linux_kernel/arch/ia64/kernel/pci-dma.c

// SPDX-License-Identifier: GPL-2.0
/*
 * Dynamic DMA mapping support.
 */

#include <linux/types.h>
#include <linux/mm.h>
#include <linux/string.h>
#include <linux/pci.h>
#include <linux/module.h>
#include <linux/dmar.h>
#include <asm/iommu.h>
#include <asm/machvec.h>
#include <linux/dma-mapping.h>
#include <linux/kernel.h>
#include <asm/page.h>

int no_iommu __read_mostly;
#ifdef CONFIG_IOMMU_DEBUG
int force_iommu __read_mostly = 1;
#else
int force_iommu __read_mostly;
#endif

int iommu_pass_through;

static int __init pci_iommu_init(void)
{
	if (iommu_detected)
		intel_iommu_init();

	return 0;
}

/* Must execute after PCI subsystem */
fs_initcall(pci_iommu_init);

void __init pci_iommu_alloc(void)
{
	/*
	 * The order of these functions is important for
	 * fall-back/fail-over reasons
	 */
	detect_intel_iommu();

#ifdef CONFIG_SWIOTLB
	if (!iommu_detected) {
#ifdef CONFIG_IA64_GENERIC
		printk(KERN_INFO "PCI-DMA: Re-initialize machine vector.\n");
		machvec_init("dig");
		swiotlb_dma_init();
#else
		panic("Unable to find Intel IOMMU");
#endif /* CONFIG_IA64_GENERIC */
	}
#endif /* CONFIG_SWIOTLB */
}