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(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