Skip to content

Commit

Permalink
iwlwifi: enable active scanning
Browse files Browse the repository at this point in the history 
This patch enables active scan on active channels.

Signed-off-by: Tomas Winkler <tomas.winkler@intel.com>
Signed-off-by: Zhu Yi <yi.zhu@intel.com>
Signed-off-by: John W. Linville <linville@tuxdriver.com>
  • Loading branch information
Tomas Winkler authored and John W. Linville committed Jul 14, 2008
1 parent d16dc48 commit fe905f1
Showing 1 changed file with 45 additions and 41 deletions.
86 changes: 45 additions & 41 deletions drivers/net/wireless/iwlwifi/iwl-scan.c
View file
Original file line number Diff line number Diff line change
Expand Up @@ -38,8 +38,11 @@
/* For active scan, listen ACTIVE_DWELL_TIME (msec) on each channel after
* sending probe req. This should be set long enough to hear probe responses
* from more than one AP. */
#define IWL_ACTIVE_DWELL_TIME_24 (20) /* all times in msec */
#define IWL_ACTIVE_DWELL_TIME_52 (10)
#define IWL_ACTIVE_DWELL_TIME_24 (30) /* all times in msec */
#define IWL_ACTIVE_DWELL_TIME_52 (20)

#define IWL_ACTIVE_DWELL_FACTOR_24GHZ (3)
#define IWL_ACTIVE_DWELL_FACTOR_52GHZ (2)

/* For faster active scanning, scan will move to the next channel if fewer than
* PLCP_QUIET_THRESH packets are heard on this channel within
Expand All @@ -48,7 +51,7 @@
* no other traffic).
* Disable "quiet" feature by setting PLCP_QUIET_THRESH to 0. */
#define IWL_PLCP_QUIET_THRESH __constant_cpu_to_le16(1) /* packets */
#define IWL_ACTIVE_QUIET_TIME __constant_cpu_to_le16(5) /* msec */
#define IWL_ACTIVE_QUIET_TIME __constant_cpu_to_le16(10) /* msec */

/* For passive scan, listen PASSIVE_DWELL_TIME (msec) on each channel.
* Must be set longer than active dwell time.
Expand All @@ -58,10 +61,15 @@
#define IWL_PASSIVE_DWELL_BASE (100)
#define IWL_CHANNEL_TUNE_TIME 5

#define IWL_SCAN_PROBE_MASK(n) cpu_to_le32((BIT(n) | (BIT(n) - BIT(1))))


static int scan_tx_ant[3] = {
RATE_MCS_ANT_A_MSK, RATE_MCS_ANT_B_MSK, RATE_MCS_ANT_C_MSK
};



static int iwl_is_empty_essid(const char *essid, int essid_len)
{
/* Single white space is for Linksys APs */
Expand Down Expand Up @@ -226,8 +234,9 @@ static void iwl_rx_scan_start_notif(struct iwl_priv *priv,
"(TSF: 0x%08X:%08X) - %d (beacon timer %u)\n",
notif->channel,
notif->band ? "bg" : "a",
notif->tsf_high,
notif->tsf_low, notif->status, notif->beacon_timer);
le32_to_cpu(notif->tsf_high),
le32_to_cpu(notif->tsf_low),
notif->status, notif->beacon_timer);
}

/* Service SCAN_RESULTS_NOTIFICATION (0x83) */
Expand Down Expand Up @@ -332,19 +341,21 @@ void iwl_setup_rx_scan_handlers(struct iwl_priv *priv)
EXPORT_SYMBOL(iwl_setup_rx_scan_handlers);

static inline u16 iwl_get_active_dwell_time(struct iwl_priv *priv,
enum ieee80211_band band)
enum ieee80211_band band,
u8 n_probes)
{
if (band == IEEE80211_BAND_5GHZ)
return IWL_ACTIVE_DWELL_TIME_52;
return IWL_ACTIVE_DWELL_TIME_52 +
IWL_ACTIVE_DWELL_FACTOR_52GHZ * (n_probes + 1);
else
return IWL_ACTIVE_DWELL_TIME_24;
return IWL_ACTIVE_DWELL_TIME_24 +
IWL_ACTIVE_DWELL_FACTOR_24GHZ * (n_probes + 1);
}

static u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
enum ieee80211_band band)
enum ieee80211_band band)
{
u16 active = iwl_get_active_dwell_time(priv, band);
u16 passive = (band != IEEE80211_BAND_5GHZ) ?
u16 passive = (band == IEEE80211_BAND_2GHZ) ?
IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_24 :
IWL_PASSIVE_DWELL_BASE + IWL_PASSIVE_DWELL_TIME_52;

