drivers/net/wireless/bcm43xx/bcm43xx_dma.c

   1 /*
   2
   3   Broadcom BCM43xx wireless driver
   4
   5   DMA ringbuffer and descriptor allocation/management
   6
   7   Copyright (c) 2005, 2006 Michael Buesch <mbuesch@freenet.de>
   8
   9   Some code in this file is derived from the b44.c driver
  10   Copyright (C) 2002 David S. Miller
  11   Copyright (C) Pekka Pietikainen
  12
  13   This program is free software; you can redistribute it and/or modify
  14   it under the terms of the GNU General Public License as published by
  15   the Free Software Foundation; either version 2 of the License, or
  16   (at your option) any later version.
  17
  18   This program is distributed in the hope that it will be useful,
  19   but WITHOUT ANY WARRANTY; without even the implied warranty of
  20   MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  21   GNU General Public License for more details.
  22
  23   You should have received a copy of the GNU General Public License
  24   along with this program; see the file COPYING.  If not, write to
  25   the Free Software Foundation, Inc., 51 Franklin Steet, Fifth Floor,
  26   Boston, MA 02110-1301, USA.
  27
  28 */
  29
  30 #include "bcm43xx.h"
  31 #include "bcm43xx_dma.h"
  32 #include "bcm43xx_main.h"
  33 #include "bcm43xx_debugfs.h"
  34 #include "bcm43xx_power.h"
  35 #include "bcm43xx_xmit.h"
  36
  37 #include <linux/dma-mapping.h>
  38 #include <linux/pci.h>
  39 #include <linux/delay.h>
  40 #include <linux/skbuff.h>
  41
  42
  43 static inline int free_slots(struct bcm43xx_dmaring *ring)
  44 {
  45         return (ring->nr_slots - ring->used_slots);
  46 }
  47
  48 static inline int next_slot(struct bcm43xx_dmaring *ring, int slot)
  49 {
  50         assert(slot >= -1 && slot <= ring->nr_slots - 1);
  51         if (slot == ring->nr_slots - 1)
  52                 return 0;
  53         return slot + 1;
  54 }
  55
  56 static inline int prev_slot(struct bcm43xx_dmaring *ring, int slot)
  57 {
  58         assert(slot >= 0 && slot <= ring->nr_slots - 1);
  59         if (slot == 0)
  60                 return ring->nr_slots - 1;
  61         return slot - 1;
  62 }
  63
  64 /* Request a slot for usage. */
  65 static inline
  66 int request_slot(struct bcm43xx_dmaring *ring)
  67 {
  68         int slot;
  69
  70         assert(ring->tx);
  71         assert(!ring->suspended);
  72         assert(free_slots(ring) != 0);
  73
  74         slot = next_slot(ring, ring->current_slot);
  75         ring->current_slot = slot;
  76         ring->used_slots++;
  77
  78         /* Check the number of available slots and suspend TX,
  79          * if we are running low on free slots.
  80          */
  81         if (unlikely(free_slots(ring) < ring->suspend_mark)) {
  82                 netif_stop_queue(ring->bcm->net_dev);
  83                 ring->suspended = 1;
  84         }
  85 #ifdef CONFIG_BCM43XX_DEBUG
  86         if (ring->used_slots > ring->max_used_slots)
  87                 ring->max_used_slots = ring->used_slots;
  88 #endif /* CONFIG_BCM43XX_DEBUG*/
  89
  90         return slot;
  91 }
  92
  93 /* Return a slot to the free slots. */
  94 static inline
  95 void return_slot(struct bcm43xx_dmaring *ring, int slot)
  96 {
  97         assert(ring->tx);
  98
  99         ring->used_slots--;
 100
 101         /* Check if TX is suspended and check if we have
 102          * enough free slots to resume it again.
 103          */
 104         if (unlikely(ring->suspended)) {
 105                 if (free_slots(ring) >= ring->resume_mark) {
 106                         ring->suspended = 0;
 107                         netif_wake_queue(ring->bcm->net_dev);
 108                 }
 109         }
 110 }
 111
 112 u16 bcm43xx_dmacontroller_base(int dma64bit, int controller_idx)
 113 {
 114         static const u16 map64[] = {
 115                 BCM43xx_MMIO_DMA64_BASE0,
 116                 BCM43xx_MMIO_DMA64_BASE1,
 117                 BCM43xx_MMIO_DMA64_BASE2,
 118                 BCM43xx_MMIO_DMA64_BASE3,
 119                 BCM43xx_MMIO_DMA64_BASE4,
 120                 BCM43xx_MMIO_DMA64_BASE5,
 121         };
 122         static const u16 map32[] = {
 123                 BCM43xx_MMIO_DMA32_BASE0,
 124                 BCM43xx_MMIO_DMA32_BASE1,
 125                 BCM43xx_MMIO_DMA32_BASE2,
 126                 BCM43xx_MMIO_DMA32_BASE3,
 127                 BCM43xx_MMIO_DMA32_BASE4,
 128                 BCM43xx_MMIO_DMA32_BASE5,
 129         };
 130
 131         if (dma64bit) {
 132                 assert(controller_idx >= 0 &&
 133                        controller_idx < ARRAY_SIZE(map64));
 134                 return map64[controller_idx];
 135         }
 136         assert(controller_idx >= 0 &&
 137                controller_idx < ARRAY_SIZE(map32));
 138         return map32[controller_idx];
 139 }
 140
 141 static inline
 142 dma_addr_t map_descbuffer(struct bcm43xx_dmaring *ring,
 143                           unsigned char *buf,
 144                           size_t len,
 145                           int tx)
 146 {
 147         dma_addr_t dmaaddr;
 148         int direction = PCI_DMA_FROMDEVICE;
 149
 150         if (tx)
 151                 direction = PCI_DMA_TODEVICE;
 152
 153         dmaaddr = pci_map_single(ring->bcm->pci_dev,
 154                                          buf, len,
 155                                          direction);
 156
 157         return dmaaddr;
 158 }
 159
 160 static inline
 161 void unmap_descbuffer(struct bcm43xx_dmaring *ring,
 162                       dma_addr_t addr,
 163                       size_t len,
 164                       int tx)
 165 {
 166         if (tx) {
 167                 pci_unmap_single(ring->bcm->pci_dev,
 168                                  addr, len,
 169                                  PCI_DMA_TODEVICE);
 170         } else {
 171                 pci_unmap_single(ring->bcm->pci_dev,
 172                                  addr, len,
 173                                  PCI_DMA_FROMDEVICE);
 174         }
 175 }
 176
 177 static inline
 178 void sync_descbuffer_for_cpu(struct bcm43xx_dmaring *ring,
 179                              dma_addr_t addr,
 180                              size_t len)
 181 {
 182         assert(!ring->tx);
 183
 184         pci_dma_sync_single_for_cpu(ring->bcm->pci_dev,
 185                                     addr, len, PCI_DMA_FROMDEVICE);
 186 }
 187
 188 static inline
 189 void sync_descbuffer_for_device(struct bcm43xx_dmaring *ring,
 190                                 dma_addr_t addr,
