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authorBen Cahill <ben.m.cahill@intel.com>2008-01-14 17:46:17 -0800
committerDavid S. Miller <davem@davemloft.net>2008-01-28 15:09:56 -0800
commit3058f02137359efb412975cf94a9fa7c25413387 (patch)
tree673e1c9a579dce85f09cae8af577af61f54d4ef6 /drivers
parent87e4f7dfe56dbaa5470e047d991c077f8e479d21 (diff)
downloadlinux-3058f02137359efb412975cf94a9fa7c25413387.tar.gz
iwlwifi: document scan command
Document scan command. Signed-off-by: Ben Cahill <ben.m.cahill@intel.com> Signed-off-by: Zhu Yi <yi.zhu@intel.com> Signed-off-by: John W. Linville <linville@tuxdriver.com>
Diffstat (limited to 'drivers')
-rw-r--r--drivers/net/wireless/iwlwifi/iwl-3945-commands.h143
-rw-r--r--drivers/net/wireless/iwlwifi/iwl-4965-commands.h147
2 files changed, 234 insertions, 56 deletions
diff --git a/drivers/net/wireless/iwlwifi/iwl-3945-commands.h b/drivers/net/wireless/iwlwifi/iwl-3945-commands.h
index 3cac2c8ccf6..0c80ed5d7ea 100644
--- a/drivers/net/wireless/iwlwifi/iwl-3945-commands.h
+++ b/drivers/net/wireless/iwlwifi/iwl-3945-commands.h
@@ -1020,6 +1020,10 @@ struct iwl3945_rate_scaling_cmd {
/*
* REPLY_BT_CONFIG = 0x9b (command, has simple generic response)
+ *
+ * 3945 and 4965 support hardware handshake with Bluetooth device on
+ * same platform. Bluetooth device alerts wireless device when it will Tx;
+ * wireless device can delay or kill its own Tx to accomodate.
*/
struct iwl3945_bt_cmd {
u8 flags;
@@ -1258,20 +1262,47 @@ struct iwl3945_ct_kill_config {
*
*****************************************************************************/
+/**
+ * struct iwl3945_scan_channel - entry in REPLY_SCAN_CMD channel table
+ *
+ * One for each channel in the scan list.
+ * Each channel can independently select:
+ * 1) SSID for directed active scans
+ * 2) Txpower setting (for rate specified within Tx command)
+ * 3) How long to stay on-channel (behavior may be modified by quiet_time,
+ * quiet_plcp_th, good_CRC_th)
+ *
+ * To avoid uCode errors, make sure the following are true (see comments
+ * under struct iwl3945_scan_cmd about max_out_time and quiet_time):
+ * 1) If using passive_dwell (i.e. passive_dwell != 0):
+ * active_dwell <= passive_dwell (< max_out_time if max_out_time != 0)
+ * 2) quiet_time <= active_dwell
+ * 3) If restricting off-channel time (i.e. max_out_time !=0):
+ * passive_dwell < max_out_time
+ * active_dwell < max_out_time
+ */
struct iwl3945_scan_channel {
- /* type is defined as:
- * 0:0 active (0 - passive)
- * 1:4 SSID direct
- * If 1 is set then corresponding SSID IE is transmitted in probe
+ /*
+ * type is defined as:
+ * 0:0 1 = active, 0 = passive
+ * 1:4 SSID direct bit map; if a bit is set, then corresponding
+ * SSID IE is transmitted in probe request.
* 5:7 reserved
*/
u8 type;
- u8 channel;
+ u8 channel; /* band is selected by iwl3945_scan_cmd "flags" field */
struct iwl3945_tx_power tpc;
- __le16 active_dwell;
- __le16 passive_dwell;
+ __le16 active_dwell; /* in 1024-uSec TU (time units), typ 5-50 */
+ __le16 passive_dwell; /* in 1024-uSec TU (time units), typ 20-500 */
} __attribute__ ((packed));
+/**
+ * struct iwl3945_ssid_ie - directed scan network information element
+ *
+ * Up to 4 of these may appear in REPLY_SCAN_CMD, selected by "type" field
+ * in struct iwl3945_scan_channel; each channel may select different ssids from
+ * among the 4 entries. SSID IEs get transmitted in reverse order of entry.
+ */
struct iwl3945_ssid_ie {
u8 id;
u8 len;
@@ -1285,40 +1316,98 @@ struct iwl3945_ssid_ie {
/*
* REPLY_SCAN_CMD = 0x80 (command)
+ *
+ * The hardware scan command is very powerful; the driver can set it up to
+ * maintain (relatively) normal network traffic while doing a scan in the
+ * background. The max_out_time and suspend_time control the ratio of how
+ * long the device stays on an associated network channel ("service channel")
+ * vs. how long it's away from the service channel, tuned to other channels
+ * for scanning.
