arch/xtensa/kernel/pci-dma.c

   1 // SPDX-License-Identifier: GPL-2.0-or-later
   2 /*
   3  * DMA coherent memory allocation.
   4  *
   5  * Copyright (C) 2002 - 2005 Tensilica Inc.
   6  * Copyright (C) 2015 Cadence Design Systems Inc.
   7  *
   8  * Based on version for i386.
   9  *
  10  * Chris Zankel <chris@zankel.net>
  11  * Joe Taylor <joe@tensilica.com, joetylr@yahoo.com>
  12  */
  13
  14 #include <linux/dma-map-ops.h>
  15 #include <linux/dma-direct.h>
  16 #include <linux/gfp.h>
  17 #include <linux/highmem.h>
  18 #include <linux/mm.h>
  19 #include <linux/types.h>
  20 #include <asm/cacheflush.h>
  21 #include <asm/io.h>
  22 #include <asm/platform.h>
  23
  24 static void do_cache_op(phys_addr_t paddr, size_t size,
  25                         void (*fn)(unsigned long, unsigned long))
  26 {
  27         unsigned long off = paddr & (PAGE_SIZE - 1);
  28         unsigned long pfn = PFN_DOWN(paddr);
  29         struct page *page = pfn_to_page(pfn);
  30
  31         if (!PageHighMem(page))
  32                 fn((unsigned long)phys_to_virt(paddr), size);
  33         else
  34                 while (size > 0) {
  35                         size_t sz = min_t(size_t, size, PAGE_SIZE - off);
  36                         void *vaddr = kmap_atomic(page);
  37
  38                         fn((unsigned long)vaddr + off, sz);
  39                         kunmap_atomic(vaddr);
  40                         off = 0;
  41                         ++page;
  42                         size -= sz;
  43                 }
  44 }
  45
  46 void arch_sync_dma_for_cpu(phys_addr_t paddr, size_t size,
  47                 enum dma_data_direction dir)
  48 {
  49         switch (dir) {
  50         case DMA_BIDIRECTIONAL:
  51         case DMA_FROM_DEVICE:
  52                 do_cache_op(paddr, size, __invalidate_dcache_range);
  53                 break;
  54
  55         case DMA_NONE:
  56                 BUG();
  57                 break;
  58
  59         default:
  60                 break;
  61         }
  62 }
  63
  64 void arch_sync_dma_for_device(phys_addr_t paddr, size_t size,
  65                 enum dma_data_direction dir)
  66 {
  67         switch (dir) {
  68         case DMA_BIDIRECTIONAL:
  69         case DMA_TO_DEVICE:
  70                 if (XCHAL_DCACHE_IS_WRITEBACK)
  71                         do_cache_op(paddr, size, __flush_dcache_range);
  72                 break;
  73
  74         case DMA_NONE:
  75                 BUG();
  76                 break;
  77
  78         default:
  79                 break;
  80         }
  81 }
  82
  83 void arch_dma_prep_coherent(struct page *page, size_t size)
  84 {
  85         __invalidate_dcache_range((unsigned long)page_address(page), size);
  86 }
  87
  88 /*
  89  * Memory caching is platform-dependent in noMMU xtensa configurations.
  90  * This function should be implemented in platform code in order to enable
  91  * coherent DMA memory operations when CONFIG_MMU is not enabled.
  92  */
  93 #ifdef CONFIG_MMU
  94 void *arch_dma_set_uncached(void *p, size_t size)
  95 {
  96         return p + XCHAL_KSEG_BYPASS_VADDR - XCHAL_KSEG_CACHED_VADDR;
  97 }
  98 #endif /* CONFIG_MMU */