[802.11] Enhance support for driver PHY differences

The prior net80211 model of physical-layer behavior for drivers was
overly simplistic and limited the drivers that could be written.  To
be more flexible, split the driver-provided list of supported rates by
band, and add a means for specifying a list of supported channels.
Allow drivers to specify a hardware channel value that will be tied to
uses of the channel.

Expose net80211_duration() to drivers, and make the rate it uses in
its computations configurable, so that it can be used in calculating
durations that must be set in hardware for ACK and CTS packets. Add
net80211_cts_duration() for the common case of calculating the
duration for a CTS packet.

Signed-off-by: Michael Brown <mcb30@etherboot.org>

1 files changed, 76 insertions, 14 deletions

diff --git a/src/net/80211/net80211.c b/src/net/80211/net80211.c
index 7d10aaa2..32547b5f 100644
--- a/src/net/80211/net80211.c
+++ b/src/net/80211/net80211.c
@@ -154,7 +154,6 @@ static void net80211_netdev_irq ( struct net_device *netdev, int enable );
  * @defgroup net80211_linklayer 802.11 link-layer protocol functions
  * @{
  */
-static u16 net80211_duration ( struct net80211_device *dev, int bytes );
 static int net80211_ll_push ( struct net_device *netdev,
 			      struct io_buffer *iobuf, const void *ll_dest,
 			      const void *ll_source, uint16_t net_proto );
@@ -171,6 +170,7 @@ static int net80211_ll_mc_hash ( unsigned int af, const void *net_addr,
  */
 static void net80211_add_channels ( struct net80211_device *dev, int start,
 				    int len, int txpower );
+static void net80211_filter_hw_channels ( struct net80211_device *dev );
 static void net80211_set_rtscts_rate ( struct net80211_device *dev );
 static int net80211_process_capab ( struct net80211_device *dev,
 				    u16 capab );
@@ -430,10 +430,9 @@ static inline int net80211_rate_is_erp ( u16 rate )
  *
  * No other frame types are currently supported by gPXE.
  */
-static u16 net80211_duration ( struct net80211_device *dev, int bytes )
+u16 net80211_duration ( struct net80211_device *dev, int bytes, u16 rate )
 {
 	struct net80211_channel *chan = &dev->channels[dev->channel];
-	u16 rate = dev->rates[dev->rate];
 	u32 kbps = rate * 100;
 
 	if ( chan->band == NET80211_BAND_5GHZ || net80211_rate_is_erp ( rate ) ) {
@@ -496,7 +495,7 @@ static int net80211_ll_push ( struct net_device *netdev,
 
 	/* We don't send fragmented frames, so duration is the time
 	   for an SIFS + 10-byte ACK. */
-	hdr->duration = net80211_duration ( dev, 10 );
+	hdr->duration = net80211_duration ( dev, 10, dev->rates[dev->rate] );
 
 	memcpy ( hdr->addr1, dev->bssid, ETH_ALEN );
 	memcpy ( hdr->addr2, ll_source, ETH_ALEN );
@@ -712,7 +711,7 @@ int net80211_tx_mgmt ( struct net80211_device *dev, u16 fc, u8 dest[6],
 
 	hdr->fc = IEEE80211_THIS_VERSION | IEEE80211_TYPE_MGMT |
 	    ( fc & ~IEEE80211_FC_PROTECTED );
-	hdr->duration = net80211_duration ( dev, 10 );
+	hdr->duration = net80211_duration ( dev, 10, dev->rates[dev->rate] );
 	hdr->seq = IEEE80211_MAKESEQ ( ++dev->last_tx_seqnr, 0 );
 
 	memcpy ( hdr->addr1, dest, ETH_ALEN );	/* DA = RA */
@@ -908,6 +907,7 @@ static void net80211_add_channels ( struct net80211_device *dev, int start,
 	for ( i = dev->nr_channels; len-- && i < NET80211_MAX_CHANNELS; i++ ) {
 		dev->channels[i].channel_nr = chan;
 		dev->channels[i].maxpower = txpower;
+		dev->channels[i].hw_value = 0;
 
 		if ( chan >= 1 && chan <= 14 ) {
 			dev->channels[i].band = NET80211_BAND_2GHZ;
@@ -927,6 +927,65 @@ static void net80211_add_channels ( struct net80211_device *dev, int start,
 }
 
