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/hw.h"
  20 #include "hw/pci/pci.h"
  21
  22 #include "rocker.h"
  23 #include "rocker_hw.h"
  24 #include "rocker_desc.h"
  25
  26 struct desc_ring {
  27     hwaddr base_addr;
  28     uint32_t size;
  29     uint32_t head;
  30     uint32_t tail;
  31     uint32_t ctrl;
  32     uint32_t credits;
  33     Rocker *r;
  34     DescInfo *info;
  35     int index;
  36     desc_ring_consume *consume;
  37     unsigned msix_vector;
  38 };
  39
  40 struct desc_info {
  41     DescRing *ring;
  42     RockerDesc desc;
  43     char *buf;
  44     size_t buf_size;
  45 };
  46
  47 uint16_t desc_buf_size(DescInfo *info)
  48 {
  49     return le16_to_cpu(info->desc.buf_size);
  50 }
  51
  52 uint16_t desc_tlv_size(DescInfo *info)
  53 {
  54     return le16_to_cpu(info->desc.tlv_size);
  55 }
  56
  57 char *desc_get_buf(DescInfo *info, bool read_only)
  58 {
  59     PCIDevice *dev = PCI_DEVICE(info->ring->r);
  60     size_t size = read_only ? le16_to_cpu(info->desc.tlv_size) :
  61                               le16_to_cpu(info->desc.buf_size);
  62
  63     if (size > info->buf_size) {
  64         info->buf = g_realloc(info->buf, size);
  65         info->buf_size = size;
  66     }
  67
  68     pci_dma_read(dev, le64_to_cpu(info->desc.buf_addr), info->buf, size);
  69
  70     return info->buf;
  71 }
  72
  73 int desc_set_buf(DescInfo *info, size_t tlv_size)
  74 {
  75     PCIDevice *dev = PCI_DEVICE(info->ring->r);
  76
  77     if (tlv_size > info->buf_size) {
  78         DPRINTF("ERROR: trying to write more to desc buf than it "
  79                 "can hold buf_size %zu tlv_size %zu\n",
  80                 info->buf_size, tlv_size);
  81         return -ROCKER_EMSGSIZE;
  82     }
  83
  84     info->desc.tlv_size = cpu_to_le16(tlv_size);
  85     pci_dma_write(dev, le64_to_cpu(info->desc.buf_addr), info->buf, tlv_size);
  86
  87     return ROCKER_OK;
  88 }
  89
  90 DescRing *desc_get_ring(DescInfo *info)
  91 {
  92     return info->ring;
  93 }
  94
  95 int desc_ring_index(DescRing *ring)
  96 {
  97     return ring->index;
  98 }
  99
 100 static bool desc_ring_empty(DescRing *ring)
 101 {
 102     return ring->head == ring->tail;
 103 }
 104
 105 bool desc_ring_set_base_addr(DescRing *ring, uint64_t base_addr)
 106 {
 107     if (base_addr & 0x7) {
 108         DPRINTF("ERROR: ring[%d] desc base addr (0x" TARGET_FMT_plx
 109                 ") not 8-byte aligned\n", ring->index, base_addr);
 110         return false;
 111     }
 112
 113     ring->base_addr = base_addr;
 114
 115     return true;
 116 }
 117
 118 uint64_t desc_ring_get_base_addr(DescRing *ring)
 119 {
 120     return ring->base_addr;
 121 }
 122
 123 bool desc_ring_set_size(DescRing *ring, uint32_t size)
 124 {
 125     int i;
 126
 127     if (size < 2 || size > 0x10000 || (size & (size - 1))) {
 128         DPRINTF("ERROR: ring[%d] size (%d) not a power of 2 "
 129                 "or in range [2, 64K]\n", ring->index, size);
 130         return false;
 131     }
 132
 133     for (i = 0; i < ring->size; i++) {
 134         g_free(ring->info[i].buf);
 135     }
 136
 137     ring->size = size;
 138     ring->head = ring->tail = 0;
 139
 140     ring->info = g_renew(DescInfo, ring->info, size);
 141
 142     memset(ring->info, 0, size * sizeof(DescInfo));
 143
 144     for (i = 0; i < size; i++) {
 145         ring->info[i].ring = ring;
 146     }
 147
 148     return true;
 149 }
 150
 151 uint32_t desc_ring_get_size(DescRing *ring)
 152 {
 153     return ring->size;
 154 }
 155
 156 static DescInfo *desc_read(DescRing *ring, uint32_t index)
 157 {
 158     PCIDevice *dev = PCI_DEVICE(ring->r);
 159     DescInfo *info = &ring->info[index];
 160     hwaddr addr = ring->base_addr + (sizeof(RockerDesc) * index);
 161
 162     pci_dma_read(dev, addr, &info->desc, sizeof(info->desc));
 163
 164     return info;
 165 }
 166
 167 static void desc_write(DescRing *ring, uint32_t index)
 168 {
 169     PCIDevice *dev = PCI_DEVICE(ring->r);
 170     DescInfo *info = &ring->info[index];
 171     hwaddr addr = ring->base_addr + (sizeof(RockerDesc) * index);
 172
 173     pci_dma_write(dev, addr, &info->desc, sizeof(info->desc));
 174 }
 175
 176 static bool desc_ring_base_addr_check(DescRing *ring)
 177 {
 178     if (!ring->base_addr) {
 179         DPRINTF("ERROR: ring[%d] not-initialized desc base address!\n",
 180                 ring->index);
 181         return false;
 182     }
 183     return true;
 184 }
 185
 186 static DescInfo *__desc_ring_fetch_desc(DescRing *ring)
 187 {
 188     return desc_read(ring, ring->tail);
 189 }
