1 /* 2 * Microblaze support for cache consistent memory. 3 * Copyright (C) 2010 Michal Simek <monstr@monstr.eu> 4 * Copyright (C) 2010 PetaLogix 5 * Copyright (C) 2005 John Williams <jwilliams@itee.uq.edu.au> 6 * 7 * Based on PowerPC version derived from arch/arm/mm/consistent.c 8 * Copyright (C) 2001 Dan Malek (dmalek@jlc.net) 9 * Copyright (C) 2000 Russell King 10 * 11 * This program is free software; you can redistribute it and/or modify 12 * it under the terms of the GNU General Public License version 2 as 13 * published by the Free Software Foundation. 14 */ 15 16 #include <linux/export.h> 17 #include <linux/signal.h> 18 #include <linux/sched.h> 19 #include <linux/kernel.h> 20 #include <linux/errno.h> 21 #include <linux/string.h> 22 #include <linux/types.h> 23 #include <linux/ptrace.h> 24 #include <linux/mman.h> 25 #include <linux/mm.h> 26 #include <linux/swap.h> 27 #include <linux/stddef.h> 28 #include <linux/vmalloc.h> 29 #include <linux/init.h> 30 #include <linux/delay.h> 31 #include <linux/memblock.h> 32 #include <linux/highmem.h> 33 #include <linux/pci.h> 34 #include <linux/interrupt.h> 35 #include <linux/gfp.h> 36 #include <linux/dma-noncoherent.h> 37 38 #include <asm/pgalloc.h> 39 #include <linux/io.h> 40 #include <linux/hardirq.h> 41 #include <linux/mmu_context.h> 42 #include <asm/mmu.h> 43 #include <linux/uaccess.h> 44 #include <asm/pgtable.h> 45 #include <asm/cpuinfo.h> 46 #include <asm/tlbflush.h> 47 48 #ifndef CONFIG_MMU 49 /* I have to use dcache values because I can't relate on ram size */ 50 # define UNCACHED_SHADOW_MASK (cpuinfo.dcache_high - cpuinfo.dcache_base + 1) 51 #endif 52 53 /* 54 * Consistent memory allocators. Used for DMA devices that want to 55 * share uncached memory with the processor core. 56 * My crufty no-MMU approach is simple. In the HW platform we can optionally 57 * mirror the DDR up above the processor cacheable region. So, memory accessed 58 * in this mirror region will not be cached. It's alloced from the same 59 * pool as normal memory, but the handle we return is shifted up into the 60 * uncached region. This will no doubt cause big problems if memory allocated 61 * here is not also freed properly. -- JW 62 */ 63 void *arch_dma_alloc(struct device *dev, size_t size, dma_addr_t *dma_handle, 64 gfp_t gfp, unsigned long attrs) 65 { 66 unsigned long order, vaddr; 67 void *ret; 68 unsigned int i, err = 0; 69 struct page *page, *end; 70 71 #ifdef CONFIG_MMU 72 phys_addr_t pa; 73 struct vm_struct *area; 74 unsigned long va; 75 #endif 76 77 if (in_interrupt()) 78 BUG(); 79 80 /* Only allocate page size areas. */ 81 size = PAGE_ALIGN(size); 82 order = get_order(size); 83 84 vaddr = __get_free_pages(gfp | __GFP_ZERO, order); 85 if (!vaddr) 86 return NULL; 87 88 /* 89 * we need to ensure that there are no cachelines in use, 90 * or worse dirty in this area. 91 */ 92 flush_dcache_range(virt_to_phys((void *)vaddr), 93 virt_to_phys((void *)vaddr) + size); 94 95 #ifndef CONFIG_MMU 96 ret = (void *)vaddr; 97 /* 98 * Here's the magic! Note if the uncached shadow is not implemented, 99 * it's up to the calling code to also test that condition and make 100 * other arranegments, such as manually flushing the cache and so on. 101 */ 102 # ifdef CONFIG_XILINX_UNCACHED_SHADOW 103 ret = (void *)((unsigned) ret | UNCACHED_SHADOW_MASK); 104 # endif 105 if ((unsigned int)ret > cpuinfo.dcache_base && 106 (unsigned int)ret < cpuinfo.dcache_high) 107 pr_warn("ERROR: Your cache coherent area is CACHED!!!