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// SPDX-License-Identifier: MIT
/*
* Copyright © 2022 Intel Corporation
*/
#include <pciaccess.h>
#include "igt_core.h"
#include "igt_pci.h"
static int find_pci_cap_offset_at(struct pci_device *dev, enum pci_cap_id cap_id,
int start_offset)
{
uint8_t offset = 0xff;
uint16_t cap_header = 0xffff;
int loop = (PCI_CFG_SPACE_SIZE - PCI_TYPE0_1_HEADER_SIZE)
/ sizeof(cap_header);
if (pci_device_cfg_read_u8(dev, &offset, start_offset))
return -1;
while (loop--) {
igt_assert_f(offset != 0xff, "pci config space inaccessible\n");
if (offset < PCI_TYPE0_1_HEADER_SIZE)
break;
if (pci_device_cfg_read_u16(dev, &cap_header, (offset & 0xFC)))
return -1;
if (!cap_id || cap_id == (cap_header & 0xFF))
return offset;
offset = cap_header >> 8;
}
igt_fail_on_f(loop <= 0 && offset, "pci capability offset doesn't terminate\n");
return 0;
}
/**
* find_pci_cap_offset:
* @dev: pci device
* @cap_id: searched capability id, 0 means any capability
*
* return:
* -1 on config read error, 0 if capability is not found,
* otherwise offset at which capability with cap_id is found
*/
int find_pci_cap_offset(struct pci_device *dev, enum pci_cap_id cap_id)
{
return find_pci_cap_offset_at(dev, cap_id, PCI_CAPS_START);
}
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