hw/net/rocker/rocker_desc.c

   1 /*
   2  * QEMU rocker switch emulation - Descriptor ring support
   3  *
   4  * Copyright (c) 2014 Scott Feldman <sfeldma@gmail.com>
   5  *
   6  * This program is free software; you can redistribute it and/or modify
   7  * it under the terms of the GNU General Public License as published by
   8  * the Free Software Foundation; either version 2 of the License, or
   9  * (at your option) any later version.
  10  *
  11  * This program is distributed in the hope that it will be useful,
  12  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  13  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
  14  * GNU General Public License for more details.
  15  */
  16
  17 #include "qemu/osdep.h"
  18 #include "net/net.h"
  19 #include "hw/pci/pci.h"
  20
  21 #include "rocker.h"
  22 #include "rocker_hw.h"
  23 #include "rocker_desc.h"
  24
  25 struct desc_ring {
  26     hwaddr base_addr;
  27     uint32_t size;
  28     uint32_t head;
  29     uint32_t tail;
  30     uint32_t ctrl;
  31     uint32_t credits;
  32     Rocker *r;
  33     DescInfo *info;
  34     int index;
  35     desc_ring_consume *consume;
  36     unsigned msix_vector;
  37 };
  38
  39 struct desc_info {
  40     DescRing *ring;
  41     RockerDesc desc;
  42     char *buf;
  43     size_t buf_size;
  44 };
  45
  46 uint16_t desc_buf_size(DescInfo *info)
  47 {
  48     return le16_to_cpu(info->desc.buf_size);
  49 }
  50
  51 uint16_t desc_tlv_size(DescInfo *info)
  52 {
  53     return le16_to_cpu(info->desc.tlv_size);
  54 }
  55
  56 char *desc_get_buf(DescInfo *info, bool read_only)
  57 {
  58     PCIDevice *dev = PCI_DEVICE(info->ring->r);
  59     size_t size = read_only ? le16_to_cpu(info->desc.tlv_size) :
  60                               le16_to_cpu(info->desc.buf_size);
  61
  62     if (size > info->buf_size) {
  63         info->buf = g_realloc(info->buf, size);
  64         info->buf_size = size;
  65     }
  66
  67     pci_dma_read(dev, le64_to_cpu(info->desc.buf_addr), info->buf, size);
  68
  69     return info->buf;
  70 }
  71
  72 int desc_set_buf(DescInfo *info, size_t tlv_size)
  73 {
  74     PCIDevice *dev = PCI_DEVICE(info->ring->r);
  75
  76     if (tlv_size > info->buf_size) {
  77         DPRINTF("ERROR: trying to write more to desc buf than it "
  78                 "can hold buf_size %zu tlv_size %zu\n",
  79                 info->buf_size, tlv_size);
  80         return -ROCKER_EMSGSIZE;
  81     }
  82
  83     info->desc.tlv_size = cpu_to_le16(tlv_size);
  84     pci_dma_write(dev, le64_to_cpu(info->desc.buf_addr), info->buf, tlv_size);
  85
  86     return ROCKER_OK;
  87 }
  88
  89 DescRing *desc_get_ring(DescInfo *info)
  90 {
  91     return info->ring;
  92 }
  93
  94 int desc_ring_index(DescRing *ring)
  95 {
  96     return ring->index;
  97 }
  98
  99 static bool desc_ring_empty(DescRing *ring)
 100 {
 101     return ring->head == ring->tail;
 102 }
 103
 104 bool desc_ring_set_base_addr(DescRing *ring, uint64_t base_addr)
 105 {
 106     if (base_addr & 0x7) {
 107         DPRINTF("ERROR: ring[%d] desc base addr (0x" TARGET_FMT_plx
 108                 ") not 8-byte aligned\n", ring->index, base_addr);
 109         return false;
 110     }
 111
 112     ring->base_addr = base_addr;
 113
 114     return true;
 115 }
 116
 117 uint64_t desc_ring_get_base_addr(DescRing *ring)
