release/src-rt-6.x.4708/linux/linux-2.6.36/drivers/net/wireless/iwlwifi/iwl-rx.c

   1 /******************************************************************************
   2  *
   3  * Copyright(c) 2003 - 2010 Intel Corporation. All rights reserved.
   4  *
   5  * Portions of this file are derived from the ipw3945 project, as well
   6  * as portions of the ieee80211 subsystem header files.
   7  *
   8  * This program is free software; you can redistribute it and/or modify it
   9  * under the terms of version 2 of the GNU General Public License as
  10  * published by the Free Software Foundation.
  11  *
  12  * This program is distributed in the hope that it will be useful, but WITHOUT
  13  * ANY WARRANTY; without even the implied warranty of MERCHANTABILITY or
  14  * FITNESS FOR A PARTICULAR PURPOSE.  See the GNU General Public License for
  15  * more details.
  16  *
  17  * You should have received a copy of the GNU General Public License along with
  18  * this program; if not, write to the Free Software Foundation, Inc.,
  19  * 51 Franklin Street, Fifth Floor, Boston, MA 02110, USA
  20  *
  21  * The full GNU General Public License is included in this distribution in the
  22  * file called LICENSE.
  23  *
  24  * Contact Information:
  25  *  Intel Linux Wireless <ilw@linux.intel.com>
  26  * Intel Corporation, 5200 N.E. Elam Young Parkway, Hillsboro, OR 97124-6497
  27  *
  28  *****************************************************************************/
  29
  30 #include <linux/etherdevice.h>
  31 #include <linux/slab.h>
  32 #include <net/mac80211.h>
  33 #include <asm/unaligned.h>
  34 #include "iwl-eeprom.h"
  35 #include "iwl-dev.h"
  36 #include "iwl-core.h"
  37 #include "iwl-sta.h"
  38 #include "iwl-io.h"
  39 #include "iwl-calib.h"
  40 #include "iwl-helpers.h"
  41 /************************** RX-FUNCTIONS ****************************/
  42 /*
  43  * Rx theory of operation
  44  *
  45  * Driver allocates a circular buffer of Receive Buffer Descriptors (RBDs),
  46  * each of which point to Receive Buffers to be filled by the NIC.  These get
  47  * used not only for Rx frames, but for any command response or notification
  48  * from the NIC.  The driver and NIC manage the Rx buffers by means
  49  * of indexes into the circular buffer.
  50  *
  51  * Rx Queue Indexes
  52  * The host/firmware share two index registers for managing the Rx buffers.
  53  *
  54  * The READ index maps to the first position that the firmware may be writing
  55  * to -- the driver can read up to (but not including) this position and get
  56  * good data.
  57  * The READ index is managed by the firmware once the card is enabled.
  58  *
  59  * The WRITE index maps to the last position the driver has read from -- the
  60  * position preceding WRITE is the last slot the firmware can place a packet.
  61  *
  62  * The queue is empty (no good data) if WRITE = READ - 1, and is full if
  63  * WRITE = READ.
  64  *
  65  * During initialization, the host sets up the READ queue position to the first
  66  * INDEX position, and WRITE to the last (READ - 1 wrapped)
  67  *
  68  * When the firmware places a packet in a buffer, it will advance the READ index
  69  * and fire the RX interrupt.  The driver can then query the READ index and
  70  * process as many packets as possible, moving the WRITE index forward as it
  71  * resets the Rx queue buffers with new memory.
  72  *
  73  * The management in the driver is as follows:
  74  * + A list of pre-allocated SKBs is stored in iwl->rxq->rx_free.  When
  75  *   iwl->rxq->free_count drops to or below RX_LOW_WATERMARK, work is scheduled
  76  *   to replenish the iwl->rxq->rx_free.
  77  * + In iwl_rx_replenish (scheduled) if 'processed' != 'read' then the
  78  *   iwl->rxq is replenished and the READ INDEX is updated (updating the
  79  *   'processed' and 'read' driver indexes as well)
  80  * + A received packet is processed and handed to the kernel network stack,
  81  *   detached from the iwl->rxq.  The driver 'processed' index is updated.
  82  * + The Host/Firmware iwl->rxq is replenished at tasklet time from the rx_free
  83  *   list. If there are no allocated buffers in iwl->rxq->rx_free, the READ
  84  *   INDEX is not incremented and iwl->status(RX_STALLED) is set.  If there
  85  *   were enough free buffers and RX_STALLED is set it is cleared.
