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Cong Wang650275d2012-02-03 15:34:16 +08001#include <linux/prefetch.h>
2
Linus Torvalds1da177e2005-04-16 15:20:36 -07003/**
4 * iommu_fill_pdir - Insert coalesced scatter/gather chunks into the I/O Pdir.
5 * @ioc: The I/O Controller.
6 * @startsg: The scatter/gather list of coalesced chunks.
7 * @nents: The number of entries in the scatter/gather list.
8 * @hint: The DMA Hint.
9 *
10 * This function inserts the coalesced scatter/gather list chunks into the
11 * I/O Controller's I/O Pdir.
12 */
13static inline unsigned int
14iommu_fill_pdir(struct ioc *ioc, struct scatterlist *startsg, int nents,
15 unsigned long hint,
16 void (*iommu_io_pdir_entry)(u64 *, space_t, unsigned long,
17 unsigned long))
18{
19 struct scatterlist *dma_sg = startsg; /* pointer to current DMA */
20 unsigned int n_mappings = 0;
21 unsigned long dma_offset = 0, dma_len = 0;
22 u64 *pdirp = NULL;
23
24 /* Horrible hack. For efficiency's sake, dma_sg starts one
25 * entry below the true start (it is immediately incremented
26 * in the loop) */
27 dma_sg--;
28
29 while (nents-- > 0) {
30 unsigned long vaddr;
31 long size;
32
33 DBG_RUN_SG(" %d : %08lx/%05x %08lx/%05x\n", nents,
34 (unsigned long)sg_dma_address(startsg), cnt,
35 sg_virt_addr(startsg), startsg->length
36 );
37
38
39 /*
40 ** Look for the start of a new DMA stream
41 */
42
43 if (sg_dma_address(startsg) & PIDE_FLAG) {
44 u32 pide = sg_dma_address(startsg) & ~PIDE_FLAG;
45
46 BUG_ON(pdirp && (dma_len != sg_dma_len(dma_sg)));
47
48 dma_sg++;
49
50 dma_len = sg_dma_len(startsg);
51 sg_dma_len(startsg) = 0;
52 dma_offset = (unsigned long) pide & ~IOVP_MASK;
53 n_mappings++;
54#if defined(ZX1_SUPPORT)
55 /* Pluto IOMMU IO Virt Address is not zero based */
56 sg_dma_address(dma_sg) = pide | ioc->ibase;
57#else
58 /* SBA, ccio, and dino are zero based.
59 * Trying to save a few CPU cycles for most users.
60 */
61 sg_dma_address(dma_sg) = pide;
62#endif
63 pdirp = &(ioc->pdir_base[pide >> IOVP_SHIFT]);
64 prefetchw(pdirp);
65 }
66
67 BUG_ON(pdirp == NULL);
68
69 vaddr = sg_virt_addr(startsg);
70 sg_dma_len(dma_sg) += startsg->length;
71 size = startsg->length + dma_offset;
72 dma_offset = 0;
73#ifdef IOMMU_MAP_STATS
74 ioc->msg_pages += startsg->length >> IOVP_SHIFT;
75#endif
76 do {
77 iommu_io_pdir_entry(pdirp, KERNEL_SPACE,
78 vaddr, hint);
79 vaddr += IOVP_SIZE;
80 size -= IOVP_SIZE;
81 pdirp++;
82 } while(unlikely(size > 0));
83 startsg++;
84 }
85 return(n_mappings);
86}
87
88
89/*
90** First pass is to walk the SG list and determine where the breaks are
91** in the DMA stream. Allocates PDIR entries but does not fill them.
92** Returns the number of DMA chunks.
93**
94** Doing the fill separate from the coalescing/allocation keeps the
95** code simpler. Future enhancement could make one pass through
96** the sglist do both.
97*/
98
99static inline unsigned int
FUJITA Tomonorid1b51632008-02-04 22:28:03 -0800100iommu_coalesce_chunks(struct ioc *ioc, struct device *dev,
FUJITA Tomonori7c8cda62008-03-04 14:29:28 -0800101 struct scatterlist *startsg, int nents,
102 int (*iommu_alloc_range)(struct ioc *, struct device *, size_t))
Linus Torvalds1da177e2005-04-16 15:20:36 -0700103{
104 struct scatterlist *contig_sg; /* contig chunk head */
105 unsigned long dma_offset, dma_len; /* start/len of DMA stream */
106 unsigned int n_mappings = 0;
FUJITA Tomonorid1b51632008-02-04 22:28:03 -0800107 unsigned int max_seg_size = dma_get_max_seg_size(dev);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700108
109 while (nents > 0) {
110
111 /*
112 ** Prepare for first/next DMA stream
113 */
114 contig_sg = startsg;
115 dma_len = startsg->length;
116 dma_offset = sg_virt_addr(startsg) & ~IOVP_MASK;
117
118 /* PARANOID: clear entries */
119 sg_dma_address(startsg) = 0;
120 sg_dma_len(startsg) = 0;
121
122 /*
123 ** This loop terminates one iteration "early" since
124 ** it's always looking one "ahead".
125 */
126 while(--nents > 0) {
127 unsigned long prevstartsg_end, startsg_end;
128
129 prevstartsg_end = sg_virt_addr(startsg) +
130 startsg->length;
131
132 startsg++;
133 startsg_end = sg_virt_addr(startsg) +
134 startsg->length;
135
136 /* PARANOID: clear entries */
137 sg_dma_address(startsg) = 0;
138 sg_dma_len(startsg) = 0;
139
140 /*
141 ** First make sure current dma stream won't
142 ** exceed DMA_CHUNK_SIZE if we coalesce the
143 ** next entry.
144 */
Milind Arun Choudhary3cb1d952007-03-06 02:44:13 -0800145 if(unlikely(ALIGN(dma_len + dma_offset + startsg->length,
Linus Torvalds1da177e2005-04-16 15:20:36 -0700146 IOVP_SIZE) > DMA_CHUNK_SIZE))
147 break;
148
FUJITA Tomonorid1b51632008-02-04 22:28:03 -0800149 if (startsg->length + dma_len > max_seg_size)
150 break;
151
Linus Torvalds1da177e2005-04-16 15:20:36 -0700152 /*
153 ** Next see if we can append the next chunk (i.e.
154 ** it must end on one page and begin on another
155 */
156 if (unlikely(((prevstartsg_end | sg_virt_addr(startsg)) & ~PAGE_MASK) != 0))
157 break;
158
159 dma_len += startsg->length;
160 }
161
162 /*
163 ** End of DMA Stream
164 ** Terminate last VCONTIG block.
165 ** Allocate space for DMA stream.
166 */
167 sg_dma_len(contig_sg) = dma_len;
Milind Arun Choudhary3cb1d952007-03-06 02:44:13 -0800168 dma_len = ALIGN(dma_len + dma_offset, IOVP_SIZE);
Linus Torvalds1da177e2005-04-16 15:20:36 -0700169 sg_dma_address(contig_sg) =
170 PIDE_FLAG
FUJITA Tomonori7c8cda62008-03-04 14:29:28 -0800171 | (iommu_alloc_range(ioc, dev, dma_len) << IOVP_SHIFT)
Linus Torvalds1da177e2005-04-16 15:20:36 -0700172 | dma_offset;
173 n_mappings++;
174 }
175
176 return n_mappings;
177}
178