arch/cris/arch-v32/drivers/pci/dma.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Dynamic DMA mapping support.
   4  *
   5  * On cris there is no hardware dynamic DMA address translation,
   6  * so consistent alloc/free are merely page allocation/freeing.
   7  * The rest of the dynamic DMA mapping interface is implemented
   8  * in asm/pci.h.
   9  *
  10  * Borrowed from i386.
  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 <asm/io.h>
  19
  20 static void *v32_dma_alloc(struct device *dev, size_t size,
  21                 dma_addr_t *dma_handle, gfp_t gfp, unsigned long attrs)
  22 {
  23         void *ret;
  24
  25         /* ignore region specifiers */
  26         gfp &= ~(__GFP_DMA | __GFP_HIGHMEM);
  27
  28         if (dev == NULL || (dev->coherent_dma_mask < 0xffffffff))
  29                 gfp |= GFP_DMA;
  30
  31         ret = (void *)__get_free_pages(gfp,  get_order(size));
  32
  33         if (ret != NULL) {
  34                 memset(ret, 0, size);
  35                 *dma_handle = virt_to_phys(ret);
  36         }
  37         return ret;
  38 }
  39
  40 static void v32_dma_free(struct device *dev, size_t size, void *vaddr,
  41                 dma_addr_t dma_handle, unsigned long attrs)
  42 {
  43         free_pages((unsigned long)vaddr, get_order(size));
  44 }
  45
  46 static inline dma_addr_t v32_dma_map_page(struct device *dev,
  47                 struct page *page, unsigned long offset, size_t size,
  48                 enum dma_data_direction direction, unsigned long attrs)
  49 {
  50         return page_to_phys(page) + offset;
  51 }
  52
  53 static inline int v32_dma_map_sg(struct device *dev, struct scatterlist *sg,
  54                 int nents, enum dma_data_direction direction,
  55                 unsigned long attrs)
  56 {
  57         printk("Map sg\n");
  58         return nents;
  59 }
  60
  61 static inline int v32_dma_supported(struct device *dev, u64 mask)
  62 {
  63         /*
  64          * we fall back to GFP_DMA when the mask isn't all 1s,
  65          * so we can't guarantee allocations that must be
  66          * within a tighter range than GFP_DMA..
  67          */
  68         if (mask < 0x00ffffff)
  69                 return 0;
  70         return 1;
  71 }
  72
  73 const struct dma_map_ops v32_dma_ops = {
  74         .alloc                  = v32_dma_alloc,
  75         .free                   = v32_dma_free,
  76         .map_page               = v32_dma_map_page,
  77         .map_sg                 = v32_dma_map_sg,
  78         .dma_supported          = v32_dma_supported,
  79 };
  80 EXPORT_SYMBOL(v32_dma_ops);