  86  *
  87  *
  88  * Driver sequence:
  89  *
  90  * iwl_rx_queue_alloc()   Allocates rx_free
  91  * iwl_rx_replenish()     Replenishes rx_free list from rx_used, and calls
  92  *                            iwl_rx_queue_restock
  93  * iwl_rx_queue_restock() Moves available buffers from rx_free into Rx
  94  *                            queue, updates firmware pointers, and updates
  95  *                            the WRITE index.  If insufficient rx_free buffers
  96  *                            are available, schedules iwl_rx_replenish
  97  *
  98  * -- enable interrupts --
  99  * ISR - iwl_rx()         Detach iwl_rx_mem_buffers from pool up to the
 100  *                            READ INDEX, detaching the SKB from the pool.
 101  *                            Moves the packet buffer from queue to rx_used.
 102  *                            Calls iwl_rx_queue_restock to refill any empty
 103  *                            slots.
 104  * ...
 105  *
 106  */
 107
 108 /**
 109  * iwl_rx_queue_space - Return number of free slots available in queue.
 110  */
 111 int iwl_rx_queue_space(const struct iwl_rx_queue *q)
 112 {
 113         int s = q->read - q->write;
 114         if (s <= 0)
 115                 s += RX_QUEUE_SIZE;
 116         /* keep some buffer to not confuse full and empty queue */
 117         s -= 2;
 118         if (s < 0)
 119                 s = 0;
 120         return s;
 121 }
 122 EXPORT_SYMBOL(iwl_rx_queue_space);
 123
 124 /**
 125  * iwl_rx_queue_update_write_ptr - Update the write pointer for the RX queue
 126  */
 127 void iwl_rx_queue_update_write_ptr(struct iwl_priv *priv, struct iwl_rx_queue *q)
 128 {
 129         unsigned long flags;
 130         u32 rx_wrt_ptr_reg = priv->hw_params.rx_wrt_ptr_reg;
 131         u32 reg;
 132
 133         spin_lock_irqsave(&q->lock, flags);
 134
 135         if (q->need_update == 0)
 136                 goto exit_unlock;
 137
 138         /* If power-saving is in use, make sure device is awake */
 139         if (test_bit(STATUS_POWER_PMI, &priv->status)) {
 140                 reg = iwl_read32(priv, CSR_UCODE_DRV_GP1);
 141
 142                 if (reg & CSR_UCODE_DRV_GP1_BIT_MAC_SLEEP) {
 143                         IWL_DEBUG_INFO(priv, "Rx queue requesting wakeup, GP1 = 0x%x\n",
 144                                       reg);
 145                         iwl_set_bit(priv, CSR_GP_CNTRL,
 146                                     CSR_GP_CNTRL_REG_FLAG_MAC_ACCESS_REQ);
 147                         goto exit_unlock;
 148                 }
 149
 150                 q->write_actual = (q->write & ~0x7);
 151                 iwl_write_direct32(priv, rx_wrt_ptr_reg, q->write_actual);
 152
 153         /* Else device is assumed to be awake */
 154         } else {
 155                 /* Device expects a multiple of 8 */
 156                 q->write_actual = (q->write & ~0x7);
 157                 iwl_write_direct32(priv, rx_wrt_ptr_reg, q->write_actual);
 158         }
 159
 160         q->need_update = 0;
 161
 162  exit_unlock:
 163         spin_unlock_irqrestore(&q->lock, flags);
 164 }
 165 EXPORT_SYMBOL(iwl_rx_queue_update_write_ptr);
 166
 167 int iwl_rx_queue_alloc(struct iwl_priv *priv)
 168 {
 169         struct iwl_rx_queue *rxq = &priv->rxq;
 170         struct device *dev = &priv->pci_dev->dev;
 171         int i;
 172
 173         spin_lock_init(&rxq->lock);
 174         INIT_LIST_HEAD(&rxq->rx_free);
 175         INIT_LIST_HEAD(&rxq->rx_used);
 176
 177         /* Alloc the circular buffer of Read Buffer Descriptors (RBDs) */
 178         rxq->bd = dma_alloc_coherent(dev, 4 * RX_QUEUE_SIZE, &rxq->bd_dma,
 179                                      GFP_KERNEL);
 180         if (!rxq->bd)
 181                 goto err_bd;
 182
 183         rxq->rb_stts = dma_alloc_coherent(dev, sizeof(struct iwl_rb_status),
 184                                           &rxq->rb_stts_dma, GFP_KERNEL);
 185         if (!rxq->rb_stts)
 186                 goto err_rb;
 187
 188         /* Fill the rx_used queue with _all_ of the Rx buffers */
 189         for (i = 0; i < RX_FREE_BUFFERS + RX_QUEUE_SIZE; i++)
 190                 list_add_tail(&rxq->pool[i].list, &rxq->rx_used);
 191
 192         /* Set us so that we have processed and used all buffers, but have
 193          * not restocked the Rx queue with fresh buffers */
 194         rxq->read = rxq->write = 0;
 195         rxq->write_actual = 0;
 196         rxq->free_count = 0;
 197         rxq->need_update = 0;
 198         return 0;
