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awilliam
GitHub Repository: awilliam/linux-vfio
 Path: blob/master/arch/xtensa/kernel/pci-dma.c
10817 views
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/*

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 * arch/xtensa/kernel/pci-dma.c

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 *

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 * DMA coherent memory allocation.

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 *

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 * This program is free software; you can redistribute  it and/or modify it

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 * under  the terms of  the GNU General  Public License as published by the

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 * Free Software Foundation;  either version 2 of the  License, or (at your

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 * option) any later version.

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 *

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 * Copyright (C) 2002 - 2005 Tensilica Inc.

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 *

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 * Based on version for i386.

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 *

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 * Chris Zankel <[email protected]>

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 * Joe Taylor <[email protected], [email protected]>

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 */

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#include <linux/types.h>

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#include <linux/mm.h>

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#include <linux/string.h>

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#include <linux/pci.h>

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#include <linux/gfp.h>

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#include <asm/io.h>

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#include <asm/cacheflush.h>

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/*

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 * Note: We assume that the full memory space is always mapped to 'kseg'

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 *	 Otherwise we have to use page attributes (not implemented).

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 */

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void *

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dma_alloc_coherent(struct device *dev,size_t size,dma_addr_t *handle,gfp_t flag)

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{

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	unsigned long ret;

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	unsigned long uncached = 0;

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	/* ignore region speicifiers */

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	flag &= ~(__GFP_DMA | __GFP_HIGHMEM);

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	if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))

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		flag |= GFP_DMA;

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	ret = (unsigned long)__get_free_pages(flag, get_order(size));

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	if (ret == 0)

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		return NULL;

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	/* We currently don't support coherent memory outside KSEG */

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	if (ret < XCHAL_KSEG_CACHED_VADDR

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	    || ret >= XCHAL_KSEG_CACHED_VADDR + XCHAL_KSEG_SIZE)

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		BUG();

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	if (ret != 0) {

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		memset((void*) ret, 0, size);

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		uncached = ret+XCHAL_KSEG_BYPASS_VADDR-XCHAL_KSEG_CACHED_VADDR;

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		*handle = virt_to_bus((void*)ret);

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		__flush_invalidate_dcache_range(ret, size);

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	}

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	return (void*)uncached;

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}

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void dma_free_coherent(struct device *hwdev, size_t size,

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			 void *vaddr, dma_addr_t dma_handle)

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{

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	long addr=(long)vaddr+XCHAL_KSEG_CACHED_VADDR-XCHAL_KSEG_BYPASS_VADDR;

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	if (addr < 0 || addr >= XCHAL_KSEG_SIZE)

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		BUG();

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	free_pages(addr, get_order(size));

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}

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void consistent_sync(void *vaddr, size_t size, int direction)

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{

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	switch (direction) {

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	case PCI_DMA_NONE:

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		BUG();

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	case PCI_DMA_FROMDEVICE:        /* invalidate only */

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		__invalidate_dcache_range((unsigned long)vaddr,

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				          (unsigned long)size);

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		break;

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	case PCI_DMA_TODEVICE:          /* writeback only */

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	case PCI_DMA_BIDIRECTIONAL:     /* writeback and invalidate */

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		__flush_invalidate_dcache_range((unsigned long)vaddr,

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				    		(unsigned long)size);

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		break;

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	}

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}

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