arch/x86/include/asm/iommu_table.h

   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
  33 struct 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 const                     \
  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,  0, 0, 0)
  67
  68 #define IOMMU_INIT_POST_FINISH(detect)                                  \
  69         __IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  0, 0, 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 vs the _FINISH differs in that the _FINISH variant will
  83  * continue detecting other IOMMUs in the call list after the
  84  * the detection routine returns a positive number. The _FINISH will
  85  * stop the execution chain. Both will still call the 'init' and
  86  * 'late_init' functions if they are set.
  87  */
  88 #define IOMMU_INIT_FINISH(_detect, _depend, _init, _late_init)          \
  89         __IOMMU_INIT(_detect, _depend, _init, _late_init, 1)
  90
  91 #define IOMMU_INIT(_detect, _depend, _init, _late_init)                 \
  92         __IOMMU_INIT(_detect, _depend, _init, _late_init, 0)
  93
  94 void sort_iommu_table(struct iommu_table_entry *start,
  95                       struct iommu_table_entry *finish);
  96
  97 void check_iommu_entries(struct iommu_table_entry *start,
  98                          struct iommu_table_entry *finish);
  99
 100 #endif /* _ASM_X86_IOMMU_TABLE_H */