arch/microblaze/mm/consistent.c

   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/module.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/bootmem.h>
  32 #include <linux/highmem.h>
  33 #include <linux/pci.h>
  34 #include <linux/interrupt.h>
  35 #include <linux/gfp.h>
  36
  37 #include <asm/pgalloc.h>
  38 #include <linux/io.h>
  39 #include <linux/hardirq.h>
  40 #include <asm/mmu_context.h>
  41 #include <asm/mmu.h>
  42 #include <linux/uaccess.h>
  43 #include <asm/pgtable.h>
  44 #include <asm/cpuinfo.h>
  45 #include <asm/tlbflush.h>
  46
  47 #ifndef CONFIG_MMU
  48 /* I have to use dcache values because I can't relate on ram size */
  49 # define UNCACHED_SHADOW_MASK (cpuinfo.dcache_high - cpuinfo.dcache_base + 1)
  50 #endif
  51
  52 /*
  53  * Consistent memory allocators. Used for DMA devices that want to
  54  * share uncached memory with the processor core.
  55  * My crufty no-MMU approach is simple. In the HW platform we can optionally
  56  * mirror the DDR up above the processor cacheable region.  So, memory accessed
  57  * in this mirror region will not be cached.  It's alloced from the same
  58  * pool as normal memory, but the handle we return is shifted up into the
  59  * uncached region.  This will no doubt cause big problems if memory allocated
  60  * here is not also freed properly. -- JW
  61  */
  62 void *consistent_alloc(gfp_t gfp, size_t size, dma_addr_t *dma_handle)
  63 {
  64         unsigned long order, vaddr;
  65         void *ret;
  66         unsigned int i, err = 0;
  67         struct page *page, *end;
  68
  69 #ifdef CONFIG_MMU
  70         phys_addr_t pa;
  71         struct vm_struct *area;
  72         unsigned long va;
  73 #endif
  74
  75         if (in_interrupt())
  76                 BUG();
  77
  78         /* Only allocate page size areas. */
  79         size = PAGE_ALIGN(size);
  80         order = get_order(size);
  81
  82         vaddr = __get_free_pages(gfp, order);
  83         if (!vaddr)
  84                 return NULL;
  85
  86         /*
  87          * we need to ensure that there are no cachelines in use,
  88          * or worse dirty in this area.
  89          */
  90         flush_dcache_range(virt_to_phys((void *)vaddr),
  91                                         virt_to_phys((void *)vaddr) + size);
  92
  93 #ifndef CONFIG_MMU
  94         ret = (void *)vaddr;
  95         /*
  96          * Here's the magic!  Note if the uncached shadow is not implemented,
  97          * it's up to the calling code to also test that condition and make
  98          * other arranegments, such as manually flushing the cache and so on.
  99          */
 100 # ifdef CONFIG_XILINX_UNCACHED_SHADOW
 101         ret = (void *)((unsigned) ret | UNCACHED_SHADOW_MASK);
 102 # endif
 103         if ((unsigned int)ret > cpuinfo.dcache_base &&
 104                                 (unsigned int)ret < cpuinfo.dcache_high)
 105                 printk(KERN_WARNING
 106                         "ERROR: Your cache coherent area is CACHED!!!\n");
 107
 108         /* dma_handle is same as physical (shadowed) address */
 109         *dma_handle = (dma_addr_t)ret;
 110 #else
 111         /* Allocate some common virtual space to map the new pages. */
 112         area = get_vm_area(size, VM_ALLOC);
 113         if (!area) {
 114                 free_pages(vaddr, order);
 115                 return NULL;
 116         }
 117         va = (unsigned long) area->addr;
 118         ret = (void *)va;
 119
 120         /* This gives us the real physical address of the first page. */
 121         *dma_handle = pa = virt_to_bus((void *)vaddr);
 122 #endif
 123
 124         /*
 125          * free wasted pages.  We skip the first page since we know
 126          * that it will have count = 1 and won't require freeing.
 127          * We also mark the pages in use as reserved so that
 128          * remap_page_range works.
