text: /*
   * This file is part of wl1251
   *
   * Copyright (c) 1998-2007 Texas Instruments Incorporated
   * Copyright (C) 2008 Nokia Corporation
   *
   * 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.
   *
   * 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 St, Fifth Floor, Boston, MA
   * 02110-1301 USA
   *
   */
  
  #include <linux/skbuff.h>
  #include <linux/gfp.h>
  #include <net/mac80211.h>
  
  #include "wl1251.h"
  #include "reg.h"
  #include "io.h"
  #include "rx.h"
  #include "cmd.h"
  #include "acx.h"
  
  static void wl1251_rx_header(struct wl1251 *wl,
  			     struct wl1251_rx_descriptor *desc)
  {
  	u32 rx_packet_ring_addr;
  
  	rx_packet_ring_addr = wl->data_path->rx_packet_ring_addr;
  	if (wl->rx_current_buffer)
  		rx_packet_ring_addr += wl->data_path->rx_packet_ring_chunk_size;
  
  	wl1251_mem_read(wl, rx_packet_ring_addr, desc, sizeof(*desc));
  }
  
  static void wl1251_rx_status(struct wl1251 *wl,
  			     struct wl1251_rx_descriptor *desc,
  			     struct ieee80211_rx_status *status,
  			     u8 beacon)
  {
  	u64 mactime;
  	int ret;
  
  	memset(status, 0, sizeof(struct ieee80211_rx_status));
  
  	status->band = IEEE80211_BAND_2GHZ;
  	status->mactime = desc->timestamp;
  
  	/*
  	 * The rx status timestamp is a 32 bits value while the TSF is a
  	 * 64 bits one.
  	 * For IBSS merging, TSF is mandatory, so we have to get it
  	 * somehow, so we ask for ACX_TSF_INFO.
  	 * That could be moved to the get_tsf() hook, but unfortunately,
  	 * this one must be atomic, while our SPI routines can sleep.
  	 */
  	if ((wl->bss_type == BSS_TYPE_IBSS) && beacon) {
  		ret = wl1251_acx_tsf_info(wl, &mactime);
  		if (ret == 0)
  			status->mactime = mactime;
  	}
  
  	status->signal = desc->rssi;
  
  	/*
  	 * FIXME: guessing that snr needs to be divided by two, otherwise
  	 * the values don't make any sense
  	 */
  	wl->noise = desc->rssi - desc->snr / 2;
  
  	status->freq = ieee80211_channel_to_frequency(desc->channel,
  						      status->band);
  
  	status->flag |= RX_FLAG_MACTIME_START;
  
  	if (!wl->monitor_present && (desc->flags & RX_DESC_ENCRYPTION_MASK)) {
  		status->flag |= RX_FLAG_IV_STRIPPED | RX_FLAG_MMIC_STRIPPED;
  
  		if (likely(!(desc->flags & RX_DESC_DECRYPT_FAIL)))
  			status->flag |= RX_FLAG_DECRYPTED;
  
  		if (unlikely(desc->flags & RX_DESC_MIC_FAIL))
  			status->flag |= RX_FLAG_MMIC_ERROR;
  	}
  
  	if (unlikely(!(desc->flags & RX_DESC_VALID_FCS)))
  		status->flag |= RX_FLAG_FAILED_FCS_CRC;
  
  	switch (desc->rate) {
  		/* skip 1 and 12 Mbps because they have same value 0x0a */
  	case RATE_2MBPS:
  		status->rate_idx = 1;
  		break;
  	case RATE_5_5MBPS:
  		status->rate_idx = 2;
  		break;
  	case RATE_11MBPS:
  		status->rate_idx = 3;
  		break;
  	case RATE_6MBPS:
  		status->rate_idx = 4;
  		break;
  	case RATE_9MBPS:
  		status->rate_idx = 5;
  		break;
  	case RATE_18MBPS:
  		status->rate_idx = 7;
  		break;
  	case RATE_24MBPS:
  		status->rate_idx = 8;
  		break;
  	case RATE_36MBPS:
  		status->rate_idx = 9;
  		break;
  	case RATE_48MBPS:
  		status->rate_idx = 10;
  		break;
  	case RATE_54MBPS:
  		status->rate_idx = 11;
  		break;
  	}
  