+ *
+ * max_out_time is the max time off-channel (in usec), and suspend_time
+ * is how long (in "extended beacon" format) that the scan is "suspended"
+ * after returning to the service channel. That is, suspend_time is the
+ * time that we stay on the service channel, doing normal work, between
+ * scan segments. The driver may set these parameters differently to support
+ * scanning when associated vs. not associated, and light vs. heavy traffic
+ * loads when associated.
+ *
+ * After receiving this command, the device's scan engine does the following;
+ *
+ * 1) Sends SCAN_START notification to driver
+ * 2) Checks to see if it has time to do scan for one channel
+ * 3) Sends NULL packet, with power-save (PS) bit set to 1,
+ * to tell AP that we're going off-channel
+ * 4) Tunes to first channel in scan list, does active or passive scan
+ * 5) Sends SCAN_RESULT notification to driver
+ * 6) Checks to see if it has time to do scan on *next* channel in list
+ * 7) Repeats 4-6 until it no longer has time to scan the next channel
+ * before max_out_time expires
+ * 8) Returns to service channel
+ * 9) Sends NULL packet with PS=0 to tell AP that we're back
+ * 10) Stays on service channel until suspend_time expires
+ * 11) Repeats entire process 2-10 until list is complete
+ * 12) Sends SCAN_COMPLETE notification
+ *
+ * For fast, efficient scans, the scan command also has support for staying on
+ * a channel for just a short time, if doing active scanning and getting no
+ * responses to the transmitted probe request. This time is controlled by
+ * quiet_time, and the number of received packets below which a channel is
+ * considered "quiet" is controlled by quiet_plcp_threshold.
+ *
+ * For active scanning on channels that have regulatory restrictions against
+ * blindly transmitting, the scan can listen before transmitting, to make sure
+ * that there is already legitimate activity on the channel. If enough
+ * packets are cleanly received on the channel (controlled by good_CRC_th,
+ * typical value 1), the scan engine starts transmitting probe requests.
+ *
+ * Driver must use separate scan commands for 2.4 vs. 5 GHz bands.
+ *
+ * To avoid uCode errors, see timing restrictions described under
+ * struct iwl3945_scan_channel.
*/
struct iwl3945_scan_cmd {
__le16 len;
u8 reserved0;
- u8 channel_count;
- __le16 quiet_time; /* dwell only this long on quiet chnl
- * (active scan) */
- __le16 quiet_plcp_th; /* quiet chnl is < this # pkts (typ. 1) */
- __le16 good_CRC_th; /* passive -> active promotion threshold */
+ u8 channel_count; /* # channels in channel list */
+ __le16 quiet_time; /* dwell only this # millisecs on quiet channel
+ * (only for active scan) */
+ __le16 quiet_plcp_th; /* quiet chnl is < this # pkts (typ. 1) */
+ __le16 good_CRC_th; /* passive -> active promotion threshold */
__le16 reserved1;
- __le32 max_out_time; /* max usec to be out of associated (service)
- * chnl */
- __le32 suspend_time; /* pause scan this long when returning to svc
- * chnl.
- * 3945 -- 31:24 # beacons, 19:0 additional usec,
- * 4965 -- 31:22 # beacons, 21:0 additional usec.
- */
- __le32 flags;
- __le32 filter_flags;
-
+ __le32 max_out_time; /* max usec to be away from associated (service)
+ * channel */
+ __le32 suspend_time; /* pause scan this long (in "extended beacon
+ * format") when returning to service channel:
+ * 3945; 31:24 # beacons, 19:0 additional usec,
+ * 4965; 31:22 # beacons, 21:0 additional usec.
+ */
+ __le32 flags; /* RXON_FLG_* */
+ __le32 filter_flags; /* RXON_FILTER_* */
+
+ /* For active scans (set to all-0s for passive scans).
+ * Does not include payload. Must specify Tx rate; no rate scaling. */
struct iwl3945_tx_cmd tx_cmd;
+
+ /* For directed active scans (set to all-0s otherwise) */
struct iwl3945_ssid_ie direct_scan[PROBE_OPTION_MAX];
- u8 data[0];
/*
- * The channels start after the probe request payload and are of type:
+ * Probe request frame, followed by channel list.
+ *
+ * Size of probe request frame is specified by byte count in tx_cmd.
+ * Channel list follows immediately after probe request frame.
+ * Number of channels in list is specified by channel_count.
+ * Each channel in list is of type:
*
* struct iwl3945_scan_channel channels[0];
*
* NOTE: Only one band of channels can be scanned per pass. You
- * can not mix 2.4GHz channels and 5.2GHz channels and must
- * request a scan multiple times (not concurrently)
- *
+ * must not mix 2.4GHz channels and 5.2GHz channels, and you must wait
+ * for one scan to complete (i.e. receive SCAN_COMPLETE_NOTIFICATION)
+ * before requesting another scan.
