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 
34 struct 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 
96 void sort_iommu_table(struct iommu_table_entry *start,
97 		      struct iommu_table_entry *finish);
98 
99 void check_iommu_entries(struct iommu_table_entry *start,
100 			 struct iommu_table_entry *finish);
101 
102 #endif /* _ASM_X86_IOMMU_TABLE_H */
103