1/*
2 * DMA helper functions
3 *
4 * Copyright (c) 2009 Red Hat
5 *
6 * This work is licensed under the terms of the GNU General Public License
7 * (GNU GPL), version 2 or later.
8 */
9
10#ifndef DMA_H
11#define DMA_H
12
13#include "exec/memory.h"
14#include "exec/address-spaces.h"
15#include "block/block.h"
16#include "block/accounting.h"
17
18typedef struct ScatterGatherEntry ScatterGatherEntry;
19
20typedef enum {
21 DMA_DIRECTION_TO_DEVICE = 0,
22 DMA_DIRECTION_FROM_DEVICE = 1,
23} DMADirection;
24
25struct QEMUSGList {
26 ScatterGatherEntry *sg;
27 int nsg;
28 int nalloc;
29 size_t size;
30 DeviceState *dev;
31 AddressSpace *as;
32};
33
34#ifndef CONFIG_USER_ONLY
35
36/*
37 * When an IOMMU is present, bus addresses become distinct from
38 * CPU/memory physical addresses and may be a different size. Because
39 * the IOVA size depends more on the bus than on the platform, we more
40 * or less have to treat these as 64-bit always to cover all (or at
41 * least most) cases.
42 */
43typedef uint64_t dma_addr_t;
44
45#define DMA_ADDR_BITS 64
46#define DMA_ADDR_FMT "%" PRIx64
47
48static inline void dma_barrier(AddressSpace *as, DMADirection dir)
49{
50 /*
51 * This is called before DMA read and write operations
52 * unless the _relaxed form is used and is responsible
53 * for providing some sane ordering of accesses vs
54 * concurrently running VCPUs.
55 *
56 * Users of map(), unmap() or lower level st/ld_*
57 * operations are responsible for providing their own
58 * ordering via barriers.
59 *
60 * This primitive implementation does a simple smp_mb()
61 * before each operation which provides pretty much full
62 * ordering.
63 *
64 * A smarter implementation can be devised if needed to
65 * use lighter barriers based on the direction of the
66 * transfer, the DMA context, etc...
67 */
68 smp_mb();
69}
70
71/* Checks that the given range of addresses is valid for DMA. This is
72 * useful for certain cases, but usually you should just use
73 * dma_memory_{read,write}() and check for errors */
74static inline bool dma_memory_valid(AddressSpace *as,
75 dma_addr_t addr, dma_addr_t len,
76 DMADirection dir)
77{
78 return address_space_access_valid(as, addr, len,
79 dir == DMA_DIRECTION_FROM_DEVICE,
80 MEMTXATTRS_UNSPECIFIED);
81}
82
83static inline int dma_memory_rw_relaxed(AddressSpace *as, dma_addr_t addr,
84 void *buf, dma_addr_t len,
85 DMADirection dir)
86{
87 return (bool)address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED,
88 buf, len, dir == DMA_DIRECTION_FROM_DEVICE);
89}
90
91static inline int dma_memory_read_relaxed(AddressSpace *as, dma_addr_t addr,
92 void *buf, dma_addr_t len)
93{
94 return dma_memory_rw_relaxed(as, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
95}
96
97static inline int dma_memory_write_relaxed(AddressSpace *as, dma_addr_t addr,
98 const void *buf, dma_addr_t len)
99{
100 return dma_memory_rw_relaxed(as, addr, (void *)buf, len,
101 DMA_DIRECTION_FROM_DEVICE);
102}
103
104static inline int dma_memory_rw(AddressSpace *as, dma_addr_t addr,
105 void *buf, dma_addr_t len,
106 DMADirection dir)
107{
108 dma_barrier(as, dir);
109
110 return dma_memory_rw_relaxed(as, addr, buf, len, dir);
111}
112
113static inline int dma_memory_read(AddressSpace *as, dma_addr_t addr,
