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 49static 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 */ 80void *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 */ 140void consistent_free(void *vaddr) 141{ 142 if (in_interrupt()) 143 BUG(); 144 vfree(vaddr); 145} 146 147/* 148 * make an area consistent. 149 */ 150void 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 175void 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} 183