carlfw/src/hostif.c

   1 /*
   2  * carl9170 firmware - used by the ar9170 wireless device
   3  *
   4  * Host interface routines
   5  *
   6  * Copyright (c) 2000-2005 ZyDAS Technology Corporation
   7  * Copyright (c) 2007-2009 Atheros Communications, Inc.
   8  * Copyright    2009    Johannes Berg <johannes@sipsolutions.net>
   9  * Copyright 2009-2011  Christian Lamparter <chunkeey@googlemail.com>
  10  *
  11  * This program is free software; you can redistribute it and/or modify
  12  * it under the terms of the GNU General Public License as published by
  13  * the Free Software Foundation; either version 2 of the License, or
  14  * (at your option) any later version.
  15  *
  16  * This program is distributed in the hope that it will be useful,
  17  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  18  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  19  * GNU General Public License for more details.
  20  *
  21  * You should have received a copy of the GNU General Public License along
  22  * with this program; if not, write to the Free Software Foundation, Inc.,
  23  * 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
  24  */
  25
  26 #include "carl9170.h"
  27 #include "hostif.h"
  28 #include "printf.h"
  29 #include "wl.h"
  30
  31 static bool length_check(struct dma_desc *desc)
  32 {
  33         volatile struct carl9170_tx_superframe *super = DESC_PAYLOAD(desc);
  34
  35         if (unlikely(desc->totalLen < sizeof(struct carl9170_tx_superdesc)))
  36                 return false;
  37
  38         /*
  39          * check if the DMA is complete, or clipped.
  40          *
  41          * NB: The hardware aligns the descriptor length to
  42          * a 4 byte boundary. This makes the direct comparison
  43          * difficult, or unnecessary complex for a hot-path.
  44          */
  45         if (unlikely(super->s.len > desc->totalLen))
  46                 return false;
  47
  48         return true;
  49 }
  50
  51 static void handle_download(void)
  52 {
  53         struct dma_desc *desc;
  54
  55         /*
  56          * Under normal conditions, all completed descs should have
  57          * the AR9170_OWN_BITS_SE status flag set.
  58          * However there seems to be a undocumented case where the flag
  59          * is _SW ( handle_download_exception )
  60          */
  61
  62         for_each_desc_bits(desc, &fw.pta.down_queue, AR9170_OWN_BITS_SE) {
  63                 if (unlikely((length_check(desc) == false))) {
  64                         /*
  65                          * There is no easy way of telling what was lost.
  66                          *
  67                          * Therefore we just reclaim the data.
  68                          * The driver has to have some sort frame
  69                          * timeout mechanism.
  70                          */
  71
  72                         dma_reclaim(&fw.pta.down_queue, desc);
  73                         down_trigger();
  74                 } else {
  75                         wlan_tx(desc);
  76                 }
  77         }
  78
  79 #ifdef CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT
  80         xorl(AR9170_GPIO_REG_PORT_DATA, 2);
  81 #endif /* CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT */
  82 }
  83
  84 static void handle_upload(void)
  85 {
  86         struct dma_desc *desc;
  87
  88         for_each_desc_not_bits(desc, &fw.pta.up_queue, AR9170_OWN_BITS_HW) {
  89                 /*
  90                  * BIG FAT NOTE:
  91                  *
  92                  * DO NOT compare the descriptor addresses.
  93                  */
  94                 if (DESC_PAYLOAD(desc) == (void *) &dma_mem.reserved.rsp) {
  95                         fw.usb.int_desc = desc;
  96                         fw.usb.int_desc_available = 1;
  97                 } else {
  98 #ifdef CONFIG_CARL9170FW_LOOPBACK
  99                         dma_reclaim(&fw.pta.down_queue, desc);
 100                         down_trigger();
 101 #else
 102                         dma_reclaim(&fw.wlan.rx_queue, desc);
 103                         wlan_trigger(AR9170_DMA_TRIGGER_RXQ);
 104 #endif /* CONFIG_CARL9170FW_LOOPBACK */
 105                 }
 106         }
 107
 108 #ifdef CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT
 109         xorl(AR9170_GPIO_REG_PORT_DATA, 2);
 110 #endif /* CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT */
 111 }
 112
 113 static void handle_download_exception(void)
 114 {
 115         struct dma_desc *desc, *target;
 116
 117         /* actually, the queue should be stopped by now? */
 118         usb_stop_down_queue();
 119
 120         target = (void *)((get(AR9170_PTA_REG_DN_CURR_ADDRH) << 16) |
 121                   get(AR9170_PTA_REG_DN_CURR_ADDRL));
 122
 123         /*
 124          * Put "forgotten" packets from the head of the queue, back
 125          * to the current position
 126          */
 127         __while_desc_bits(desc, &fw.pta.down_queue, AR9170_OWN_BITS_HW) {
 128                 if (desc == target)
 129                         break;
 130
 131                 dma_reclaim(&fw.pta.down_queue,
 132                     dma_unlink_head(&fw.pta.down_queue));
 133         }
 134
 135         __for_each_desc_continue(desc, &fw.pta.down_queue) {
 136                 if ((desc->status & AR9170_OWN_BITS) == AR9170_OWN_BITS_SW) {
 137                         dma_fix_downqueue(desc);
 138                 }
 139         }
 140
 141
 142         usb_start_down_queue();
 143
 144         down_trigger();
 145 }
 146
 147 /* handle interrupts from DMA chip */
 148 void handle_host_interface(void)
 149 {
 150         uint32_t pta_int;
 151
 152         pta_int = get(AR9170_PTA_REG_INT_FLAG);
 153
 154 #define HANDLER(intr, flag, func)                       \
 155         do {                                            \
 156                 if ((intr & flag) != 0) {               \
 157                         func();                         \
 158                 }                                       \
 159         } while (0)
 160
 161         HANDLER(pta_int, AR9170_PTA_INT_FLAG_DN, handle_download);
 162
 163         HANDLER(pta_int, AR9170_PTA_INT_FLAG_UP, handle_upload);
 164
 165         /* This is just guesswork and MAGIC */
 166         pta_int = get(AR9170_PTA_REG_DMA_STATUS);
 167         HANDLER(pta_int, 0x1, handle_download_exception);
 168
 169 #undef HANDLER
 170 }