path: root/arch/powerpc/kernel/eeh_driver.c

// SPDX-License-Identifier: GPL-2.0-or-later
/*
 * PCI Error Recovery Driver for RPA-compliant PPC64 platform.
 * Copyright IBM Corp. 2004 2005
 * Copyright Linas Vepstas <linas@linas.org> 2004, 2005
 *
 * Send comments and feedback to Linas Vepstas <linas@austin.ibm.com>
 */
#include <linux/delay.h>
#include <linux/interrupt.h>
#include <linux/irq.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/pci_hotplug.h>
#include <asm/eeh.h>
#include <asm/eeh_event.h>
#include <asm/ppc-pci.h>
#include <asm/pci-bridge.h>
#include <asm/rtas.h>

struct eeh_rmv_data {
	struct list_head removed_vf_list;
	int removed_dev_count;
};

static int eeh_result_priority(enum pci_ers_result result)
{
	switch (result) {
	case PCI_ERS_RESULT_NONE:
		return 1;
	case PCI_ERS_RESULT_NO_AER_DRIVER:
		return 2;
	case PCI_ERS_RESULT_RECOVERED:
		return 3;
	case PCI_ERS_RESULT_CAN_RECOVER:
		return 4;
	case PCI_ERS_RESULT_DISCONNECT:
		return 5;
	case PCI_ERS_RESULT_NEED_RESET:
		return 6;
	default:
		WARN_ONCE(1, "Unknown pci_ers_result value: %d\n", result);
		return 0;
	}
};

static const char *pci_ers_result_name(enum pci_ers_result result)
{
	switch (result) {
	case PCI_ERS_RESULT_NONE:
		return "none";
	case PCI_ERS_RESULT_CAN_RECOVER:
		return "can recover";
	case PCI_ERS_RESULT_NEED_RESET:
		return "need reset";
	case PCI_ERS_RESULT_DISCONNECT:
		return "disconnect";
	case PCI_ERS_RESULT_RECOVERED:
		return "recovered";
	case PCI_ERS_RESULT_NO_AER_DRIVER:
		return "no AER driver";
	default:
		WARN_ONCE(1, "Unknown result type: %d\n", result);
		return "unknown";
	}
};

static enum pci_ers_result pci_ers_merge_result(enum pci_ers_result old,
						enum pci_ers_result new)
{
	if (eeh_result_priority(new) > eeh_result_priority(old))
		return new;
	return old;
}

static bool eeh_dev_removed(struct eeh_dev *edev)
{
	return !edev || (edev->mode & EEH_DEV_REMOVED);
}

static bool eeh_edev_actionable(struct eeh_dev *edev)
{
	if (!edev->pdev)
		return false;
	if (edev->pdev->error_state == pci_channel_io_perm_failure)
		return false;
	if (eeh_dev_removed(edev))
		return false;
	if (eeh_pe_passed(edev->pe))
		return false;

	return true;
}

/**
 * eeh_pcid_get - Get the PCI device driver
 * @pdev: PCI device
 *
 * The function is used to retrieve the PCI device driver for
 * the indicated PCI device. Besides, we will increase the reference
 * of the PCI device driver to prevent that being unloaded on
 * the fly. Otherwise, kernel crash would be seen.
 */
static inline struct pci_driver *eeh_pcid_get(struct pci_dev *pdev)
{
	if (!pdev || !pdev->dev.driver)
		return NULL;

	if (!try_module_get(pdev->dev.driver->owner))
		return NULL;

	return to_pci_driver(pdev->dev.driver);
}

/**
 * eeh_pcid_put - Dereference on the PCI device driver
 * @pdev: PCI device
 *
 * The function is called to do dereference on the PCI device
 * driver of the indicated PCI device.
 */
static inline void eeh_pcid_put(struct pci_dev *pdev)
{
	if (!pdev || !pdev->dev.driver)
		return;

	module_put(pdev->dev.driver->owner);
}

/**
 * eeh_disable_irq - Disable interrupt for the recovering device
 * @dev: PCI device
 *
 * This routine must be called when reporting temporary or permanent
 * error to the particular PCI device to disable interrupt of that
 * device. If the device has enabled MSI or MSI-X interrupt, we needn't
 * do real work because EEH should freeze DMA transfers for those PCI
 * devices encountering EEH errors, which includes MSI or MSI-X.
 */
static void eeh_disable_irq(struct eeh_dev *edev)
{
	/* Don't disable MSI and MSI-X interrupts. They are
	 * effectively disabled by the DMA Stopped state
	 * when an EEH error occurs.
	 */
	if (edev->pdev->msi_enabled || edev->pdev->msix_enabled)
		return;

	if (!irq_has_action(edev->pdev->irq))
		return;

	edev->