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/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 } 199 200