1/* SPDX-License-Identifier: GPL-2.0 */
  2#ifndef _ASM_X86_IOMMU_TABLE_H
  3#define _ASM_X86_IOMMU_TABLE_H
  4
  5#include <asm/swiotlb.h>
  6
  7/*
  8 * History lesson:
  9 * The execution chain of IOMMUs in 2.6.36 looks as so:
 10 *
 11 *            [xen-swiotlb]
 12 *                 |
 13 *         +----[swiotlb *]--+
 14 *        /         |         \
 15 *       /          |          \
 16 *    [GART]     [Calgary]  [Intel VT-d]
 17 *     /
 18 *    /
 19 * [AMD-Vi]
 20 *
 21 * *: if SWIOTLB detected 'iommu=soft'/'swiotlb=force' it would skip
 22 * over the rest of IOMMUs and unconditionally initialize the SWIOTLB.
 23 * Also it would surreptitiously initialize set the swiotlb=1 if there were
 24 * more than 4GB and if the user did not pass in 'iommu=off'. The swiotlb
 25 * flag would be turned off by all IOMMUs except the Calgary one.
 26 *
 27 * The IOMMU_INIT* macros allow a similar tree (or more complex if desired)
 28 * to be built by defining who we depend on.
 29 *
 30 * And all that needs to be done is to use one of the macros in the IOMMU
 31 * and the pci-dma.c will take care of the rest.
 32 */
 33
 34struct iommu_table_entry {
 35	initcall_t	detect;
 36	initcall_t	depend;
 37	void		(*early_init)(void); /* No memory allocate available. */
 38	void		(*late_init)(void); /* Yes, can allocate memory. */
 39#define IOMMU_FINISH_IF_DETECTED (1<<0)
 40#define IOMMU_DETECTED		 (1<<1)
 41	int		flags;
 42};
 43/*
 44 * Macro fills out an entry in the .iommu_table that is equivalent
 45 * to the fields that 'struct iommu_table_entry' has. The entries
 46 * that are put in the .iommu_table section are not put in any order
 47 * hence during boot-time we will have to resort them based on
 48 * dependency. */
 49
 50
 51#define __IOMMU_INIT(_detect, _depend, _early_init, _late_init, _finish)\
 52	static const struct iommu_table_entry				\
 53		__iommu_entry_##_detect __used				\
 54	__attribute__ ((unused, __section__(".iommu_table"),		\
 55			aligned((sizeof(void *)))))	\
 56	= {_detect, _depend, _early_init, _late_init,			\
 57	   _finish ? IOMMU_FINISH_IF_DETECTED : 0}
 58/*
 59 * The simplest IOMMU definition. Provide the detection routine
 60 * and it will be run after the SWIOTLB and the other IOMMUs
 61 * that utilize this macro. If the IOMMU is detected (ie, the
 62 * detect routine returns a positive value), the other IOMMUs
 63 * are also checked. You can use IOMMU_INIT_POST_FINISH if you prefer
 64 * to stop detecting the other IOMMUs after yours has been detected.
 65 */
 66#define IOMMU_INIT_POST(_detect)					\
 67	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  NULL, NULL, 0)
 68
 69#define IOMMU_INIT_POST_FINISH(detect)					\
 70	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  NULL, NULL, 1)
 71
 72/*
 73 * A more sophisticated version of IOMMU_INIT. This variant requires:
 74 *  a). A detection routine function.
 75 *  b). The name of the detection routine we depend on to get called
 76 *      before us.
 77 *  c). The init routine which gets called if the detection routine
 78 *      returns a positive value from the pci_iommu_alloc. This means
 79 *      no presence of a memory allocator.
 80 *  d). Similar to the 'init', except that this gets called from pci_iommu_init
 81 *      where we do have a memory allocator.
 82 *
 83 * The standard IOMMU_INIT differs from the IOMMU_INIT_FINISH variant
 84 * in that the former will continue detecting other IOMMUs in the call
 85 * list after the detection routine returns a positive number, while the
 86 * latter will stop the execution chain upon first successful detection.
 87 * Both variants will still call the 'init' and 'late_init' functions if
 88 * they are set.
 89 */
 90#define IOMMU_INIT_FINISH(_detect, _depend, _init, _late_init)		\
 91	__IOMMU_INIT(_detect, _depend, _init, _late_init, 1)
 92
 93#define IOMMU_INIT(_detect, _depend, _init, _late_init)			\
 94	__IOMMU_INIT(_detect, _depend, _init, _late_init, 0)
 95
 96void sort_iommu_table(struct iommu_table_entry *start,
 97		      struct iommu_table_entry *finish);
 98
 99void check_iommu_entries(struct iommu_table_entry *start,
100			 struct iommu_table_entry *finish);
101
102#endif /* _ASM_X86_IOMMU_TABLE_H */