drivers/pci/pcie/aer/aerdrv_acpi.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Access ACPI _OSC method
 *
 * Copyright (C) 2006 Intel Corp.
 *	Tom Long Nguyen (tom.l.nguyen@intel.com)
 *	Zhang Yanmin (yanmin.zhang@intel.com)
 *
 */

#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/pm.h>
#include <linux/suspend.h>
#include <linux/acpi.h>
#include <linux/pci-acpi.h>
#include <linux/delay.h>
#include <acpi/apei.h>
#include "aerdrv.h"

#ifdef CONFIG_ACPI_APEI
static inline int hest_match_pci(struct acpi_hest_aer_common *p,
				 struct pci_dev *pci)
{
	return   ACPI_HEST_SEGMENT(p->bus) == pci_domain_nr(pci->bus) &&
		 ACPI_HEST_BUS(p->bus)     == pci->bus->number &&
		 p->device                 == PCI_SLOT(pci->devfn) &&
		 p->function               == PCI_FUNC(pci->devfn);
}

static inline bool hest_match_type(struct acpi_hest_header *hest_hdr,
				struct pci_dev *dev)
{
	u16 hest_type = hest_hdr->type;
	u8 pcie_type = pci_pcie_type(dev);

	if ((hest_type == ACPI_HEST_TYPE_AER_ROOT_PORT &&
		pcie_type == PCI_EXP_TYPE_ROOT_PORT) ||
	    (hest_type == ACPI_HEST_TYPE_AER_ENDPOINT &&
		pcie_type == PCI_EXP_TYPE_ENDPOINT) ||
	    (hest_type == ACPI_HEST_TYPE_AER_BRIDGE &&
		(dev->class >> 16) == PCI_BASE_CLASS_BRIDGE))
		return true;
	return false;
}

struct aer_hest_parse_info {
	struct pci_dev *pci_dev;
	int firmware_first;
};

static int hest_source_is_pcie_aer(struct acpi_hest_header *hest_hdr)
{
	if (hest_hdr->type == ACPI_HEST_TYPE_AER_ROOT_PORT ||
	    hest_hdr->type == ACPI_HEST_TYPE_AER_ENDPOINT ||
	    hest_hdr->type == ACPI_HEST_TYPE_AER_BRIDGE)
		return 1;
	return 0;
}

static int aer_hest_parse(struct acpi_hest_header *hest_hdr, void *data)
{
	struct aer_hest_parse_info *info = data;
	struct acpi_hest_aer_common *p;
	int ff;

	if (!hest_source_is_pcie_aer(hest_hdr))
		return 0;

	p = (struct acpi_hest_aer_common *)(hest_hdr + 1);
	ff = !!(p->flags & ACPI_HEST_FIRMWARE_FIRST);

	/*
	 * If no specific device is supplied, determine whether
	 * FIRMWARE_FIRST is set for *any* PCIe device.
	 */
	if (!info->pci_dev) {
		info->firmware_first |= ff;
		return 0;
	}

	/* Otherwise, check the specific device */
	if (p->flags & ACPI_HEST_GLOBAL) {
		if (hest_match_type(hest_hdr, info->pci_dev))
			info->firmware_first = ff;
	} else
		if (hest_match_pci(p, info->pci_dev))
			info->firmware_first = ff;

	return 0;
}

static void aer_set_firmware_first(struct pci_dev *pci_dev)
{
	int rc;
	struct aer_hest_parse_info info = {
		.pci_dev	= pci_dev,
		.firmware_first	= 0,
	};

	rc = apei_hest_parse(aer_hest_parse, &info);

	if (rc)
		pci_dev->__aer_firmware_first = 0;
	else
		pci_dev->__aer_firmware_first = info.firmware_first;
	pci_dev->__aer_firmware_first_valid = 1;
}

int pcie_aer_get_firmware_first(struct pci_dev *dev)
{
	if (!pci_is_pcie(dev))
		return 0;

	if (!dev->__aer_firmware_first_valid)
		aer_set_firmware_first(dev);
	return dev->__aer_firmware_first;
}

static bool aer_firmware_first;

/**
 * aer_acpi_firmware_first - Check if APEI should control AER.
 */
bool aer_acpi_firmware_first(void)
{
	static bool parsed = false;
	struct aer_hest_parse_info info = {
		.pci_dev	= NULL,	/* Check all PCIe devices */
		.firmware_first	= 0,
	};

	if (!parsed) {
		apei_hest_parse(aer_hest_parse, &info);
		aer_firmware_first = info.firmware_first;
		parsed = true;
	}
	return aer_firmware_first;
}
#endif