 118 {
 119     return ring->base_addr;
 120 }
 121
 122 bool desc_ring_set_size(DescRing *ring, uint32_t size)
 123 {
 124     int i;
 125
 126     if (size < 2 || size > 0x10000 || (size & (size - 1))) {
 127         DPRINTF("ERROR: ring[%d] size (%d) not a power of 2 "
 128                 "or in range [2, 64K]\n", ring->index, size);
 129         return false;
 130     }
 131
 132     for (i = 0; i < ring->size; i++) {
 133         g_free(ring->info[i].buf);
 134     }
 135
 136     ring->size = size;
 137     ring->head = ring->tail = 0;
 138
 139     ring->info = g_renew(DescInfo, ring->info, size);
 140
 141     memset(ring->info, 0, size * sizeof(DescInfo));
 142
 143     for (i = 0; i < size; i++) {
 144         ring->info[i].ring = ring;
 145     }
 146
 147     return true;
 148 }
 149
 150 uint32_t desc_ring_get_size(DescRing *ring)
 151 {
 152     return ring->size;
 153 }
 154
 155 static DescInfo *desc_read(DescRing *ring, uint32_t index)
 156 {
 157     PCIDevice *dev = PCI_DEVICE(ring->r);
 158     DescInfo *info = &ring->info[index];
 159     hwaddr addr = ring->base_addr + (sizeof(RockerDesc) * index);
 160
 161     pci_dma_read(dev, addr, &info->desc, sizeof(info->desc));
 162
 163     return info;
 164 }
 165
 166 static void desc_write(DescRing *ring, uint32_t index)
 167 {
 168     PCIDevice *dev = PCI_DEVICE(ring->r);
 169     DescInfo *info = &ring->info[index];
 170     hwaddr addr = ring->base_addr + (sizeof(RockerDesc) * index);
 171
 172     pci_dma_write(dev, addr, &info->desc, sizeof(info->desc));
 173 }
 174
 175 static bool desc_ring_base_addr_check(DescRing *ring)
 176 {
 177     if (!ring->base_addr) {
 178         DPRINTF("ERROR: ring[%d] not-initialized desc base address!\n",
 179                 ring->index);
 180         return false;
 181     }
 182     return true;
 183 }
 184
 185 static DescInfo *__desc_ring_fetch_desc(DescRing *ring)
 186 {
 187     return desc_read(ring, ring->tail);
 188 }
 189
 190 DescInfo *desc_ring_fetch_desc(DescRing *ring)
 191 {
 192     if (desc_ring_empty(ring) || !desc_ring_base_addr_check(ring)) {
 193         return NULL;
 194     }
 195
 196     return desc_read(ring, ring->tail);
 197 }
 198
 199 static bool __desc_ring_post_desc(DescRing *ring, int err)
 200 {
 201     uint16_t comp_err = 0x8000 | (uint16_t)-err;
 202     DescInfo *info = &ring->info[ring->tail];
 203
 204     info->desc.comp_err = cpu_to_le16(comp_err);
 205     desc_write(ring, ring->tail);
 206     ring->tail = (ring->tail + 1) % ring->size;
 207
 208     /* return true if starting credit count */
 209
 210     return ring->credits++ == 0;
 211 }
 212
 213 bool desc_ring_post_desc(DescRing *ring, int err)
 214 {
 215     if (desc_ring_empty(ring)) {
 216         DPRINTF("ERROR: ring[%d] trying to post desc to empty ring\n",
 217                 ring->index);
 218         return false;
 219     }
 220
 221     if (!desc_ring_base_addr_check(ring)) {
 222         return false;
 223     }
 224
 225     return __desc_ring_post_desc(ring, err);
 226 }
 227
 228 static bool ring_pump(DescRing *ring)
 229 {
 230     DescInfo *info;
 231     bool primed = false;
 232     int err;
 233
 234     /* If the ring has a consumer, call consumer for each
 235      * desc starting at tail and stopping when tail reaches
 236      * head (the empty ring condition).