 191                                 size_t len)
 192 {
 193         assert(!ring->tx);
 194
 195         pci_dma_sync_single_for_cpu(ring->bcm->pci_dev,
 196                                     addr, len, PCI_DMA_TODEVICE);
 197 }
 198
 199 /* Unmap and free a descriptor buffer. */
 200 static inline
 201 void free_descriptor_buffer(struct bcm43xx_dmaring *ring,
 202                             struct bcm43xx_dmadesc_meta *meta,
 203                             int irq_context)
 204 {
 205         assert(meta->skb);
 206         if (irq_context)
 207                 dev_kfree_skb_irq(meta->skb);
 208         else
 209                 dev_kfree_skb(meta->skb);
 210         meta->skb = NULL;
 211 }
 212
 213 static int alloc_ringmemory(struct bcm43xx_dmaring *ring)
 214 {
 215         ring->descbase = pci_alloc_consistent(ring->bcm->pci_dev, BCM43xx_DMA_RINGMEMSIZE,
 216                                             &(ring->dmabase));
 217         if (!ring->descbase) {
 218                 /* Allocation may have failed due to pci_alloc_consistent
 219                    insisting on use of GFP_DMA, which is more restrictive
 220                    than necessary...  */
 221                 struct dma_desc *rx_ring;
 222                 dma_addr_t rx_ring_dma;
 223
 224                 rx_ring = kzalloc(BCM43xx_DMA_RINGMEMSIZE, GFP_KERNEL);
 225                 if (!rx_ring)
 226                         goto out_err;
 227
 228                 rx_ring_dma = pci_map_single(ring->bcm->pci_dev, rx_ring,
 229                                              BCM43xx_DMA_RINGMEMSIZE,
 230                                              PCI_DMA_BIDIRECTIONAL);
 231
 232                 if (pci_dma_mapping_error(rx_ring_dma) ||
 233                     rx_ring_dma + BCM43xx_DMA_RINGMEMSIZE > ring->bcm->dma_mask) {
 234                         /* Sigh... */
 235                         if (!pci_dma_mapping_error(rx_ring_dma))
 236                                 pci_unmap_single(ring->bcm->pci_dev,
 237                                                  rx_ring_dma, BCM43xx_DMA_RINGMEMSIZE,
 238                                                  PCI_DMA_BIDIRECTIONAL);
 239                         rx_ring_dma = pci_map_single(ring->bcm->pci_dev,
 240                                                  rx_ring, BCM43xx_DMA_RINGMEMSIZE,
 241                                                  PCI_DMA_BIDIRECTIONAL);
 242                         if (pci_dma_mapping_error(rx_ring_dma) ||
 243                             rx_ring_dma + BCM43xx_DMA_RINGMEMSIZE > ring->bcm->dma_mask) {
 244                                 assert(0);
 245                                 if (!pci_dma_mapping_error(rx_ring_dma))
 246                                         pci_unmap_single(ring->bcm->pci_dev,
 247                                                          rx_ring_dma, BCM43xx_DMA_RINGMEMSIZE,
 248                                                          PCI_DMA_BIDIRECTIONAL);
 249                                 goto out_err;
 250                         }
 251                 }
 252
 253                 ring->descbase = rx_ring;
 254                 ring->dmabase = rx_ring_dma;
 255         }
 256         memset(ring->descbase, 0, BCM43xx_DMA_RINGMEMSIZE);
 257
 258         return 0;
 259 out_err:
 260         printk(KERN_ERR PFX "DMA ringmemory allocation failed\n");
 261         return -ENOMEM;
 262 }
 263
 264 static void free_ringmemory(struct bcm43xx_dmaring *ring)
 265 {
 266         struct device *dev = &(ring->bcm->pci_dev->dev);
 267
 268         dma_free_coherent(dev, BCM43xx_DMA_RINGMEMSIZE,
 269                           ring->descbase, ring->dmabase);
 270 }
 271
 272 /* Reset the RX DMA channel */
 273 int bcm43xx_dmacontroller_rx_reset(struct bcm43xx_private *bcm,
 274                                    u16 mmio_base, int dma64)
 275 {
 276         int i;
 277         u32 value;
 278         u16 offset;
 279
 280         offset = dma64 ? BCM43xx_DMA64_RXCTL : BCM43xx_DMA32_RXCTL;
 281         bcm43xx_write32(bcm, mmio_base + offset, 0);
 282         for (i = 0; i < 1000; i++) {
 283                 offset = dma64 ? BCM43xx_DMA64_RXSTATUS : BCM43xx_DMA32_RXSTATUS;
 284                 value = bcm43xx_read32(bcm, mmio_base + offset);
 285                 if (dma64) {
 286                         value &= BCM43xx_DMA64_RXSTAT;
 287                         if (value == BCM43xx_DMA64_RXSTAT_DISABLED) {
 288                                 i = -1;
 289                                 break;
 290                         }
 291                 } else {
 292                         value &= BCM43xx_DMA32_RXSTATE;
 293                         if (value == BCM43xx_DMA32_RXSTAT_DISABLED) {
 294                                 i = -1;
 295                                 break;
 296                         }
 297                 }
 298                 udelay(10);
 299         }
 300         if (i != -1) {
 301                 printk(KERN_ERR PFX "Error: Wait on DMA RX status timed out.\n");
 302                 return -ENODEV;
 303         }
 304
 305         return 0;
 306 }
 307
 308 /* Reset the RX DMA channel */
 309 int bcm43xx_dmacontroller_tx_reset(struct bcm43xx_private *bcm,
 310                                    u16 mmio_base, int dma64)
 311 {
 312         int i;
 313         u32 value;
 314         u16 offset;
 315
 316         for (i = 0; i < 1000; i++) {
 317                 offset = dma64 ? BCM43xx_DMA64_TXSTATUS : BCM43xx_DMA32_TXSTATUS;
 318                 value = bcm43xx_read32(bcm, mmio_base + offset);
 319                 if (dma64) {
 320                         value &= BCM43xx_DMA64_TXSTAT;
 321                         if (value == BCM43xx_DMA64_TXSTAT_DISABLED ||
 322                             value == BCM43xx_DMA64_TXSTAT_IDLEWAIT ||
 323                             value == BCM43xx_DMA64_TXSTAT_STOPPED)
 324                                 break;
 325                 } else {
 326                         value &= BCM43xx_DMA32_TXSTATE;
 327                         if (value == BCM43xx_DMA32_TXSTAT_DISABLED ||
 328                             value == BCM43xx_DMA32_TXSTAT_IDLEWAIT ||
 329                             value == BCM43xx_DMA32_TXSTAT_STOPPED)
 330                                 break;
 331                 }
 332                 udelay(10);
 333         }
 334         offset = dma64 ? BCM43xx_DMA64_TXCTL : BCM43xx_DMA32_TXCTL;
 335         bcm43xx_write32(bcm, mmio_base + offset, 0);
 336         for (i = 0; i < 1000; i++) {
 337                 offset = dma64 ? BCM43xx_DMA64_TXSTATUS : BCM43xx_DMA32_TXSTATUS;
