PCI bridge
285 *
286 * RETURN: Status
287 *
288 * DESCRIPTION: Get the device info for a single PCI device object. Get the
289 * _ADR (contains PCI device and function numbers), and for PCI
290 * bridge devices, get the bus number from PCI configuration
291 * space.
292 *
293 ******************************************************************************/
294
295static acpi_status
296acpi_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(object: pci_device, out_type: &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 device_node: pci_device, value: &return_value);
320 if (ACPI_FAILURE(status)) {
321 return (AE_OK);
322 }
323
324 /*
325 * From _ADR, get the PCI Device and Function and
326 * 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 previous
333 * device bus number
334 */
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_type
343 */
344 *is_bridge = FALSE;
345 status = acpi_os_read_pci_configuration(pci_id,
346 PCI_CFG_HEADER_TYPE_REG,
347 value: &pci_value, width: 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 value: &pci_value, width: 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 value: &pci_value, width: 8);
378 if (ACPI_FAILURE(status)) {
379 return (status);
380 }
381
382 *bus_number = (u16)pci_value;
383 return (AE_OK);
384}
385