arch/m68k/sun3x/dvma.c

   1 /*
   2  * Virtual DMA allocation
   3  *
   4  * (C) 1999 Thomas Bogendoerfer (tsbogend@alpha.franken.de)
   5  *
   6  * 11/26/2000 -- disabled the existing code because it didn't work for
   7  * me in 2.4.  Replaced with a significantly more primitive version
   8  * similar to the sun3 code.  the old functionality was probably more
   9  * desirable, but....   -- Sam Creasey (sammy@oh.verio.com)
  10  *
  11  */
  12
  13 #include <linux/kernel.h>
  14 #include <linux/init.h>
  15 #include <linux/bitops.h>
  16 #include <linux/mm.h>
  17 #include <linux/bootmem.h>
  18 #include <linux/vmalloc.h>
  19
  20 #include <asm/sun3x.h>
  21 #include <asm/dvma.h>
  22 #include <asm/io.h>
  23 #include <asm/page.h>
  24 #include <asm/pgtable.h>
  25 #include <asm/pgalloc.h>
  26
  27 /* IOMMU support */
  28
  29 #define IOMMU_ADDR_MASK            0x03ffe000
  30 #define IOMMU_CACHE_INHIBIT        0x00000040
  31 #define IOMMU_FULL_BLOCK           0x00000020
  32 #define IOMMU_MODIFIED             0x00000010
  33 #define IOMMU_USED                 0x00000008
  34 #define IOMMU_WRITE_PROTECT        0x00000004
  35 #define IOMMU_DT_MASK              0x00000003
  36 #define IOMMU_DT_INVALID           0x00000000
  37 #define IOMMU_DT_VALID             0x00000001
  38 #define IOMMU_DT_BAD               0x00000002
  39
  40
  41 static volatile unsigned long *iommu_pte = (unsigned long *)SUN3X_IOMMU;
  42
  43
  44 #define dvma_entry_paddr(index)         (iommu_pte[index] & IOMMU_ADDR_MASK)
  45 #define dvma_entry_vaddr(index,paddr)   ((index << DVMA_PAGE_SHIFT) |  \
  46                                          (paddr & (DVMA_PAGE_SIZE-1)))
  47 #if 0
  48 #define dvma_entry_set(index,addr)      (iommu_pte[index] =            \
  49                                             (addr & IOMMU_ADDR_MASK) | \
  50                                              IOMMU_DT_VALID | IOMMU_CACHE_INHIBIT)
  51 #else
  52 #define dvma_entry_set(index,addr)      (iommu_pte[index] =            \
  53                                             (addr & IOMMU_ADDR_MASK) | \
  54                                              IOMMU_DT_VALID)
  55 #endif
  56 #define dvma_entry_clr(index)           (iommu_pte[index] = IOMMU_DT_INVALID)
  57 #define dvma_entry_hash(addr)           ((addr >> DVMA_PAGE_SHIFT) ^ \
  58                                          ((addr & 0x03c00000) >>     \
  59                                                 (DVMA_PAGE_SHIFT+4)))
  60
  61 #ifdef DEBUG
  62 /* code to print out a dvma mapping for debugging purposes */
  63 void dvma_print (unsigned long dvma_addr)
  64 {
  65
  66         unsigned long index;
  67
  68         index = dvma_addr >> DVMA_PAGE_SHIFT;
  69
  70         pr_info("idx %lx dvma_addr %08lx paddr %08lx\n", index, dvma_addr,
  71                 dvma_entry_paddr(index));
  72 }
  73 #endif
  74
  75
  76 /* create a virtual mapping for a page assigned within the IOMMU
  77    so that the cpu can reach it easily */
  78 inline int dvma_map_cpu(unsigned long kaddr,
  79                                unsigned long vaddr, int len)
  80 {
  81         pgd_t *pgd;
  82         unsigned long end;
  83         int ret = 0;
  84
  85         kaddr &= PAGE_MASK;
  86         vaddr &= PAGE_MASK;
  87
  88         end = PAGE_ALIGN(vaddr + len);
  89
  90         pr_debug("dvma: mapping kern %08lx to virt %08lx\n", kaddr, vaddr);
  91         pgd = pgd_offset_k(vaddr);
  92
  93         do {
  94                 pmd_t *pmd;
  95                 unsigned long end2;
  96
  97                 if((pmd = pmd_alloc(&init_mm, pgd, vaddr)) == NULL) {
  98                         ret = -ENOMEM;
  99                         goto out;
 100                 }
 101
 102                 if((end & PGDIR_MASK) > (vaddr & PGDIR_MASK))
 103                         end2 = (vaddr + (PGDIR_SIZE-1)) & PGDIR_MASK;
 104                 else
 105                         end2 = end;
 106
 107                 do {
 108                         pte_t *pte;
 109                         unsigned long end3;
 110
 111                         if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
 112                                 ret = -ENOMEM;
 113                                 goto out;
 114                         }
 115
 116                         if((end2 & PMD_MASK) > (vaddr & PMD_MASK))
 117                                 end3 = (vaddr + (PMD_SIZE-1)) & PMD_MASK;
 118                         else
 119                                 end3 = end2;
 120
 121                         do {
 122                                 pr_debug("mapping %08lx phys to %08lx\n",
 123                                          __pa(kaddr), vaddr);
 124                                 set_pte(pte, pfn_pte(virt_to_pfn(kaddr),
 125                                                      PAGE_KERNEL));
 126                                 pte++;
 127                                 kaddr += PAGE_SIZE;
 128                                 vaddr += PAGE_SIZE;
 129                         } while(vaddr < end3);
 130
 131                 } while(vaddr < end2);
 132
 133         } while(vaddr < end);
 134
 135         flush_tlb_all();
 136
 137  out:
 138         return ret;
 139 }
 140
 141
 142 inline int dvma_map_iommu(unsigned long kaddr, unsigned long baddr,
 143                                  int len)
 144 {
 145         unsigned long end, index;
 146
 147         index = baddr >> DVMA_PAGE_SHIFT;
 148         end = ((baddr+len) >> DVMA_PAGE_SHIFT);
 149
 150         if(len & ~DVMA_PAGE_MASK)
 151                 end++;
 152
 153         for(; index < end ; index++) {
 154 //              if(dvma_entry_use(index))
 155 //                      BUG();
 156 //              pr_info("mapping pa %lx to ba %lx\n", __pa(kaddr),
 157 //                      index << DVMA_PAGE_SHIFT);
 158
 159                 dvma_entry_set(index, __pa(kaddr));
 160
 161                 iommu_pte[index] |= IOMMU_FULL_BLOCK;
 162 //              dvma_entry_inc(index);
 163
 164                 kaddr += DVMA_PAGE_SIZE;
 165         }
 166
 167 #ifdef DEBUG
 168         for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
 169                 dvma_print(index << DVMA_PAGE_SHIFT);
 170 #endif
 171         return 0;
 172
 173 }
 174
 175 void dvma_unmap_iommu(unsigned long baddr, int len)
 176 {
 177
 178         int index, end;
 179
 180
 181         index = baddr >> DVMA_PAGE_SHIFT;
 182         end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);
 183
 184         for(; index < end ; index++) {
 185                 pr_debug("freeing bus mapping %08x\n",
 186                          index << DVMA_PAGE_SHIFT);
 187 #if 0
 188                 if(!dvma_entry_use(index))
 189                         pr_info("dvma_unmap freeing unused entry %04x\n",
 190                                 index);
 191                 else
 192                         dvma_entry_dec(index);
 193 #endif
 194                 dvma_entry_clr(index);
 195         }
 196
 197 }
 198