 338                 value = bcm43xx_read32(bcm, mmio_base + offset);
 339                 if (dma64) {
 340                         value &= BCM43xx_DMA64_TXSTAT;
 341                         if (value == BCM43xx_DMA64_TXSTAT_DISABLED) {
 342                                 i = -1;
 343                                 break;
 344                         }
 345                 } else {
 346                         value &= BCM43xx_DMA32_TXSTATE;
 347                         if (value == BCM43xx_DMA32_TXSTAT_DISABLED) {
 348                                 i = -1;
 349                                 break;
 350                         }
 351                 }
 352                 udelay(10);
 353         }
 354         if (i != -1) {
 355                 printk(KERN_ERR PFX "Error: Wait on DMA TX status timed out.\n");
 356                 return -ENODEV;
 357         }
 358         /* ensure the reset is completed. */
 359         udelay(300);
 360
 361         return 0;
 362 }
 363
 364 static void fill_descriptor(struct bcm43xx_dmaring *ring,
 365                             struct bcm43xx_dmadesc_generic *desc,
 366                             dma_addr_t dmaaddr,
 367                             u16 bufsize,
 368                             int start, int end, int irq)
 369 {
 370         int slot;
 371
 372         slot = bcm43xx_dma_desc2idx(ring, desc);
 373         assert(slot >= 0 && slot < ring->nr_slots);
 374
 375         if (ring->dma64) {
 376                 u32 ctl0 = 0, ctl1 = 0;
 377                 u32 addrlo, addrhi;
 378                 u32 addrext;
 379
 380                 addrlo = (u32)(dmaaddr & 0xFFFFFFFF);
 381                 addrhi = (((u64)dmaaddr >> 32) & ~BCM43xx_DMA64_ROUTING);
 382                 addrext = (((u64)dmaaddr >> 32) >> BCM43xx_DMA64_ROUTING_SHIFT);
 383                 addrhi |= ring->routing;
 384                 if (slot == ring->nr_slots - 1)
 385                         ctl0 |= BCM43xx_DMA64_DCTL0_DTABLEEND;
 386                 if (start)
 387                         ctl0 |= BCM43xx_DMA64_DCTL0_FRAMESTART;
 388                 if (end)
 389                         ctl0 |= BCM43xx_DMA64_DCTL0_FRAMEEND;
 390                 if (irq)
 391                         ctl0 |= BCM43xx_DMA64_DCTL0_IRQ;
 392                 ctl1 |= (bufsize - ring->frameoffset)
 393                         & BCM43xx_DMA64_DCTL1_BYTECNT;
 394                 ctl1 |= (addrext << BCM43xx_DMA64_DCTL1_ADDREXT_SHIFT)
 395                         & BCM43xx_DMA64_DCTL1_ADDREXT_MASK;
 396
 397                 desc->dma64.control0 = cpu_to_le32(ctl0);
 398                 desc->dma64.control1 = cpu_to_le32(ctl1);
 399                 desc->dma64.address_low = cpu_to_le32(addrlo);
 400                 desc->dma64.address_high = cpu_to_le32(addrhi);
 401         } else {
 402                 u32 ctl;
 403                 u32 addr;
 404                 u32 addrext;
 405
 406                 addr = (u32)(dmaaddr & ~BCM43xx_DMA32_ROUTING);
 407                 addrext = (u32)(dmaaddr & BCM43xx_DMA32_ROUTING)
 408                            >> BCM43xx_DMA32_ROUTING_SHIFT;
 409                 addr |= ring->routing;
 410                 ctl = (bufsize - ring->frameoffset)
 411                       & BCM43xx_DMA32_DCTL_BYTECNT;
 412                 if (slot == ring->nr_slots - 1)
 413                         ctl |= BCM43xx_DMA32_DCTL_DTABLEEND;
 414                 if (start)
 415                         ctl |= BCM43xx_DMA32_DCTL_FRAMESTART;
 416                 if (end)
 417                         ctl |= BCM43xx_DMA32_DCTL_FRAMEEND;
 418                 if (irq)
 419                         ctl |= BCM43xx_DMA32_DCTL_IRQ;
 420                 ctl |= (addrext << BCM43xx_DMA32_DCTL_ADDREXT_SHIFT)
 421                        & BCM43xx_DMA32_DCTL_ADDREXT_MASK;
 422
 423                 desc->dma32.control = cpu_to_le32(ctl);
 424                 desc->dma32.address = cpu_to_le32(addr);
 425         }
 426 }
 427
 428 static int setup_rx_descbuffer(struct bcm43xx_dmaring *ring,
 429                                struct bcm43xx_dmadesc_generic *desc,
 430                                struct bcm43xx_dmadesc_meta *meta,
 431                                gfp_t gfp_flags)
 432 {
 433         struct bcm43xx_rxhdr *rxhdr;
 434         struct bcm43xx_hwxmitstatus *xmitstat;
 435         dma_addr_t dmaaddr;
 436         struct sk_buff *skb;
 437
 438         assert(!ring->tx);
 439
 440         skb = __dev_alloc_skb(ring->rx_buffersize, gfp_flags);
 441         if (unlikely(!skb))
 442                 return -ENOMEM;
 443         dmaaddr = map_descbuffer(ring, skb->data, ring->rx_buffersize, 0);
 444         /* This hardware bug work-around adapted from the b44 driver.
 445            The chip may be unable to do PCI DMA to/from anything above 1GB */
 446         if (pci_dma_mapping_error(dmaaddr) ||
 447             dmaaddr + ring->rx_buffersize > ring->bcm->dma_mask) {
 448                 /* This one has 30-bit addressing... */
 449                 if (!pci_dma_mapping_error(dmaaddr))
 450                         pci_unmap_single(ring->bcm->pci_dev,
 451                                          dmaaddr, ring->rx_buffersize,
 452                                          PCI_DMA_FROMDEVICE);
 453                 dev_kfree_skb_any(skb);
 454                 skb = __dev_alloc_skb(ring->rx_buffersize,GFP_DMA);
 455                 if (skb == NULL)
 456                         return -ENOMEM;
 457                 dmaaddr = pci_map_single(ring->bcm->pci_dev,
 458                                          skb->data, ring->rx_buffersize,
 459                                          PCI_DMA_FROMDEVICE);
 460                 if (pci_dma_mapping_error(dmaaddr) ||
 461                     dmaaddr + ring->rx_buffersize > ring->bcm->dma_mask) {
 462                         assert(0);
 463                         dev_kfree_skb_any(skb);
 464                         return -ENOMEM;
 465                 }
 466         }
 467         meta->skb = skb;
 468         meta->dmaaddr = dmaaddr;
 469         skb->dev = ring->bcm->net_dev;
 470
 471         fill_descriptor(ring, desc, dmaaddr,
 472                         ring->rx_buffersize, 0, 0, 0);
 473
 474         rxhdr = (struct bcm43xx_rxhdr *)(skb->data);
 475         rxhdr->frame_length = 0;
 476         rxhdr->flags1 = 0;
 477         xmitstat = (struct bcm43xx_hwxmitstatus *)(skb->data);
 478         xmitstat->cookie = 0;
 479
 480         return 0;
 481 }
 482
 483 /* Allocate the initial descbuffers.
