linux/arch/m68k/sun3x/dvma.c
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   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
  41static 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 */
  63void 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 */
  78inline 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(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
 146inline int dvma_map_iommu(unsigned long kaddr, unsigned long baddr,
 147                                 int len)
 148{
 149        unsigned long end, index;
 150
 151        index = baddr >> DVMA_PAGE_SHIFT;
 152        end = ((baddr+len) >> DVMA_PAGE_SHIFT);
 153
 154        if(len & ~DVMA_PAGE_MASK)
 155                end++;
 156
 157        for(; index < end ; index++) {
 158//              if(dvma_entry_use(index))
 159//                      BUG();
 160//              pr_info("mapping pa %lx to ba %lx\n", __pa(kaddr),
 161//                      index << DVMA_PAGE_SHIFT);
 162
 163                dvma_entry_set(index, __pa(kaddr));
 164
 165                iommu_pte[index] |= IOMMU_FULL_BLOCK;
 166//              dvma_entry_inc(index);
 167
 168                kaddr += DVMA_PAGE_SIZE;
 169        }
 170
 171#ifdef DEBUG
 172        for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
 173                dvma_print(index << DVMA_PAGE_SHIFT);
 174#endif
 175        return 0;
 176
 177}
 178
 179void dvma_unmap_iommu(unsigned long baddr, int len)
 180{
 181
 182        int index, end;
 183
 184
 185        index = baddr >> DVMA_PAGE_SHIFT;
 186        end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);
 187
 188        for(; index < end ; index++) {
 189                pr_debug("freeing bus mapping %08x\n",
 190                         index << DVMA_PAGE_SHIFT);
 191#if 0
 192                if(!dvma_entry_use(index))
 193                        pr_info("dvma_unmap freeing unused entry %04x\n",
 194                                index);
 195                else
 196                        dvma_entry_dec(index);
 197#endif
 198                dvma_entry_clr(index);
 199        }
 200
 201}
 202