 237      */
 238
 239     if (ring->consume) {
 240         while (ring->head != ring->tail) {
 241             info = __desc_ring_fetch_desc(ring);
 242             err = ring->consume(ring->r, info);
 243             if (__desc_ring_post_desc(ring, err)) {
 244                 primed = true;
 245             }
 246         }
 247     }
 248
 249     return primed;
 250 }
 251
 252 bool desc_ring_set_head(DescRing *ring, uint32_t new)
 253 {
 254     uint32_t tail = ring->tail;
 255     uint32_t head = ring->head;
 256
 257     if (!desc_ring_base_addr_check(ring)) {
 258         return false;
 259     }
 260
 261     if (new >= ring->size) {
 262         DPRINTF("ERROR: trying to set head (%d) past ring[%d] size (%d)\n",
 263                 new, ring->index, ring->size);
 264         return false;
 265     }
 266
 267     if (((head < tail) && ((new >= tail) || (new < head))) ||
 268         ((head > tail) && ((new >= tail) && (new < head)))) {
 269         DPRINTF("ERROR: trying to wrap ring[%d] "
 270                 "(head %d, tail %d, new head %d)\n",
 271                 ring->index, head, tail, new);
 272         return false;
 273     }
 274
 275     if (new == ring->head) {
 276         DPRINTF("WARNING: setting head (%d) to current head position\n", new);
 277     }
 278
 279     ring->head = new;
 280
 281     return ring_pump(ring);
 282 }
 283
 284 uint32_t desc_ring_get_head(DescRing *ring)
 285 {
 286     return ring->head;
 287 }
 288
 289 uint32_t desc_ring_get_tail(DescRing *ring)
 290 {
 291     return ring->tail;
 292 }
 293
 294 void desc_ring_set_ctrl(DescRing *ring, uint32_t val)
 295 {
 296     if (val & ROCKER_DMA_DESC_CTRL_RESET) {
 297         DPRINTF("ring[%d] resetting\n", ring->index);
 298         desc_ring_reset(ring);
 299     }
 300 }
 301
 302 bool desc_ring_ret_credits(DescRing *ring, uint32_t credits)
 303 {
 304     if (credits > ring->credits) {
 305         DPRINTF("ERROR: trying to return more credits (%d) "
 306                 "than are outstanding (%d)\n", credits, ring->credits);
 307         ring->credits = 0;
 308         return false;
 309     }
 310
 311     ring->credits -= credits;
 312
 313     /* return true if credits are still outstanding */
 314
 315     return ring->credits > 0;
 316 }
 317
 318 uint32_t desc_ring_get_credits(DescRing *ring)
 319 {
 320     return ring->credits;
 321 }
 322
 323 void desc_ring_set_consume(DescRing *ring, desc_ring_consume *consume,
 324                            unsigned vector)
 325 {
 326     ring->consume = consume;
 327     ring->msix_vector = vector;
 328 }
 329
 330 unsigned desc_ring_get_msix_vector(DescRing *ring)
 331 {
 332     return ring->msix_vector;
 333 }
 334
 335 DescRing *desc_ring_alloc(Rocker *r, int index)
 336 {
 337     DescRing *ring;
 338
 339     ring = g_new0(DescRing, 1);
 340
 341     ring->r = r;
 342     ring->index = index;
 343
 344     return ring;
 345 }
 346
 347 void desc_ring_free(DescRing *ring)
 348 {
 349     g_free(ring->info);
 350     g_free(ring);
 351 }
 352
 353 void desc_ring_reset(DescRing *ring)
 354 {
 355     ring->base_addr = 0;
 356     ring->size = 0;
 357     ring->head = 0;
 358     ring->tail = 0;
 359     ring->ctrl = 0;
 360     ring->credits = 0;
 361 }