 484  * This is used for an RX ring only.
 485  */
 486 static int alloc_initial_descbuffers(struct bcm43xx_dmaring *ring)
 487 {
 488         int i, err = -ENOMEM;
 489         struct bcm43xx_dmadesc_generic *desc;
 490         struct bcm43xx_dmadesc_meta *meta;
 491
 492         for (i = 0; i < ring->nr_slots; i++) {
 493                 desc = bcm43xx_dma_idx2desc(ring, i, &meta);
 494
 495                 err = setup_rx_descbuffer(ring, desc, meta, GFP_KERNEL);
 496                 if (err)
 497                         goto err_unwind;
 498         }
 499         mb();
 500         ring->used_slots = ring->nr_slots;
 501         err = 0;
 502 out:
 503         return err;
 504
 505 err_unwind:
 506         for (i--; i >= 0; i--) {
 507                 desc = bcm43xx_dma_idx2desc(ring, i, &meta);
 508
 509                 unmap_descbuffer(ring, meta->dmaaddr, ring->rx_buffersize, 0);
 510                 dev_kfree_skb(meta->skb);
 511         }
 512         goto out;
 513 }
 514
 515 /* Do initial setup of the DMA controller.
 516  * Reset the controller, write the ring busaddress
 517  * and switch the "enable" bit on.
 518  */
 519 static int dmacontroller_setup(struct bcm43xx_dmaring *ring)
 520 {
 521         int err = 0;
 522         u32 value;
 523         u32 addrext;
 524
 525         if (ring->tx) {
 526                 if (ring->dma64) {
 527                         u64 ringbase = (u64)(ring->dmabase);
 528
 529                         addrext = ((ringbase >> 32) >> BCM43xx_DMA64_ROUTING_SHIFT);
 530                         value = BCM43xx_DMA64_TXENABLE;
 531                         value |= (addrext << BCM43xx_DMA64_TXADDREXT_SHIFT)
 532                                 & BCM43xx_DMA64_TXADDREXT_MASK;
 533                         bcm43xx_dma_write(ring, BCM43xx_DMA64_TXCTL, value);
 534                         bcm43xx_dma_write(ring, BCM43xx_DMA64_TXRINGLO,
 535                                         (ringbase & 0xFFFFFFFF));
 536                         bcm43xx_dma_write(ring, BCM43xx_DMA64_TXRINGHI,
 537                                         ((ringbase >> 32) & ~BCM43xx_DMA64_ROUTING)
 538                                         | ring->routing);
 539                 } else {
 540                         u32 ringbase = (u32)(ring->dmabase);
 541
 542                         addrext = (ringbase >> BCM43xx_DMA32_ROUTING_SHIFT);
 543                         value = BCM43xx_DMA32_TXENABLE;
 544                         value |= (addrext << BCM43xx_DMA32_TXADDREXT_SHIFT)
 545                                 & BCM43xx_DMA32_TXADDREXT_MASK;
 546                         bcm43xx_dma_write(ring, BCM43xx_DMA32_TXCTL, value);
 547                         bcm43xx_dma_write(ring, BCM43xx_DMA32_TXRING,
 548                                         (ringbase & ~BCM43xx_DMA32_ROUTING)
 549                                         | ring->routing);
 550                 }
 551         } else {
 552                 err = alloc_initial_descbuffers(ring);
 553                 if (err)
 554                         goto out;
 555                 if (ring->dma64) {
 556                         u64 ringbase = (u64)(ring->dmabase);
 557
 558                         addrext = ((ringbase >> 32) >> BCM43xx_DMA64_ROUTING_SHIFT);
 559                         value = (ring->frameoffset << BCM43xx_DMA64_RXFROFF_SHIFT);
 560                         value |= BCM43xx_DMA64_RXENABLE;
 561                         value |= (addrext << BCM43xx_DMA64_RXADDREXT_SHIFT)
 562                                 & BCM43xx_DMA64_RXADDREXT_MASK;
 563                         bcm43xx_dma_write(ring, BCM43xx_DMA64_RXCTL, value);
 564                         bcm43xx_dma_write(ring, BCM43xx_DMA64_RXRINGLO,
 565                                         (ringbase & 0xFFFFFFFF));
 566                         bcm43xx_dma_write(ring, BCM43xx_DMA64_RXRINGHI,
 567                                         ((ringbase >> 32) & ~BCM43xx_DMA64_ROUTING)
 568                                         | ring->routing);
 569                         bcm43xx_dma_write(ring, BCM43xx_DMA64_RXINDEX, 200);
 570                 } else {
 571                         u32 ringbase = (u32)(ring->dmabase);
 572
 573                         addrext = (ringbase >> BCM43xx_DMA32_ROUTING_SHIFT);
 574                         value = (ring->frameoffset << BCM43xx_DMA32_RXFROFF_SHIFT);
 575                         value |= BCM43xx_DMA32_RXENABLE;
 576                         value |= (addrext << BCM43xx_DMA32_RXADDREXT_SHIFT)
 577                                 & BCM43xx_DMA32_RXADDREXT_MASK;
 578                         bcm43xx_dma_write(ring, BCM43xx_DMA32_RXCTL, value);
 579                         bcm43xx_dma_write(ring, BCM43xx_DMA32_RXRING,
 580                                         (ringbase & ~BCM43xx_DMA32_ROUTING)
 581                                         | ring->routing);
 582                         bcm43xx_dma_write(ring, BCM43xx_DMA32_RXINDEX, 200);
 583                 }
 584         }
 585
 586 out:
 587         return err;
 588 }
 589
 590 /* Shutdown the DMA controller. */
 591 static void dmacontroller_cleanup(struct bcm43xx_dmaring *ring)
 592 {
 593         if (ring->tx) {
 594                 bcm43xx_dmacontroller_tx_reset(ring->bcm, ring->mmio_base, ring->dma64);
 595                 if (ring->dma64) {
 596                         bcm43xx_dma_write(ring, BCM43xx_DMA64_TXRINGLO, 0);
 597                         bcm43xx_dma_write(ring, BCM43xx_DMA64_TXRINGHI, 0);
 598                 } else
 599                         bcm43xx_dma_write(ring, BCM43xx_DMA32_TXRING, 0);
 600         } else {
 601                 bcm43xx_dmacontroller_rx_reset(ring->bcm, ring->mmio_base, ring->dma64);
 602                 if (ring->dma64) {
 603                         bcm43xx_dma_write(ring, BCM43xx_DMA64_RXRINGLO, 0);
 604                         bcm43xx_dma_write(ring, BCM43xx_DMA64_RXRINGHI, 0);
 605                 } else
 606                         bcm43xx_dma_write(ring, BCM43xx_DMA32_RXRING, 0);
 607         }
 608 }
 609
 610 static void free_all_descbuffers(struct bcm43xx_dmaring *ring)
 611 {
 612         struct bcm43xx_dmadesc_generic *desc;
 613         struct bcm43xx_dmadesc_meta *meta;
 614         int i;
 615
 616         if (!ring->used_slots)
 617                 return;
 618         for (i = 0; i < ring->nr_slots; i++) {
