dma.h

   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 <stdio.h>
  14 #include "memory.h"
  15 #include "hw/hw.h"
  16 #include "block.h"
  17 #include "kvm.h"
  18
  19 typedef struct DMAContext DMAContext;
  20 typedef struct ScatterGatherEntry ScatterGatherEntry;
  21
  22 typedef enum {
  23     DMA_DIRECTION_TO_DEVICE = 0,
  24     DMA_DIRECTION_FROM_DEVICE = 1,
  25 } DMADirection;
  26
  27 struct QEMUSGList {
  28     ScatterGatherEntry *sg;
  29     int nsg;
  30     int nalloc;
  31     size_t size;
  32     DMAContext *dma;
  33 };
  34
  35 #ifndef CONFIG_USER_ONLY
  36
  37 /*
  38  * When an IOMMU is present, bus addresses become distinct from
  39  * CPU/memory physical addresses and may be a different size.  Because
  40  * the IOVA size depends more on the bus than on the platform, we more
  41  * or less have to treat these as 64-bit always to cover all (or at
  42  * least most) cases.
  43  */
  44 typedef uint64_t dma_addr_t;
  45
  46 #define DMA_ADDR_BITS 64
  47 #define DMA_ADDR_FMT "%" PRIx64
  48
  49 typedef int DMATranslateFunc(DMAContext *dma,
  50                              dma_addr_t addr,
  51                              hwaddr *paddr,
  52                              hwaddr *len,
  53                              DMADirection dir);
  54 typedef void* DMAMapFunc(DMAContext *dma,
  55                          dma_addr_t addr,
  56                          dma_addr_t *len,
  57                          DMADirection dir);
  58 typedef void DMAUnmapFunc(DMAContext *dma,
  59                           void *buffer,
  60                           dma_addr_t len,
  61                           DMADirection dir,
  62                           dma_addr_t access_len);
  63
  64 struct DMAContext {
  65     AddressSpace *as;
  66     DMATranslateFunc *translate;
  67     DMAMapFunc *map;
  68     DMAUnmapFunc *unmap;
  69 };
  70
  71 /* A global DMA context corresponding to the address_space_memory
  72  * AddressSpace, for sysbus devices which do DMA.
  73  */
  74 extern DMAContext dma_context_memory;
  75
  76 static inline void dma_barrier(DMAContext *dma, DMADirection dir)
  77 {
  78     /*
  79      * This is called before DMA read and write operations
  80      * unless the _relaxed form is used and is responsible
  81      * for providing some sane ordering of accesses vs
  82      * concurrently running VCPUs.
  83      *
  84      * Users of map(), unmap() or lower level st/ld_*
  85      * operations are responsible for providing their own
  86      * ordering via barriers.
  87      *
  88      * This primitive implementation does a simple smp_mb()
  89      * before each operation which provides pretty much full
  90      * ordering.
  91      *
  92      * A smarter implementation can be devised if needed to
  93      * use lighter barriers based on the direction of the
  94      * transfer, the DMA context, etc...
  95      */
  96     if (kvm_enabled()) {
  97         smp_mb();
  98     }
  99 }
 100
 101 static inline bool dma_has_iommu(DMAContext *dma)
 102 {
 103     return dma && dma->translate;
 104 }
 105
 106 /* Checks that the given range of addresses is valid for DMA.  This is
 107  * useful for certain cases, but usually you should just use
 108  * dma_memory_{read,write}() and check for errors */
 109 bool iommu_dma_memory_valid(DMAContext *dma, dma_addr_t addr, dma_addr_t len,
 110                             DMADirection dir);
 111 static inline bool dma_memory_valid(DMAContext *dma,
 112                                     dma_addr_t addr, dma_addr_t len,
 113                                     DMADirection dir)
 114 {
 115     if (!dma_has_iommu(dma)) {
 116         return true;
 117     } else {
 118         return iommu_dma_memory_valid(dma, addr, len, dir);
 119     }
 120 }
 121
 122 int iommu_dma_memory_rw(DMAContext *dma, dma_addr_t addr,
 123                         void *buf, dma_addr_t len, DMADirection dir);
 124 static inline int dma_memory_rw_relaxed(DMAContext *dma, dma_addr_t addr,
 125                                         void *buf, dma_addr_t len,
 126                                         DMADirection dir)
 127 {
 128     if (!dma_has_iommu(dma)) {
 129         /* Fast-path for no IOMMU */
 130         address_space_rw(dma->as, addr, buf, len, dir == DMA_DIRECTION_FROM_DEVICE);
 131         return 0;
 132     } else {
 133         return iommu_dma_memory_rw(dma, addr, buf, len, dir);
 134     }
 135 }
 136
 137 static inline int dma_memory_read_relaxed(DMAContext *dma, dma_addr_t addr,
 138                                           void *buf, dma_addr_t len)
 139 {
 140     return dma_memory_rw_relaxed(dma, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
 141 }
 142
 143 static inline int dma_memory_write_relaxed(DMAContext *dma, dma_addr_t addr,
 144                                            const void *buf, dma_addr_t len)
 145 {
 146     return dma_memory_rw_relaxed(dma, addr, (void *)buf, len,
 147                                  DMA_DIRECTION_FROM_DEVICE);
 148 }
 149
 150 static inline int dma_memory_rw(DMAContext *dma, dma_addr_t addr,
 151                                 void *buf, dma_addr_t len,
 152                                 DMADirection dir)
 153 {
 154     dma_barrier(dma, dir);
 155
 156     return dma_memory_rw_relaxed(dma, addr, buf, len, dir);
 157 }
 158
 159 static inline int dma_memory_read(DMAContext *dma, dma_addr_t addr,