 190
 191 DescInfo *desc_ring_fetch_desc(DescRing *ring)
 192 {
 193     if (desc_ring_empty(ring) || !desc_ring_base_addr_check(ring)) {
 194         return NULL;
 195     }
 196
 197     return desc_read(ring, ring->tail);
 198 }
 199
 200 static bool __desc_ring_post_desc(DescRing *ring, int err)
 201 {
 202     uint16_t comp_err = 0x8000 | (uint16_t)-err;
 203     DescInfo *info = &ring->info[ring->tail];
 204
 205     info->desc.comp_err = cpu_to_le16(comp_err);
 206     desc_write(ring, ring->tail);
 207     ring->tail = (ring->tail + 1) % ring->size;
 208
 209     /* return true if starting credit count */
 210
 211     return ring->credits++ == 0;
 212 }
 213
 214 bool desc_ring_post_desc(DescRing *ring, int err)
 215 {
 216     if (desc_ring_empty(ring)) {
 217         DPRINTF("ERROR: ring[%d] trying to post desc to empty ring\n",
 218                 ring->index);
 219         return false;
 220     }
 221
 222     if (!desc_ring_base_addr_check(ring)) {
 223         return false;
 224     }
 225
 226     return __desc_ring_post_desc(ring, err);
 227 }
 228
 229 static bool ring_pump(DescRing *ring)
 230 {
 231     DescInfo *info;
 232     bool primed = false;
 233     int err;
 234
 235     /* If the ring has a consumer, call consumer for each
 236      * desc starting at tail and stopping when tail reaches
 237      * head (the empty ring condition).
 238      */
 239
 240     if (ring->consume) {
 241         while (ring->head != ring->tail) {
 242             info = __desc_ring_fetch_desc(ring);
 243             err = ring->consume(ring->r, info);
 244             if (__desc_ring_post_desc(ring, err)) {
 245                 primed = true;
 246             }
 247         }
 248     }
 249
 250     return primed;
 251 }
 252
 253 bool desc_ring_set_head(DescRing *ring, uint32_t new)
 254 {
 255     uint32_t tail = ring->tail;
 256     uint32_t head = ring->head;
 257
 258     if (!desc_ring_base_addr_check(ring)) {
 259         return false;
 260     }
 261
 262     if (new >= ring->size) {
 263         DPRINTF("ERROR: trying to set head (%d) past ring[%d] size (%d)\n",
 264                 new, ring->index, ring->size);
 265         return false;
 266     }
 267
 268     if (((head < tail) && ((new >= tail) || (new < head))) ||
 269         ((head > tail) && ((new >= tail) && (new < head)))) {
 270         DPRINTF("ERROR: trying to wrap ring[%d] "
 271                 "(head %d, tail %d, new head %d)\n",
 272                 ring->index, head, tail, new);
 273         return false;
 274     }
 275
 276     if (new == ring->head) {
 277         DPRINTF("WARNING: setting head (%d) to current head position\n", new);
 278     }
 279
 280     ring->head = new;
 281
 282     return ring_pump(ring);
 283 }
 284
 285 uint32_t desc_ring_get_head(DescRing *ring)
 286 {
 287     return ring->head;
 288 }
 289
 290 uint32_t desc_ring_get_tail(DescRing *ring)
 291 {
 292     return ring->tail;
 293 }
 294
 295 void desc_ring_set_ctrl(DescRing *ring, uint32_t val)
 296 {
 297     if (val & ROCKER_DMA_DESC_CTRL_RESET) {
 298         DPRINTF("ring[%d] resetting\n", ring->index);
 299         desc_ring_reset(ring);
 300     }
 301 }
 302
 303 bool desc_ring_ret_credits(DescRing *ring, uint32_t credits)
 304 {
 305     if (credits > ring->credits) {
 306         DPRINTF("ERROR: trying to return more credits (%d) "
 307                 "than are outstanding (%d)\n", credits, ring->credits);
 308         ring->credits = 0;
 309         return false;
 310     }
 311
 312     ring->credits -= credits;
 313
 314     /* return true if credits are still outstanding */
 315
 316     return ring->credits > 0;
 317 }
 318
 319 uint32_t desc_ring_get_credits(DescRing *ring)
 320 {
 321     return ring->credits;
 322 }
 323
 324 void desc_ring_set_consume(DescRing *ring, desc_ring_consume *consume,
 325                            unsigned vector)
 326 {
 327     ring->consume = consume;
 328     ring->msix_vector = vector;
 329 }
 330
 331 unsigned desc_ring_get_msix_vector(DescRing *ring)
 332 {
 333     return ring->msix_vector;
 334 }
 335
 336 DescRing *desc_ring_alloc(Rocker *r, int index)
 337 {
 338     DescRing *ring;
 339
 340     ring = g_new0(DescRing, 1);
 341
 342     ring->r = r;
 343     ring->index = index;
 344
 345     return ring;
 346 }
 347
 348 void desc_ring_free(DescRing *ring)
 349 {
 350     g_free(ring->info);
 351     g_free(ring);
 352 }
 353
 354 void desc_ring_reset(DescRing *ring)
 355 {
 356     ring->base_addr = 0;
 357     ring->size = 0;
 358     ring->head = 0;
 359     ring->tail = 0;
 360     ring->ctrl = 0;
 361     ring->credits = 0;
 362 }