include/sysemu/dma.h

   1 /*
   2  * DMA helper functions
   3  *
   4  * Copyright (c) 2009, 2020 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
  18 typedef struct ScatterGatherEntry ScatterGatherEntry;
  19
  20 typedef enum {
  21     DMA_DIRECTION_TO_DEVICE = 0,
  22     DMA_DIRECTION_FROM_DEVICE = 1,
  23 } DMADirection;
  24
  25 struct 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  */
  43 typedef uint64_t dma_addr_t;
  44
  45 #define DMA_ADDR_BITS 64
  46 #define DMA_ADDR_FMT "%" PRIx64
  47
  48 static 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 */
  74 static 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
  83 static inline MemTxResult dma_memory_rw_relaxed(AddressSpace *as,
  84                                                 dma_addr_t addr,
  85                                                 void *buf, dma_addr_t len,
  86                                                 DMADirection dir)
  87 {
  88     return address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED,
  89                             buf, len, dir == DMA_DIRECTION_FROM_DEVICE);
  90 }
  91
  92 static inline MemTxResult dma_memory_read_relaxed(AddressSpace *as,
  93                                                   dma_addr_t addr,
  94                                                   void *buf, dma_addr_t len)
  95 {
  96     return dma_memory_rw_relaxed(as, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
  97 }
  98
  99 static inline MemTxResult dma_memory_write_relaxed(AddressSpace *as,
 100                                                    dma_addr_t addr,
 101                                                    const void *buf,
 102                                                    dma_addr_t len)
 103 {
 104     return dma_memory_rw_relaxed(as, addr, (void *)buf, len,
 105                                  DMA_DIRECTION_FROM_DEVICE);
 106 }
 107
 108 /**
 109  * dma_memory_rw: Read from or write to an address space from DMA controller.
 110  *
 111  * Return a MemTxResult indicating whether the operation succeeded
 112  * or failed (eg unassigned memory, device rejected the transaction,
 113  * IOMMU fault).
 114  *
 115  * @as: #AddressSpace to be accessed
 116  * @addr: address within that address space
 117  * @buf: buffer with the data transferred
 118  * @len: the number of bytes to read or write
 119  * @dir: indicates the transfer direction
 120  */
 121 static inline MemTxResult dma_memory_rw(AddressSpace *as, dma_addr_t addr,
 122                                         void *buf, dma_addr_t len,
 123                                         DMADirection dir)
 124 {
 125     dma_barrier(as, dir);
 126
 127     return dma_memory_rw_relaxed(as, addr, buf, len, dir);
 128 }
 129
 130 /**
 131  * dma_memory_read: Read from an address space from DMA controller.
 132  *
 133  * Return a MemTxResult indicating whether the operation succeeded
 134  * or failed (eg unassigned memory, device rejected the transaction,
 135  * IOMMU fault).  Called within RCU critical section.
 136  *
 137  * @as: #AddressSpace to be accessed
 138  * @addr: address within that address space
 139  * @buf: buffer with the data transferred
 140  * @len: length of the data transferred
 141  */
 142 static inline MemTxResult dma_memory_read(AddressSpace *as, dma_addr_t addr,
 143                                           void *buf, dma_addr_t len)
 144 {
 145     return dma_memory_rw(as, addr, buf, len, DMA_DIRECTION_TO_DEVICE);
 146 }
 147
 148 /**
 149  * address_space_write: Write to address space from DMA controller.
 150  *
 151  * Return a MemTxResult indicating whether the operation succeeded
 152  * or failed (eg unassigned memory, device rejected the transaction,
 153  * IOMMU fault).
 154  *
 155  * @as: #AddressSpace to be accessed
 156  * @addr: address within that address space
 157  * @buf: buffer with the data transferred
 158  * @len: the number of bytes to write
 159  */
 160 static inline MemTxResult dma_memory_write(AddressSpace *as, dma_addr_t addr,
 161                                            const void *buf, dma_addr_t len)
 162 {
 163     return dma_memory_rw(as, addr, (void *)buf, len,
 164                          DMA_DIRECTION_FROM_DEVICE);
 165 }
 166
 167 /**
 168  * dma_memory_set: Fill memory with a constant byte from DMA controller.
 169  *
 170  * Return a MemTxResult indicating whether the operation succeeded
 171  * or failed (eg unassigned memory, device rejected the transaction,
 172  * IOMMU fault).
 173  *
 174  * @as: #AddressSpace to be accessed
 175  * @addr: address within that address space
 176  * @c: constant byte to fill the memory
 177  * @len: the number of bytes to fill with the constant byte
 178  */
 179 MemTxResult dma_memory_set(AddressSpace *as, dma_addr_t addr,
 180                            uint8_t c, dma_addr_t len);
 181
 182 /**
 183  * address_space_map: Map a physical memory region into a host virtual address.
 184  *
 185  * May map a subset of the requested range, given by and returned in @plen.
 186  * May return %NULL and set *@plen to zero(0), if resources needed to perform
 187  * the mapping are exhausted.
