// SPDX-License-Identifier: BSD-3-Clause OR GPL-2.0
/*******************************************************************************
*
* Module Name: hwpci - Obtain PCI bus, device, and function numbers
*
******************************************************************************/
#include <acpi/acpi.h>
#include "accommon.h"
#define _COMPONENT ACPI_NAMESPACE
ACPI_MODULE_NAME("hwpci")
/* PCI configuration space values */
#define PCI_CFG_HEADER_TYPE_REG 0x0E
#define PCI_CFG_PRIMARY_BUS_NUMBER_REG 0x18
#define PCI_CFG_SECONDARY_BUS_NUMBER_REG 0x19
/* PCI header values */
#define PCI_HEADER_TYPE_MASK 0x7F
#define PCI_TYPE_BRIDGE 0x01
#define PCI_TYPE_CARDBUS_BRIDGE 0x02
typedef struct acpi_pci_device {
acpi_handle device;
struct acpi_pci_device *next;
} acpi_pci_device;
/* Local prototypes */
static acpi_status
acpi_hw_build_pci_list(acpi_handle root_pci_device,
acpi_handle pci_region,
struct acpi_pci_device **return_list_head);
static acpi_status
acpi_hw_process_pci_list(struct acpi_pci_id *pci_id,
struct acpi_pci_device *list_head);
static void acpi_hw_delete_pci_list(struct acpi_pci_device *list_head);
static acpi_status
acpi_hw_get_pci_device_info(struct acpi_pci_id *pci_id,
acpi_handle pci_device,
u16 *bus_number, u8 *is_bridge);
/*******************************************************************************
*
* FUNCTION: acpi_hw_derive_pci_id
*
* PARAMETERS: pci_id - Initial values for the PCI ID. May be
* modified by this function.
* root_pci_device - A handle to a PCI device object. This
* object must be a PCI Root Bridge having a
* _HID value of either PNP0A03 or PNP0A08
* pci_region - A handle to a PCI configuration space
* Operation Region being initialized
*
* RETURN: Status
*
* DESCRIPTION: This function derives a full PCI ID for a PCI device,
* consisting of a Segment number, Bus number, Device number,
* and function code.
*
* The PCI hardware dynamically configures PCI bus numbers
* depending on the bus topology discovered during system
* initialization. This function is invoked during configuration
* of a PCI_Config Operation Region in order to (possibly) update
* the Bus/Device/Function numbers in the pci_id with the actual
* values as determined by the hardware and operating system
* configuration.
*
* The pci_id parameter is initially populated during the Operation
* Region initialization. This function is then called, and is
* will make any necessary modifications to the Bus, Device, or
* Function number PCI ID subfields as appropriate for the
* current hardware and OS configuration.
*
* NOTE: Created 08/2010. Replaces the previous OSL acpi_os_derive_pci_id
* interface since this feature is OS-independent. This module
* specifically avoids any use of recursion by building a local
* temporary device list.
*
******************************************************************************/
acpi_status
acpi_hw_derive_pci_id(struct acpi_pci_id *pci_id,
acpi_handle root_pci_device, acpi_handle pci_region)
{
acpi_status status;
struct acpi_pci_device *list_head;
ACPI_FUNCTION_TRACE(hw_derive_pci_id);
if (!pci_id) {
return_ACPI_STATUS(AE_BAD_PARAMETER);
}
/* Build a list of PCI devices, from pci_region up to root_pci_device */
status =
acpi_hw_build_pci_list(root_pci_device, pci_region, &list_head);
if (ACPI_SUCCESS(status)) {
/* Walk the list, updating the PCI device/function/bus numbers */
status = acpi_hw_process_pci_list(pci_id, list_head);
/* Delete the list */
acpi_hw_delete_pci_list(list_head);
}
return_ACPI_STATUS(status);
}
/*******************************************************************************
*
* FUNCTION: acpi_hw_build_pci_list
*
* PARAMETERS: root_pci_device - A handle to a PCI device object. This
* object is guaranteed to be a PCI Root
* Bridge having a _HID value of either
* PNP0A03 or PNP0A08
* pci_region - A handle to the PCI configuration space
* Operation Region
* return_list_head - Where the PCI device list is returned
*
* RETURN: Status
*
* DESCRIPTION: Builds a list of devices from the input PCI region up to the
* Root PCI device for this namespace subtree.
*
******************************************************************************/
static acpi_status
acpi_hw_build_pci_list(acpi_handle root_pci_device,
acpi_handle pci_region,
struct acpi_pci_device **return_list_head)
{
acpi_handle current_device;
acpi_handle parent_device;
acpi_status status;
struct acpi_pci_device *list_element;
/*
* Ascend namespace branch until the root_pci_device is reached, building
* a list of device nodes. Loop will exit when either the PCI device is
* found, or the root of the namespace is reached.
*/
*return_list_head = NULL;
current_device = pci_region;
while (1) {
status = acpi_get_parent(current_device, &parent_device);
if (ACPI_FAILURE(status)) {
/* Must delete the list before exit */
acpi_hw_delete_pci_list(*return_list_head);
return (status);
}
/* Finished when we reach the PCI root device (PNP0A03 or PNP0A08) */
if (parent_device == root_pci_device) {
return (AE_OK);
}
list_element = ACPI_ALLOCATE(sizeof(struct acpi_pci_device));
if (!list_element) {
/* Must delete the list before exit */
acpi_hw_delete_pci_list(*return_list_head);
return (AE_NO_MEMORY);
}
/* Put new element at the head of the list */
list_element->next = *return_list_head;
list_element->device = parent_device;
*return_list_head = list_element;
current_device = parent_device;
}
}
/*******************************************************************************
*
* FUNCTION: acpi_hw_process_pci_list
*
* PARAMETERS: pci_id - Initial values for the PCI ID. May be
* modified by this function.
