dmaengine: ioatdma: Ignore IOAT devices under hotplug-capable PCI host bridge

#include <linux/interrupt.h>

#include <linux/dca.h>

#include <linux/slab.h>

#include <linux/acpi.h>

#include "dma.h"

#include "dma_v2.h"

#include "registers.h"

	return d;

}

/*

 * The dmaengine core assumes that async DMA devices will only be removed

 * when they not used anymore, or it assumes dma_async_device_unregister()

 * will only be called by dma driver exit routines. But this assumption is

 * not true for the IOAT driver, which calls dma_async_device_unregister()

 * from ioat_remove(). So current IOAT driver doesn't support device

 * hot-removal because it may cause system crash to hot-remove inuse IOAT

 * devices.

 *

 * This is a hack to disable IOAT devices under ejectable PCI host bridge

 * so it won't break PCI host bridge hot-removal.

 */

static bool ioat_pci_has_ejectable_acpi_ancestor(struct pci_dev *pdev)

{

#ifdef CONFIG_ACPI

	struct pci_bus *bus = pdev->bus;

	struct acpi_device *adev;

	while (bus->parent)

		bus = bus->parent;

	for (adev = ACPI_COMPANION(bus->bridge); adev; adev = adev->parent)

		if (adev->flags.ejectable)

			return true;

#endif

	return false;

}

static int ioat_pci_probe(struct pci_dev *pdev, const struct pci_device_id *id)

{

	void __iomem * const *iomap;

	struct ioatdma_device *device;

	int err;

	if (ioat_pci_has_ejectable_acpi_ancestor(pdev)) {

		dev_dbg(&pdev->dev, "ignore ejectable IOAT device.\n");

		return -ENODEV;

	}

	err = pcim_enable_device(pdev);

	if (err)

		return err;