132 lines
3.4 KiB
C
132 lines
3.4 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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static void *mn10300_dma_alloc(struct device *dev, size_t size,
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dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
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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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static void mn10300_dma_free(struct device *dev, size_t size, void *vaddr,
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dma_addr_t dma_handle, unsigned long attrs)
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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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static int mn10300_dma_map_sg(struct device *dev, struct scatterlist *sglist,
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int nents, enum dma_data_direction direction,
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unsigned long attrs)
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{
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struct scatterlist *sg;
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int i;
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for_each_sg(sglist, sg, nents, i) {
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BUG_ON(!sg_page(sg));
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sg->dma_address = sg_phys(sg);
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}
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mn10300_dcache_flush_inv();
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return nents;
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}
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static dma_addr_t mn10300_dma_map_page(struct device *dev, struct page *page,
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unsigned long offset, size_t size,
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enum dma_data_direction direction, unsigned long attrs)
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{
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return page_to_bus(page) + offset;
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}
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static void mn10300_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle,
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size_t size, enum dma_data_direction direction)
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{
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mn10300_dcache_flush_inv();
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}
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static void mn10300_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
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int nelems, enum dma_data_direction direction)
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{
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mn10300_dcache_flush_inv();
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}
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static int mn10300_dma_supported(struct device *dev, u64 mask)
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{
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/*
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* we fall back to GFP_DMA when the mask isn't all 1s, so we can't
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* guarantee allocations that must be within a tighter range than
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* GFP_DMA
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*/
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if (mask < 0x00ffffff)
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return 0;
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return 1;
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}
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struct dma_map_ops mn10300_dma_ops = {
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.alloc = mn10300_dma_alloc,
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.free = mn10300_dma_free,
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.map_page = mn10300_dma_map_page,
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.map_sg = mn10300_dma_map_sg,
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.sync_single_for_device = mn10300_dma_sync_single_for_device,
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.sync_sg_for_device = mn10300_dma_sync_sg_for_device,
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};
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