linux/arch/x86/include/asm/iommu.h

#ifndef _ASM_X86_IOMMU_H
#define _ASM_X86_IOMMU_H

extern void pci_iommu_shutdown(void);
extern void no_iommu_init(void);
extern struct dma_mapping_ops nommu_dma_ops;
extern int force_iommu, no_iommu;
extern int iommu_detected;
extern int dmar_disabled;

extern unsigned long iommu_nr_pages(unsigned long addr, unsigned long len);

/* 10 seconds */
#define DMAR_OPERATION_TIMEOUT ((cycles_t) tsc_khz*10*1000)

#ifdef CONFIG_GART_IOMMU
extern int gart_iommu_aperture;
extern int gart_iommu_aperture_allowed;
extern int gart_iommu_aperture_disabled;

extern void early_gart_iommu_check(void);
extern void gart_iommu_init(void);
extern void gart_iommu_shutdown(void);
extern void __init gart_parse_options(char *);
extern void gart_iommu_hole_init(void);

#else
#define gart_iommu_aperture            0
#define gart_iommu_aperture_allowed    0
#define gart_iommu_aperture_disabled   1

static inline void early_gart_iommu_check(void)
{
}
static inline void gart_iommu_init(void)
{
}
static inline void gart_iommu_shutdown(void)
{
}
static inline void gart_parse_options(char *options)
{
}
static inline void gart_iommu_hole_init(void)
{
}
#endif

#endif /* _ASM_X86_IOMMU_H */