arch/m68k/sun3x/dvma.c

   1 // SPDX-License-Identifier: GPL-2.0
   2 /*
   3  * Virtual DMA allocation
   4  *
   5  * (C) 1999 Thomas Bogendoerfer (tsbogend@alpha.franken.de)
   6  *
   7  * 11/26/2000 -- disabled the existing code because it didn't work for
   8  * me in 2.4.  Replaced with a significantly more primitive version
   9  * similar to the sun3 code.  the old functionality was probably more
  10  * desirable, but....   -- Sam Creasey (sammy@oh.verio.com)
  11  *
  12  */
  13
  14 #include <linux/kernel.h>
  15 #include <linux/init.h>
  16 #include <linux/bitops.h>
  17 #include <linux/mm.h>
  18 #include <linux/bootmem.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 #ifdef DEBUG
  63 /* code to print out a dvma mapping for debugging purposes */
  64 void dvma_print (unsigned long dvma_addr)
  65 {
  66
  67         unsigned long index;
  68
  69         index = dvma_addr >> DVMA_PAGE_SHIFT;
  70
  71         pr_info("idx %lx dvma_addr %08lx paddr %08lx\n", index, dvma_addr,
  72                 dvma_entry_paddr(index));
  73 }
  74 #endif
  75
  76
  77 /* create a virtual mapping for a page assigned within the IOMMU
  78    so that the cpu can reach it easily */
  79 inline int dvma_map_cpu(unsigned long kaddr,
  80                                unsigned long vaddr, int len)
  81 {
  82         pgd_t *pgd;
  83         unsigned long end;
  84         int ret = 0;
  85
  86         kaddr &= PAGE_MASK;
  87         vaddr &= PAGE_MASK;
  88
  89         end = PAGE_ALIGN(vaddr + len);
  90
  91         pr_debug("dvma: mapping kern %08lx to virt %08lx\n", kaddr, vaddr);
  92         pgd = pgd_offset_k(vaddr);
  93
  94         do {
  95                 pmd_t *pmd;
  96                 unsigned long end2;
  97
  98                 if((pmd = pmd_alloc(&init_mm, pgd, vaddr)) == NULL) {
  99                         ret = -ENOMEM;
 100                         goto out;
 101                 }
 102
 103                 if((end & PGDIR_MASK) > (vaddr & PGDIR_MASK))
 104                         end2 = (vaddr + (PGDIR_SIZE-1)) & PGDIR_MASK;
 105                 else
 106                         end2 = end;
 107
 108                 do {
 109                         pte_t *pte;
 110                         unsigned long end3;
 111
 112                         if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
 113                                 ret = -ENOMEM;
 114                                 goto out;
 115                         }
 116
 117                         if((end2 & PMD_MASK) > (vaddr & PMD_MASK))
 118                                 end3 = (vaddr + (PMD_SIZE-1)) & PMD_MASK;
 119                         else
 120                                 end3 = end2;
 121
 122                         do {
 123                                 pr_debug("mapping %08lx phys to %08lx\n",
 124                                          __pa(kaddr), vaddr);
 125                                 set_pte(pte, pfn_pte(virt_to_pfn(kaddr),
 126                                                      PAGE_KERNEL));
 127                                 pte++;
 128                                 kaddr += PAGE_SIZE;
 129                                 vaddr += PAGE_SIZE;
 130                         } while(vaddr < end3);
 131
 132                 } while(vaddr < end2);
 133
 134         } while(vaddr < end);
 135
 136         flush_tlb_all();
 137
 138  out:
 139         return ret;
 140 }
 141
 142
 143 inline int dvma_map_iommu(unsigned long kaddr, unsigned long baddr,
 144                                  int len)
 145 {
 146         unsigned long end, index;
 147
 148         index = baddr >> DVMA_PAGE_SHIFT;
 149         end = ((baddr+len) >> DVMA_PAGE_SHIFT);
 150
 151         if(len & ~DVMA_PAGE_MASK)
 152                 end++;
 153
 154         for(; index < end ; index++) {
 155 //              if(dvma_entry_use(index))
 156 //                      BUG();
 157 //              pr_info("mapping pa %lx to ba %lx\n", __pa(kaddr),
 158 //                      index << DVMA_PAGE_SHIFT);
 159
 160                 dvma_entry_set(index, __pa(kaddr));
 161
 162                 iommu_pte[index] |= IOMMU_FULL_BLOCK;
 163 //              dvma_entry_inc(index);
 164
 165                 kaddr += DVMA_PAGE_SIZE;
 166         }
 167
 168 #ifdef DEBUG
 169         for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
 170                 dvma_print(index << DVMA_PAGE_SHIFT);
 171 #endif
 172         return 0;
 173
 174 }
 175
 176 void dvma_unmap_iommu(unsigned long baddr, int len)
 177 {
 178
 179         int index, end;
 180
 181
 182         index = baddr >> DVMA_PAGE_SHIFT;
 183         end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);
 184
 185         for(; index < end ; index++) {
 186                 pr_debug("freeing bus mapping %08x\n",
 187                          index << DVMA_PAGE_SHIFT);
 188 #if 0
 189                 if(!dvma_entry_use(index))
 190                         pr_info("dvma_unmap freeing unused entry %04x\n",
 191                                 index);
 192                 else
 193                         dvma_entry_dec(index);
 194 #endif
 195                 dvma_entry_clr(index);
 196         }
 197
 198 }
 199