 619                 desc = bcm43xx_dma_idx2desc(ring, i, &meta);
 620
 621                 if (!meta->skb) {
 622                         assert(ring->tx);
 623                         continue;
 624                 }
 625                 if (ring->tx) {
 626                         unmap_descbuffer(ring, meta->dmaaddr,
 627                                         meta->skb->len, 1);
 628                 } else {
 629                         unmap_descbuffer(ring, meta->dmaaddr,
 630                                         ring->rx_buffersize, 0);
 631                 }
 632                 free_descriptor_buffer(ring, meta, 0);
 633         }
 634 }
 635
 636 /* Main initialization function. */
 637 static
 638 struct bcm43xx_dmaring * bcm43xx_setup_dmaring(struct bcm43xx_private *bcm,
 639                                                int controller_index,
 640                                                int for_tx,
 641                                                int dma64)
 642 {
 643         struct bcm43xx_dmaring *ring;
 644         int err;
 645         int nr_slots;
 646
 647         ring = kzalloc(sizeof(*ring), GFP_KERNEL);
 648         if (!ring)
 649                 goto out;
 650
 651         nr_slots = BCM43xx_RXRING_SLOTS;
 652         if (for_tx)
 653                 nr_slots = BCM43xx_TXRING_SLOTS;
 654
 655         ring->meta = kcalloc(nr_slots, sizeof(struct bcm43xx_dmadesc_meta),
 656                              GFP_KERNEL);
 657         if (!ring->meta)
 658                 goto err_kfree_ring;
 659
 660         ring->routing = BCM43xx_DMA32_CLIENTTRANS;
 661         if (dma64)
 662                 ring->routing = BCM43xx_DMA64_CLIENTTRANS;
 663
 664         ring->bcm = bcm;
 665         ring->nr_slots = nr_slots;
 666         ring->suspend_mark = ring->nr_slots * BCM43xx_TXSUSPEND_PERCENT / 100;
 667         ring->resume_mark = ring->nr_slots * BCM43xx_TXRESUME_PERCENT / 100;
 668         assert(ring->suspend_mark < ring->resume_mark);
 669         ring->mmio_base = bcm43xx_dmacontroller_base(dma64, controller_index);
 670         ring->index = controller_index;
 671         ring->dma64 = !!dma64;
 672         if (for_tx) {
 673                 ring->tx = 1;
 674                 ring->current_slot = -1;
 675         } else {
 676                 if (ring->index == 0) {
 677                         ring->rx_buffersize = BCM43xx_DMA0_RX_BUFFERSIZE;
 678                         ring->frameoffset = BCM43xx_DMA0_RX_FRAMEOFFSET;
 679                 } else if (ring->index == 3) {
 680                         ring->rx_buffersize = BCM43xx_DMA3_RX_BUFFERSIZE;
 681                         ring->frameoffset = BCM43xx_DMA3_RX_FRAMEOFFSET;
 682                 } else
 683                         assert(0);
 684         }
 685
 686         err = alloc_ringmemory(ring);
 687         if (err)
 688                 goto err_kfree_meta;
 689         err = dmacontroller_setup(ring);
 690         if (err)
 691                 goto err_free_ringmemory;
 692         return ring;
 693
 694 out:
 695         printk(KERN_ERR PFX "Error in bcm43xx_setup_dmaring\n");
 696         return ring;
 697
 698 err_free_ringmemory:
 699         free_ringmemory(ring);
 700 err_kfree_meta:
 701         kfree(ring->meta);
 702 err_kfree_ring:
 703         kfree(ring);
 704         ring = NULL;
 705         goto out;
 706 }
 707
 708 /* Main cleanup function. */
 709 static void bcm43xx_destroy_dmaring(struct bcm43xx_dmaring *ring)
 710 {
 711         if (!ring)
 712                 return;
 713
 714         dprintk(KERN_INFO PFX "DMA-%s 0x%04X (%s) max used slots: %d/%d\n",
 715                 (ring->dma64) ? "64" : "32",
 716                 ring->mmio_base,
 717                 (ring->tx) ? "TX" : "RX",
 718                 ring->max_used_slots, ring->nr_slots);
 719         /* Device IRQs are disabled prior entering this function,
 720          * so no need to take care of concurrency with rx handler stuff.
 721          */
 722         dmacontroller_cleanup(ring);
 723         free_all_descbuffers(ring);
 724         free_ringmemory(ring);
 725
 726         kfree(ring->meta);
 727         kfree(ring);
 728 }
 729
 730 void bcm43xx_dma_free(struct bcm43xx_private *bcm)
 731 {
 732         struct bcm43xx_dma *dma;
 733
 734         if (bcm43xx_using_pio(bcm))
 735                 return;
 736         dma = bcm43xx_current_dma(bcm);
 737
 738         bcm43xx_destroy_dmaring(dma->rx_ring3);
 739         dma->rx_ring3 = NULL;
 740         bcm43xx_destroy_dmaring(dma->rx_ring0);
 741         dma->rx_ring0 = NULL;
 742
 743         bcm43xx_destroy_dmaring(dma->tx_ring5);
 744         dma->tx_ring5 = NULL;
 745         bcm43xx_destroy_dmaring(dma->tx_ring4);
 746         dma->tx_ring4 = NULL;
 747         bcm43xx_destroy_dmaring(dma->tx_ring3);
 748         dma->tx_ring3 = NULL;
 749         bcm43xx_destroy_dmaring(dma->tx_ring2);
 750         dma->tx_ring2 = NULL;
 751         bcm43xx_destroy_dmaring(dma->tx_ring1);
 752         dma->tx_ring1 = NULL;
 753         bcm43xx_destroy_dmaring(dma->tx_ring0);
 754         dma->tx_ring0 = NULL;
 755 }
 756
 757 int bcm43xx_dma_init(struct bcm43xx_private *bcm)
 758 {
 759         struct bcm43xx_dma *dma = bcm43xx_current_dma(bcm);
 760         struct bcm43xx_dmaring *ring;
 761         int err = -ENOMEM;
 762         int dma64 = 0;
 763
 764         bcm->dma_mask = bcm43xx_get_supported_dma_mask(bcm);
 765         if (bcm->dma_mask == DMA_64BIT_MASK)
 766                 dma64 = 1;
 767         err = pci_set_dma_mask(bcm->pci_dev, bcm->dma_mask);
 768         if (err)
 769                 goto no_dma;
 770         err = pci_set_consistent_dma_mask(bcm->pci_dev, bcm->dma_mask);
 771         if (err)
 772                 goto no_dma;
 773
 774         /* setup TX DMA channels. */
 775         ring = bcm43xx_setup_dmaring(bcm, 0, 1, dma64);
 776         if (!ring)
 777                 goto out;
 778         dma->tx_ring0 = ring;
 779
 780         ring = bcm43xx_setup_dmaring(bcm, 1, 1, dma64);
 781         if (!ring)
 782                 goto err_destroy_tx0;
 783         dma->tx_ring1 = ring;
 784
 785         ring = bcm43xx_setup_dmaring(bcm, 2, 1, dma64);
 786         if (!ring)
 787                 goto err_destroy_tx1;
 788         dma->tx_ring2 = ring;
 789
 790         ring = bcm43xx_setup_dmaring(bcm, 3, 1, dma64);
 791         if (!ring)
 792                 goto err_destroy_tx2;