Expand All @@ -358,15 +369,12 @@ static u16 iwl_get_passive_dwell_time(struct iwl_priv *priv,
passive = (passive * 98) / 100 - IWL_CHANNEL_TUNE_TIME * 2;
}

if (passive <= active)
passive = active + 1;

return passive;
}

static int iwl_get_channels_for_scan(struct iwl_priv *priv,
enum ieee80211_band band,
u8 is_active, u8 direct_mask,
u8 is_active, u8 n_probes,
struct iwl_scan_channel *scan_ch)
{
const struct ieee80211_channel *channels = NULL;
Expand All @@ -383,9 +391,12 @@ static int iwl_get_channels_for_scan(struct iwl_priv *priv,

channels = sband->channels;

active_dwell = iwl_get_active_dwell_time(priv, band);
active_dwell = iwl_get_active_dwell_time(priv, band, n_probes);
passive_dwell = iwl_get_passive_dwell_time(priv, band);

if (passive_dwell <= active_dwell)
passive_dwell = active_dwell + 1;

for (i = 0, added = 0; i < sband->n_channels; i++) {
if (channels[i].flags & IEEE80211_CHAN_DISABLED)
continue;
Expand All @@ -407,27 +418,26 @@ static int iwl_get_channels_for_scan(struct iwl_priv *priv,
else
scan_ch->type = SCAN_CHANNEL_TYPE_ACTIVE;

if (scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE)
scan_ch->type |= cpu_to_le32(direct_mask << 1);
if ((scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) && n_probes)
scan_ch->type |= IWL_SCAN_PROBE_MASK(n_probes);

scan_ch->active_dwell = cpu_to_le16(active_dwell);
scan_ch->passive_dwell = cpu_to_le16(passive_dwell);

/* Set txpower levels to defaults */
scan_ch->dsp_atten = 110;

/* NOTE: if we were doing 6Mb OFDM for scans we'd use
* power level:
* scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
*/
if (band == IEEE80211_BAND_5GHZ)
scan_ch->tx_gain = ((1 << 5) | (3 << 3)) | 3;
else {
else
scan_ch->tx_gain = ((1 << 5) | (5 << 3));
/* NOTE: if we were doing 6Mb OFDM for scans we'd use
* power level:
* scan_ch->tx_gain = ((1 << 5) | (2 << 3)) | 3;
*/
}

IWL_DEBUG_SCAN("Scanning %d [%s %d]\n",
channel,
IWL_DEBUG_SCAN("Scanning ch=%d prob=0x%X [%s %d]\n",
channel, le32_to_cpu(scan_ch->type),
(scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
"ACTIVE" : "PASSIVE",
(scan_ch->type & SCAN_CHANNEL_TYPE_ACTIVE) ?
Expand Down Expand Up @@ -676,7 +686,7 @@ static u32 iwl_scan_tx_ant(struct iwl_priv *priv, enum ieee80211_band band)
break;
}
}

IWL_DEBUG_SCAN("select TX ANT = %c\n", 'A' + ind);
return scan_tx_ant[ind];
}

Expand All @@ -696,7 +706,7 @@ static void iwl_bg_request_scan(struct work_struct *data)
u32 tx_ant;
u16 cmd_len;
enum ieee80211_band band;
u8 direct_mask;
u8 n_probes = 2;
u8 rx_chain = 0x7; /* bitmap: ABC chains */

conf = ieee80211_get_hw_conf(priv->hw);
Expand Down Expand Up @@ -796,17 +806,16 @@ static void iwl_bg_request_scan(struct work_struct *data)
scan->direct_scan[0].len = priv->direct_ssid_len;
memcpy(scan->direct_scan[0].ssid,
priv->direct_ssid, priv->direct_ssid_len);
direct_mask = 1;
n_probes++;
} else if (!iwl_is_associated(priv) && priv->essid_len) {
IWL_DEBUG_SCAN("Start direct scan for '%s' (not associated)\n",
iwl_escape_essid(priv->essid, priv->essid_len));
scan->direct_scan[0].id = WLAN_EID_SSID;
scan->direct_scan[0].len = priv->essid_len;
memcpy(scan->direct_scan[0].ssid, priv->essid, priv->essid_len);
direct_mask = 1;
n_probes++;
} else {
IWL_DEBUG_SCAN("Start indirect scan.\n");
direct_mask = 0;
}

scan->tx_cmd.tx_flags = TX_CMD_FLG_SEQ_CTL_MSK;
Expand Down Expand Up @@ -863,16 +872,11 @@ static void iwl_bg_request_scan(struct work_struct *data)
scan->filter_flags |= (RXON_FILTER_ACCEPT_GRP_MSK |
RXON_FILTER_BCON_AWARE_MSK);

if (direct_mask)
scan->channel_count =
iwl_get_channels_for_scan(priv, band, 1, /* active */
direct_mask,
(void *)&scan->data[le16_to_cpu(scan->tx_cmd.len)]);
else
scan->channel_count =
iwl_get_channels_for_scan(priv, band, 0, /* passive */
direct_mask,
(void *)&scan->data[le16_to_cpu(scan->tx_cmd.len)]);
scan->channel_count =
iwl_get_channels_for_scan(priv, band, 1, /* active */
n_probes,
(void *)&scan->data[le16_to_cpu(scan->tx_cmd.len)]);

if (scan->channel_count == 0) {
IWL_DEBUG_SCAN("channel count %d\n", scan->channel_count);
goto done;
Expand Down

0 comments on commit fe905f1

Please sign in to comment.