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 <asm/uaccess.h> 48#include <asm/smp.h> 49 50static 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 */ 81void *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 */ 141void consistent_free(void *vaddr) 142{ 143 if (in_interrupt()) 144 BUG(); 145 vfree(vaddr); 146} 147 148/* 149 * make an area consistent. 150 */ 151void 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 176void 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} 184