 793         dma->tx_ring3 = ring;
 794
 795         ring = bcm43xx_setup_dmaring(bcm, 4, 1, dma64);
 796         if (!ring)
 797                 goto err_destroy_tx3;
 798         dma->tx_ring4 = ring;
 799
 800         ring = bcm43xx_setup_dmaring(bcm, 5, 1, dma64);
 801         if (!ring)
 802                 goto err_destroy_tx4;
 803         dma->tx_ring5 = ring;
 804
 805         /* setup RX DMA channels. */
 806         ring = bcm43xx_setup_dmaring(bcm, 0, 0, dma64);
 807         if (!ring)
 808                 goto err_destroy_tx5;
 809         dma->rx_ring0 = ring;
 810
 811         if (bcm->current_core->rev < 5) {
 812                 ring = bcm43xx_setup_dmaring(bcm, 3, 0, dma64);
 813                 if (!ring)
 814                         goto err_destroy_rx0;
 815                 dma->rx_ring3 = ring;
 816         }
 817
 818         dprintk(KERN_INFO PFX "%d-bit DMA initialized\n",
 819                 (bcm->dma_mask == DMA_64BIT_MASK) ? 64 :
 820                 (bcm->dma_mask == DMA_32BIT_MASK) ? 32 : 30);
 821         err = 0;
 822 out:
 823         return err;
 824
 825 err_destroy_rx0:
 826         bcm43xx_destroy_dmaring(dma->rx_ring0);
 827         dma->rx_ring0 = NULL;
 828 err_destroy_tx5:
 829         bcm43xx_destroy_dmaring(dma->tx_ring5);
 830         dma->tx_ring5 = NULL;
 831 err_destroy_tx4:
 832         bcm43xx_destroy_dmaring(dma->tx_ring4);
 833         dma->tx_ring4 = NULL;
 834 err_destroy_tx3:
 835         bcm43xx_destroy_dmaring(dma->tx_ring3);
 836         dma->tx_ring3 = NULL;
 837 err_destroy_tx2:
 838         bcm43xx_destroy_dmaring(dma->tx_ring2);
 839         dma->tx_ring2 = NULL;
 840 err_destroy_tx1:
 841         bcm43xx_destroy_dmaring(dma->tx_ring1);
 842         dma->tx_ring1 = NULL;
 843 err_destroy_tx0:
 844         bcm43xx_destroy_dmaring(dma->tx_ring0);
 845         dma->tx_ring0 = NULL;
 846 no_dma:
 847 #ifdef CONFIG_BCM43XX_PIO
 848         printk(KERN_WARNING PFX "DMA not supported on this device."
 849                                 " Falling back to PIO.\n");
 850         bcm->__using_pio = 1;
 851         return -ENOSYS;
 852 #else
 853         printk(KERN_ERR PFX "FATAL: DMA not supported and PIO not configured. "
 854                             "Please recompile the driver with PIO support.\n");
 855         return -ENODEV;
 856 #endif /* CONFIG_BCM43XX_PIO */
 857 }
 858
 859 /* Generate a cookie for the TX header. */
 860 static u16 generate_cookie(struct bcm43xx_dmaring *ring,
 861                            int slot)
 862 {
 863         u16 cookie = 0x1000;
 864
 865         /* Use the upper 4 bits of the cookie as
 866          * DMA controller ID and store the slot number
 867          * in the lower 12 bits.
 868          * Note that the cookie must never be 0, as this
 869          * is a special value used in RX path.
 870          */
 871         switch (ring->index) {
 872         case 0:
 873                 cookie = 0xA000;
 874                 break;
 875         case 1:
 876                 cookie = 0xB000;
 877                 break;
 878         case 2:
 879                 cookie = 0xC000;
 880                 break;
 881         case 3:
 882                 cookie = 0xD000;
 883                 break;
 884         case 4:
 885                 cookie = 0xE000;
 886                 break;
 887         case 5:
 888                 cookie = 0xF000;
 889                 break;
 890         }
 891         assert(((u16)slot & 0xF000) == 0x0000);
 892         cookie |= (u16)slot;
 893
 894         return cookie;
 895 }
 896
 897 /* Inspect a cookie and find out to which controller/slot it belongs. */
 898 static
 899 struct bcm43xx_dmaring * parse_cookie(struct bcm43xx_private *bcm,
 900                                       u16 cookie, int *slot)
 901 {
 902         struct bcm43xx_dma *dma = bcm43xx_current_dma(bcm);
 903         struct bcm43xx_dmaring *ring = NULL;
 904
 905         switch (cookie & 0xF000) {
 906         case 0xA000:
 907                 ring = dma->tx_ring0;
 908                 break;
 909         case 0xB000:
 910                 ring = dma->tx_ring1;
 911                 break;
 912         case 0xC000:
 913                 ring = dma->tx_ring2;
 914                 break;
 915         case 0xD000:
 916                 ring = dma->tx_ring3;
 917                 break;
 918         case 0xE000:
 919                 ring = dma->tx_ring4;
 920                 break;
 921         case 0xF000:
 922                 ring = dma->tx_ring5;
 923                 break;
 924         default:
 925                 assert(0);
 926         }
 927         *slot = (cookie & 0x0FFF);
 928         assert(*slot >= 0 && *slot < ring->nr_slots);
 929
 930         return ring;
 931 }
 932
 933 static void dmacontroller_poke_tx(struct bcm43xx_dmaring *ring,
 934                                   int slot)
 935 {
 936         u16 offset;
 937         int descsize;
 938
 939         /* Everything is ready to start. Buffers are DMA mapped and
 940          * associated with slots.
 941          * "slot" is the last slot of the new frame we want to transmit.
 942          * Close your seat belts now, please.
 943          */
 944         wmb();
 945         slot = next_slot(ring, slot);
 946         offset = (ring->dma64) ? BCM43xx_DMA64_TXINDEX : BCM43xx_DMA32_TXINDEX;
 947         descsize = (ring->dma64) ? sizeof(struct bcm43xx_dmadesc64)
 948                 : sizeof(struct bcm43xx_dmadesc32);
 949         bcm43xx_dma_write(ring, offset,
 950                         (u32)(slot * descsize));
 951 }
 952
 953 static void dma_tx_fragment(struct bcm43xx_dmaring *ring,
 954                             struct sk_buff *skb,
 955                             u8 cur_frag)
 956 {
 957         int slot;
 958         struct bcm43xx_dmadesc_generic *desc;
 959         struct bcm43xx_dmadesc_meta *meta;
 960         dma_addr_t dmaaddr;
 961         struct sk_buff *bounce_skb;
 962
 963         assert(skb_shinfo(skb)->nr_frags == 0);
 964
 965         slot = request_slot(ring);
 966         desc = bcm43xx_dma_idx2desc(ring, slot, &meta);
 967
 968         /* Add a device specific TX header. */
 969         assert(skb_headroom(skb) >= sizeof(struct bcm43xx_txhdr));
 970         /* Reserve enough headroom for the device tx header. */
 971         __skb_push(skb, sizeof(struct bcm43xx_txhdr));
 972         /* Now calculate and add the tx header.
