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/*
* Linux device driver for Digi's WiWave WLAN card
*
* Copyright © 2008 Digi International, Inc
*
* Author: Andres Salomon <dilinger@debian.org>
*
* 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/kernel.h>
#include <linux/string.h>
#include <linux/module.h>
#include <net/mac80211.h>
#include "pipermain.h"
#include "mac.h"
#include "airoha.h"
#include "phy.h"
#define PHY_DEBUG (0)
#if PHY_DEBUG
static int dlevel = DVERBOSE;
#define dprintk(level, fmt, arg...) if (level >= dlevel) \
printk(KERN_ERR PIPER_DRIVER_NAME \
": %s - " fmt, __func__, ##arg)
#else
#define dprintk(level, fmt, arg...) do {} while (0)
#endif
#define NUMBER_OF_WORD32(x) ((x + 3) >> 2)
static int is_ofdm_rate(int rate)
{
return (rate % 3) == 0;
}
void phy_set_plcp(unsigned char *frame, unsigned length, struct ieee80211_rate *rate, int aes_len)
{
int ofdm = is_ofdm_rate(rate->bitrate);
int plcp_len = length + FCS_LEN + aes_len;
struct tx_frame_hdr *hdr;
if (ofdm) {
/* OFDM header */
struct ofdm_hdr *ofdm;
ofdm = (struct ofdm_hdr *) &frame[sizeof(struct tx_frame_hdr)];
memset(ofdm, 0, sizeof(*ofdm));
ofdm->rate = rate->hw_value;
ofdm->length = cpu_to_le16(plcp_len);
} else {
/* PSK/CCK header */
struct psk_cck_hdr *pskcck;
int us_len;
pskcck = (struct psk_cck_hdr *) &frame[sizeof(struct tx_frame_hdr)];
pskcck->signal = rate->bitrate;
pskcck->service = PLCP_SERVICE_LOCKED;
/* convert length from bytes to usecs */
switch (rate->bitrate) {
case 10:
us_len = plcp_len * 8;
break;
case 20:
us_len = plcp_len * 4;
break;
case 55:
us_len = (16 * plcp_len + 10) / 11;
break;
case 110:
us_len = (8 * plcp_len + 10) / 11;
/* set length extension bit if needed */
dprintk(DALL, "us_len = %d, plcp_len = %d, (11 * us_len) = %d, \
(11 * us_len) / 8 = %d\n", us_len, plcp_len,
(11 * us_len), (11 * us_len) / 8);
if ((11 * us_len) / 8 > plcp_len) {
pskcck->service |= PLCP_SERVICE_LENEXT;
dprintk(DALL, "Set PLCP_SERVICE_LENEXT, \
pskcck->service = 0x%4.4X\n", pskcck->service);
} else {
dprintk(DALL, "Did not set PLCP_SERVICE_LENEXT, \
pskcck->service = 0x%4.4X\n", pskcck->service);
}
break;
default:
digi_dbg("rate = %p, rate->bitrate%d\n", rate, rate->bitrate);
WARN_ON(1);
us_len = 0;
}
pskcck->length = cpu_to_le16(us_len);
dprintk(DALL, "pskcck .length = %d, signal = %d, service = %d\n",
pskcck->length, pskcck->signal, pskcck->service);
dprintk(DALL, "rate->bitrate=%x (@%dM), pckcck->length=%d\n",
rate->bitrate, rate->bitrate/10, pskcck->length);
}
hdr = (struct tx_frame_hdr *) frame;
hdr->pad = 0;
hdr->length = NUMBER_OF_WORD32((length + aes_len + TX_HEADER_LENGTH));
hdr->modulation_type = ofdm ? MOD_TYPE_OFDM : MOD_TYPE_PSKCCK;
dprintk(DVVERBOSE, "frame hdr .length = %d, .modulation_type = %d\n",
hdr->length, hdr->modulation_type);
dprintk(DVERBOSE, "TX: %d byte %s packet @ %dmbit\n", length,
ofdm ? "OFDM" : "PSK/CCK", rate->bitrate/10);
}
EXPORT_SYMBOL_GPL(phy_set_plcp);
static int get_signal(struct rx_frame_hdr *hdr, enum ieee80211_band rf_band, int transceiver)
{
int gain;
int signal;
if (transceiver == RF_AIROHA_2236) {
const u8 lnaTable_al2236[] =
{
0, 0, 20, 36
};
// Map high gain values to dbm
const signed char gainTable_al2236[] =
{
-85, -85, -88, -88, -92
};
