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/memblock.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/tlbflush.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 static 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         p4d_t *p4d;
  83         pud_t *pud;
  84         unsigned long end;
  85         int ret = 0;
  86
  87         kaddr &= PAGE_MASK;
  88         vaddr &= PAGE_MASK;
  89
  90         end = PAGE_ALIGN(vaddr + len);
  91
  92         pr_debug("dvma: mapping kern %08lx to virt %08lx\n", kaddr, vaddr);
  93         pgd = pgd_offset_k(vaddr);
  94         p4d = p4d_offset(pgd, vaddr);
  95         pud = pud_offset(p4d, vaddr);
  96
  97         do {
  98                 pmd_t *pmd;
  99                 unsigned long end2;
 100
 101                 if((pmd = pmd_alloc(&init_mm, pud, vaddr)) == NULL) {
 102                         ret = -ENOMEM;
 103                         goto out;
 104                 }
 105
 106                 if((end & PGDIR_MASK) > (vaddr & PGDIR_MASK))
 107                         end2 = (vaddr + (PGDIR_SIZE-1)) & PGDIR_MASK;
 108                 else
 109                         end2 = end;
 110
 111                 do {
 112                         pte_t *pte;
 113                         unsigned long end3;
 114
 115                         if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
 116                                 ret = -ENOMEM;
 117                                 goto out;
 118                         }
 119
 120                         if((end2 & PMD_MASK) > (vaddr & PMD_MASK))
 121                                 end3 = (vaddr + (PMD_SIZE-1)) & PMD_MASK;
 122                         else
 123                                 end3 = end2;
 124
 125                         do {
 126                                 pr_debug("mapping %08lx phys to %08lx\n",
 127                                          __pa(kaddr), vaddr);
 128                                 set_pte(pte, pfn_pte(virt_to_pfn((void *)kaddr),
 129                                                      PAGE_KERNEL));
 130                                 pte++;
 131                                 kaddr += PAGE_SIZE;
 132                                 vaddr += PAGE_SIZE;
 133                         } while(vaddr < end3);
 134
 135                 } while(vaddr < end2);
 136
 137         } while(vaddr < end);
 138
 139         flush_tlb_all();
 140
 141  out:
 142         return ret;
 143 }
 144
 145
 146 int dvma_map_iommu(unsigned long kaddr, unsigned long baddr, int len)
 147 {
 148         unsigned long end, index;
 149
 150         index = baddr >> DVMA_PAGE_SHIFT;
 151         end = ((baddr+len) >> DVMA_PAGE_SHIFT);
 152
 153         if(len & ~DVMA_PAGE_MASK)
 154                 end++;
 155
 156         for(; index < end ; index++) {
 157 //              if(dvma_entry_use(index))
 158 //                      BUG();
 159 //              pr_info("mapping pa %lx to ba %lx\n", __pa(kaddr),
 160 //                      index << DVMA_PAGE_SHIFT);
 161
 162                 dvma_entry_set(index, __pa(kaddr));
 163
 164                 iommu_pte[index] |= IOMMU_FULL_BLOCK;
 165 //              dvma_entry_inc(index);
 166
 167                 kaddr += DVMA_PAGE_SIZE;
 168         }
 169
 170 #ifdef DEBUG
 171         for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
 172                 dvma_print(index << DVMA_PAGE_SHIFT);
 173 #endif
 174         return 0;
 175
 176 }
 177
 178 void dvma_unmap_iommu(unsigned long baddr, int len)
 179 {
 180
 181         int index, end;
 182
 183
 184         index = baddr >> DVMA_PAGE_SHIFT;
 185         end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);
 186
 187         for(; index < end ; index++) {
 188                 pr_debug("freeing bus mapping %08x\n",
 189                          index << DVMA_PAGE_SHIFT);
 190 #if 0
 191                 if(!dvma_entry_use(index))
 192                         pr_info("dvma_unmap freeing unused entry %04x\n",
 193                                 index);
 194                 else
 195                         dvma_entry_dec(index);
 196 #endif
 197                 dvma_entry_clr(index);
 198         }
 199
 200 }