1/*
  2 * This file is part of wl1251
  3 *
  4 * Copyright (c) 1998-2007 Texas Instruments Incorporated
  5 * Copyright (C) 2008 Nokia Corporation
  6 *
  7 * This program is free software; you can redistribute it and/or
  8 * modify it under the terms of the GNU General Public License
  9 * version 2 as published by the Free Software Foundation.
 10 *
 11 * This program is distributed in the hope that it will be useful, but
 12 * WITHOUT ANY WARRANTY; without even the implied warranty of
 13 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the GNU
 14 * General Public License for more details.
 15 *
 16 * You should have received a copy of the GNU General Public License
 17 * along with this program; if not, write to the Free Software
 18 * Foundation, Inc., 51 Franklin St, Fifth Floor, Boston, MA
 19 * 02110-1301 USA
 20 *
 21 */
 22
 23#include <linux/skbuff.h>
 24#include <linux/gfp.h>
 25#include <net/mac80211.h>
 26
 27#include "wl1251.h"
 28#include "reg.h"
 29#include "io.h"
 30#include "rx.h"
 31#include "cmd.h"
 32#include "acx.h"
 33
 34static void wl1251_rx_header(struct wl1251 *wl,
 35			     struct wl1251_rx_descriptor *desc)
 36{
 37	u32 rx_packet_ring_addr;
 38
 39	rx_packet_ring_addr = wl->data_path->rx_packet_ring_addr;
 40	if (wl->rx_current_buffer)
 41		rx_packet_ring_addr += wl->data_path->rx_packet_ring_chunk_size;
 42
 43	wl1251_mem_read(wl, rx_packet_ring_addr, desc, sizeof(*desc));
 44}
 45
 46static void wl1251_rx_status(struct wl1251 *wl,
 47			     struct wl1251_rx_descriptor *desc,
 48			     struct ieee80211_rx_status *status,
 49			     u8 beacon)
 50{
 51	u64 mactime;
 52	int ret;
 53
 54	memset(status, 0, sizeof(struct ieee80211_rx_status));
 55
 56	status->band = IEEE80211_BAND_2GHZ;
 57	status->mactime = desc->timestamp;
 58
 59	/*
 60	 * The rx status timestamp is a 32 bits value while the TSF is a
 61	 * 64 bits one.
 62	 * For IBSS merging, TSF is mandatory, so we have to get it
 63	 * somehow, so we ask for ACX_TSF_INFO.
 64	 * That could be moved to the get_tsf() hook, but unfortunately,
 65	 * this one must be atomic, while our SPI routines can sleep.
 66	 */
 67	if ((wl->bss_type == BSS_TYPE_IBSS) && beacon) {
 68		ret = wl1251_acx_tsf_info(wl, &mactime);
 69		if (ret == 0)
 70			status->mactime = mactime;
 71	}
 72
 73	status->signal = desc->rssi;
 74
 75	/*
 76	 * FIXME: guessing that snr needs to be divided by two, otherwise
 77	 * the values don't make any sense
 78	 */
 79	wl->noise = desc->rssi - desc->snr / 2;
 80
 81	status->freq = ieee80211_channel_to_frequency(desc->channel,
 82						      status->band);
 83
 84	status->flag |= RX_FLAG_MACTIME_MPDU;
 85
 86	if (desc->flags & RX_DESC_ENCRYPTION_MASK) {
 87		status->flag |= RX_FLAG_IV_STRIPPED | RX_FLAG_MMIC_STRIPPED;
 88
 89		if (likely(!(desc->flags & RX_DESC_DECRYPT_FAIL)))
 90			status->flag |= RX_FLAG_DECRYPTED;
 91
 92		if (unlikely(desc->flags & RX_DESC_MIC_FAIL))
 93			status->flag |= RX_FLAG_MMIC_ERROR;
 94	}
 95
 96	if (unlikely(!(desc->flags & RX_DESC_VALID_FCS)))
 97		status->flag |= RX_FLAG_FAILED_FCS_CRC;
 98
 99	switch (desc->rate) {
100		/* skip 1 and 12 Mbps because they have same value 0x0a */
101	case RATE_2MBPS:
102		status->rate_idx = 1;
103		break;
104	case RATE_5_5MBPS:
105		status->rate_idx = 2;
106		break;
107	case RATE_11MBPS:
