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 "net/net.h"
  18 #include "hw/hw.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     if (!info->buf) {
  68         return NULL;
  69     }
  70
  71     if (pci_dma_read(dev, le64_to_cpu(info->desc.buf_addr), info->buf, size)) {
  72         return NULL;
  73     }
  74
  75     return info->buf;
  76 }
  77
  78 int desc_set_buf(DescInfo *info, size_t tlv_size)
  79 {
  80     PCIDevice *dev = PCI_DEVICE(info->ring->r);
  81
  82     if (tlv_size > info->buf_size) {
  83         DPRINTF("ERROR: trying to write more to desc buf than it "
  84                 "can hold buf_size %zu tlv_size %zu\n",
  85                 info->buf_size, tlv_size);
  86         return -ROCKER_EMSGSIZE;
  87     }
  88
  89     info->desc.tlv_size = cpu_to_le16(tlv_size);
  90     pci_dma_write(dev, le64_to_cpu(info->desc.buf_addr), info->buf, tlv_size);
  91
  92     return ROCKER_OK;
  93 }
  94
  95 DescRing *desc_get_ring(DescInfo *info)
  96 {
  97     return info->ring;
  98 }
  99
 100 int desc_ring_index(DescRing *ring)
 101 {
 102     return ring->index;
 103 }
 104
 105 static bool desc_ring_empty(DescRing *ring)
 106 {
 107     return ring->head == ring->tail;
 108 }
 109
 110 bool desc_ring_set_base_addr(DescRing *ring, uint64_t base_addr)
 111 {
 112     if (base_addr & 0x7) {
 113         DPRINTF("ERROR: ring[%d] desc base addr (0x" TARGET_FMT_plx
 114                 ") not 8-byte aligned\n", ring->index, base_addr);
 115         return false;
 116     }
 117
 118     ring->base_addr = base_addr;
 119
 120     return true;
 121 }
 122
 123 uint64_t desc_ring_get_base_addr(DescRing *ring)
 124 {
 125     return ring->base_addr;
 126 }
 127
 128 bool desc_ring_set_size(DescRing *ring, uint32_t size)
 129 {
 130     int i;
 131
 132     if (size < 2 || size > 0x10000 || (size & (size - 1))) {
 133         DPRINTF("ERROR: ring[%d] size (%d) not a power of 2 "
 134                 "or in range [2, 64K]\n", ring->index, size);
 135         return false;
 136     }
 137
 138     for (i = 0; i < ring->size; i++) {
 139         g_free(ring->info[i].buf);
 140     }
 141
 142     ring->size = size;
 143     ring->head = ring->tail = 0;
 144
 145     ring->info = g_renew(DescInfo, ring->info, size);
 146     if (!ring->info) {
 147         return false;
 148     }
 149
 150     memset(ring->info, 0, size * sizeof(DescInfo));
 151
 152     for (i = 0; i < size; i++) {
 153         ring->info[i].ring = ring;
 154     }
 155
 156     return true;
 157 }
 158
 159 uint32_t desc_ring_get_size(DescRing *ring)
 160 {
 161     return ring->size;
 162 }
 163
 164 static DescInfo *desc_read(DescRing *ring, uint32_t index)
 165 {
 166     PCIDevice *dev = PCI_DEVICE(ring->r);
 167     DescInfo *info = &ring->info[index];
 168     hwaddr addr = ring->base_addr + (sizeof(RockerDesc) * index);
 169
 170     pci_dma_read(dev, addr, &info->desc, sizeof(info->desc));
 171
 172     return info;
 173 }
 174
 175 static void desc_write(DescRing *ring, uint32_t index)
 176 {
 177     PCIDevice *dev = PCI_DEVICE(ring->r);
 178     DescInfo *info = &ring->info[index];
 179     hwaddr addr = ring->base_addr + (sizeof(RockerDesc) * index);
 180
 181     pci_dma_write(dev, addr, &info->desc, sizeof(info->desc));
 182 }
 183
 184 static bool desc_ring_base_addr_check(DescRing *ring)
 185 {
 186     if (!ring->base_addr) {
 187         DPRINTF("ERROR: ring[%d] not-initialized desc base address!\n",
 188                 ring->index);
 189         return false;
 190     }
 191     return true;
 192 }
 193
 194 static DescInfo *__desc_ring_fetch_desc(DescRing *ring)
 195 {
 196     return desc_read(ring, ring->tail);
 197 }
 198
 199 DescInfo *desc_ring_fetch_desc(DescRing *ring)
 200 {
 201     if (desc_ring_empty(ring) || !desc_ring_base_addr_check(ring)) {
 202         return NULL;
 203     }
 204
 205     return desc_read(ring, ring->tail);
 206 }
 207
 208 static bool __desc_ring_post_desc(DescRing *ring, int err)
 209 {
 210     uint16_t comp_err = 0x8000 | (uint16_t)-err;
 211     DescInfo *info = &ring->info[ring->tail];
 212
 213     info->desc.comp_err = cpu_to_le16(comp_err);
 214     desc_write(ring, ring->tail);
 215     ring->tail = (ring->tail + 1) % ring->size;
 216
 217     /* return true if starting credit count */
 218
 219     return ring->credits++ == 0;
 220 }
 221
 222 bool desc_ring_post_desc(DescRing *ring, int err)
 223 {
 224     if (desc_ring_empty(ring)) {
 225         DPRINTF("ERROR: ring[%d] trying to post desc to empty ring\n",
 226                 ring->index);
 227         return false;
 228     }
 229
 230     if (!desc_ring_base_addr_check(ring)) {
 231         return false;
 232     }
 233
 234     return __desc_ring_post_desc(ring, err);
 235 }
 236
 237 static bool ring_pump(DescRing *ring)
 238 {
 239     DescInfo *info;
 240     bool primed = false;
 241     int err;
 242
 243     /* If the ring has a consumer, call consumer for each
 244      * desc starting at tail and stopping when tail reaches
 245      * head (the empty ring condition).
