linux_dsm_epyc7002/include/linux/swiotlb.h
Konrad Rzeszutek Wilk 7453c549f5 swiotlb: Export swiotlb_max_segment to users
So they can figure out what is the optimal number of pages
that can be contingously stitched together without fear of
bounce buffer.

We also expose an mechanism for sub-users of SWIOTLB API, such
as Xen-SWIOTLB to set the max segment value. And lastly
if swiotlb=force is set (which mandates we bounce buffer everything)
we set max_segment so at least we can bounce buffer one 4K page
instead of a giant 512KB one for which we may not have space.

Signed-off-by: Konrad Rzeszutek Wilk <konrad.wilk@oracle.com>
Reported-and-Tested-by: Juergen Gross <jgross@suse.com>
2017-01-06 13:00:01 -05:00

128 lines
3.7 KiB
C

#ifndef __LINUX_SWIOTLB_H
#define __LINUX_SWIOTLB_H
#include <linux/dma-direction.h>
#include <linux/init.h>
#include <linux/types.h>
struct device;
struct page;
struct scatterlist;
enum swiotlb_force {
SWIOTLB_NORMAL, /* Default - depending on HW DMA mask etc. */
SWIOTLB_FORCE, /* swiotlb=force */
SWIOTLB_NO_FORCE, /* swiotlb=noforce */
};
extern enum swiotlb_force swiotlb_force;
/*
* Maximum allowable number of contiguous slabs to map,
* must be a power of 2. What is the appropriate value ?
* The complexity of {map,unmap}_single is linearly dependent on this value.
*/
#define IO_TLB_SEGSIZE 128
/*
* log of the size of each IO TLB slab. The number of slabs is command line
* controllable.
*/
#define IO_TLB_SHIFT 11
extern void swiotlb_init(int verbose);
int swiotlb_init_with_tbl(char *tlb, unsigned long nslabs, int verbose);
extern unsigned long swiotlb_nr_tbl(void);
unsigned long swiotlb_size_or_default(void);
extern int swiotlb_late_init_with_tbl(char *tlb, unsigned long nslabs);
/*
* Enumeration for sync targets
*/
enum dma_sync_target {
SYNC_FOR_CPU = 0,
SYNC_FOR_DEVICE = 1,
};
/* define the last possible byte of physical address space as a mapping error */
#define SWIOTLB_MAP_ERROR (~(phys_addr_t)0x0)
extern phys_addr_t swiotlb_tbl_map_single(struct device *hwdev,
dma_addr_t tbl_dma_addr,
phys_addr_t phys, size_t size,
enum dma_data_direction dir,
unsigned long attrs);
extern void swiotlb_tbl_unmap_single(struct device *hwdev,
phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir,
unsigned long attrs);
extern void swiotlb_tbl_sync_single(struct device *hwdev,
phys_addr_t tlb_addr,
size_t size, enum dma_data_direction dir,
enum dma_sync_target target);
/* Accessory functions. */
extern void
*swiotlb_alloc_coherent(struct device *hwdev, size_t size,
dma_addr_t *dma_handle, gfp_t flags);
extern void
swiotlb_free_coherent(struct device *hwdev, size_t size,
void *vaddr, dma_addr_t dma_handle);
extern dma_addr_t swiotlb_map_page(struct device *dev, struct page *page,
unsigned long offset, size_t size,
enum dma_data_direction dir,
unsigned long attrs);
extern void swiotlb_unmap_page(struct device *hwdev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir,
unsigned long attrs);
extern int
swiotlb_map_sg_attrs(struct device *hwdev, struct scatterlist *sgl, int nelems,
enum dma_data_direction dir,
unsigned long attrs);
extern void
swiotlb_unmap_sg_attrs(struct device *hwdev, struct scatterlist *sgl,
int nelems, enum dma_data_direction dir,
unsigned long attrs);
extern void
swiotlb_sync_single_for_cpu(struct device *hwdev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir);
extern void
swiotlb_sync_sg_for_cpu(struct device *hwdev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir);
extern void
swiotlb_sync_single_for_device(struct device *hwdev, dma_addr_t dev_addr,
size_t size, enum dma_data_direction dir);
extern void
swiotlb_sync_sg_for_device(struct device *hwdev, struct scatterlist *sg,
int nelems, enum dma_data_direction dir);
extern int
swiotlb_dma_mapping_error(struct device *hwdev, dma_addr_t dma_addr);
extern int
swiotlb_dma_supported(struct device *hwdev, u64 mask);
#ifdef CONFIG_SWIOTLB
extern void __init swiotlb_free(void);
unsigned int swiotlb_max_segment(void);
#else
static inline void swiotlb_free(void) { }
static inline unsigned int swiotlb_max_segment(void) { return 0; }
#endif
extern void swiotlb_print_info(void);
extern int is_swiotlb_buffer(phys_addr_t paddr);
extern void swiotlb_set_max_segment(unsigned int);
#endif /* __LINUX_SWIOTLB_H */