* list_head - Device list created by
* acpi_hw_build_pci_list
*
* RETURN: Status
*
* DESCRIPTION: Walk downward through the PCI device list, getting the device
* info for each, via the PCI configuration space and updating
* the PCI ID as necessary. Deletes the list during traversal.
*
******************************************************************************/
static acpi_status
acpi_hw_process_pci_list(struct acpi_pci_id *pci_id,
struct acpi_pci_device *list_head)
{
acpi_status status = AE_OK;
struct acpi_pci_device *info;
u16 bus_number;
u8 is_bridge = TRUE;
ACPI_FUNCTION_NAME(hw_process_pci_list);
ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
"Input PciId: Seg %4.4X Bus %4.4X Dev %4.4X Func %4.4X\n",
pci_id->segment, pci_id->bus, pci_id->device,
pci_id->function));
bus_number = pci_id->bus;
/*
* Descend down the namespace tree, collecting PCI device, function,
* and bus numbers. bus_number is only important for PCI bridges.
* Algorithm: As we descend the tree, use the last valid PCI device,
* function, and bus numbers that are discovered, and assign them
* to the PCI ID for the target device.
*/
info = list_head;
while (info) {
status = acpi_hw_get_pci_device_info(pci_id, info->device,
&bus_number, &is_bridge);
if (ACPI_FAILURE(status)) {
return (status);
}
info = info->next;
}
ACPI_DEBUG_PRINT((ACPI_DB_OPREGION,
"Output PciId: Seg %4.4X Bus %4.4X Dev %4.4X Func %4.4X "
"Status %X BusNumber %X IsBridge %X\n",
pci_id->segment, pci_id->bus, pci_id->device,
pci_id->function, status, bus_number, is_bridge));
return (AE_OK);
}
/*******************************************************************************
*
* FUNCTION: acpi_hw_delete_pci_list
*
* PARAMETERS: list_head - Device list created by
* acpi_hw_build_pci_list
*
* RETURN: None
*
* DESCRIPTION: Free the entire PCI list.
*
******************************************************************************/
static void acpi_hw_delete_pci_list(struct acpi_pci_device *list_head)
{
struct acpi_pci_device *next;
struct acpi_pci_device *previous;
next = list_head;
while (next) {
previous = next;
next = previous->next;
ACPI_FREE(previous);
}
}
/*******************************************************************************
*
* FUNCTION: acpi_hw_get_pci_device_info
*
* PARAMETERS: pci_id - Initial values for the PCI ID. May be
* modified by this function.
* pci_device - Handle for the PCI device object
* bus_number - Where a PCI bridge bus number is returned
* is_bridge - Return value, indicates if this PCI
* device is a PCI bridge
*
* RETURN: Status
*
* DESCRIPTION: Get the device info for a single PCI device object. Get the
* _ADR (contains PCI device and function numbers), and for PCI
* bridge devices, get the bus number from PCI configuration
* space.
*
******************************************************************************/
static acpi_status
acpi_hw_get_pci_device_info(struct acpi_pci_id *pci_id,
acpi_handle pci_device,
u16 *bus_number, u8 *is_bridge)
{
acpi_status status;
acpi_object_type object_type;
u64 return_value;
u64 pci_value;
/* We only care about objects of type Device */
status = acpi_get_type(pci_device, &object_type);
if (ACPI_FAILURE(status)) {
return (status);
}
if (object_type != ACPI_TYPE_DEVICE) {
return (AE_OK);
}
/* We need an _ADR. Ignore device if not present */
status = acpi_ut_evaluate_numeric_object(METHOD_NAME__ADR,
pci_device, &return_value);
if (ACPI_FAILURE(status)) {
return (AE_OK);
}
/*
* From _ADR, get the PCI Device and Function and
* update the PCI ID.
*/
pci_id->device = ACPI_HIWORD(ACPI_LODWORD(return_value));
pci_id->function = ACPI_LOWORD(ACPI_LODWORD(return_value));
/*
* If the previous device was a bridge, use the previous
* device bus number
*/
if (*is_bridge) {
pci_id->bus = *bus_number;
}
/*
* Get the bus numbers from PCI Config space:
*
* First, get the PCI header_type
*/
*is_bridge = FALSE;
status = acpi_os_read_pci_configuration(pci_id,
PCI_CFG_HEADER_TYPE_REG,
&pci_value, 8);
if (ACPI_FAILURE(status)) {
return (status);
}
/* We only care about bridges (1=pci_bridge, 2=card_bus_bridge) */
pci_value &= PCI_HEADER_TYPE_MASK;
if ((pci_value != PCI_TYPE_BRIDGE) &&
(pci_value != PCI_TYPE_CARDBUS_BRIDGE)) {
return (AE_OK);
}
/* Bridge: Get the Primary bus_number */
status = acpi_os_read_pci_configuration(pci_id,
PCI_CFG_PRIMARY_BUS_NUMBER_REG,
&pci_value, 8);
if (ACPI_FAILURE(status)) {
return (status);
}
*is_bridge = TRUE;
pci_id->bus = (u16)pci_value;
/* Bridge: Get the Secondary bus_number */
status = acpi_os_read_pci_configuration(pci_id,
PCI_CFG_SECONDARY_BUS_NUMBER_REG,
&pci_value, 8);
if (ACPI_FAILURE(status)) {
return (status);
}
*bus_number = (u16)pci_value;
return (AE_OK);
}