arch/nds32/kernel/dma.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 // Copyright (C) 2005-2017 Andes Technology Corporation
   3
   4 #include <linux/types.h>
   5 #include <linux/mm.h>
   6 #include <linux/dma-noncoherent.h>
   7 #include <linux/cache.h>
   8 #include <linux/highmem.h>
   9 #include <asm/cacheflush.h>
  10 #include <asm/tlbflush.h>
  11 #include <asm/proc-fns.h>
  12
  13 static inline void cache_op(phys_addr_t paddr, size_t size,
  14                 void (*fn)(unsigned long start, unsigned long end))
  15 {
  16         struct page *page = pfn_to_page(paddr >> PAGE_SHIFT);
  17         unsigned offset = paddr & ~PAGE_MASK;
  18         size_t left = size;
  19         unsigned long start;
  20
  21         do {
  22                 size_t len = left;
  23
  24                 if (PageHighMem(page)) {
  25                         void *addr;
  26
  27                         if (offset + len > PAGE_SIZE) {
  28                                 if (offset >= PAGE_SIZE) {
  29                                         page += offset >> PAGE_SHIFT;
  30                                         offset &= ~PAGE_MASK;
  31                                 }
  32                                 len = PAGE_SIZE - offset;
  33                         }
  34
  35                         addr = kmap_atomic(page);
  36                         start = (unsigned long)(addr + offset);
  37                         fn(start, start + len);
  38                         kunmap_atomic(addr);
  39                 } else {
  40                         start = (unsigned long)phys_to_virt(paddr);
  41                         fn(start, start + size);
  42                 }
  43                 offset = 0;
  44                 page++;
  45                 left -= len;
  46         } while (left);
  47 }
  48
  49 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
  50                 enum dma_data_direction dir)
  51 {
  52         switch (dir) {
  53         case DMA_FROM_DEVICE:
  54                 break;
  55         case DMA_TO_DEVICE:
  56         case DMA_BIDIRECTIONAL:
  57                 cache_op(paddr, size, cpu_dma_wb_range);
  58                 break;
  59         default:
  60                 BUG();
  61         }
  62 }
  63
  64 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
  65                 enum dma_data_direction dir)
  66 {
  67         switch (dir) {
  68         case DMA_TO_DEVICE:
  69                 break;
  70         case DMA_FROM_DEVICE:
  71         case DMA_BIDIRECTIONAL:
  72                 cache_op(paddr, size, cpu_dma_inval_range);
  73                 break;
  74         default:
  75                 BUG();
  76         }
  77 }
  78
  79 void arch_dma_prep_coherent(struct page *page, size_t size)
  80 {
  81         cache_op(page_to_phys(page), size, cpu_dma_wbinval_range);
  82 }