 246      */
 247
 248     if (ring->consume) {
 249         while (ring->head != ring->tail) {
 250             info = __desc_ring_fetch_desc(ring);
 251             err = ring->consume(ring->r, info);
 252             if (__desc_ring_post_desc(ring, err)) {
 253                 primed = true;
 254             }
 255         }
 256     }
 257
 258     return primed;
 259 }
 260
 261 bool desc_ring_set_head(DescRing *ring, uint32_t new)
 262 {
 263     uint32_t tail = ring->tail;
 264     uint32_t head = ring->head;
 265
 266     if (!desc_ring_base_addr_check(ring)) {
 267         return false;
 268     }
 269
 270     if (new >= ring->size) {
 271         DPRINTF("ERROR: trying to set head (%d) past ring[%d] size (%d)\n",
 272                 new, ring->index, ring->size);
 273         return false;
 274     }
 275
 276     if (((head < tail) && ((new >= tail) || (new < head))) ||
 277         ((head > tail) && ((new >= tail) && (new < head)))) {
 278         DPRINTF("ERROR: trying to wrap ring[%d] "
 279                 "(head %d, tail %d, new head %d)\n",
 280                 ring->index, head, tail, new);
 281         return false;
 282     }
 283
 284     if (new == ring->head) {
 285         DPRINTF("WARNING: setting head (%d) to current head position\n", new);
 286     }
 287
 288     ring->head = new;
 289
 290     return ring_pump(ring);
 291 }
 292
 293 uint32_t desc_ring_get_head(DescRing *ring)
 294 {
 295     return ring->head;
 296 }
 297
 298 uint32_t desc_ring_get_tail(DescRing *ring)
 299 {
 300     return ring->tail;
 301 }
 302
 303 void desc_ring_set_ctrl(DescRing *ring, uint32_t val)
 304 {
 305     if (val & ROCKER_DMA_DESC_CTRL_RESET) {
 306         DPRINTF("ring[%d] resetting\n", ring->index);
 307         desc_ring_reset(ring);
 308     }
 309 }
 310
 311 bool desc_ring_ret_credits(DescRing *ring, uint32_t credits)
 312 {
 313     if (credits > ring->credits) {
 314         DPRINTF("ERROR: trying to return more credits (%d) "
 315                 "than are outstanding (%d)\n", credits, ring->credits);
 316         ring->credits = 0;
 317         return false;
 318     }
 319
 320     ring->credits -= credits;
 321
 322     /* return true if credits are still outstanding */
 323
 324     return ring->credits > 0;
 325 }
 326
 327 uint32_t desc_ring_get_credits(DescRing *ring)
 328 {
 329     return ring->credits;
 330 }
 331
 332 void desc_ring_set_consume(DescRing *ring, desc_ring_consume *consume,
 333                            unsigned vector)
 334 {
 335     ring->consume = consume;
 336     ring->msix_vector = vector;
 337 }
 338
 339 unsigned desc_ring_get_msix_vector(DescRing *ring)
 340 {
 341     return ring->msix_vector;
 342 }
 343
 344 DescRing *desc_ring_alloc(Rocker *r, int index)
 345 {
 346     DescRing *ring;
 347
 348     ring = g_new0(DescRing, 1);
 349     if (!ring) {
 350         return NULL;
 351     }
 352
 353     ring->r = r;
 354     ring->index = index;
 355
 356     return ring;
 357 }
 358
 359 void desc_ring_free(DescRing *ring)
 360 {
 361     g_free(ring->info);
 362     g_free(ring);
 363 }
 364
 365 void desc_ring_reset(DescRing *ring)
 366 {
 367     ring->base_addr = 0;
 368     ring->size = 0;
 369     ring->head = 0;
 370     ring->tail = 0;
 371     ring->ctrl = 0;
 372     ring->credits = 0;
 373 }