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/slab.h>
  19 #include <linux/vmalloc.h>
  20
  21 #include <asm/sun3x.h>
  22 #include <asm/dvma.h>
  23 #include <asm/io.h>
  24 #include <asm/page.h>
  25 #include <asm/pgtable.h>
  26 #include <asm/pgalloc.h>
  27
  28 /* IOMMU support */
  29
  30 #define IOMMU_ADDR_MASK            0x03ffe000
  31 #define IOMMU_CACHE_INHIBIT        0x00000040
  32 #define IOMMU_FULL_BLOCK           0x00000020
  33 #define IOMMU_MODIFIED             0x00000010
  34 #define IOMMU_USED                 0x00000008
  35 #define IOMMU_WRITE_PROTECT        0x00000004
  36 #define IOMMU_DT_MASK              0x00000003
  37 #define IOMMU_DT_INVALID           0x00000000
  38 #define IOMMU_DT_VALID             0x00000001
  39 #define IOMMU_DT_BAD               0x00000002
  40
  41
  42 static volatile unsigned long *iommu_pte = (unsigned long *)SUN3X_IOMMU;
  43
  44
  45 #define dvma_entry_paddr(index)         (iommu_pte[index] & IOMMU_ADDR_MASK)
  46 #define dvma_entry_vaddr(index,paddr)   ((index << DVMA_PAGE_SHIFT) |  \
  47                                          (paddr & (DVMA_PAGE_SIZE-1)))
  48 #if 0
  49 #define dvma_entry_set(index,addr)      (iommu_pte[index] =            \
  50                                             (addr & IOMMU_ADDR_MASK) | \
  51                                              IOMMU_DT_VALID | IOMMU_CACHE_INHIBIT)
  52 #else
  53 #define dvma_entry_set(index,addr)      (iommu_pte[index] =            \
  54                                             (addr & IOMMU_ADDR_MASK) | \
  55                                              IOMMU_DT_VALID)
  56 #endif
  57 #define dvma_entry_clr(index)           (iommu_pte[index] = IOMMU_DT_INVALID)
  58 #define dvma_entry_hash(addr)           ((addr >> DVMA_PAGE_SHIFT) ^ \
  59                                          ((addr & 0x03c00000) >>     \
  60                                                 (DVMA_PAGE_SHIFT+4)))
  61
  62 #undef DEBUG
  63
  64 #ifdef DEBUG
  65 /* code to print out a dvma mapping for debugging purposes */
  66 void dvma_print (unsigned long dvma_addr)
  67 {
  68
  69         unsigned long index;
  70
  71         index = dvma_addr >> DVMA_PAGE_SHIFT;
  72
  73         printk("idx %lx dvma_addr %08lx paddr %08lx\n", index, dvma_addr,
  74                dvma_entry_paddr(index));
  75
  76
  77 }
  78 #endif
  79
  80
  81 /* create a virtual mapping for a page assigned within the IOMMU
  82    so that the cpu can reach it easily */
  83 inline int dvma_map_cpu(unsigned long kaddr,
  84                                unsigned long vaddr, int len)
  85 {
  86         pgd_t *pgd;
  87         unsigned long end;
  88         int ret = 0;
  89
  90         kaddr &= PAGE_MASK;
  91         vaddr &= PAGE_MASK;
  92
  93         end = PAGE_ALIGN(vaddr + len);
  94
  95 #ifdef DEBUG
  96         printk("dvma: mapping kern %08lx to virt %08lx\n",
  97                kaddr, vaddr);
  98 #endif
  99         pgd = pgd_offset_k(vaddr);
 100
 101         do {
 102                 pmd_t *pmd;
 103                 unsigned long end2;
 104
 105                 if((pmd = pmd_alloc(&init_mm, pgd, vaddr)) == NULL) {
 106                         ret = -ENOMEM;
 107                         goto out;
 108                 }
 109
 110                 if((end & PGDIR_MASK) > (vaddr & PGDIR_MASK))
 111                         end2 = (vaddr + (PGDIR_SIZE-1)) & PGDIR_MASK;
 112                 else
 113                         end2 = end;
 114
 115                 do {
 116                         pte_t *pte;
 117                         unsigned long end3;
 118
 119                         if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
 120                                 ret = -ENOMEM;
 121                                 goto out;
 122                         }
 123
 124                         if((end2 & PMD_MASK) > (vaddr & PMD_MASK))
 125                                 end3 = (vaddr + (PMD_SIZE-1)) & PMD_MASK;
 126                         else
 127                                 end3 = end2;
 128
 129                         do {
 130 #ifdef DEBUG
 131                                 printk("mapping %08lx phys to %08lx\n",
 132                                        __pa(kaddr), vaddr);
 133 #endif
 134                                 set_pte(pte, pfn_pte(virt_to_pfn(kaddr),
 135                                                      PAGE_KERNEL));
 136                                 pte++;
 137                                 kaddr += PAGE_SIZE;
 138                                 vaddr += PAGE_SIZE;
 139                         } while(vaddr < end3);
 140
 141                 } while(vaddr < end2);
 142
 143         } while(vaddr < end);
 144
 145         flush_tlb_all();
 146
 147  out:
 148         return ret;
 149 }
 150
 151
 152 inline int dvma_map_iommu(unsigned long kaddr, unsigned long baddr,
 153                                  int len)
 154 {
 155         unsigned long end, index;
 156
 157         index = baddr >> DVMA_PAGE_SHIFT;
 158         end = ((baddr+len) >> DVMA_PAGE_SHIFT);
 159
 160         if(len & ~DVMA_PAGE_MASK)
 161                 end++;
 162
 163         for(; index < end ; index++) {
 164 //              if(dvma_entry_use(index))
 165 //                      BUG();
 166 //              printk("mapping pa %lx to ba %lx\n", __pa(kaddr), index << DVMA_PAGE_SHIFT);
 167
 168                 dvma_entry_set(index, __pa(kaddr));
 169
 170                 iommu_pte[index] |= IOMMU_FULL_BLOCK;
 171 //              dvma_entry_inc(index);
 172
 173                 kaddr += DVMA_PAGE_SIZE;
 174         }
 175
 176 #ifdef DEBUG
 177         for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
 178                 dvma_print(index << DVMA_PAGE_SHIFT);
 179 #endif
 180         return 0;
 181
 182 }
 183
 184 void dvma_unmap_iommu(unsigned long baddr, int len)
 185 {
 186
 187         int index, end;
 188
 189
 190         index = baddr >> DVMA_PAGE_SHIFT;
 191         end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);
 192
 193         for(; index < end ; index++) {
 194 #ifdef DEBUG
 195                 printk("freeing bus mapping %08x\n", index << DVMA_PAGE_SHIFT);
 196 #endif
 197 #if 0
 198                 if(!dvma_entry_use(index))
 199                         printk("dvma_unmap freeing unused entry %04x\n",
 200                                index);
 201                 else
 202                         dvma_entry_dec(index);
 203 #endif
 204                 dvma_entry_clr(index);
 205         }
 206
 207 }
 208