release/src-rt-6.x.4708/linux/linux-2.6.36/arch/sh/mm/cache-sh7705.c

   1 /*
   2  * arch/sh/mm/cache-sh7705.c
   3  *
   4  * Copyright (C) 1999, 2000  Niibe Yutaka
   5  * Copyright (C) 2004  Alex Song
   6  *
   7  * This file is subject to the terms and conditions of the GNU General Public
   8  * License.  See the file "COPYING" in the main directory of this archive
   9  * for more details.
  10  *
  11  */
  12 #include <linux/init.h>
  13 #include <linux/mman.h>
  14 #include <linux/mm.h>
  15 #include <linux/fs.h>
  16 #include <linux/threads.h>
  17 #include <asm/addrspace.h>
  18 #include <asm/page.h>
  19 #include <asm/pgtable.h>
  20 #include <asm/processor.h>
  21 #include <asm/cache.h>
  22 #include <asm/io.h>
  23 #include <asm/uaccess.h>
  24 #include <asm/pgalloc.h>
  25 #include <asm/mmu_context.h>
  26 #include <asm/cacheflush.h>
  27
  28 /*
  29  * The 32KB cache on the SH7705 suffers from the same synonym problem
  30  * as SH4 CPUs
  31  */
  32 static inline void cache_wback_all(void)
  33 {
  34         unsigned long ways, waysize, addrstart;
  35
  36         ways = current_cpu_data.dcache.ways;
  37         waysize = current_cpu_data.dcache.sets;
  38         waysize <<= current_cpu_data.dcache.entry_shift;
  39
  40         addrstart = CACHE_OC_ADDRESS_ARRAY;
  41
  42         do {
  43                 unsigned long addr;
  44
  45                 for (addr = addrstart;
  46                      addr < addrstart + waysize;
  47                      addr += current_cpu_data.dcache.linesz) {
  48                         unsigned long data;
  49                         int v = SH_CACHE_UPDATED | SH_CACHE_VALID;
  50
  51                         data = __raw_readl(addr);
  52
  53                         if ((data & v) == v)
  54                                 __raw_writel(data & ~v, addr);
  55
  56                 }
  57
  58                 addrstart += current_cpu_data.dcache.way_incr;
  59         } while (--ways);
  60 }
  61
  62 /*
  63  * Write back the range of D-cache, and purge the I-cache.
  64  *
  65  * Called from kernel/module.c:sys_init_module and routine for a.out format.
  66  */
  67 static void sh7705_flush_icache_range(void *args)
  68 {
  69         struct flusher_data *data = args;
  70         unsigned long start, end;
  71
  72         start = data->addr1;
  73         end = data->addr2;
  74
  75         __flush_wback_region((void *)start, end - start);
  76 }
  77
  78 /*
  79  * Writeback&Invalidate the D-cache of the page
  80  */
  81 static void __flush_dcache_page(unsigned long phys)
  82 {
  83         unsigned long ways, waysize, addrstart;
  84         unsigned long flags;
  85
  86         phys |= SH_CACHE_VALID;
  87
  88         /*
  89          * Here, phys is the physical address of the page. We check all the
  90          * tags in the cache for those with the same page number as this page
  91          * (by masking off the lowest 2 bits of the 19-bit tag; these bits are
  92          * derived from the offset within in the 4k page). Matching valid
  93          * entries are invalidated.
  94          *
  95          * Since 2 bits of the cache index are derived from the virtual page
  96          * number, knowing this would reduce the number of cache entries to be
  97          * searched by a factor of 4. However this function exists to deal with
  98          * potential cache aliasing, therefore the optimisation is probably not
  99          * possible.
 100          */
 101         local_irq_save(flags);
 102         jump_to_uncached();
 103
 104         ways = current_cpu_data.dcache.ways;
 105         waysize = current_cpu_data.dcache.sets;
 106         waysize <<= current_cpu_data.dcache.entry_shift;
 107
 108         addrstart = CACHE_OC_ADDRESS_ARRAY;
 109
 110         do {
 111                 unsigned long addr;
 112
 113                 for (addr = addrstart;
 114                      addr < addrstart + waysize;
 115                      addr += current_cpu_data.dcache.linesz) {
 116                         unsigned long data;
 117
 118                         data = __raw_readl(addr) & (0x1ffffC00 | SH_CACHE_VALID);
 119                         if (data == phys) {
 120                                 data &= ~(SH_CACHE_VALID | SH_CACHE_UPDATED);
 121                                 __raw_writel(data, addr);
 122                         }
 123                 }
 124
 125                 addrstart += current_cpu_data.dcache.way_incr;
 126         } while (--ways);
 127
 128         back_to_cached();
 129         local_irq_restore(flags);
 130 }
 131
 132 /*
 133  * Write back & invalidate the D-cache of the page.
 134  * (To avoid "alias" issues)
 135  */
 136 static void sh7705_flush_dcache_page(void *arg)
 137 {
 138         struct page *page = arg;
 139         struct address_space *mapping = page_mapping(page);
 140
 141         if (mapping && !mapping_mapped(mapping))
 142                 set_bit(PG_dcache_dirty, &page->flags);
 143         else
 144                 __flush_dcache_page(__pa(page_address(page)));
 145 }
 146
 147 static void sh7705_flush_cache_all(void *args)
 148 {
 149         unsigned long flags;
 150
 151         local_irq_save(flags);
 152         jump_to_uncached();
 153
 154         cache_wback_all();
 155         back_to_cached();
 156         local_irq_restore(flags);
 157 }
 158
 159 /*
 160  * Write back and invalidate I/D-caches for the page.
 161  *
 162  * ADDRESS: Virtual Address (U0 address)
 163  */
 164 static void sh7705_flush_cache_page(void *args)
 165 {
 166         struct flusher_data *data = args;
 167         unsigned long pfn = data->addr2;
 168
 169         __flush_dcache_page(pfn << PAGE_SHIFT);
 170 }
 171
 172 /*
 173  * This is called when a page-cache page is about to be mapped into a
 174  * user process' address space.  It offers an opportunity for a
 175  * port to ensure d-cache/i-cache coherency if necessary.
 176  *
 177  * Not entirely sure why this is necessary on SH3 with 32K cache but
 178  * without it we get occasional "Memory fault" when loading a program.
 179  */
 180 static void sh7705_flush_icache_page(void *page)
 181 {
 182         __flush_purge_region(page_address(page), PAGE_SIZE);
 183 }
 184
 185 void __init sh7705_cache_init(void)
 186 {
 187         local_flush_icache_range        = sh7705_flush_icache_range;
 188         local_flush_dcache_page         = sh7705_flush_dcache_page;
 189         local_flush_cache_all           = sh7705_flush_cache_all;
 190         local_flush_cache_mm            = sh7705_flush_cache_all;
 191         local_flush_cache_dup_mm        = sh7705_flush_cache_all;
 192         local_flush_cache_range         = sh7705_flush_cache_all;
 193         local_flush_cache_page          = sh7705_flush_cache_page;
 194         local_flush_icache_page         = sh7705_flush_icache_page;
 195 }