The header comments diverged a bit from the implementation. Lets re-sync them. Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com> LKML-Reference: <1286564028-2352-3-git-send-email-konrad.wilk@oracle.com> Signed-off-by: H. Peter Anvin <hpa@linux.intel.com>
		
			
				
	
	
		
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			100 lines
		
	
	
	
		
			3.7 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
#ifndef _ASM_X86_IOMMU_TABLE_H
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#define _ASM_X86_IOMMU_TABLE_H
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#include <asm/swiotlb.h>
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/*
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 * History lesson:
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 * The execution chain of IOMMUs in 2.6.36 looks as so:
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 *
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 *            [xen-swiotlb]
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 *                 |
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 *         +----[swiotlb *]--+
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 *        /         |         \
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 *       /          |          \
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 *    [GART]     [Calgary]  [Intel VT-d]
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 *     /
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 *    /
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 * [AMD-Vi]
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 *
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 * *: if SWIOTLB detected 'iommu=soft'/'swiotlb=force' it would skip
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 * over the rest of IOMMUs and unconditionally initialize the SWIOTLB.
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 * Also it would surreptitiously initialize set the swiotlb=1 if there were
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 * more than 4GB and if the user did not pass in 'iommu=off'. The swiotlb
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 * flag would be turned off by all IOMMUs except the Calgary one.
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 *
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 * The IOMMU_INIT* macros allow a similar tree (or more complex if desired)
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 * to be built by defining who we depend on.
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 *
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 * And all that needs to be done is to use one of the macros in the IOMMU
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 * and the pci-dma.c will take care of the rest.
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 */
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struct iommu_table_entry {
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	initcall_t	detect;
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	initcall_t	depend;
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	void		(*early_init)(void); /* No memory allocate available. */
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	void		(*late_init)(void); /* Yes, can allocate memory. */
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#define IOMMU_FINISH_IF_DETECTED (1<<0)
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#define IOMMU_DETECTED		 (1<<1)
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	int		flags;
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};
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/*
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 * Macro fills out an entry in the .iommu_table that is equivalent
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 * to the fields that 'struct iommu_table_entry' has. The entries
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 * that are put in the .iommu_table section are not put in any order
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 * hence during boot-time we will have to resort them based on
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 * dependency. */
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#define __IOMMU_INIT(_detect, _depend, _early_init, _late_init, _finish)\
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	static const struct iommu_table_entry const			\
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		__iommu_entry_##_detect __used				\
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	__attribute__ ((unused, __section__(".iommu_table"),		\
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			aligned((sizeof(void *)))))	\
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	= {_detect, _depend, _early_init, _late_init,			\
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	   _finish ? IOMMU_FINISH_IF_DETECTED : 0}
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/*
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 * The simplest IOMMU definition. Provide the detection routine
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 * and it will be run after the SWIOTLB and the other IOMMUs
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 * that utilize this macro. If the IOMMU is detected (ie, the
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 * detect routine returns a positive value), the other IOMMUs
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 * are also checked. You can use IOMMU_INIT_POST_FINISH if you prefer
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 * to stop detecting the other IOMMUs after yours has been detected.
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 */
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#define IOMMU_INIT_POST(_detect)					\
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	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  0, 0, 0)
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#define IOMMU_INIT_POST_FINISH(detect)					\
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	__IOMMU_INIT(_detect, pci_swiotlb_detect_4gb,  0, 0, 1)
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/*
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 * A more sophisticated version of IOMMU_INIT. This variant requires:
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 *  a). A detection routine function.
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 *  b). The name of the detection routine we depend on to get called
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 *      before us.
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 *  c). The init routine which gets called if the detection routine
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 *      returns a positive value from the pci_iommu_alloc. This means
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 *      no presence of a memory allocator.
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 *  d). Similar to the 'init', except that this gets called from pci_iommu_init
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 *      where we do have a memory allocator.
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 *
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 * The standard vs the _FINISH differs in that the _FINISH variant will
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 * continue detecting other IOMMUs in the call list after the
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 * the detection routine returns a positive number. The _FINISH will
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 * stop the execution chain. Both will still call the 'init' and
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 * 'late_init' functions if they are set.
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 */
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#define IOMMU_INIT_FINISH(_detect, _depend, _init, _late_init)		\
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	__IOMMU_INIT(_detect, _depend, _init, _late_init, 1)
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#define IOMMU_INIT(_detect, _depend, _init, _late_init)			\
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	__IOMMU_INIT(_detect, _depend, _init, _late_init, 0)
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void sort_iommu_table(struct iommu_table_entry *start,
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		      struct iommu_table_entry *finish);
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void check_iommu_entries(struct iommu_table_entry *start,
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			 struct iommu_table_entry *finish);
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#endif /* _ASM_X86_IOMMU_TABLE_H */
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