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 "exec/memory.h" 15 #include "exec/address-spaces.h" 16 #include "hw/hw.h" 17 #include "block/block.h" 18 #include "block/accounting.h" 19 #include "sysemu/kvm.h" 20 21 typedef struct ScatterGatherEntry ScatterGatherEntry; 22 23 typedef enum { 24 DMA_DIRECTION_TO_DEVICE = 0, 25 DMA_DIRECTION_FROM_DEVICE = 1, 26 } DMADirection; 27 28 struct QEMUSGList { 29 ScatterGatherEntry *sg; 30 int nsg; 31 int nalloc; 32 size_t size; 33 DeviceState *dev; 34 AddressSpace *as; 35 }; 36 37 #ifndef CONFIG_USER_ONLY 38 39 /* 40 * When an IOMMU is present, bus addresses become distinct from 41 * CPU/memory physical addresses and may be a different size. Because 42 * the IOVA size depends more on the bus than on the platform, we more 43 * or less have to treat these as 64-bit always to cover all (or at 44 * least most) cases. 45 */ 46 typedef uint64_t dma_addr_t; 47 48 #define DMA_ADDR_BITS 64 49 #define DMA_ADDR_FMT "%" PRIx64 50 51 static inline void dma_barrier(AddressSpace *as, DMADirection dir) 52 { 53 /* 54 * This is called before DMA read and write operations 55 * unless the _relaxed form is used and is responsible 56 * for providing some sane ordering of accesses vs 57 * concurrently running VCPUs. 58 * 59 * Users of map(), unmap() or lower level st/ld_* 60 * operations are responsible for providing their own 61 * ordering via barriers. 62 * 63 * This primitive implementation does a simple smp_mb() 64 * before each operation which provides pretty much full 65 * ordering. 66 * 67 * A smarter implementation can be devised if needed to 68 * use lighter barriers based on the direction of the 69 * transfer, the DMA context, etc... 70 */ 71 if (kvm_enabled()) { 72 smp_mb(); 73 } 74 } 75 76 /* Checks that the given range of addresses is valid for DMA. This is 77 * useful for certain cases, but usually you should just use 78 * dma_memory_{read,write}() and check for errors */ 79 static inline bool dma_memory_valid(AddressSpace *as, 80 dma_addr_t addr, dma_addr_t len, 81 DMADirection dir) 82 { 83 return address_space_access_valid(as, addr, len, 84 dir == DMA_DIRECTION_FROM_DEVICE); 85 } 86 87 static inline int dma_memory_rw_relaxed(AddressSpace *as, dma_addr_t addr, 88 void *buf, dma_addr_t len, 89 DMADirection dir) 90 { 91 return (bool)address_space_rw(as, addr, MEMTXATTRS_UNSPECIFIED, 92 buf, len, dir == DMA_DIRECTION_FROM_DEVICE); 93 } 94 95 static inline int dma_memory_read_relaxed(AddressSpace *as, dma_addr_t addr, 96 void *buf, dma_addr_t len) 97 { 98 return dma_memory_rw_relaxed(as, addr, buf, len, DMA_DIRECTION_TO_DEVICE); 99 } 100 101 static inline int dma_memory_write_relaxed(AddressSpace *as, dma_addr_t addr, 102 const void *buf, dma_addr_t len) 103 { 104 return dma_memory_rw_relaxed(as, addr, (void *)buf, len, 105 DMA_DIRECTION_FROM_DEVICE); 106 } 107 108 static inline int dma_memory_rw(AddressSpace *as, dma_addr_t addr, 109 void *buf, dma_addr_t len, 110 DMADirection dir) 111 { 112 dma_barrier(as, dir); 113 114 return dma_memory_rw_relaxed(as, addr, buf, len, dir); 115 } 116 117 static inline int dma_memory_read(AddressSpace *as, dma_addr_t addr, 118 void *buf, dma_addr_t len) 119 { 120 return dma_memory_rw(as, addr, buf, len, DMA_DIRECTION_TO_DEVICE); 121 } 122 123 static inline int dma_memory_write(AddressSpace *as, dma_addr_t addr, 124 const void *buf, dma_addr_t len) 125 { 126 return dma_memory_rw(as, addr, (void *)buf, len, 127 DMA_DIRECTION_FROM_DEVICE); 128 } 129 130 int dma_memory_set(AddressSpace *as, dma_addr_t addr, uint8_t c, dma_addr_t len); 131 132 static inline void *dma_memory_map(AddressSpace *as, 133 dma_addr_t addr, dma_addr_t *len, 134 DMADirection dir) 135 { 136 hwaddr xlen = *len; 137 void *p; 138 139 p = address_space_map(as, addr, &xlen, dir == DMA_DIRECTION_FROM_DEVICE); 140 *len = xlen; 141 return p; 142 } 143 144 static inline void dma_memory_unmap(AddressSpace *as, 145 void *buffer, dma_addr_t len, 146 DMADirection dir, dma_addr_t access_len) 147 { 148 address_space_unmap(as, buffer, (hwaddr)len, 149 dir == DMA_DIRECTION_FROM_DEVICE, access_len); 150 } 151 152 #define DEFINE_LDST_DMA(_lname, _sname, _bits, _end) \ 153 static inline uint##_bits##_t ld##_lname##_##_end##_dma(AddressSpace *as, \ 154 dma_addr_t addr) \ 155 { \ 156 uint##_bits##_t val; \ 157 dma_memory_read(as, addr, &val, (_bits) / 8); \ 158 return _end##_bits##_to_cpu(val); \ 159 } \ 160 static inline void st##_sname##_##_end##_dma(AddressSpace *as, \ 161 dma_addr_t addr, \ 162 uint##_bits##_t val) \ 163 { \ 164 val = cpu_to_##_end##_bits(val); \ 165 dma_memory_write(as, addr, &val, (_bits) / 8); \ 166 } 167 168 static inline uint8_t ldub_dma(AddressSpace *as, dma_addr_t addr) 169 { 170 uint8_t val; 171 172 dma_memory_read(as, addr, &val, 1); 173 return val; 174 } 175 176 static inline void stb_dma(AddressSpace *as, dma_addr_t addr, uint8_t val) 177 { 178 dma_memory_write(as, addr, &val, 1); 179 } 180 181 DEFINE_LDST_DMA(uw, w, 16, le); 182 DEFINE_LDST_DMA(l, l, 32, le); 183 DEFINE_LDST_DMA(q, q, 64, le); 184 DEFINE_LDST_DMA(uw, w, 16, be); 185 DEFINE_LDST_DMA(l, l, 32, be); 186 DEFINE_LDST_DMA(q, q, 64, be); 187 188 #undef DEFINE_LDST_DMA 189 190 struct ScatterGatherEntry { 191 dma_addr_t base; 192 dma_addr_t len; 193 }; 194 195 void qemu_sglist_init(QEMUSGList *qsg, DeviceState *dev, int alloc_hint, 196 AddressSpace *as); 197 void qemu_sglist_add(QEMUSGList *qsg, dma_addr_t base, dma_addr_t len); 198 void qemu_sglist_destroy(QEMUSGList *qsg); 199 #endif 200 201 typedef BlockAIOCB *DMAIOFunc(BlockBackend *blk, int64_t sector_num, 202 QEMUIOVector *iov, int nb_sectors, 203 BlockCompletionFunc *cb, void *opaque); 204 205 BlockAIOCB *dma_blk_io(BlockBackend *blk, 206 QEMUSGList *sg, uint64_t sector_num, 207 DMAIOFunc *io_func, BlockCompletionFunc *cb, 208 void *opaque, DMADirection dir); 209 BlockAIOCB *dma_blk_read(BlockBackend *blk, 210 QEMUSGList *sg, uint64_t sector, 211 BlockCompletionFunc *cb, void *opaque); 212 BlockAIOCB *dma_blk_write(BlockBackend *blk, 213 QEMUSGList *sg, uint64_t sector, 214 BlockCompletionFunc *cb, void *opaque); 215 uint64_t dma_buf_read(uint8_t *ptr, int32_t len, QEMUSGList *sg); 216 uint64_t dma_buf_write(uint8_t *ptr, int32_t len, QEMUSGList *sg); 217 218 void dma_acct_start(BlockBackend *blk, BlockAcctCookie *cookie, 219 QEMUSGList *sg, enum BlockAcctType type); 220 221 #endif 222