path: root/drivers/net/wireless/p54/txrx.c

/*
 * Common code for mac80211 Prism54 drivers
 *
 * Copyright (c) 2006, Michael Wu <flamingice@sourmilk.net>
 * Copyright (c) 2007-2009, Christian Lamparter <chunkeey@web.de>
 * Copyright 2008, Johannes Berg <johannes@sipsolutions.net>
 *
 * Based on:
 * - the islsm (softmac prism54) driver, which is:
 *   Copyright 2004-2006 Jean-Baptiste Note <jbnote@gmail.com>, et al.
 * - stlc45xx driver
 *   Copyright (C) 2008 Nokia Corporation and/or its subsidiary(-ies).
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include <linux/export.h>
#include <linux/init.h>
#include <linux/firmware.h>
#include <linux/etherdevice.h>
#include <asm/div64.h>

#include <net/mac80211.h>

#include "p54.h"
#include "lmac.h"

#ifdef P54_MM_DEBUG
static void p54_dump_tx_queue(struct p54_common *priv)
{
	unsigned long flags;
	struct ieee80211_tx_info *info;
	struct p54_tx_info *range;
	struct sk_buff *skb;
	struct p54_hdr *hdr;
	unsigned int i = 0;
	u32 prev_addr;
	u32 largest_hole = 0, free;

	spin_lock_irqsave(&priv->tx_queue.lock, flags);
	wiphy_debug(priv->hw->wiphy, "/ --- tx queue dump (%d entries) ---\n",
		    skb_queue_len(&priv->tx_queue));

	prev_addr = priv->rx_start;
	skb_queue_walk(&priv->tx_queue, skb) {
		info = IEEE80211_SKB_CB(skb);
		range = (void *) info->rate_driver_data;
		hdr = (void *) skb->data;

		free = range->start_addr - prev_addr;
		wiphy_debug(priv->hw->wiphy,
			    "| [%02d] => [skb:%p skb_len:0x%04x "
			    "hdr:{flags:%02x len:%04x req_id:%04x type:%02x} "
			    "mem:{start:%04x end:%04x, free:%d}]\n",
			    i++, skb, skb->len,
			    le16_to_cpu(hdr->flags), le16_to_cpu(hdr->len),
			    le32_to_cpu(hdr->req_id), le16_to_cpu(hdr->type),
			    range->start_addr, range->end_addr, free);

		prev_addr = range->end_addr;
		largest_hole = max(largest_hole, free);
	}
	free = priv->rx_end - prev_addr;
	largest_hole = max(largest_hole, free);
	wiphy_debug(priv->hw->wiphy,
		    "\\ --- [free: %d], largest free block: %d ---\n",
		    free, largest_hole);
	spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
}
#endif /* P54_MM_DEBUG */

/*
 * So, the firmware is somewhat stupid and doesn't know what places in its
 * memory incoming data should go to. By poking around in the firmware, we
 * can find some unused memory to upload our packets to. However, data that we
 * want the card to TX needs to stay intact until the card has told us that
 * it is done with it. This function finds empty places we can upload to and
 * marks allocated areas as reserved if necessary. p54_find_and_unlink_skb or
 * p54_free_skb frees allocated areas.
 */
static int p54_assign_address(struct p54_common *priv, struct sk_buff *skb)
{
	struct sk_buff *entry, *target_skb = NULL;
	struct ieee80211_tx_info *info;
	struct p54_tx_info *range;
	struct p54_hdr *data = (void *) skb->data;
	unsigned long flags;
	u32 last_addr = priv->rx_start;
	u32 target_addr = priv->rx_start;
	u16 len = priv->headroom + skb->len + priv->tailroom + 3;

	info = IEEE80211_SKB_CB(skb);
	range = (void *) info->rate_driver_data;
	len = (range->extra_len + len) & ~0x3;

	spin_lock_irqsave(&priv->tx_queue.lock, flags);
	if (unlikely(skb_queue_len(&priv->tx_queue) == 32)) {
		/*
		 * The tx_queue is now really full.
		 *
		 * TODO: check if the device has crashed and reset it.
		 */
		spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
		return -EBUSY;
	}

	skb_queue_walk(&priv->tx_queue, entry) {
		u32 hole_size;
		info = IEEE80211_SKB_CB(entry);
		range = (void *) info->rate_driver_data;
		hole_size = range->start_addr - last_addr;

		if (!target_skb && hole_size >= len) {
			target_skb = entry->prev;
			hole_size -= len;
			target_addr = last_addr;
			break;
		}
		last_addr = range->end_addr;
	}
	if (unlikely(!target_skb)) {
		if (priv->rx_end - last_addr >= len) {
			target_skb = priv->tx_queue.prev;
			if (!skb_queue_empty(&priv->tx_queue)) {
				info = IEEE80211_SKB_CB(target_skb);
				range = (void *)info->rate_driver_data;
				target_addr = range->end_addr;
			}
		} else {
			spin_unlock_irqrestore(&priv->tx_queue.lock, flags);
			return -ENOSPC;
		}
	}

	info = IEEE80211_SKB_CB(skb);
	range = (void *) info->rate_driver_data;
	range->s