77 lines
2.0 KiB
C
77 lines
2.0 KiB
C
/* MN10300 Dynamic DMA mapping support
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*
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* Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
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* Written by David Howells (dhowells@redhat.com)
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* Derived from: arch/i386/kernel/pci-dma.c
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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 Licence
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* as published by the Free Software Foundation; either version
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* 2 of the Licence, 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/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 <linux/export.h>
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#include <asm/io.h>
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static unsigned long pci_sram_allocated = 0xbc000000;
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void *dma_alloc_coherent(struct device *dev, size_t size,
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dma_addr_t *dma_handle, int gfp)
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{
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unsigned long addr;
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void *ret;
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pr_debug("dma_alloc_coherent(%s,%zu,%x)\n",
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dev ? dev_name(dev) : "?", size, gfp);
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if (0xbe000000 - pci_sram_allocated >= size) {
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size = (size + 255) & ~255;
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addr = pci_sram_allocated;
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pci_sram_allocated += size;
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ret = (void *) addr;
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goto done;
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}
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/* ignore region specifiers */
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gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
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if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
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gfp |= GFP_DMA;
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addr = __get_free_pages(gfp, get_order(size));
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if (!addr)
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return NULL;
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/* map the coherent memory through the uncached memory window */
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ret = (void *) (addr | 0x20000000);
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/* fill the memory with obvious rubbish */
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memset((void *) addr, 0xfb, size);
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/* write back and evict all cache lines covering this region */
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mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);
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done:
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*dma_handle = virt_to_bus((void *) addr);
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printk("dma_alloc_coherent() = %p [%x]\n", ret, *dma_handle);
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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 *dev, size_t size, void *vaddr,
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dma_addr_t dma_handle)
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{
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unsigned long addr = (unsigned long) vaddr & ~0x20000000;
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if (addr >= 0x9c000000)
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return;
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free_pages(addr, get_order(size));
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}
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EXPORT_SYMBOL(dma_free_coherent);
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