*/
+ u8 data[0];
} __attribute__ ((packed));
/* Can abort will notify by complete notification with abort status. */
diff --git a/drivers/net/wireless/iwlwifi/iwl-4965-commands.h b/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
index 7988c752a66..9237f8b3bb8 100644
--- a/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
+++ b/drivers/net/wireless/iwlwifi/iwl-4965-commands.h
@@ -1615,6 +1615,10 @@ struct iwl4965_link_quality_cmd {
/*
* REPLY_BT_CONFIG = 0x9b (command, has simple generic response)
+ *
+ * 3945 and 4965 support hardware handshake with Bluetooth device on
+ * same platform. Bluetooth device alerts wireless device when it will Tx;
+ * wireless device can delay or kill its own Tx to accomodate.
*/
struct iwl4965_bt_cmd {
u8 flags;
@@ -1857,20 +1861,47 @@ struct iwl4965_ct_kill_config {
*
*****************************************************************************/
+/**
+ * struct iwl4965_scan_channel - entry in REPLY_SCAN_CMD channel table
+ *
+ * One for each channel in the scan list.
+ * Each channel can independently select:
+ * 1) SSID for directed active scans
+ * 2) Txpower setting (for rate specified within Tx command)
+ * 3) How long to stay on-channel (behavior may be modified by quiet_time,
+ * quiet_plcp_th, good_CRC_th)
+ *
+ * To avoid uCode errors, make sure the following are true (see comments
+ * under struct iwl4965_scan_cmd about max_out_time and quiet_time):
+ * 1) If using passive_dwell (i.e. passive_dwell != 0):
+ * active_dwell <= passive_dwell (< max_out_time if max_out_time != 0)
+ * 2) quiet_time <= active_dwell
+ * 3) If restricting off-channel time (i.e. max_out_time !=0):
+ * passive_dwell < max_out_time
+ * active_dwell < max_out_time
+ */
struct iwl4965_scan_channel {
- /* type is defined as:
- * 0:0 active (0 - passive)
- * 1:4 SSID direct
- * If 1 is set then corresponding SSID IE is transmitted in probe
+ /*
+ * type is defined as:
+ * 0:0 1 = active, 0 = passive
+ * 1:4 SSID direct bit map; if a bit is set, then corresponding
+ * SSID IE is transmitted in probe request.
* 5:7 reserved
*/
u8 type;
- u8 channel;
+ u8 channel; /* band is selected by iwl4965_scan_cmd "flags" field */
struct iwl4965_tx_power tpc;
- __le16 active_dwell;
- __le16 passive_dwell;
+ __le16 active_dwell; /* in 1024-uSec TU (time units), typ 5-50 */
+ __le16 passive_dwell; /* in 1024-uSec TU (time units), typ 20-500 */
} __attribute__ ((packed));
+/**
+ * struct iwl4965_ssid_ie - directed scan network information element
+ *
+ * Up to 4 of these may appear in REPLY_SCAN_CMD, selected by "type" field
+ * in struct iwl4965_scan_channel; each channel may select different ssids from
+ * among the 4 entries. SSID IEs get transmitted in reverse order of entry.
+ */
struct iwl4965_ssid_ie {
u8 id;
u8 len;
@@ -1884,40 +1915,98 @@ struct iwl4965_ssid_ie {
/*
* REPLY_SCAN_CMD = 0x80 (command)
+ *
+ * The hardware scan command is very powerful; the driver can set it up to
+ * maintain (relatively) normal network traffic while doing a scan in the
+ * background. The max_out_time and suspend_time control the ratio of how
+ * long the device stays on an associated network channel ("service channel")
+ * vs. how long it's away from the service channel, i.e. tuned to other channels
+ * for scanning.
+ *
+ * max_out_time is the max time off-channel (in usec), and suspend_time
+ * is how long (in "extended beacon" format) that the scan is "suspended"
+ * after returning to the service channel. That is, suspend_time is the
+ * time that we stay on the service channel, doing normal work, between
+ * scan segments. The driver may set these parameters differently to support
+ * scanning when associated vs. not associated, and light vs. heavy traffic
+ * loads when associated.