 188  * Use only for reads OR writes - not for read-modify-write operations.
 189  *
 190  * @as: #AddressSpace to be accessed
 191  * @addr: address within that address space
 192  * @len: pointer to length of buffer; updated on return
 193  * @dir: indicates the transfer direction
 194  */
 195 static inline void *dma_memory_map(AddressSpace *as,
 196                                    dma_addr_t addr, dma_addr_t *len,
 197                                    DMADirection dir)
 198 {
 199     hwaddr xlen = *len;
 200     void *p;
 201
 202     p = address_space_map(as, addr, &xlen, dir == DMA_DIRECTION_FROM_DEVICE,
 203                           MEMTXATTRS_UNSPECIFIED);
 204     *len = xlen;
 205     return p;
 206 }
 207
 208 /**
 209  * address_space_unmap: Unmaps a memory region previously mapped
 210  *                      by dma_memory_map()
 211  *
 212  * Will also mark the memory as dirty if @dir == %DMA_DIRECTION_FROM_DEVICE.
 213  * @access_len gives the amount of memory that was actually read or written
 214  * by the caller.
 215  *
 216  * @as: #AddressSpace used
 217  * @buffer: host pointer as returned by address_space_map()
 218  * @len: buffer length as returned by address_space_map()
 219  * @dir: indicates the transfer direction
 220  * @access_len: amount of data actually transferred
 221  */
 222 static inline void dma_memory_unmap(AddressSpace *as,
 223                                     void *buffer, dma_addr_t len,
 224                                     DMADirection dir, dma_addr_t access_len)
 225 {
 226     address_space_unmap(as, buffer, (hwaddr)len,
 227                         dir == DMA_DIRECTION_FROM_DEVICE, access_len);
 228 }
 229
 230 #define DEFINE_LDST_DMA(_lname, _sname, _bits, _end) \
 231     static inline uint##_bits##_t ld##_lname##_##_end##_dma(AddressSpace *as, \
 232                                                             dma_addr_t addr) \
 233     {                                                                   \
 234         uint##_bits##_t val;                                            \
 235         dma_memory_read(as, addr, &val, (_bits) / 8);                   \
 236         return _end##_bits##_to_cpu(val);                               \
 237     }                                                                   \
 238     static inline void st##_sname##_##_end##_dma(AddressSpace *as,      \
 239                                                  dma_addr_t addr,       \
 240                                                  uint##_bits##_t val)   \
 241     {                                                                   \
 242         val = cpu_to_##_end##_bits(val);                                \
 243         dma_memory_write(as, addr, &val, (_bits) / 8);                  \
 244     }
 245
 246 static inline uint8_t ldub_dma(AddressSpace *as, dma_addr_t addr)
 247 {
 248     uint8_t val;
 249
 250     dma_memory_read(as, addr, &val, 1);
 251     return val;
 252 }
 253
 254 static inline void stb_dma(AddressSpace *as, dma_addr_t addr, uint8_t val)
 255 {
 256     dma_memory_write(as, addr, &val, 1);
 257 }
 258
 259 DEFINE_LDST_DMA(uw, w, 16, le);
 260 DEFINE_LDST_DMA(l, l, 32, le);
 261 DEFINE_LDST_DMA(q, q, 64, le);
 262 DEFINE_LDST_DMA(uw, w, 16, be);
 263 DEFINE_LDST_DMA(l, l, 32, be);
 264 DEFINE_LDST_DMA(q, q, 64, be);
 265
 266 #undef DEFINE_LDST_DMA
 267
 268 struct ScatterGatherEntry {
 269     dma_addr_t base;
 270     dma_addr_t len;
 271 };
 272
 273 void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint,
 274                       AddressSpace *as);
 275 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len);
 276 void qemu_sglist_destroy(QEMUSGList *qsg);
 277 #endif
 278
 279 typedef BlockAIOCB *DMAIOFunc(int64_t offset, QEMUIOVector *iov,
 280                               BlockCompletionFunc *cb, void *cb_opaque,
 281                               void *opaque);
 282
 283 BlockAIOCB *dma_blk_io(AioContext *ctx,
 284                        QEMUSGList *sg, uint64_t offset, uint32_t align,
 285                        DMAIOFunc *io_func, void *io_func_opaque,
 286                        BlockCompletionFunc *cb, void *opaque, DMADirection dir);
 287 BlockAIOCB *dma_blk_read(BlockBackend *blk,
 288                          QEMUSGList *sg, uint64_t offset, uint32_t align,
 289                          BlockCompletionFunc *cb, void *opaque);
 290 BlockAIOCB *dma_blk_write(BlockBackend *blk,
 291                           QEMUSGList *sg, uint64_t offset, uint32_t align,
 292                           BlockCompletionFunc *cb, void *opaque);
 293 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg);
 294 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg);
 295
 296 void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie,
 297                     QEMUSGList *sg, enum BlockAcctType type);
 298
 299 #endif