arch/frv/mm/dma-alloc.c

   1 /* dma-alloc.c: consistent DMA memory allocation
   2  *
   3  * Derived from arch/ppc/mm/cachemap.c
   4  *
   5  *  PowerPC version derived from arch/arm/mm/consistent.c
   6  *    Copyright (C) 2001 Dan Malek (dmalek@jlc.net)
   7  *
   8  *  linux/arch/arm/mm/consistent.c
   9  *
  10  *  Copyright (C) 2000 Russell King
  11  *
  12  * Consistent memory allocators.  Used for DMA devices that want to
  13  * share uncached memory with the processor core.  The function return
  14  * is the virtual address and 'dma_handle' is the physical address.
  15  * Mostly stolen from the ARM port, with some changes for PowerPC.
  16  *                                              -- Dan
  17  * Modified for 36-bit support.  -Matt
  18  *
  19  * This program is free software; you can redistribute it and/or modify
  20  * it under the terms of the GNU General Public License version 2 as
  21  * published by the Free Software Foundation.
  22  */
  23
  24 #include <linux/module.h>
  25 #include <linux/signal.h>
  26 #include <linux/sched.h>
  27 #include <linux/kernel.h>
  28 #include <linux/errno.h>
  29 #include <linux/string.h>
  30 #include <linux/types.h>
  31 #include <linux/ptrace.h>
  32 #include <linux/mman.h>
  33 #include <linux/mm.h>
  34 #include <linux/swap.h>
  35 #include <linux/stddef.h>
  36 #include <linux/vmalloc.h>
  37 #include <linux/init.h>
  38 #include <linux/pci.h>
  39 #include <linux/hardirq.h>
  40 #include <linux/gfp.h>
  41
  42 #include <asm/pgalloc.h>
  43 #include <asm/io.h>
  44 #include <asm/mmu_context.h>
  45 #include <asm/pgtable.h>
  46 #include <asm/mmu.h>
  47 #include <linux/uaccess.h>
  48 #include <asm/smp.h>
  49
  50 static int map_page(unsigned long va, unsigned long pa, pgprot_t prot)
  51 {
  52         pgd_t *pge;
  53         pud_t *pue;
  54         pmd_t *pme;
  55         pte_t *pte;
  56         int err = -ENOMEM;
  57
  58         /* Use upper 10 bits of VA to index the first level map */
  59         pge = pgd_offset_k(va);
  60         pue = pud_offset(pge, va);
  61         pme = pmd_offset(pue, va);
  62
  63         /* Use middle 10 bits of VA to index the second-level map */
  64         pte = pte_alloc_kernel(pme, va);
  65         if (pte != 0) {
  66                 err = 0;
  67                 set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot));
  68         }
  69
  70         return err;
  71 }
  72
  73 /*
  74  * This function will allocate the requested contiguous pages and
  75  * map them into the kernel's vmalloc() space.  This is done so we
  76  * get unique mapping for these pages, outside of the kernel's 1:1
  77  * virtual:physical mapping.  This is necessary so we can cover large
  78  * portions of the kernel with single large page TLB entries, and
  79  * still get unique uncached pages for consistent DMA.
  80  */
  81 void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
  82 {
  83         struct vm_struct *area;
  84         unsigned long page, va, pa;
  85         void *ret;
  86         int order, err, i;
  87
  88         if (in_interrupt())
  89                 BUG();
  90
  91         /* only allocate page size areas */
  92         size = PAGE_ALIGN(size);
  93         order = get_order(size);
  94
  95         page = __get_free_pages(gfp, order);
  96         if (!page) {
  97                 BUG();
  98                 return NULL;
  99         }
 100
 101         /* allocate some common virtual space to map the new pages */
 102         area = get_vm_area(size, VM_ALLOC);
 103         if (area == 0) {
 104                 free_pages(page, order);
 105                 return NULL;
 106         }
 107         va = VMALLOC_VMADDR(area->addr);
 108         ret = (void *) va;
 109
 110         /* this gives us the real physical address of the first page */
 111         *dma_handle = pa = virt_to_bus((void *) page);
 112
 113         /* set refcount=1 on all pages in an order>0 allocation so that vfree() will actually free
 114          * all pages that were allocated.
 115          */
 116         if (order > 0) {
 117                 struct page *rpage = virt_to_page(page);
 118                 split_page(rpage, order);
 119         }
 120
 121         err = 0;
 122         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 123                 err = map_page(va + i, pa + i, PAGE_KERNEL_NOCACHE);
 124
 125         if (err) {
 126                 vfree((void *) va);
 127                 return NULL;
 128         }
 129
 130         /* we need to ensure that there are no cachelines in use, or worse dirty in this area
 131          * - can't do until after virtual address mappings are created
 132          */
 133         frv_cache_invalidate(va, va + size);
 134
 135         return ret;
 136 }
 137
 138 /*
 139  * free page(s) as defined by the above mapping.
 140  */
 141 void consistent_free(void *vaddr)
 142 {
 143         if (in_interrupt())
 144                 BUG();
 145         vfree(vaddr);
 146 }
 147
 148 /*
 149  * make an area consistent.
 150  */
 151 void consistent_sync(void *vaddr, size_t size, int direction)
 152 {
 153         unsigned long start = (unsigned long) vaddr;
 154         unsigned long end   = start + size;
 155
 156         switch (direction) {
 157         case PCI_DMA_NONE:
 158                 BUG();
 159         case PCI_DMA_FROMDEVICE:        /* invalidate only */
 160                 frv_cache_invalidate(start, end);
 161                 break;
 162         case PCI_DMA_TODEVICE:          /* writeback only */
 163                 frv_dcache_writeback(start, end);
 164                 break;
 165         case PCI_DMA_BIDIRECTIONAL:     /* writeback and invalidate */
 166                 frv_dcache_writeback(start, end);
 167                 break;
 168         }
 169 }
 170
 171 /*
 172  * consistent_sync_page make a page are consistent. identical
 173  * to consistent_sync, but takes a struct page instead of a virtual address
 174  */
 175
 176 void consistent_sync_page(struct page *page, unsigned long offset,
 177                           size_t size, int direction)
 178 {
 179         void *start;
 180
 181         start = page_address(page) + offset;
 182         consistent_sync(start, size, direction);
 183 }