  	/* for 1 and 12 Mbps we have to check the modulation */
  	if (desc->rate == RATE_1MBPS) {
  		if (!(desc->mod_pre & OFDM_RATE_BIT))
  			/* CCK -> RATE_1MBPS */
  			status->rate_idx = 0;
  		else
  			/* OFDM -> RATE_12MBPS */
  			status->rate_idx = 6;
  	}
  
  	if (desc->mod_pre & SHORT_PREAMBLE_BIT)
  		status->flag |= RX_FLAG_SHORTPRE;
  }
  
  static void wl1251_rx_body(struct wl1251 *wl,
  			   struct wl1251_rx_descriptor *desc)
  {
  	struct sk_buff *skb;
  	struct ieee80211_rx_status status;
  	u8 *rx_buffer, beacon = 0;
  	u16 length, *fc;
  	u32 curr_id, last_id_inc, rx_packet_ring_addr;
  
  	length = WL1251_RX_ALIGN(desc->length  - PLCP_HEADER_LENGTH);
  	curr_id = (desc->flags & RX_DESC_SEQNUM_MASK) >> RX_DESC_PACKETID_SHIFT;
  	last_id_inc = (wl->rx_last_id + 1) % (RX_MAX_PACKET_ID + 1);
  
  	if (last_id_inc != curr_id) {
  		wl1251_warning("curr ID:%d, last ID inc:%d",
  			       curr_id, last_id_inc);
  		wl->rx_last_id = curr_id;
  	} else {
  		wl->rx_last_id = last_id_inc;
  	}
  
  	rx_packet_ring_addr = wl->data_path->rx_packet_ring_addr +
  		sizeof(struct wl1251_rx_descriptor) + 20;
  	if (wl->rx_current_buffer)
  		rx_packet_ring_addr += wl->data_path->rx_packet_ring_chunk_size;
  
  	skb = __dev_alloc_skb(length, GFP_KERNEL);
  	if (!skb) {
  		wl1251_error("Couldn't allocate RX frame");
  		return;
  	}
  
  	rx_buffer = skb_put(skb, length);
  	wl1251_mem_read(wl, rx_packet_ring_addr, rx_buffer, length);
  
  	/* The actual length doesn't include the target's alignment */
  	skb_trim(skb, desc->length - PLCP_HEADER_LENGTH);
  
  	fc = (u16 *)skb->data;
  
  	if ((*fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_BEACON)
  		beacon = 1;
  
  	wl1251_rx_status(wl, desc, &status, beacon);
  
  	wl1251_debug(DEBUG_RX, "rx skb 0x%p: %d B %s", skb, skb->len,
  		     beacon ? "beacon" : "");
  
  	memcpy(IEEE80211_SKB_RXCB(skb), &status, sizeof(status));
  	ieee80211_rx_ni(wl->hw, skb);
  }
  
  static void wl1251_rx_ack(struct wl1251 *wl)
  {
  	u32 data, addr;
  
  	if (wl->rx_current_buffer) {
  		addr = ACX_REG_INTERRUPT_TRIG_H;
  		data = INTR_TRIG_RX_PROC1;
  	} else {
  		addr = ACX_REG_INTERRUPT_TRIG;
  		data = INTR_TRIG_RX_PROC0;
  	}
  
  	wl1251_reg_write32(wl, addr, data);
  
  	/* Toggle buffer ring */
  	wl->rx_current_buffer = !wl->rx_current_buffer;
  }
  
  
  void wl1251_rx(struct wl1251 *wl)
  {
  	struct wl1251_rx_descriptor *rx_desc;
  
  	if (wl->state != WL1251_STATE_ON)
  		return;
  
  	rx_desc = wl->rx_descriptor;
  
  	/* We first read the frame's header */
  	wl1251_rx_header(wl, rx_desc);
  
  	/* Now we can read the body */
  	wl1251_rx_body(wl, rx_desc);
  
  	/* Finally, we need to ACK the RX */
  	wl1251_rx_ack(wl);
  }
  