\n"); 108 109 /* dma_handle is same as physical (shadowed) address */ 110 *dma_handle = (dma_addr_t)ret; 111 #else 112 /* Allocate some common virtual space to map the new pages. */ 113 area = get_vm_area(size, VM_ALLOC); 114 if (!area) { 115 free_pages(vaddr, order); 116 return NULL; 117 } 118 va = (unsigned long) area->addr; 119 ret = (void *)va; 120 121 /* This gives us the real physical address of the first page. */ 122 *dma_handle = pa = __virt_to_phys(vaddr); 123 #endif 124 125 /* 126 * free wasted pages. We skip the first page since we know 127 * that it will have count = 1 and won't require freeing. 128 * We also mark the pages in use as reserved so that 129 * remap_page_range works. 130 */ 131 page = virt_to_page(vaddr); 132 end = page + (1 << order); 133 134 split_page(page, order); 135 136 for (i = 0; i < size && err == 0; i += PAGE_SIZE) { 137 #ifdef CONFIG_MMU 138 /* MS: This is the whole magic - use cache inhibit pages */ 139 err = map_page(va + i, pa + i, _PAGE_KERNEL | _PAGE_NO_CACHE); 140 #endif 141 142 SetPageReserved(page); 143 page++; 144 } 145 146 /* Free the otherwise unused pages. */ 147 while (page < end) { 148 __free_page(page); 149 page++; 150 } 151 152 if (err) { 153 free_pages(vaddr, order); 154 return NULL; 155 } 156 157 return ret; 158 } 159 160 #ifdef CONFIG_MMU 161 static pte_t *consistent_virt_to_pte(void *vaddr) 162 { 163 unsigned long addr = (unsigned long)vaddr; 164 165 return pte_offset_kernel(pmd_offset(pgd_offset_k(addr), addr), addr); 166 } 167 168 long arch_dma_coherent_to_pfn(struct device *dev, void *vaddr, 169 dma_addr_t dma_addr) 170 { 171 pte_t *ptep = consistent_virt_to_pte(vaddr); 172 173 if (pte_none(*ptep) || !pte_present(*ptep)) 174 return 0; 175 176 return pte_pfn(*ptep); 177 } 178 #endif 179 180 /* 181 * free page(s) as defined by the above mapping. 182 */ 183 void arch_dma_free(struct device *dev, size_t size, void *vaddr, 184 dma_addr_t dma_addr, unsigned long attrs) 185 { 186 struct page *page; 187 188 if (in_interrupt()) 189 BUG(); 190 191 size = PAGE_ALIGN(size); 192 193 #ifndef CONFIG_MMU 194 /* Clear SHADOW_MASK bit in address, and free as per usual */ 195 # ifdef CONFIG_XILINX_UNCACHED_SHADOW 196 vaddr = (void *)((unsigned)vaddr & ~UNCACHED_SHADOW_MASK); 197 # endif 198 page = virt_to_page(vaddr); 199 200 do { 201 __free_reserved_page(page); 202 page++; 203 } while (size -= PAGE_SIZE); 204 #else 205 do { 206 pte_t *ptep = consistent_virt_to_pte(vaddr); 207 unsigned long pfn; 208 209 if (!pte_none(*ptep) && pte_present(*ptep)) { 210 pfn = pte_pfn(*ptep); 211 pte_clear(&init_mm, (unsigned int)vaddr, ptep); 212 if (pfn_valid(pfn)) { 213 page = pfn_to_page(pfn); 214 __free_reserved_page(page); 215 } 216 } 217 vaddr += PAGE_SIZE; 218 } while (size -= PAGE_SIZE); 219 220 /* flush tlb */ 221 flush_tlb_all(); 222 #endif 223 } 224