 973          * The tx header includes the PLCP header.
 974          */
 975         bcm43xx_generate_txhdr(ring->bcm,
 976                                (struct bcm43xx_txhdr *)skb->data,
 977                                skb->data + sizeof(struct bcm43xx_txhdr),
 978                                skb->len - sizeof(struct bcm43xx_txhdr),
 979                                (cur_frag == 0),
 980                                generate_cookie(ring, slot));
 981         dmaaddr = map_descbuffer(ring, skb->data, skb->len, 1);
 982         if (dma_mapping_error(dmaaddr) || dmaaddr + skb->len > ring->bcm->dma_mask) {
 983                 /* chip cannot handle DMA to/from > 1GB, use bounce buffer (copied from b44 driver) */
 984                 if (!dma_mapping_error(dmaaddr))
 985                         unmap_descbuffer(ring, dmaaddr, skb->len, 1);
 986                 bounce_skb = __dev_alloc_skb(skb->len, GFP_ATOMIC|GFP_DMA);
 987                 if (!bounce_skb)
 988                         return;
 989                 dmaaddr = map_descbuffer(ring, bounce_skb->data, bounce_skb->len, 1);
 990                 if (dma_mapping_error(dmaaddr) || dmaaddr + skb->len > ring->bcm->dma_mask) {
 991                         if (!dma_mapping_error(dmaaddr))
 992                                 unmap_descbuffer(ring, dmaaddr, skb->len, 1);
 993                         dev_kfree_skb_any(bounce_skb);
 994                         assert(0);
 995                         return;
 996                 }
 997                 skb_copy_from_linear_data(skb, skb_put(bounce_skb, skb->len),
 998                                           skb->len);
 999                 dev_kfree_skb_any(skb);
1000                 skb = bounce_skb;
1001         }
1002
1003         meta->skb = skb;
1004         meta->dmaaddr = dmaaddr;
1005
1006         fill_descriptor(ring, desc, dmaaddr,
1007                         skb->len, 1, 1, 1);
1008
1009         /* Now transfer the whole frame. */
1010         dmacontroller_poke_tx(ring, slot);
1011 }
1012
1013 int bcm43xx_dma_tx(struct bcm43xx_private *bcm,
1014                    struct ieee80211_txb *txb)
1015 {
1016         /* We just received a packet from the kernel network subsystem.
1017          * Add headers and DMA map the memory. Poke
1018          * the device to send the stuff.
1019          * Note that this is called from atomic context.
1020          */
1021         struct bcm43xx_dmaring *ring = bcm43xx_current_dma(bcm)->tx_ring1;
1022         u8 i;
1023         struct sk_buff *skb;
1024
1025         assert(ring->tx);
1026         if (unlikely(free_slots(ring) < txb->nr_frags)) {
1027                 /* The queue should be stopped,
1028                  * if we are low on free slots.
1029                  * If this ever triggers, we have to lower the suspend_mark.
1030                  */
1031                 dprintkl(KERN_ERR PFX "Out of DMA descriptor slots!\n");
1032                 return -ENOMEM;
1033         }
1034
1035         for (i = 0; i < txb->nr_frags; i++) {
1036                 skb = txb->fragments[i];
1037                 /* Take skb from ieee80211_txb_free */
1038                 txb->fragments[i] = NULL;
1039                 dma_tx_fragment(ring, skb, i);
1040         }
1041         ieee80211_txb_free(txb);
1042
1043         return 0;
1044 }
1045
1046 void bcm43xx_dma_handle_xmitstatus(struct bcm43xx_private *bcm,
1047                                    struct bcm43xx_xmitstatus *status)
1048 {
1049         struct bcm43xx_dmaring *ring;
1050         struct bcm43xx_dmadesc_generic *desc;
1051         struct bcm43xx_dmadesc_meta *meta;
1052         int is_last_fragment;
1053         int slot;
1054         u32 tmp;
1055
1056         ring = parse_cookie(bcm, status->cookie, &slot);
1057         assert(ring);
1058         assert(ring->tx);
1059         while (1) {
1060                 assert(slot >= 0 && slot < ring->nr_slots);
1061                 desc = bcm43xx_dma_idx2desc(ring, slot, &meta);
1062
1063                 if (ring->dma64) {
1064                         tmp = le32_to_cpu(desc->dma64.control0);
1065                         is_last_fragment = !!(tmp & BCM43xx_DMA64_DCTL0_FRAMEEND);
1066                 } else {
1067                         tmp = le32_to_cpu(desc->dma32.control);
1068                         is_last_fragment = !!(tmp & BCM43xx_DMA32_DCTL_FRAMEEND);
1069                 }
1070                 unmap_descbuffer(ring, meta->dmaaddr, meta->skb->len, 1);
1071                 free_descriptor_buffer(ring, meta, 1);
1072                 /* Everything belonging to the slot is unmapped
1073                  * and freed, so we can return it.
