mirror of https://gitee.com/openkylin/linux.git
124 lines
3.3 KiB
C
124 lines
3.3 KiB
C
/* pci-dma.c: Dynamic DMA mapping support for the FRV CPUs that have MMUs
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*
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* Copyright (C) 2004 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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*
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* This program is free software; you can redistribute it and/or
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* modify it under the terms of the GNU General Public License
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* as published by the Free Software Foundation; either version
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* 2 of the License, or (at your option) any later version.
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*/
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#include <linux/types.h>
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#include <linux/slab.h>
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#include <linux/dma-mapping.h>
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#include <linux/list.h>
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#include <linux/pci.h>
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#include <linux/highmem.h>
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#include <linux/scatterlist.h>
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#include <asm/io.h>
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void *dma_alloc_coherent(struct device *hwdev, size_t size, dma_addr_t *dma_handle, gfp_t gfp)
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{
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void *ret;
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ret = consistent_alloc(gfp, size, dma_handle);
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if (ret)
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memset(ret, 0, size);
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return ret;
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}
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EXPORT_SYMBOL(dma_alloc_coherent);
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void dma_free_coherent(struct device *hwdev, size_t size, void *vaddr, dma_addr_t dma_handle)
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{
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consistent_free(vaddr);
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}
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EXPORT_SYMBOL(dma_free_coherent);
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/*
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* Map a single buffer of the indicated size for DMA in streaming mode.
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* The 32-bit bus address to use is returned.
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*
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* Once the device is given the dma address, the device owns this memory
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* until either pci_unmap_single or pci_dma_sync_single is performed.
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*/
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dma_addr_t dma_map_single(struct device *dev, void *ptr, size_t size,
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enum dma_data_direction direction)
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{
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if (direction == DMA_NONE)
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BUG();
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frv_cache_wback_inv((unsigned long) ptr, (unsigned long) ptr + size);
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return virt_to_bus(ptr);
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}
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EXPORT_SYMBOL(dma_map_single);
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/*
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* Map a set of buffers described by scatterlist in streaming
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* mode for DMA. This is the scather-gather version of the
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* above dma_map_single interface. Here the scatter gather list
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* elements are each tagged with the appropriate dma address
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* and length. They are obtained via sg_dma_{address,length}(SG).
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*
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* NOTE: An implementation may be able to use a smaller number of
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* DMA address/length pairs than there are SG table elements.
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* (for example via virtual mapping capabilities)
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* The routine returns the number of addr/length pairs actually
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* used, at most nents.
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*
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* Device ownership issues as mentioned above for dma_map_single are
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* the same here.
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*/
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int dma_map_sg(struct device *dev, struct scatterlist *sg, int nents,
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enum dma_data_direction direction)
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{
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unsigned long dampr2;
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void *vaddr;
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int i;
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if (direction == DMA_NONE)
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BUG();
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dampr2 = __get_DAMPR(2);
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for (i = 0; i < nents; i++) {
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vaddr = kmap_atomic(sg_page(&sg[i]), __KM_CACHE);
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frv_dcache_writeback((unsigned long) vaddr,
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(unsigned long) vaddr + PAGE_SIZE);
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}
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kunmap_atomic(vaddr, __KM_CACHE);
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if (dampr2) {
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__set_DAMPR(2, dampr2);
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__set_IAMPR(2, dampr2);
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}
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return nents;
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}
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EXPORT_SYMBOL(dma_map_sg);
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/*
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* Map a single page of the indicated size for DMA in streaming mode.
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* The 32-bit bus address to use is returned.
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*
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* Device ownership issues as mentioned above for dma_map_single are
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* the same here.
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*/
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dma_addr_t dma_map_page(struct device *dev, struct page *page, unsigned long offset,
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size_t size, enum dma_data_direction direction)
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{
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BUG_ON(direction == DMA_NONE);
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flush_dcache_page(page);
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return (dma_addr_t) page_to_phys(page) + offset;
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}
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EXPORT_SYMBOL(dma_map_page);
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