114 void *buf, dma_addr_t len)
115{
116 return dma_memory_rw(as, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
117}
118
119static inline int dma_memory_write(AddressSpace *as, dma_addr_t addr,
120 const void *buf, dma_addr_t len)
121{
122 return dma_memory_rw(as, addr, (void *)buf, len,
123 DMA_DIRECTION_FROM_DEVICE);
124}
125
126int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len);
127
128static inline void *dma_memory_map(AddressSpace *as,
129 dma_addr_t addr, dma_addr_t *len,
130 DMADirection dir)
131{
132 hwaddr xlen = *len;
133 void *p;
134
135 p = address_space_map(as, addr, &xlen, dir == DMA_DIRECTION_FROM_DEVICE,
136 MEMTXATTRS_UNSPECIFIED);
137 *len = xlen;
138 return p;
139}
140
141static inline void dma_memory_unmap(AddressSpace *as,
142 void *buffer, dma_addr_t len,
143 DMADirection dir, dma_addr_t access_len)
144{
145 address_space_unmap(as, buffer, (hwaddr)len,
146 dir == DMA_DIRECTION_FROM_DEVICE, access_len);
147}
148
149#define DEFINE_LDST_DMA(_lname, _sname, _bits, _end) \
150 static inline uint##_bits##_t ld##_lname##_##_end##_dma(AddressSpace *as, \
151 dma_addr_t addr) \
152 { \
153 uint##_bits##_t val; \
154 dma_memory_read(as, addr, &val, (_bits) / 8); \
155 return _end##_bits##_to_cpu(val); \
156 } \
157 static inline void st##_sname##_##_end##_dma(AddressSpace *as, \
158 dma_addr_t addr, \
159 uint##_bits##_t val) \
160 { \
161 val = cpu_to_##_end##_bits(val); \
162 dma_memory_write(as, addr, &val, (_bits) / 8); \
163 }
164
165static inline uint8_t ldub_dma(AddressSpace *as, dma_addr_t addr)
166{
167 uint8_t val;
168
169 dma_memory_read(as, addr, &val, 1);
170 return val;
171}
172
173static inline void stb_dma(AddressSpace *as, dma_addr_t addr, uint8_t val)
174{
175 dma_memory_write(as, addr, &val, 1);
176}
177
178DEFINE_LDST_DMA(uw, w, 16, le);
179DEFINE_LDST_DMA(l, l, 32, le);
180DEFINE_LDST_DMA(q, q, 64, le);
181DEFINE_LDST_DMA(uw, w, 16, be);
182DEFINE_LDST_DMA(l, l, 32, be);
183DEFINE_LDST_DMA(q, q, 64, be);
184
185#undef DEFINE_LDST_DMA
186
187struct ScatterGatherEntry {
188 dma_addr_t base;
189 dma_addr_t len;
190};
191
192void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
193 AddressSpace *as);
194void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len);
195void qemu_sglist_destroy(QEMUSGList *qsg);
196#endif
197
198typedef BlockAIOCB *DMAIOFunc(int64_t offset, QEMUIOVector *iov,
199 BlockCompletionFunc *cb, void *cb_opaque,
200 void *opaque);
201
202BlockAIOCB *dma_blk_io(AioContext *ctx,
203 QEMUSGList *sg, uint64_t offset, uint32_t align,
204 DMAIOFunc *io_func, void *io_func_opaque,
205 BlockCompletionFunc *cb, void *opaque, DMADirection dir);
206BlockAIOCB *dma_blk_read(BlockBackend *blk,
207 QEMUSGList *sg, uint64_t offset, uint32_t align,
208 BlockCompletionFunc *cb, void *opaque);
209BlockAIOCB *dma_blk_write(BlockBackend *blk,
210 QEMUSGList *sg, uint64_t offset, uint32_t align,
211 BlockCompletionFunc *cb, void *opaque);
212uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg);
213uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg);
214
215void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
216 QEMUSGList *sg, enum BlockAcctType type);
217
218#endif
219