/*
* carl9170 firmware - used by the ar9170 wireless device
*
* Host interface routines
*
* Copyright (c) 2000-2005 ZyDAS Technology Corporation
* Copyright (c) 2007-2009 Atheros Communications, Inc.
* Copyright 2009 Johannes Berg <[email protected]>
* Copyright 2009-2011 Christian Lamparter <[email protected]>
*
* This program is free software; you can redistribute it and/or modify
* it under the terms of the GNU General Public License as published by
* the Free Software Foundation; either version 2 of the License, or
* (at your option) any later version.
*
* This program is distributed in the hope that it will be useful,
* but WITHOUT ANY WARRANTY; without even the implied warranty of
* MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the
* GNU General Public License for more details.
*
* You should have received a copy of the GNU General Public License along
* with this program; if not, write to the Free Software Foundation, Inc.,
* 51 Franklin Street, Fifth Floor, Boston, MA 02110-1301 USA.
*/

#include "carl9170.h"
#include "hostif.h"
#include "printf.h"
#include "wl.h"

static bool length_check(struct dma_desc *desc)
{
volatile struct carl9170_tx_superframe *super = __get_super(desc);

if (unlikely(desc->totalLen < sizeof(struct carl9170_tx_superdesc)))
return false;

/*
* check if the DMA is complete, or clipped.
*
* NB: The hardware aligns the descriptor length to
* a 4 byte boundary. This makes the direct comparison
* difficult, or unnecessary complex for a hot-path.
*/
if (unlikely(super->s.len > desc->totalLen))
return false;

return true;
}

static void handle_download(void)
{
struct dma_desc *desc;

/*
* Under normal conditions, all completed descs should have
* the AR9170_OWN_BITS_SE status flag set.
* However there seems to be a undocumented case where the flag
* is _SW ( handle_download_exception )
*/

for_each_desc_not_bits(desc, &fw.pta.down_queue, AR9170_OWN_BITS_HW) {
if (unlikely((length_check(desc) == false))) {
/*
* There is no easy way of telling what was lost.
*
* Therefore we just reclaim the data.
* The driver has to have some sort frame
* timeout mechanism.
*/

wlan_tx_complete(__get_super(desc), false);
dma_reclaim(&fw.pta.down_queue, desc);
down_trigger();
} else {
wlan_tx(desc);
}
}

#ifdef CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT
xorl(AR9170_GPIO_REG_PORT_DATA, 2);
#endif /* CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT */
}

static void handle_upload(void)
{
struct dma_desc *desc;

for_each_desc_not_bits(desc, &fw.pta.up_queue, AR9170_OWN_BITS_HW) {
/*
* BIG FAT NOTE:
*
* DO NOT compare the descriptor addresses.
*/
if (DESC_PAYLOAD(desc) == (void *) &dma_mem.reserved.rsp) {
fw.usb.int_desc = desc;
fw.usb.int_desc_available = 1;
} else {
dma_reclaim(&fw.wlan.rx_queue, desc);
wlan_trigger(AR9170_DMA_TRIGGER_RXQ);
}
}

#ifdef CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT
xorl(AR9170_GPIO_REG_PORT_DATA, 2);
#endif /* CONFIG_CARL9170FW_DEBUG_LED_HEARTBEAT */
}

static void handle_download_exception(void)
{
struct dma_desc *desc, *target;

/* actually, the queue should be stopped by now? */
usb_stop_down_queue();

target = (void *)((get(AR9170_PTA_REG_DN_CURR_ADDRH) << 16) |
get(AR9170_PTA_REG_DN_CURR_ADDRL));

/*
* Put "forgotten" packets from the head of the queue, back
* to the current position
*/
__while_desc_bits(desc, &fw.pta.down_queue, AR9170_OWN_BITS_HW) {
if (desc == target)
break;

dma_reclaim(&fw.pta.down_queue,
dma_unlink_head(&fw.pta.down_queue));
}

__for_each_desc_continue(desc, &fw.pta.down_queue) {
if ((desc->status & AR9170_OWN_BITS) == AR9170_OWN_BITS_SW)
dma_fix_downqueue(desc);
}


usb_start_down_queue();

down_trigger();
}

/* handle interrupts from DMA chip */
void handle_host_interface(void)
{
uint32_t pta_int;

pta_int = get(AR9170_PTA_REG_INT_FLAG);

#define HANDLER(intr, flag, func) \
do { \
if ((intr & flag) != 0) { \
func(); \
} \
} while (0)

HANDLER(pta_int, AR9170_PTA_INT_FLAG_DN, handle_download);

HANDLER(pta_int, AR9170_PTA_INT_FLAG_UP, handle_upload);

/* This is just guesswork and MAGIC */
pta_int = get(AR9170_PTA_REG_DMA_STATUS);
HANDLER(pta_int, 0x1, handle_download_exception);

#undef HANDLER
}