1074                  */
1075                 return_slot(ring, slot);
1076
1077                 if (is_last_fragment)
1078                         break;
1079                 slot = next_slot(ring, slot);
1080         }
1081         bcm->stats.last_tx = jiffies;
1082 }
1083
1084 static void dma_rx(struct bcm43xx_dmaring *ring,
1085                    int *slot)
1086 {
1087         struct bcm43xx_dmadesc_generic *desc;
1088         struct bcm43xx_dmadesc_meta *meta;
1089         struct bcm43xx_rxhdr *rxhdr;
1090         struct sk_buff *skb;
1091         u16 len;
1092         int err;
1093         dma_addr_t dmaaddr;
1094
1095         desc = bcm43xx_dma_idx2desc(ring, *slot, &meta);
1096
1097         sync_descbuffer_for_cpu(ring, meta->dmaaddr, ring->rx_buffersize);
1098         skb = meta->skb;
1099
1100         if (ring->index == 3) {
1101                 /* We received an xmit status. */
1102                 struct bcm43xx_hwxmitstatus *hw = (struct bcm43xx_hwxmitstatus *)skb->data;
1103                 struct bcm43xx_xmitstatus stat;
1104                 int i = 0;
1105
1106                 stat.cookie = le16_to_cpu(hw->cookie);
1107                 while (stat.cookie == 0) {
1108                         if (unlikely(++i >= 10000)) {
1109                                 assert(0);
1110                                 break;
1111                         }
1112                         udelay(2);
1113                         barrier();
1114                         stat.cookie = le16_to_cpu(hw->cookie);
1115                 }
1116                 stat.flags = hw->flags;
1117                 stat.cnt1 = hw->cnt1;
1118                 stat.cnt2 = hw->cnt2;
1119                 stat.seq = le16_to_cpu(hw->seq);
1120                 stat.unknown = le16_to_cpu(hw->unknown);
1121
1122                 bcm43xx_debugfs_log_txstat(ring->bcm, &stat);
1123                 bcm43xx_dma_handle_xmitstatus(ring->bcm, &stat);
1124                 /* recycle the descriptor buffer. */
1125                 sync_descbuffer_for_device(ring, meta->dmaaddr, ring->rx_buffersize);
1126
1127                 return;
1128         }
1129         rxhdr = (struct bcm43xx_rxhdr *)skb->data;
1130         len = le16_to_cpu(rxhdr->frame_length);
1131         if (len == 0) {
1132                 int i = 0;
1133
1134                 do {
1135                         udelay(2);
1136                         barrier();
1137                         len = le16_to_cpu(rxhdr->frame_length);
1138                 } while (len == 0 && i++ < 5);
1139                 if (unlikely(len == 0)) {
1140                         /* recycle the descriptor buffer. */
1141                         sync_descbuffer_for_device(ring, meta->dmaaddr,
1142                                                    ring->rx_buffersize);
1143                         goto drop;
1144                 }
1145         }
1146         if (unlikely(len > ring->rx_buffersize)) {
1147                 /* The data did not fit into one descriptor buffer
1148                  * and is split over multiple buffers.
1149                  * This should never happen, as we try to allocate buffers
1150                  * big enough. So simply ignore this packet.
1151                  */
1152                 int cnt = 0;
1153                 s32 tmp = len;
1154
1155                 while (1) {
1156                         desc = bcm43xx_dma_idx2desc(ring, *slot, &meta);
1157                         /* recycle the descriptor buffer. */
1158                         sync_descbuffer_for_device(ring, meta->dmaaddr,
1159                                                    ring->rx_buffersize);
1160                         *slot = next_slot(ring, *slot);
1161                         cnt++;
1162                         tmp -= ring->rx_buffersize;
1163                         if (tmp <= 0)
1164                                 break;
1165                 }
1166                 printkl(KERN_ERR PFX "DMA RX buffer too small "
1167                         "(len: %u, buffer: %u, nr-dropped: %d)\n",
1168                         len, ring->rx_buffersize, cnt);
1169                 goto drop;
1170         }
1171         len -= IEEE80211_FCS_LEN;
1172
1173         dmaaddr = meta->dmaaddr;
1174         err = setup_rx_descbuffer(ring, desc, meta, GFP_ATOMIC);
1175         if (unlikely(err)) {
1176                 dprintkl(KERN_ERR PFX "DMA RX: setup_rx_descbuffer() failed\n");
1177                 sync_descbuffer_for_device(ring, dmaaddr,
1178                                            ring->rx_buffersize);
1179                 goto drop;
1180         }
1181
1182         unmap_descbuffer(ring, dmaaddr, ring->rx_buffersize, 0);
1183         skb_put(skb, len + ring->frameoffset);
1184         skb_pull(skb, ring->frameoffset);
1185
1186         err = bcm43xx_rx(ring->bcm, skb, rxhdr);
1187         if (err) {
1188                 dev_kfree_skb_irq(skb);
1189                 goto drop;
1190         }
1191
1192 drop:
1193         return;
1194 }
1195
1196 void bcm43xx_dma_rx(struct bcm43xx_dmaring *ring)
1197 {
1198         u32 status;
1199         u16 descptr;
1200         int slot, current_slot;
1201 #ifdef CONFIG_BCM43XX_DEBUG
1202         int used_slots = 0;
1203 #endif
1204
1205         assert(!ring->tx);
1206         if (ring->dma64) {
1207                 status = bcm43xx_dma_read(ring, BCM43xx_DMA64_RXSTATUS);
1208                 descptr = (status & BCM43xx_DMA64_RXSTATDPTR);
1209                 current_slot = descptr / sizeof(struct bcm43xx_dmadesc64);
1210         } else {
1211                 status = bcm43xx_dma_read(ring, BCM43xx_DMA32_RXSTATUS);
1212                 descptr = (status & BCM43xx_DMA32_RXDPTR);
1213                 current_slot = descptr / sizeof(struct bcm43xx_dmadesc32);
1214         }
1215         assert(current_slot >= 0 && current_slot < ring->nr_slots);
1216
1217         slot = ring->current_slot;
1218         for ( ; slot != current_slot; slot = next_slot(ring, slot)) {
1219                 dma_rx(ring, &slot);
1220 #ifdef CONFIG_BCM43XX_DEBUG
1221                 if (++used_slots > ring->max_used_slots)
1222                         ring->max_used_slots = used_slots;
1223 #endif
1224         }
1225         if (ring->dma64) {
1226                 bcm43xx_dma_write(ring, BCM43xx_DMA64_RXINDEX,
1227                                 (u32)(slot * sizeof(struct bcm43xx_dmadesc64)));
1228         } else {
1229                 bcm43xx_dma_write(ring, BCM43xx_DMA32_RXINDEX,
1230                                 (u32)(slot * sizeof(struct bcm43xx_dmadesc32)));
1231         }
1232         ring->current_slot = slot;
1233 }
1234
1235 void bcm43xx_dma_tx_suspend(struct bcm43xx_dmaring *ring)
1236 {
1237         assert(ring->tx);
1238         bcm43xx_power_saving_ctl_bits(ring->bcm, -1, 1);
1239         if (ring->dma64) {
1240                 bcm43xx_dma_write(ring, BCM43xx_DMA64_TXCTL,
1241                                 bcm43xx_dma_read(ring, BCM43xx_DMA64_TXCTL)
1242                                 | BCM43xx_DMA64_TXSUSPEND);
1243         } else {
1244                 bcm43xx_dma_write(ring, BCM43xx_DMA32_TXCTL,
1245                                 bcm43xx_dma_read(ring, BCM43xx_DMA32_TXCTL)
1246                                 | BCM43xx_DMA32_TXSUSPEND);
1247         }
1248 }
1249
1250 void bcm43xx_dma_tx_resume(struct bcm43xx_dmaring *ring)
1251 {
1252         assert(ring->tx);
1253         if (ring->dma64) {
1254                 bcm43xx_dma_write(ring, BCM43xx_DMA64_TXCTL,
1255                                 bcm43xx_dma_read(ring, BCM43xx_DMA64_TXCTL)
1256                                 & ~BCM43xx_DMA64_TXSUSPEND);
1257         } else {
1258                 bcm43xx_dma_write(ring, BCM43xx_DMA32_TXCTL,
1259                                 bcm43xx_dma_read(ring, BCM43xx_DMA32_TXCTL)
1260                                 & ~BCM43xx_DMA32_TXSUSPEND);
1261         }
1262         bcm43xx_power_saving_ctl_bits(ring->bcm, -1, -1);
1263 }