// Convert received signal strength to dbm
gain = lnaTable_al2236[hdr->rssi_low_noise_amp] + 2*hdr->rssi_variable_gain_attenuator;
if (gain > 92)
signal = -96;
else if (gain > 87)
signal = gainTable_al2236[gain - 88];
else
signal = 4 - gain;
} else {
static const u8 lnaTable_al7230_24ghz[] =
{
0, 0, 18, 42
};
static const u8 lnaTable_al7230_50ghz[] =
{
0, 0, 17, 37
};
/* Convert received signal strength to dbm for RF_AIROHA_7230 */
if (rf_band == IEEE80211_BAND_2GHZ) {
gain = lnaTable_al7230_24ghz[hdr->rssi_low_noise_amp] + 2*hdr->rssi_variable_gain_attenuator;
signal = 2 - gain;
} else {
gain = lnaTable_al7230_50ghz[hdr->rssi_low_noise_amp] + 2*hdr->rssi_variable_gain_attenuator;
signal = -5 - gain;
}
}
return signal;
}
/* FIXME, following limtis should depend on the platform */
#define PIPER_MAX_SIGNAL_DBM (-30)
#define PIPER_MIN_SIGNAL_DBM (-90)
static int calculate_link_quality(int signal)
{
int quality;
if (signal < PIPER_MIN_SIGNAL_DBM)
quality = 0;
else if (signal > PIPER_MAX_SIGNAL_DBM)
quality = 100;
else
quality = (signal - PIPER_MIN_SIGNAL_DBM) * 100 /
(PIPER_MAX_SIGNAL_DBM - PIPER_MIN_SIGNAL_DBM);
dprintk(DVERBOSE, "signal: %d, quality: %d/100\n", signal, quality);
return quality;
}
unsigned int phy_determine_rssi(struct rx_frame_hdr *hdr)
{
return (hdr->rssi_low_noise_amp << 5) | hdr->rssi_variable_gain_attenuator;
}
EXPORT_SYMBOL_GPL(phy_determine_rssi);
void phy_process_plcp(struct piper_priv *piper, struct rx_frame_hdr *hdr,
struct ieee80211_rx_status *status, unsigned int *length)
{
unsigned rate, i;
struct digi_rf_ops *rf = piper->rf;
memset(status, 0, sizeof(*status));
status->band = piper->rf->getBand(piper->channel);
status->signal = get_signal(hdr, status->band, piper->pdata->rf_transceiver);
status->antenna = hdr->antenna;
status->freq = piper->rf->getFrequency(piper->channel);
status->qual = calculate_link_quality(status->signal);
if (hdr->modulation_type == MOD_TYPE_OFDM) {
/* OFDM */
struct ofdm_hdr *ofdm = &hdr->mod.ofdm;
const int ofdm_rate[] = {
480, 240, 120, 60, 540, 360, 180, 90
};
rate = ofdm_rate[ofdm->rate & 0x7];
*length = le16_to_cpu(ofdm->length);
dprintk(DVVERBOSE, "%d byte OFDM packet @ %dmbit\n",
*length, rate/10);
} else {
/* PSK/CCK */
struct psk_cck_hdr *pskcck = &hdr->mod.psk;
rate = pskcck->signal;
*length = le16_to_cpu(pskcck->length);
switch (rate) {
case 10:
*length /= 8;
break;
case 20:
*length /= 4;
break;
case 55:
*length = (11 * (*length)) / 16;
break;
case 110:
*length = (11 * (*length)) / 8;
if (pskcck->service & PLCP_SERVICE_LENEXT)
(*length)--;
break;
default:
/* WARN_ON(1); This happens to often for us to generate that long error message */
*length = 0;
}
dprintk(DVVERBOSE, "%d byte PSK/CCK packet @ %dmbit\n",
*length, rate/10);
}
/* match rate with the list of bitrates that we supplied the stack */
for (i = 0; i < rf->bands[status->band].n_bitrates; i++) {
if (rf->bands[status->band].bitrates[i].bitrate == rate)
break;
}
if (i != rf->bands[status->band].n_bitrates)
status->rate_idx = i;
else {
*length = 0;
digi_dbg(PIPER_DRIVER_NAME
": couldn't find bitrate index for %d?\n",
rate);
status->flag |= RX_FLAG_FAILED_PLCP_CRC;
return;
}
}
EXPORT_SYMBOL_GPL(phy_process_plcp);
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