1/*
2 * Virtual DMA allocation
3 *
4 * (C) 1999 Thomas Bogendoerfer (tsbogend@alpha.franken.de)
5 *
6 * 11/26/2000 -- disabled the existing code because it didn't work for
7 * me in 2.4.  Replaced with a significantly more primitive version
8 * similar to the sun3 code.  the old functionality was probably more
9 * desirable, but....   -- Sam Creasey (sammy@oh.verio.com)
10 *
11 */
12
13#include <linux/kernel.h>
14#include <linux/init.h>
15#include <linux/bitops.h>
16#include <linux/mm.h>
17#include <linux/bootmem.h>
18#include <linux/vmalloc.h>
19
20#include <asm/sun3x.h>
21#include <asm/dvma.h>
22#include <asm/io.h>
23#include <asm/page.h>
24#include <asm/pgtable.h>
25#include <asm/pgalloc.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#undef DEBUG
62
63#ifdef DEBUG
64/* code to print out a dvma mapping for debugging purposes */
65void dvma_print (unsigned long dvma_addr)
66{
67
68        unsigned long index;
69
70        index = dvma_addr >> DVMA_PAGE_SHIFT;
71
72        printk("idx %lx dvma_addr %08lx paddr %08lx\n", index, dvma_addr,
73               dvma_entry_paddr(index));
74
75
76}
77#endif
78
79
80/* create a virtual mapping for a page assigned within the IOMMU
81   so that the cpu can reach it easily */
82inline int dvma_map_cpu(unsigned long kaddr,
83			       unsigned long vaddr, int len)
84{
85	pgd_t *pgd;
86	unsigned long end;
87	int ret = 0;
88
89	kaddr &= PAGE_MASK;
90	vaddr &= PAGE_MASK;
91
92	end = PAGE_ALIGN(vaddr + len);
93
94#ifdef DEBUG
95	printk("dvma: mapping kern %08lx to virt %08lx\n",
96	       kaddr, vaddr);
97#endif
98	pgd = pgd_offset_k(vaddr);
99
100	do {
101		pmd_t *pmd;
102		unsigned long end2;
103
104		if((pmd = pmd_alloc(&init_mm, pgd, vaddr)) == NULL) {
105			ret = -ENOMEM;
106			goto out;
107		}
108
109		if((end & PGDIR_MASK) > (vaddr & PGDIR_MASK))
110			end2 = (vaddr + (PGDIR_SIZE-1)) & PGDIR_MASK;
111		else
112			end2 = end;
113
114		do {
115			pte_t *pte;
116			unsigned long end3;
117
118			if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
119				ret = -ENOMEM;
120				goto out;
121			}
122
123			if((end2 & PMD_MASK) > (vaddr & PMD_MASK))
124				end3 = (vaddr + (PMD_SIZE-1)) & PMD_MASK;
125			else
126				end3 = end2;
127
128			do {
129#ifdef DEBUG
130				printk("mapping %08lx phys to %08lx\n",
131				       __pa(kaddr), vaddr);
132#endif
133				set_pte(pte, pfn_pte(virt_to_pfn(kaddr),
134						     PAGE_KERNEL));
135				pte++;
136				kaddr += PAGE_SIZE;
137				vaddr += PAGE_SIZE;
138			} while(vaddr < end3);
139
140		} while(vaddr < end2);
141
142	} while(vaddr < end);
143
144	flush_tlb_all();
145
146 out:
147	return ret;
148}
149
150
151inline int dvma_map_iommu(unsigned long kaddr, unsigned long baddr,
152				 int len)
153{
154	unsigned long end, index;
155
156	index = baddr >> DVMA_PAGE_SHIFT;
157	end = ((baddr+len) >> DVMA_PAGE_SHIFT);
158
159	if(len & ~DVMA_PAGE_MASK)
160		end++;
161
162	for(; index < end ; index++) {
163//		if(dvma_entry_use(index))
164//			BUG();
165//		printk("mapping pa %lx to ba %lx\n", __pa(kaddr), index << DVMA_PAGE_SHIFT);
166
167		dvma_entry_set(index, __pa(kaddr));
168
169		iommu_pte[index] |= IOMMU_FULL_BLOCK;
170//		dvma_entry_inc(index);
171
172		kaddr += DVMA_PAGE_SIZE;
173	}
174
175#ifdef DEBUG
176	for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
177		dvma_print(index << DVMA_PAGE_SHIFT);
178#endif
179	return 0;
180
181}
182
183void dvma_unmap_iommu(unsigned long baddr, int len)
184{
185
186	int index, end;
187
188
189	index = baddr >> DVMA_PAGE_SHIFT;
190	end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);
191
192	for(; index < end ; index++) {
193#ifdef DEBUG
194		printk("freeing bus mapping %08x\n", index << DVMA_PAGE_SHIFT);
195#endif
196#if 0
197		if(!dvma_entry_use(index))
198			printk("dvma_unmap freeing unused entry %04x\n",
199			       index);
200		else
201			dvma_entry_dec(index);
202#endif
203		dvma_entry_clr(index);
204	}
205
206}
207
208