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