+ *
+ * After receiving this command, the device's scan engine does the following;
+ *
+ * 1) Sends SCAN_START notification to driver
+ * 2) Checks to see if it has time to do scan for one channel
+ * 3) Sends NULL packet, with power-save (PS) bit set to 1,
+ * to tell AP that we're going off-channel
+ * 4) Tunes to first channel in scan list, does active or passive scan
+ * 5) Sends SCAN_RESULT notification to driver
+ * 6) Checks to see if it has time to do scan on *next* channel in list
+ * 7) Repeats 4-6 until it no longer has time to scan the next channel
+ * before max_out_time expires
+ * 8) Returns to service channel
+ * 9) Sends NULL packet with PS=0 to tell AP that we're back
+ * 10) Stays on service channel until suspend_time expires
+ * 11) Repeats entire process 2-10 until list is complete
+ * 12) Sends SCAN_COMPLETE notification
+ *
+ * For fast, efficient scans, the scan command also has support for staying on
+ * a channel for just a short time, if doing active scanning and getting no
+ * responses to the transmitted probe request. This time is controlled by
+ * quiet_time, and the number of received packets below which a channel is
+ * considered "quiet" is controlled by quiet_plcp_threshold.
+ *
+ * For active scanning on channels that have regulatory restrictions against
+ * blindly transmitting, the scan can listen before transmitting, to make sure
+ * that there is already legitimate activity on the channel. If enough
+ * packets are cleanly received on the channel (controlled by good_CRC_th,
+ * typical value 1), the scan engine starts transmitting probe requests.
+ *
+ * Driver must use separate scan commands for 2.4 vs. 5 GHz bands.
+ *
+ * To avoid uCode errors, see timing restrictions described under
+ * struct iwl4965_scan_channel.
*/
struct iwl4965_scan_cmd {
__le16 len;
u8 reserved0;
- u8 channel_count;
- __le16 quiet_time; /* dwell only this long on quiet chnl
- * (active scan) */
- __le16 quiet_plcp_th; /* quiet chnl is < this # pkts (typ. 1) */
- __le16 good_CRC_th; /* passive -> active promotion threshold */
- __le16 rx_chain;
- __le32 max_out_time; /* max usec to be out of associated (service)
- * chnl */
- __le32 suspend_time; /* pause scan this long when returning to svc
- * chnl.
- * 3945 -- 31:24 # beacons, 19:0 additional usec,
- * 4965 -- 31:22 # beacons, 21:0 additional usec.
- */
- __le32 flags;
- __le32 filter_flags;
-
+ u8 channel_count; /* # channels in channel list */
+ __le16 quiet_time; /* dwell only this # millisecs on quiet channel
+ * (only for active scan) */
+ __le16 quiet_plcp_th; /* quiet chnl is < this # pkts (typ. 1) */
+ __le16 good_CRC_th; /* passive -> active promotion threshold */
+ __le16 rx_chain; /* RXON_RX_CHAIN_* */
+ __le32 max_out_time; /* max usec to be away from associated (service)
+ * channel */
+ __le32 suspend_time; /* pause scan this long (in "extended beacon
+ * format") when returning to service chnl:
+ * 3945; 31:24 # beacons, 19:0 additional usec,
+ * 4965; 31:22 # beacons, 21:0 additional usec.
+ */
+ __le32 flags; /* RXON_FLG_* */
+ __le32 filter_flags; /* RXON_FILTER_* */
+
+ /* For active scans (set to all-0s for passive scans).
+ * Does not include payload. Must specify Tx rate; no rate scaling. */
struct iwl4965_tx_cmd tx_cmd;
+
+ /* For directed active scans (set to all-0s otherwise) */
struct iwl4965_ssid_ie direct_scan[PROBE_OPTION_MAX];
- u8 data[0];
/*
- * The channels start after the probe request payload and are of type:
+ * Probe request frame, followed by channel list.
+ *
+ * Size of probe request frame is specified by byte count in tx_cmd.
+ * Channel list follows immediately after probe request frame.
+ * Number of channels in list is specified by channel_count.
+ * Each channel in list is of type:
*
* struct iwl4965_scan_channel channels[0];
*
* NOTE: Only one band of channels can be scanned per pass. You
- * can not mix 2.4GHz channels and 5.2GHz channels and must
- * request a scan multiple times (not concurrently)
- *
+ * must not mix 2.4GHz channels and 5.2GHz channels, and you must wait
+ * for one scan to complete (i.e. receive SCAN_COMPLETE_NOTIFICATION)
+ * before requesting another scan.
*/
+ u8 data[0];
} __attribute__ ((packed));
/* Can abort will notify by complete notification with abort status. */
@@ -2087,7 +2176,7 @@ struct statistics_rx_non_phy {
__le32 interference_data_flag; /* flag for interference data
* availability. 1 when data is
* available. */
- __le32 channel_load; /* counts RX Enable time */
+ __le32 channel_load; /* counts RX Enable time in uSec */
__le32 dsp_false_alarms; /* DSP false alarm (both OFDM
* and CCK) counter */
__le32 beacon_rssi_a;