This patch adds the support for to create a direct iommu "bypass" window on IODA2 bridges (such as Power8) allowing to bypass iommu page translation completely for 64-bit DMA capable devices, thus significantly improving DMA performances. Additionally, this adds a hook to the struct iommu_table so that the IOMMU API / VFIO can disable the bypass when external ownership is requested, since in that case, the device will be used by an environment such as userspace or a KVM guest which must not be allowed to bypass translations. Signed-off-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
		
			
				
	
	
		
			203 lines
		
	
	
	
		
			6.7 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
			
		
		
	
	
			203 lines
		
	
	
	
		
			6.7 KiB
			
		
	
	
	
		
			C
		
	
	
	
	
	
/*
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 * Copyright (C) 2001 Mike Corrigan & Dave Engebretsen, IBM Corporation
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 * Rewrite, cleanup:
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 * Copyright (C) 2004 Olof Johansson <olof@lixom.net>, IBM Corporation
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 * 
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 * This program is free software; you can redistribute it and/or modify
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 * it under the terms of the GNU General Public License as published by
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 * the Free Software Foundation; either version 2 of the License, or
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 * (at your option) any later version.
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 * 
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 * This program is distributed in the hope that it will be useful,
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 * but WITHOUT ANY WARRANTY; without even the implied warranty of
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 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
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 * GNU General Public License for more details.
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 * 
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 * You should have received a copy of the GNU General Public License
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 * along with this program; if not, write to the Free Software
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 * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307 USA
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 */
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#ifndef _ASM_IOMMU_H
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#define _ASM_IOMMU_H
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#ifdef __KERNEL__
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#include <linux/compiler.h>
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#include <linux/spinlock.h>
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#include <linux/device.h>
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#include <linux/dma-mapping.h>
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#include <linux/bitops.h>
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#include <asm/machdep.h>
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#include <asm/types.h>
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#define IOMMU_PAGE_SHIFT_4K      12
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#define IOMMU_PAGE_SIZE_4K       (ASM_CONST(1) << IOMMU_PAGE_SHIFT_4K)
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#define IOMMU_PAGE_MASK_4K       (~((1 << IOMMU_PAGE_SHIFT_4K) - 1))
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#define IOMMU_PAGE_ALIGN_4K(addr) _ALIGN_UP(addr, IOMMU_PAGE_SIZE_4K)
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#define IOMMU_PAGE_SIZE(tblptr) (ASM_CONST(1) << (tblptr)->it_page_shift)
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#define IOMMU_PAGE_MASK(tblptr) (~((1 << (tblptr)->it_page_shift) - 1))
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#define IOMMU_PAGE_ALIGN(addr, tblptr) _ALIGN_UP(addr, IOMMU_PAGE_SIZE(tblptr))
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/* Boot time flags */
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extern int iommu_is_off;
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extern int iommu_force_on;
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/*
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 * IOMAP_MAX_ORDER defines the largest contiguous block
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 * of dma space we can get.  IOMAP_MAX_ORDER = 13
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 * allows up to 2**12 pages (4096 * 4096) = 16 MB
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 */
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#define IOMAP_MAX_ORDER		13
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#define IOMMU_POOL_HASHBITS	2
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#define IOMMU_NR_POOLS		(1 << IOMMU_POOL_HASHBITS)
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struct iommu_pool {
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	unsigned long start;
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	unsigned long end;
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	unsigned long hint;
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	spinlock_t lock;
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} ____cacheline_aligned_in_smp;
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struct iommu_table {
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	unsigned long  it_busno;     /* Bus number this table belongs to */
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	unsigned long  it_size;      /* Size of iommu table in entries */
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	unsigned long  it_offset;    /* Offset into global table */
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	unsigned long  it_base;      /* mapped address of tce table */
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	unsigned long  it_index;     /* which iommu table this is */
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	unsigned long  it_type;      /* type: PCI or Virtual Bus */
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	unsigned long  it_blocksize; /* Entries in each block (cacheline) */
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	unsigned long  poolsize;
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	unsigned long  nr_pools;
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	struct iommu_pool large_pool;
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	struct iommu_pool pools[IOMMU_NR_POOLS];
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	unsigned long *it_map;       /* A simple allocation bitmap for now */
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	unsigned long  it_page_shift;/* table iommu page size */
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#ifdef CONFIG_IOMMU_API
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	struct iommu_group *it_group;
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#endif
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	void (*set_bypass)(struct iommu_table *tbl, bool enable);
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};
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/* Pure 2^n version of get_order */
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static inline __attribute_const__
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int get_iommu_order(unsigned long size, struct iommu_table *tbl)
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{
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	return __ilog2((size - 1) >> tbl->it_page_shift) + 1;
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}
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struct scatterlist;
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static inline void set_iommu_table_base(struct device *dev, void *base)
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{
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	dev->archdata.dma_data.iommu_table_base = base;
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}