 199
 200 err_rb:
 201         dma_free_coherent(&priv->pci_dev->dev, 4 * RX_QUEUE_SIZE, rxq->bd,
 202                           rxq->bd_dma);
 203 err_bd:
 204         return -ENOMEM;
 205 }
 206 EXPORT_SYMBOL(iwl_rx_queue_alloc);
 207
 208
 209 void iwl_rx_spectrum_measure_notif(struct iwl_priv *priv,
 210                                           struct iwl_rx_mem_buffer *rxb)
 211 {
 212         struct iwl_rx_packet *pkt = rxb_addr(rxb);
 213         struct iwl_spectrum_notification *report = &(pkt->u.spectrum_notif);
 214
 215         if (!report->state) {
 216                 IWL_DEBUG_11H(priv,
 217                         "Spectrum Measure Notification: Start\n");
 218                 return;
 219         }
 220
 221         memcpy(&priv->measure_report, report, sizeof(*report));
 222         priv->measurement_status |= MEASUREMENT_READY;
 223 }
 224 EXPORT_SYMBOL(iwl_rx_spectrum_measure_notif);
 225
 226 void iwl_recover_from_statistics(struct iwl_priv *priv,
 227                                 struct iwl_rx_packet *pkt)
 228 {
 229         if (test_bit(STATUS_EXIT_PENDING, &priv->status))
 230                 return;
 231         if (iwl_is_associated(priv)) {
 232                 if (priv->cfg->ops->lib->check_ack_health) {
 233                         if (!priv->cfg->ops->lib->check_ack_health(
 234                             priv, pkt)) {
 235                                 /*
 236                                  * low ack count detected
 237                                  * restart Firmware
 238                                  */
 239                                 IWL_ERR(priv, "low ack count detected, "
 240                                         "restart firmware\n");
 241                                 if (!iwl_force_reset(priv, IWL_FW_RESET, false))
 242                                         return;
 243                         }
 244                 }
 245                 if (priv->cfg->ops->lib->check_plcp_health) {
 246                         if (!priv->cfg->ops->lib->check_plcp_health(
 247                             priv, pkt)) {
 248                                 /*
 249                                  * high plcp error detected
 250                                  * reset Radio
 251                                  */
 252                                 iwl_force_reset(priv, IWL_RF_RESET, false);
 253                         }
 254                 }
 255         }
 256 }
 257 EXPORT_SYMBOL(iwl_recover_from_statistics);
 258
 259 /*
 260  * returns non-zero if packet should be dropped
 261  */
 262 int iwl_set_decrypted_flag(struct iwl_priv *priv,
 263                            struct ieee80211_hdr *hdr,
 264                            u32 decrypt_res,
 265                            struct ieee80211_rx_status *stats)
 266 {
 267         u16 fc = le16_to_cpu(hdr->frame_control);
 268
 269         if (priv->active_rxon.filter_flags & RXON_FILTER_DIS_DECRYPT_MSK)
 270                 return 0;
 271
 272         if (!(fc & IEEE80211_FCTL_PROTECTED))
 273                 return 0;
 274
 275         IWL_DEBUG_RX(priv, "decrypt_res:0x%x\n", decrypt_res);
 276         switch (decrypt_res & RX_RES_STATUS_SEC_TYPE_MSK) {
 277         case RX_RES_STATUS_SEC_TYPE_TKIP:
 278                 /* The uCode has got a bad phase 1 Key, pushes the packet.
 279                  * Decryption will be done in SW. */
 280                 if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
 281                     RX_RES_STATUS_BAD_KEY_TTAK)
 282                         break;
 283
 284         case RX_RES_STATUS_SEC_TYPE_WEP:
 285                 if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
 286                     RX_RES_STATUS_BAD_ICV_MIC) {
 287                         /* bad ICV, the packet is destroyed since the
 288                          * decryption is inplace, drop it */
 289                         IWL_DEBUG_RX(priv, "Packet destroyed\n");
 290                         return -1;
 291                 }
 292         case RX_RES_STATUS_SEC_TYPE_CCMP:
 293                 if ((decrypt_res & RX_RES_STATUS_DECRYPT_TYPE_MSK) ==
 294                     RX_RES_STATUS_DECRYPT_OK) {
 295                         IWL_DEBUG_RX(priv, "hw decrypt successfully!!!\n");
 296                         stats->flag |= RX_FLAG_DECRYPTED;
 297                 }
 298                 break;
 299
 300         default:
 301                 break;
 302         }
 303         return 0;
 304 }
 305 EXPORT_SYMBOL(iwl_set_decrypted_flag);