108		status->rate_idx = 3;
109		break;
110	case RATE_6MBPS:
111		status->rate_idx = 4;
112		break;
113	case RATE_9MBPS:
114		status->rate_idx = 5;
115		break;
116	case RATE_18MBPS:
117		status->rate_idx = 7;
118		break;
119	case RATE_24MBPS:
120		status->rate_idx = 8;
121		break;
122	case RATE_36MBPS:
123		status->rate_idx = 9;
124		break;
125	case RATE_48MBPS:
126		status->rate_idx = 10;
127		break;
128	case RATE_54MBPS:
129		status->rate_idx = 11;
130		break;
131	}
132
133	/* for 1 and 12 Mbps we have to check the modulation */
134	if (desc->rate == RATE_1MBPS) {
135		if (!(desc->mod_pre & OFDM_RATE_BIT))
136			/* CCK -> RATE_1MBPS */
137			status->rate_idx = 0;
138		else
139			/* OFDM -> RATE_12MBPS */
140			status->rate_idx = 6;
141	}
142
143	if (desc->mod_pre & SHORT_PREAMBLE_BIT)
144		status->flag |= RX_FLAG_SHORTPRE;
145}
146
147static void wl1251_rx_body(struct wl1251 *wl,
148			   struct wl1251_rx_descriptor *desc)
149{
150	struct sk_buff *skb;
151	struct ieee80211_rx_status status;
152	u8 *rx_buffer, beacon = 0;
153	u16 length, *fc;
154	u32 curr_id, last_id_inc, rx_packet_ring_addr;
155
156	length = WL1251_RX_ALIGN(desc->length  - PLCP_HEADER_LENGTH);
157	curr_id = (desc->flags & RX_DESC_SEQNUM_MASK) >> RX_DESC_PACKETID_SHIFT;
158	last_id_inc = (wl->rx_last_id + 1) % (RX_MAX_PACKET_ID + 1);
159
160	if (last_id_inc != curr_id) {
161		wl1251_warning("curr ID:%d, last ID inc:%d",
162			       curr_id, last_id_inc);
163		wl->rx_last_id = curr_id;
164	} else {
165		wl->rx_last_id = last_id_inc;
166	}
167
168	rx_packet_ring_addr = wl->data_path->rx_packet_ring_addr +
169		sizeof(struct wl1251_rx_descriptor) + 20;
170	if (wl->rx_current_buffer)
171		rx_packet_ring_addr += wl->data_path->rx_packet_ring_chunk_size;
172
173	skb = __dev_alloc_skb(length, GFP_KERNEL);
174	if (!skb) {
175		wl1251_error("Couldn't allocate RX frame");
176		return;
177	}
178
179	rx_buffer = skb_put(skb, length);
180	wl1251_mem_read(wl, rx_packet_ring_addr, rx_buffer, length);
181
182	/* The actual length doesn't include the target's alignment */
183	skb->len = desc->length  - PLCP_HEADER_LENGTH;
184
185	fc = (u16 *)skb->data;
186
187	if ((*fc & IEEE80211_FCTL_STYPE) == IEEE80211_STYPE_BEACON)
188		beacon = 1;
189
190	wl1251_rx_status(wl, desc, &status, beacon);
191
192	wl1251_debug(DEBUG_RX, "rx skb 0x%p: %d B %s", skb, skb->len,
193		     beacon ? "beacon" : "");
194
195	memcpy(IEEE80211_SKB_RXCB(skb), &status, sizeof(status));
196	ieee80211_rx_ni(wl->hw, skb);
197}
198
199static void wl1251_rx_ack(struct wl1251 *wl)
200{
201	u32 data, addr;
202
203	if (wl->rx_current_buffer) {
204		addr = ACX_REG_INTERRUPT_TRIG_H;
205		data = INTR_TRIG_RX_PROC1;
206	} else {
207		addr = ACX_REG_INTERRUPT_TRIG;
208		data = INTR_TRIG_RX_PROC0;
209	}
210
211	wl1251_reg_write32(wl, addr, data);
212
213	/* Toggle buffer ring */
214	wl->rx_current_buffer = !wl->rx_current_buffer;
215}
216
217
218void wl1251_rx(struct wl1251 *wl)
219{
220	struct wl1251_rx_descriptor *rx_desc;
221
222	if (wl->state != WL1251_STATE_ON)
223		return;
224
225	rx_desc = wl->rx_descriptor;
226
227	/* We first read the frame's header */
228	wl1251_rx_header(wl, rx_desc);
229
230	/* Now we can read the body */
231	wl1251_rx_body(wl, rx_desc);
232
233	/* Finally, we need to ACK the RX */
234	wl1251_rx_ack(wl);
235}