 129          */
 130         page = virt_to_page(vaddr);
 131         end = page + (1 << order);
 132
 133         split_page(page, order);
 134
 135         for (i = 0; i < size && err == 0; i += PAGE_SIZE) {
 136 #ifdef CONFIG_MMU
 137                 /* MS: This is the whole magic - use cache inhibit pages */
 138                 err = map_page(va + i, pa + i, _PAGE_KERNEL | _PAGE_NO_CACHE);
 139 #endif
 140
 141                 SetPageReserved(page);
 142                 page++;
 143         }
 144
 145         /* Free the otherwise unused pages. */
 146         while (page < end) {
 147                 __free_page(page);
 148                 page++;
 149         }
 150
 151         if (err) {
 152                 free_pages(vaddr, order);
 153                 return NULL;
 154         }
 155
 156         return ret;
 157 }
 158 EXPORT_SYMBOL(consistent_alloc);
 159
 160 /*
 161  * free page(s) as defined by the above mapping.
 162  */
 163 void consistent_free(size_t size, void *vaddr)
 164 {
 165         struct page *page;
 166
 167         if (in_interrupt())
 168                 BUG();
 169
 170         size = PAGE_ALIGN(size);
 171
 172 #ifndef CONFIG_MMU
 173         /* Clear SHADOW_MASK bit in address, and free as per usual */
 174 # ifdef CONFIG_XILINX_UNCACHED_SHADOW
 175         vaddr = (void *)((unsigned)vaddr & ~UNCACHED_SHADOW_MASK);
 176 # endif
 177         page = virt_to_page(vaddr);
 178
 179         do {
 180                 ClearPageReserved(page);
 181                 __free_page(page);
 182                 page++;
 183         } while (size -= PAGE_SIZE);
 184 #else
 185         do {
 186                 pte_t *ptep;
 187                 unsigned long pfn;
 188
 189                 ptep = pte_offset_kernel(pmd_offset(pgd_offset_k(
 190                                                 (unsigned int)vaddr),
 191                                         (unsigned int)vaddr),
 192                                 (unsigned int)vaddr);
 193                 if (!pte_none(*ptep) && pte_present(*ptep)) {
 194                         pfn = pte_pfn(*ptep);
 195                         pte_clear(&init_mm, (unsigned int)vaddr, ptep);
 196                         if (pfn_valid(pfn)) {
 197                                 page = pfn_to_page(pfn);
 198
 199                                 ClearPageReserved(page);
 200                                 __free_page(page);
 201                         }
 202                 }
 203                 vaddr += PAGE_SIZE;
 204         } while (size -= PAGE_SIZE);
 205
 206         /* flush tlb */
 207         flush_tlb_all();
 208 #endif
 209 }
 210 EXPORT_SYMBOL(consistent_free);
 211
 212 /*
 213  * make an area consistent.
 214  */
 215 void consistent_sync(void *vaddr, size_t size, int direction)
 216 {
 217         unsigned long start;
 218         unsigned long end;
 219
 220         start = (unsigned long)vaddr;
 221
 222         /* Convert start address back down to unshadowed memory region */
 223 #ifdef CONFIG_XILINX_UNCACHED_SHADOW
 224         start &= ~UNCACHED_SHADOW_MASK;
 225 #endif
 226         end = start + size;
 227
 228         switch (direction) {
 229         case PCI_DMA_NONE:
 230                 BUG();
 231         case PCI_DMA_FROMDEVICE:        /* invalidate only */
 232                 invalidate_dcache_range(start, end);
 233                 break;
 234         case PCI_DMA_TODEVICE:          /* writeback only */
 235                 flush_dcache_range(start, end);
 236                 break;
 237         case PCI_DMA_BIDIRECTIONAL:     /* writeback and invalidate */
 238                 flush_dcache_range(start, end);
 239                 break;
 240         }
 241 }
 242 EXPORT_SYMBOL(consistent_sync);
 243
 244 /*
 245  * consistent_sync_page makes memory consistent. identical
 246  * to consistent_sync, but takes a struct page instead of a
 247  * virtual address
 248  */
 249 void consistent_sync_page(struct page *page, unsigned long offset,
 250         size_t size, int direction)
 251 {
 252         unsigned long start = (unsigned long)page_address(page) + offset;
 253         consistent_sync((void *)start, size, direction);
 254 }
 255 EXPORT_SYMBOL(consistent_sync_page);