arch/mn10300/mm/dma-alloc.c

   1 /* MN10300 Dynamic DMA mapping support
   2  *
   3  * Copyright (C) 2007 Red Hat, Inc. All Rights Reserved.
   4  * Written by David Howells (dhowells@redhat.com)
   5  * Derived from: arch/i386/kernel/pci-dma.c
   6  *
   7  * This program is free software; you can redistribute it and/or
   8  * modify it under the terms of the GNU General Public Licence
   9  * as published by the Free Software Foundation; either version
  10  * 2 of the Licence, or (at your option) any later version.
  11  */
  12
  13 #include <linux/types.h>
  14 #include <linux/mm.h>
  15 #include <linux/string.h>
  16 #include <linux/pci.h>
  17 #include <linux/gfp.h>
  18 #include <linux/export.h>
  19 #include <asm/io.h>
  20
  21 static unsigned long pci_sram_allocated = 0xbc000000;
  22
  23 static void *mn10300_dma_alloc(struct device *dev, size_t size,
  24                 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
  25 {
  26         unsigned long addr;
  27         void *ret;
  28
  29         pr_debug("dma_alloc_coherent(%s,%zu,%x)\n",
  30                  dev ? dev_name(dev) : "?", size, gfp);
  31
  32         if (0xbe000000 - pci_sram_allocated >= size) {
  33                 size = (size + 255) & ~255;
  34                 addr = pci_sram_allocated;
  35                 pci_sram_allocated += size;
  36                 ret = (void *) addr;
  37                 goto done;
  38         }
  39
  40         if (dev == NULL || dev->coherent_dma_mask < 0xffffffff)
  41                 gfp |= GFP_DMA;
  42
  43         addr = __get_free_pages(gfp, get_order(size));
  44         if (!addr)
  45                 return NULL;
  46
  47         /* map the coherent memory through the uncached memory window */
  48         ret = (void *) (addr | 0x20000000);
  49
  50         /* fill the memory with obvious rubbish */
  51         memset((void *) addr, 0xfb, size);
  52
  53         /* write back and evict all cache lines covering this region */
  54         mn10300_dcache_flush_inv_range2(virt_to_phys((void *) addr), PAGE_SIZE);
  55
  56 done:
  57         *dma_handle = virt_to_bus((void *) addr);
  58         printk("dma_alloc_coherent() = %p [%x]\n", ret, *dma_handle);
  59         return ret;
  60 }
  61
  62 static void mn10300_dma_free(struct device *dev, size_t size, void *vaddr,
  63                 dma_addr_t dma_handle, unsigned long attrs)
  64 {
  65         unsigned long addr = (unsigned long) vaddr & ~0x20000000;
  66
  67         if (addr >= 0x9c000000)
  68                 return;
  69
  70         free_pages(addr, get_order(size));
  71 }
  72
  73 static int mn10300_dma_map_sg(struct device *dev, struct scatterlist *sglist,
  74                 int nents, enum dma_data_direction direction,
  75                 unsigned long attrs)
  76 {
  77         struct scatterlist *sg;
  78         int i;
  79
  80         for_each_sg(sglist, sg, nents, i) {
  81                 BUG_ON(!sg_page(sg));
  82
  83                 sg->dma_address = sg_phys(sg);
  84         }
  85
  86         mn10300_dcache_flush_inv();
  87         return nents;
  88 }
  89
  90 static dma_addr_t mn10300_dma_map_page(struct device *dev, struct page *page,
  91                 unsigned long offset, size_t size,
  92                 enum dma_data_direction direction, unsigned long attrs)
  93 {
  94         return page_to_bus(page) + offset;
  95 }
  96
  97 static void mn10300_dma_sync_single_for_device(struct device *dev, dma_addr_t dma_handle,
  98                                 size_t size, enum dma_data_direction direction)
  99 {
 100         mn10300_dcache_flush_inv();
 101 }
 102
 103 static void mn10300_dma_sync_sg_for_device(struct device *dev, struct scatterlist *sg,
 104                             int nelems, enum dma_data_direction direction)
 105 {
 106         mn10300_dcache_flush_inv();
 107 }
 108
 109 static int mn10300_dma_supported(struct device *dev, u64 mask)
 110 {
 111         /*
 112          * we fall back to GFP_DMA when the mask isn't all 1s, so we can't
 113          * guarantee allocations that must be within a tighter range than
 114          * GFP_DMA
 115          */
 116         if (mask < 0x00ffffff)
 117                 return 0;
 118         return 1;
 119 }
 120
 121 const struct dma_map_ops mn10300_dma_ops = {
 122         .alloc                  = mn10300_dma_alloc,
 123         .free                   = mn10300_dma_free,
 124         .map_page               = mn10300_dma_map_page,
 125         .map_sg                 = mn10300_dma_map_sg,
 126         .sync_single_for_device = mn10300_dma_sync_single_for_device,
 127         .sync_sg_for_device     = mn10300_dma_sync_sg_for_device,
 128 };