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
  40 #include <asm/pgalloc.h>
  41 #include <asm/io.h>
  42 #include <asm/hardirq.h>
  43 #include <asm/mmu_context.h>
  44 #include <asm/pgtable.h>
  45 #include <asm/mmu.h>
  46 #include <asm/uaccess.h>
  47 #include <asm/smp.h>
  48
  49 static int map_page(unsigned long va, unsigned long pa, pgprot_t prot)
  50 {
  51         pgd_t *pge;
  52         pud_t *pue;
  53         pmd_t *pme;
  54         pte_t *pte;
  55         int err = -ENOMEM;
  56
  57         /* Use upper 10 bits of VA to index the first level map */
  58         pge = pgd_offset_k(va);
  59         pue = pud_offset(pge, va);
  60         pme = pmd_offset(pue, va);
  61
  62         /* Use middle 10 bits of VA to index the second-level map */
  63         pte = pte_alloc_kernel(pme, va);
  64         if (pte != 0) {
  65                 err = 0;
  66                 set_pte(pte, mk_pte_phys(pa & PAGE_MASK, prot));
  67         }
  68
  69         return err;
  70 }
  71
  72 /*
  73  * This function will allocate the requested contiguous pages and
  74  * map them into the kernel's vmalloc() space.  This is done so we
  75  * get unique mapping for these pages, outside of the kernel's 1:1
  76  * virtual:physical mapping.  This is necessary so we can cover large
  77  * portions of the kernel with single large page TLB entries, and
  78  * still get unique uncached pages for consistent DMA.
  79  */
  80 void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
  81 {
  82         struct vm_struct *area;
  83         unsigned long page, va, pa;
  84         void *ret;
  85         int order, err, i;
  86
  87         if (in_interrupt())
  88                 BUG();
  89
  90         /* only allocate page size areas */
  91         size = PAGE_ALIGN(size);
  92         order = get_order(size);
  93
  94         page = __get_free_pages(gfp, order);
  95         if (!page) {
  96                 BUG();
  97                 return NULL;
  98         }
  99
 100         /* allocate some common virtual space to map the new pages */
 101         area = get_vm_area(size, VM_ALLOC);
 102         if (area == 0) {
 103                 free_pages(page, order);
 104                 return NULL;
 105         }
 106         va = VMALLOC_VMADDR(area->addr);
 107         ret = (void *) va;
 108
 109         /* this gives us the real physical address of the first page */
 110         *dma_handle = pa = virt_to_bus((void *) page);
 111
 112         /* set refcount=1 on all pages in an order>0 allocation so that vfree() will actually free
 113          * all pages that were allocated.
 114          */
 115         if (order > 0) {
 116                 struct page *rpage = virt_to_page(page);
 117                 split_page(rpage, order);
 118         }
 119
 120         err = 0;
 121         for (i = 0; i < size && err == 0; i += PAGE_SIZE)
 122                 err = map_page(va + i, pa + i, PAGE_KERNEL_NOCACHE);
 123
 124         if (err) {
 125                 vfree((void *) va);
 126                 return NULL;
 127         }
 128
 129         /* we need to ensure that there are no cachelines in use, or worse dirty in this area
 130          * - can't do until after virtual address mappings are created
 131          */
 132         frv_cache_invalidate(va, va + size);
 133
 134         return ret;
 135 }
 136
 137 /*
 138  * free page(s) as defined by the above mapping.
 139  */
 140 void consistent_free(void *vaddr)
 141 {
 142         if (in_interrupt())
 143                 BUG();
 144         vfree(vaddr);
 145 }
 146
 147 /*
 148  * make an area consistent.
 149  */
 150 void consistent_sync(void *vaddr, size_t size, int direction)
 151 {
 152         unsigned long start = (unsigned long) vaddr;
 153         unsigned long end   = start + size;
 154
 155         switch (direction) {
 156         case PCI_DMA_NONE:
 157                 BUG();
 158         case PCI_DMA_FROMDEVICE:        /* invalidate only */
 159                 frv_cache_invalidate(start, end);
 160                 break;
 161         case PCI_DMA_TODEVICE:          /* writeback only */
 162                 frv_dcache_writeback(start, end);
 163                 break;
 164         case PCI_DMA_BIDIRECTIONAL:     /* writeback and invalidate */
 165                 frv_dcache_writeback(start, end);
 166                 break;
 167         }
 168 }
 169
 170 /*
 171  * consistent_sync_page make a page are consistent. identical
 172  * to consistent_sync, but takes a struct page instead of a virtual address
 173  */
 174
 175 void consistent_sync_page(struct page *page, unsigned long offset,
 176                           size_t size, int direction)
 177 {
 178         void *start;
 179
 180         start = page_address(page) + offset;
 181         consistent_sync(start, size, direction);
 182 }