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static inline void *get_iommu_table_base(struct device *dev)
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{
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	return dev->archdata.dma_data.iommu_table_base;
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}
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/* Frees table for an individual device node */
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extern void iommu_free_table(struct iommu_table *tbl, const char *node_name);
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/* Initializes an iommu_table based in values set in the passed-in
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 * structure
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 */
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extern struct iommu_table *iommu_init_table(struct iommu_table * tbl,
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					    int nid);
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#ifdef CONFIG_IOMMU_API
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extern void iommu_register_group(struct iommu_table *tbl,
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				 int pci_domain_number, unsigned long pe_num);
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extern int iommu_add_device(struct device *dev);
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extern void iommu_del_device(struct device *dev);
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#else
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static inline void iommu_register_group(struct iommu_table *tbl,
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					int pci_domain_number,
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					unsigned long pe_num)
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{
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}
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static inline int iommu_add_device(struct device *dev)
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{
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	return 0;
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}
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static inline void iommu_del_device(struct device *dev)
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{
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}
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#endif /* !CONFIG_IOMMU_API */
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static inline void set_iommu_table_base_and_group(struct device *dev,
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						  void *base)
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{
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	set_iommu_table_base(dev, base);
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	iommu_add_device(dev);
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}
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extern int iommu_map_sg(struct device *dev, struct iommu_table *tbl,
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			struct scatterlist *sglist, int nelems,
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			unsigned long mask, enum dma_data_direction direction,
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			struct dma_attrs *attrs);
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extern void iommu_unmap_sg(struct iommu_table *tbl, struct scatterlist *sglist,
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			   int nelems, enum dma_data_direction direction,
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			   struct dma_attrs *attrs);
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extern void *iommu_alloc_coherent(struct device *dev, struct iommu_table *tbl,
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				  size_t size, dma_addr_t *dma_handle,
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				  unsigned long mask, gfp_t flag, int node);
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extern void iommu_free_coherent(struct iommu_table *tbl, size_t size,
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				void *vaddr, dma_addr_t dma_handle);
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extern dma_addr_t iommu_map_page(struct device *dev, struct iommu_table *tbl,
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				 struct page *page, unsigned long offset,
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				 size_t size, unsigned long mask,
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				 enum dma_data_direction direction,
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				 struct dma_attrs *attrs);
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extern void iommu_unmap_page(struct iommu_table *tbl, dma_addr_t dma_handle,
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			     size_t size, enum dma_data_direction direction,
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			     struct dma_attrs *attrs);
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extern void iommu_init_early_pSeries(void);
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extern void iommu_init_early_dart(void);
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extern void iommu_init_early_pasemi(void);
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extern void alloc_dart_table(void);
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#if defined(CONFIG_PPC64) && defined(CONFIG_PM)
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static inline void iommu_save(void)
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{
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	if (ppc_md.iommu_save)
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		ppc_md.iommu_save();
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}
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static inline void iommu_restore(void)
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{
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	if (ppc_md.iommu_restore)
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		ppc_md.iommu_restore();
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}
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#endif
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/* The API to support IOMMU operations for VFIO */
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extern int iommu_tce_clear_param_check(struct iommu_table *tbl,
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		unsigned long ioba, unsigned long tce_value,
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		unsigned long npages);
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extern int iommu_tce_put_param_check(struct iommu_table *tbl,
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		unsigned long ioba, unsigned long tce);
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extern int iommu_tce_build(struct iommu_table *tbl, unsigned long entry,
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		unsigned long hwaddr, enum dma_data_direction direction);
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extern unsigned long iommu_clear_tce(struct iommu_table *tbl,
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		unsigned long entry);
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extern int iommu_clear_tces_and_put_pages(struct iommu_table *tbl,
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		unsigned long entry, unsigned long pages);
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extern int iommu_put_tce_user_mode(struct iommu_table *tbl,
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		unsigned long entry, unsigned long tce);
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extern void iommu_flush_tce(struct iommu_table *tbl);
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extern int iommu_take_ownership(struct iommu_table *tbl);
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extern void iommu_release_ownership(struct iommu_table *tbl);
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extern enum dma_data_direction iommu_tce_direction(unsigned long tce);
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#endif /* __KERNEL__ */
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#endif /* _ASM_IOMMU_H */
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