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 */
dvma_print(unsigned long dvma_addr)63 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 */
dvma_map_cpu(unsigned long kaddr,unsigned long vaddr,int len)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
dvma_map_iommu(unsigned long kaddr,unsigned long baddr,int len)146 inline 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
dvma_unmap_iommu(unsigned long baddr,int len)179 void 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