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 = __get_super(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_not_bits(desc, &fw.pta.down_queue, AR9170_OWN_BITS_HW) {
  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                         wlan_tx_complete(__get_super(desc), false);
  73                         dma_reclaim(&fw.pta.down_queue, desc);
  74                         down_trigger();
  75                 } else {
  76                         wlan_tx(desc);
  77                 }
  78         }
  79
  80 #ifdef CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT
  81         xorl(AR9170_GPIO_REG_PORT_DATA, 2);
  82 #endif /* CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT */
  83 }
  84
  85 static void handle_upload(void)
  86 {
  87         struct dma_desc *desc;
  88
  89         for_each_desc_not_bits(desc, &fw.pta.up_queue, AR9170_OWN_BITS_HW) {
  90                 /*
  91                  * BIG FAT NOTE:
  92                  *
  93                  * DO NOT compare the descriptor addresses.
  94                  */
  95                 if (DESC_PAYLOAD(desc) == (void *) &dma_mem.reserved.rsp) {
  96                         fw.usb.int_desc = desc;
  97                         fw.usb.int_desc_available = 1;
  98                 } else {
  99                         dma_reclaim(&fw.wlan.rx_queue, desc);
 100                         wlan_trigger(AR9170_DMA_TRIGGER_RXQ);
 101                 }
 102         }
 103
 104 #ifdef CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT
 105         xorl(AR9170_GPIO_REG_PORT_DATA, 2);
 106 #endif /* CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT */
 107 }
 108
 109 static void handle_download_exception(void)
 110 {
 111         struct dma_desc *desc, *target;
 112
 113         /* actually, the queue should be stopped by now? */
 114         usb_stop_down_queue();
 115
 116         target = (void *)((get(AR9170_PTA_REG_DN_CURR_ADDRH) << 16) |
 117                   get(AR9170_PTA_REG_DN_CURR_ADDRL));
 118
 119         /*
 120          * Put "forgotten" packets from the head of the queue, back
 121          * to the current position
 122          */
 123         __while_desc_bits(desc, &fw.pta.down_queue, AR9170_OWN_BITS_HW) {
 124                 if (desc == target)
 125                         break;
 126
 127                 dma_reclaim(&fw.pta.down_queue,
 128                     dma_unlink_head(&fw.pta.down_queue));
 129         }
 130
 131         __for_each_desc_continue(desc, &fw.pta.down_queue) {
 132                 if ((desc->status & AR9170_OWN_BITS) == AR9170_OWN_BITS_SW)
 133                         dma_fix_downqueue(desc);
 134         }
 135
 136
 137         usb_start_down_queue();
 138
 139         down_trigger();
 140 }
 141
 142 /* handle interrupts from DMA chip */
 143 void handle_host_interface(void)
 144 {
 145         uint32_t pta_int;
 146
 147         pta_int = get(AR9170_PTA_REG_INT_FLAG);
 148
 149 #define HANDLER(intr, flag, func)                       \
 150         do {                                            \
 151                 if ((intr & flag) != 0) {               \
 152                         func();                         \
 153                 }                                       \
 154         } while (0)
 155
 156         HANDLER(pta_int, AR9170_PTA_INT_FLAG_DN, handle_download);
 157
 158         HANDLER(pta_int, AR9170_PTA_INT_FLAG_UP, handle_upload);
 159
 160         /* This is just guesswork and MAGIC */
 161         pta_int = get(AR9170_PTA_REG_DMA_STATUS);
 162         HANDLER(pta_int, 0x1, handle_download_exception);
 163
 164 #undef HANDLER
 165 }