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linux/arch/powerpc/include/asm/dma-mapping.h
Gavin Shan fe7e85c6f5 powerpc/powernv: Override dma_get_required_mask() 
The dma_get_required_mask() function is used by some drivers to
query the platform about what DMA mask is needed to cover all of
memory. This is a bit of a strange semantic when we have to choose
between IOMMU translation or bypass, but essentially what it means
is "what DMA mask will give best performances".

Currently, our IOMMU backend always returns a 32-bit mask here, we
don't do anything special to it when we have bypass available. This
causes some drivers to choose a 32-bit mask, thus losing the ability
to use the bypass window, thinking this is more efficient. The problem
was reported from the driver of following device:

0004:03:00.0 0107: 1000:0087 (rev 05)
0004:03:00.0 Serial Attached SCSI controller: LSI Logic / Symbios \
             Logic SAS2308 PCI-Express Fusion-MPT SAS-2 (rev 05)

This patch adds an override of that function in order to, instead,
return a 64-bit mask whenever a bypass window is available in order
for drivers to prefer this configuration.

Reported-by: Murali N. Iyer <mniyer@us.ibm.com>
Suggested-by: Benjamin Herrenschmidt <benh@kernel.crashing.org>
Signed-off-by: Gavin Shan <gwshan@linux.vnet.ibm.com>
Signed-off-by: Michael Ellerman <mpe@ellerman.id.au>
2014-09-30 17:15:20 +10:00

