1#ifndef _ASM_X86_IOMMU_TABLE_H
  2#define _ASM_X86_IOMMU_TABLE_H
  3
  4#include <asm/swiotlb.h>
  5
  6/*
  7 * History lesson:
  8 * The execution chain of IOMMUs in 2.6.36 looks as so:
  9 *
 10 *            [xen-swiotlb]
 11 *                 |
 12 *         +----[swiotlb *]--+
 13 *        /         |         \
 14 *       /          |          \
 15 *    [GART]     [Calgary]  [Intel VT-d]
 16 *     /
 17 *    /
 18 * [AMD-Vi]
 19 *
 20 * *: if SWIOTLB detected 'iommu=soft'/'swiotlb=force' it would skip
 21 * over the rest of IOMMUs and unconditionally initialize the SWIOTLB.
 22 * Also it would surreptitiously initialize set the swiotlb=1 if there were
 23 * more than 4GB and if the user did not pass in 'iommu=off'. The swiotlb
 24 * flag would be turned off by all IOMMUs except the Calgary one.
 25 *
 26 * The IOMMU_INIT* macros allow a similar tree (or more complex if desired)
 27 * to be built by defining who we depend on.
 28 *
 29 * And all that needs to be done is to use one of the macros in the IOMMU
 30 * and the pci-dma.c will take care of the rest.
 31 */
 32
 33struct iommu_table_entry {
 34	initcall_t	detect;
 35	initcall_t	depend;
 36	void		(*early_init)(void); /* No memory allocate available. */
 37	void		(*late_init)(void); /* Yes, can allocate memory. */
 38#define IOMMU_FINISH_IF_DETECTED (1<<0)
 39#define IOMMU_DETECTED		 (1<<1)
 40	int		flags;
 41};
 42/*
 43 * Macro fills out an entry in the .iommu_table that is equivalent
 44 * to the fields that 'struct iommu_table_entry' has. The entries
 45 * that are put in the .iommu_table section are not put in any order
 46 * hence during boot-time we will have to resort them based on
 47 * dependency. */
 48
 49
 50#define __IOMMU_INIT(_detect, _depend, _early_init, _late_init, _finish)\
 51	static const struct iommu_table_entry				\
 52		__iommu_entry_##_detect __used				\
 53	__attribute__ ((unused, __section__(".iommu_table"),		\
 54			aligned((sizeof(void *)))))	\
 55	= {_detect, _depend, _early_init, _late_init,			\
 56	   _finish ? IOMMU_FINISH_IF_DETECTED : 0}
 57/*
 58 * The simplest IOMMU definition. Provide the detection routine
 59 * and it will be run after the SWIOTLB and the other IOMMUs
 60 * that utilize this macro. If the IOMMU is detected (ie, the
 61 * detect routine returns a positive value), the other IOMMUs
 62 * are also checked. You can use IOMMU_INIT_POST_FINISH if you prefer
 63 * to stop detecting the other IOMMUs after yours has been detected.
 64 */
 65#define IOMMU_INIT_POST(_detect)					\
 66	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  NULL, NULL, 0)
 67
 68#define IOMMU_INIT_POST_FINISH(detect)					\
 69	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  NULL, NULL, 1)
 70
 71/*
 72 * A more sophisticated version of IOMMU_INIT. This variant requires:
 73 *  a). A detection routine function.
 74 *  b). The name of the detection routine we depend on to get called
 75 *      before us.
 76 *  c). The init routine which gets called if the detection routine
 77 *      returns a positive value from the pci_iommu_alloc. This means
 78 *      no presence of a memory allocator.
 79 *  d). Similar to the 'init', except that this gets called from pci_iommu_init
 80 *      where we do have a memory allocator.
 81 *
 82 * The standard IOMMU_INIT differs from the IOMMU_INIT_FINISH variant
 83 * in that the former will continue detecting other IOMMUs in the call
 84 * list after the detection routine returns a positive number, while the
 85 * latter will stop the execution chain upon first successful detection.
 86 * Both variants will still call the 'init' and 'late_init' functions if
 87 * they are set.
 88 */
 89#define IOMMU_INIT_FINISH(_detect, _depend, _init, _late_init)		\
 90	__IOMMU_INIT(_detect, _depend, _init, _late_init, 1)
 91
 92#define IOMMU_INIT(_detect, _depend, _init, _late_init)			\
 93	__IOMMU_INIT(_detect, _depend, _init, _late_init, 0)
 94
 95void sort_iommu_table(struct iommu_table_entry *start,
 96		      struct iommu_table_entry *finish);
 97
 98void check_iommu_entries(struct iommu_table_entry *start,
 99			 struct iommu_table_entry *finish);
100
101#endif /* _ASM_X86_IOMMU_TABLE_H */