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/slab.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
42static 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#define dvma_entry_set(index,addr)	(iommu_pte[index] =            \
49					    (addr & IOMMU_ADDR_MASK) | \
50				             IOMMU_DT_VALID)
51#define dvma_entry_clr(index)		(iommu_pte[index] = IOMMU_DT_INVALID)
52#define dvma_entry_hash(addr)		((addr >> DVMA_PAGE_SHIFT) ^ \
53					 ((addr & 0x03c00000) >>     \
54						(DVMA_PAGE_SHIFT+4)))
55
56#undef DEBUG
57
58#ifdef DEBUG
59/* code to print out a dvma mapping for debugging purposes */
60void dvma_print (unsigned long dvma_addr)
61{
62
63        unsigned long index;
64
65        index = dvma_addr >> DVMA_PAGE_SHIFT;
66
67        printk("idx %lx dvma_addr %08lx paddr %08lx\n", index, dvma_addr,
68               dvma_entry_paddr(index));
69
70
71}
72#endif
73
74
75/* create a virtual mapping for a page assigned within the IOMMU
76   so that the cpu can reach it easily */
77inline int dvma_map_cpu(unsigned long kaddr,
78			       unsigned long vaddr, int len)
79{
80	pgd_t *pgd;
81	unsigned long end;
82	int ret = 0;
83
84	kaddr &= PAGE_MASK;
85	vaddr &= PAGE_MASK;
86
87	end = PAGE_ALIGN(vaddr + len);
88
89#ifdef DEBUG
90	printk("dvma: mapping kern %08lx to virt %08lx\n",
91	       kaddr, vaddr);
92#endif
93	pgd = pgd_offset_k(vaddr);
94
95	do {
96		pmd_t *pmd;
97		unsigned long end2;
98
99		if((pmd = pmd_alloc(&init_mm, pgd, vaddr)) == NULL) {
100			ret = -ENOMEM;
101			goto out;
102		}
103
104		if((end & PGDIR_MASK) > (vaddr & PGDIR_MASK))
105			end2 = (vaddr + (PGDIR_SIZE-1)) & PGDIR_MASK;
106		else
107			end2 = end;
108
109		do {
110			pte_t *pte;
111			unsigned long end3;
112
113			if((pte = pte_alloc_kernel(pmd, vaddr)) == NULL) {
114				ret = -ENOMEM;
115				goto out;
116			}
117
118			if((end2 & PMD_MASK) > (vaddr & PMD_MASK))
119				end3 = (vaddr + (PMD_SIZE-1)) & PMD_MASK;
120			else
121				end3 = end2;
122
123			do {
124#ifdef DEBUG
125				printk("mapping %08lx phys to %08lx\n",
126				       __pa(kaddr), vaddr);
127#endif
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//		printk("mapping pa %lx to ba %lx\n", __pa(kaddr), index << DVMA_PAGE_SHIFT);
161
162		dvma_entry_set(index, __pa(kaddr));
163
164		iommu_pte[index] |= IOMMU_FULL_BLOCK;
165//		dvma_entry_inc(index);
166
167		kaddr += DVMA_PAGE_SIZE;
168	}
169
170#ifdef DEBUG
171	for(index = (baddr >> DVMA_PAGE_SHIFT); index < end; index++)
172		dvma_print(index << DVMA_PAGE_SHIFT);
173#endif
174	return 0;
175
176}
177
178void dvma_unmap_iommu(unsigned long baddr, int len)
179{
180
181	int index, end;
182
183
184	index = baddr >> DVMA_PAGE_SHIFT;
185	end = (DVMA_PAGE_ALIGN(baddr+len) >> DVMA_PAGE_SHIFT);
186
187	for(; index < end ; index++) {
188#ifdef DEBUG
189		printk("freeing bus mapping %08x\n", index << DVMA_PAGE_SHIFT);
190#endif
191		dvma_entry_clr(index);
192	}
193
194}
195