227 lines
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/*
* Copyright (C) 2004 IBM
*
* Implements the generic device dma API for powerpc.
* the pci and vio busses
*/
#ifndef _ASM_DMA_MAPPING_H
#define _ASM_DMA_MAPPING_H
#ifdef __KERNEL__
#include <linux/types.h>
#include <linux/cache.h>
/* need struct page definitions */
#include <linux/mm.h>
#include <linux/scatterlist.h>
#include <linux/dma-attrs.h>
#include <linux/dma-debug.h>
#include <asm/io.h>
#include <asm/swiotlb.h>
#define DMA_ERROR_CODE (~(dma_addr_t)0x0)
/* Some dma direct funcs must be visible for use in other dma_ops */
extern void *dma_direct_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag,
struct dma_attrs *attrs);
extern void dma_direct_free_coherent(struct device *dev, size_t size,
void *vaddr, dma_addr_t dma_handle,
struct dma_attrs *attrs);
extern int dma_direct_mmap_coherent(struct device *dev,
struct vm_area_struct *vma,
void *cpu_addr, dma_addr_t handle,
size_t size, struct dma_attrs *attrs);
#ifdef CONFIG_NOT_COHERENT_CACHE
/*
* DMA-consistent mapping functions for PowerPCs that don't support
* cache snooping. These allocate/free a region of uncached mapped
* memory space for use with DMA devices. Alternatively, you could
* allocate the space "normally" and use the cache management functions
* to ensure it is consistent.
*/
struct device;
extern void *__dma_alloc_coherent(struct device *dev, size_t size,
dma_addr_t *handle, gfp_t gfp);
extern void __dma_free_coherent(size_t size, void *vaddr);
extern void __dma_sync(void *vaddr, size_t size, int direction);
extern void __dma_sync_page(struct page *page, unsigned long offset,
size_t size, int direction);
extern unsigned long __dma_get_coherent_pfn(unsigned long cpu_addr);
#else /* ! CONFIG_NOT_COHERENT_CACHE */
/*
* Cache coherent cores.
*/
#define __dma_alloc_coherent(dev, gfp, size, handle) NULL
#define __dma_free_coherent(size, addr) ((void)0)
#define __dma_sync(addr, size, rw) ((void)0)
#define __dma_sync_page(pg, off, sz, rw) ((void)0)
#endif /* ! CONFIG_NOT_COHERENT_CACHE */
static inline unsigned long device_to_mask(struct device *dev)
{
if (dev->dma_mask && *dev->dma_mask)
return *dev->dma_mask;
/* Assume devices without mask can take 32 bit addresses */
return 0xfffffffful;
}
/*
* Available generic sets of operations
*/
#ifdef CONFIG_PPC64
extern struct dma_map_ops dma_iommu_ops;
#endif
extern struct dma_map_ops dma_direct_ops;
static inline struct dma_map_ops *get_dma_ops(struct device *dev)
{
/* We don't handle the NULL dev case for ISA for now. We could
* do it via an out of line call but it is not needed for now. The
* only ISA DMA device we support is the floppy and we have a hack
* in the floppy driver directly to get a device for us.
*/
if (unlikely(dev == NULL))
return NULL;
return dev->archdata.dma_ops;
}
static inline void set_dma_ops(struct device *dev, struct dma_map_ops *ops)
{
dev->archdata.dma_ops = ops;
}
/*
* get_dma_offset()
*
* Get the dma offset on configurations where the dma address can be determined
* from the physical address by looking at a simple offset. Direct dma and
* swiotlb use this function, but it is typically not used by implementations
* with an iommu.
*/
static inline dma_addr_t get_dma_offset(struct device *dev)
{
if (dev)
return dev->archdata.dma_data.dma_offset;
return PCI_DRAM_OFFSET;
}
static inline void set_dma_offset(struct device *dev, dma_addr_t off)
{
if (dev)
dev->archdata.dma_data.dma_offset = off;
}
/* this will be removed soon */
#define flush_write_buffers()
#include <asm-generic/dma-mapping-common.h>
static inline int dma_supported(struct device *dev, u64 mask)
{
struct dma_map_ops *dma_ops = get_dma_ops(dev);
if (unlikely(dma_ops == NULL))
return 0;
if (dma_ops->dma_supported == NULL)
return 1;
return dma_ops->dma_supported(dev, mask);
}
extern int dma_set_mask(struct device *dev, u64 dma_mask);
extern int __dma_set_mask(struct device *dev, u64 dma_mask);
extern u64 __dma_get_required_mask(struct device *dev);
#define dma_alloc_coherent(d,s,h,f) dma_alloc_attrs(d,s,h,f,NULL)
static inline void *dma_alloc_attrs(struct device *dev, size_t size,
dma_addr_t *dma_handle, gfp_t flag,
struct dma_attrs *attrs)
{
struct dma_map_ops *dma_ops = get_dma_ops(dev);
void *cpu_addr;
BUG_ON(!dma_ops);
cpu_addr = dma_ops->alloc(dev, size, dma_handle, flag, attrs);
debug_dma_alloc_coherent(dev, size, *dma_handle, cpu_addr);
return cpu_addr;
}
#define dma_free_coherent(d,s,c,h) dma_free_attrs(d,s,c,h,NULL)
static inline void dma_free_attrs(struct device *dev, size_t size,
void *cpu_addr, dma_addr_t dma_handle,
struct dma_attrs *attrs)
{
struct dma_map_ops *dma_ops = get_dma_ops(dev);
BUG_ON(!dma_ops);
debug_dma_free_coherent(dev, size, cpu_addr, dma_handle);
dma_ops->free(dev, size, cpu_addr, dma_handle, attrs);
}
static inline int dma_mapping_error(struct device *dev, dma_addr_t dma_addr)
{
struct dma_map_ops *dma_ops = get_dma_ops(dev);
debug_dma_mapping_error(dev, dma_addr);
if (dma_ops->mapping_error)
return dma_ops->mapping_error(dev, dma_addr);
#ifdef CONFIG_PPC64
return (dma_addr == DMA_ERROR_CODE);
#else
return 0;
#endif
}
static inline bool dma_capable(struct device *dev, dma_addr_t addr, size_t size)
{
#ifdef CONFIG_SWIOTLB
struct dev_archdata *sd = &dev->archdata;
if (sd->max_direct_dma_addr && addr + size > sd->max_direct_dma_addr)
return 0;
#endif
if (!dev->dma_mask)
return 0;
return addr + size - 1 <= *dev->dma_mask;
}
static inline dma_addr_t phys_to_dma(struct device *dev, phys_addr_t paddr)
{
return paddr + get_dma_offset(dev);
}
static inline phys_addr_t dma_to_phys(struct device *dev, dma_addr_t daddr)
{
return daddr - get_dma_offset(dev);
}
#define dma_alloc_noncoherent(d, s, h, f) dma_alloc_coherent(d, s, h, f)
#define dma_free_noncoherent(d, s, v, h) dma_free_coherent(d, s, v, h)
#define ARCH_HAS_DMA_MMAP_COHERENT
static inline void dma_cache_sync(struct device *dev, void *vaddr, size_t size,
enum dma_data_direction direction)
{
BUG_ON(direction == DMA_NONE);
__dma_sync(vaddr, size, (int)direction);
}
#endif /* __KERNEL__ */
#endif /* _ASM_DMA_MAPPING_H */
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