 160                                   void *buf, dma_addr_t len)
 161 {
 162     return dma_memory_rw(dma, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
 163 }
 164
 165 static inline int dma_memory_write(DMAContext *dma, dma_addr_t addr,
 166                                    const void *buf, dma_addr_t len)
 167 {
 168     return dma_memory_rw(dma, addr, (void *)buf, len,
 169                          DMA_DIRECTION_FROM_DEVICE);
 170 }
 171
 172 int iommu_dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c,
 173                          dma_addr_t len);
 174
 175 int dma_memory_set(DMAContext *dma, dma_addr_t addr, uint8_t c, dma_addr_t len);
 176
 177 void *iommu_dma_memory_map(DMAContext *dma,
 178                            dma_addr_t addr, dma_addr_t *len,
 179                            DMADirection dir);
 180 static inline void *dma_memory_map(DMAContext *dma,
 181                                    dma_addr_t addr, dma_addr_t *len,
 182                                    DMADirection dir)
 183 {
 184     if (!dma_has_iommu(dma)) {
 185         hwaddr xlen = *len;
 186         void *p;
 187
 188         p = address_space_map(dma->as, addr, &xlen, dir == DMA_DIRECTION_FROM_DEVICE);
 189         *len = xlen;
 190         return p;
 191     } else {
 192         return iommu_dma_memory_map(dma, addr, len, dir);
 193     }
 194 }
 195
 196 void iommu_dma_memory_unmap(DMAContext *dma,
 197                             void *buffer, dma_addr_t len,
 198                             DMADirection dir, dma_addr_t access_len);
 199 static inline void dma_memory_unmap(DMAContext *dma,
 200                                     void *buffer, dma_addr_t len,
 201                                     DMADirection dir, dma_addr_t access_len)
 202 {
 203     if (!dma_has_iommu(dma)) {
 204         address_space_unmap(dma->as, buffer, (hwaddr)len,
 205                             dir == DMA_DIRECTION_FROM_DEVICE, access_len);
 206     } else {
 207         iommu_dma_memory_unmap(dma, buffer, len, dir, access_len);
 208     }
 209 }
 210
 211 #define DEFINE_LDST_DMA(_lname, _sname, _bits, _end) \
 212     static inline uint##_bits##_t ld##_lname##_##_end##_dma(DMAContext *dma, \
 213                                                             dma_addr_t addr) \
 214     {                                                                   \
 215         uint##_bits##_t val;                                            \
 216         dma_memory_read(dma, addr, &val, (_bits) / 8);                  \
 217         return _end##_bits##_to_cpu(val);                               \
 218     }                                                                   \
 219     static inline void st##_sname##_##_end##_dma(DMAContext *dma,       \
 220                                                  dma_addr_t addr,       \
 221                                                  uint##_bits##_t val)   \
 222     {                                                                   \
 223         val = cpu_to_##_end##_bits(val);                                \
 224         dma_memory_write(dma, addr, &val, (_bits) / 8);                 \
 225     }
 226
 227 static inline uint8_t ldub_dma(DMAContext *dma, dma_addr_t addr)
 228 {
 229     uint8_t val;
 230
 231     dma_memory_read(dma, addr, &val, 1);
 232     return val;
 233 }
 234
 235 static inline void stb_dma(DMAContext *dma, dma_addr_t addr, uint8_t val)
 236 {
 237     dma_memory_write(dma, addr, &val, 1);
 238 }
 239
 240 DEFINE_LDST_DMA(uw, w, 16, le);
 241 DEFINE_LDST_DMA(l, l, 32, le);
 242 DEFINE_LDST_DMA(q, q, 64, le);
 243 DEFINE_LDST_DMA(uw, w, 16, be);
 244 DEFINE_LDST_DMA(l, l, 32, be);
 245 DEFINE_LDST_DMA(q, q, 64, be);
 246
 247 #undef DEFINE_LDST_DMA
 248
 249 void dma_context_init(DMAContext *dma, AddressSpace *as, DMATranslateFunc translate,
 250                       DMAMapFunc map, DMAUnmapFunc unmap);
 251
 252 struct ScatterGatherEntry {
 253     dma_addr_t base;
 254     dma_addr_t len;
 255 };
 256
 257 void qemu_sglist_init(QEMUSGList *qsg, int alloc_hint, DMAContext *dma);
 258 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len);
 259 void qemu_sglist_destroy(QEMUSGList *qsg);
 260 #endif
 261
 262 typedef BlockDriverAIOCB *DMAIOFunc(BlockDriverState *bs, int64_t sector_num,
 263                                  QEMUIOVector *iov, int nb_sectors,
 264                                  BlockDriverCompletionFunc *cb, void *opaque);
 265
 266 BlockDriverAIOCB *dma_bdrv_io(BlockDriverState *bs,
 267                               QEMUSGList *sg, uint64_t sector_num,
 268                               DMAIOFunc *io_func, BlockDriverCompletionFunc *cb,
 269                               void *opaque, DMADirection dir);
 270 BlockDriverAIOCB *dma_bdrv_read(BlockDriverState *bs,
 271                                 QEMUSGList *sg, uint64_t sector,
 272                                 BlockDriverCompletionFunc *cb, void *opaque);
 273 BlockDriverAIOCB *dma_bdrv_write(BlockDriverState *bs,
 274                                  QEMUSGList *sg, uint64_t sector,
 275                                  BlockDriverCompletionFunc *cb, void *opaque);
 276 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg);
 277 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg);
 278
 279 void dma_acct_start(BlockDriverState *bs, BlockAcctCookie *cookie,
 280                     QEMUSGList *sg, enum BlockAcctType type);
 281
 282 #endif