 /**
+ * Filter 802.11 device channels for hardware capabilities
+ *
+ * @v dev	802.11 device
+ *
+ * Hardware may support fewer channels than regulatory restrictions
+ * allow; this function filters out channels in dev->channels that are
+ * not supported by the hardware list in dev->hwinfo. It also copies
+ * over the net80211_channel::hw_value and limits maximum TX power
+ * appropriately.
+ *
+ * Channels are matched based on center frequency, ignoring band and
+ * channel number.
+ *
+ * If the driver specifies no supported channels, the effect will be
+ * as though all were supported.
+ */
+static void net80211_filter_hw_channels ( struct net80211_device *dev )
+{
+	int delta = 0, i = 0;
+	int old_freq = dev->channels[dev->channel].center_freq;
+	struct net80211_channel *chan, *hwchan;
+
+	if ( ! dev->hw->nr_channels )
+		return;
+
+	dev->channel = 0;
+	for ( chan = dev->channels; chan < dev->channels + dev->nr_channels;
+	      chan++, i++ ) {
+		int ok = 0;
+		for ( hwchan = dev->hw->channels;
+		      hwchan < dev->hw->channels + dev->hw->nr_channels;
+		      hwchan++ ) {
+			if ( hwchan->center_freq == chan->center_freq ) {
+				ok = 1;
+				break;
+			}
+		}
+
+		if ( ! ok )
+			delta++;
+		else {
+			chan->hw_value = hwchan->hw_value;
+			if ( hwchan->maxpower != 0 &&
+			     chan->maxpower > hwchan->maxpower )
+				chan->maxpower = hwchan->maxpower;
+			if ( old_freq == chan->center_freq )
+				dev->channel = i - delta;
+			if ( delta )
+				chan[-delta] = *chan;
+		}
+	}
+
+	dev->nr_channels -= delta;
+
+	if ( dev->channels[dev->channel].center_freq != old_freq )
+		dev->op->config ( dev, NET80211_CFG_CHANNEL );
+}
+
+/**
  * Update 802.11 device state to reflect received capabilities field
  *
  * @v dev	802.11 device
@@ -981,6 +1040,7 @@ static int net80211_process_ie ( struct net80211_device *dev,
 	int have_rates = 0, i;
 	int ds_channel = 0;
 	int changed = 0;
+	int band = dev->channels[dev->channel].band;
 
 	if ( ( void * ) ie >= ie_end )
 		return 0;
@@ -1042,6 +1102,7 @@ static int net80211_process_ie ( struct net80211_device *dev,
 							t->band.max_txpower );
 				}
 			}
+			net80211_filter_hw_channels ( dev );
 			break;
 
 		case IEEE80211_IE_ERP_INFO:
@@ -1067,9 +1128,8 @@ static int net80211_process_ie ( struct net80211_device *dev,
 		dev->rate = 0;
 		for ( i = 0; i < dev->nr_rates; i++ ) {
 			int ok = 0;
-			for ( j = 0; j < dev->hw->nr_supported_rates; j++ ) {
-				if ( dev->hw->supported_rates[j] ==
-				     dev->rates[i] ) {
+			for ( j = 0; j < dev->hw->nr_rates[band]; j++ ) {
+				if ( dev->hw->rates[band][j] == dev->rates[i] ){
 					ok = 1;
 					break;
 				}
@@ -1597,7 +1657,7 @@ static void net80211_step_associate ( struct process *proc )
 			int band = dev->hw->bands;
 
 			if ( active )
-				band &= ~NET80211_BAND_5GHZ;
+				band &= ~NET80211_BAND_BIT_5GHZ;
 
 			rc = net80211_prepare_probe ( dev, band, active );
 			if ( rc )
@@ -1916,7 +1976,7 @@ int net80211_prepare_probe ( struct net80211_device *dev, int band,
 {
 	assert ( dev->netdev->state & NETDEV_OPEN );
 
-	if ( active && band != NET80211_BAND_2GHZ ) {
+	if ( active && ( band & NET80211_BAND_BIT_5GHZ ) ) {
 		DBGC ( dev, "802.11 %p cannot perform active scanning on "
 		       "5GHz band\n", dev );
 		return -EINVAL_ACTIVE_SCAN;
@@ -1935,22 +1995,24 @@ int net80211_prepare_probe ( struct net80211_device *dev, int band,
 	if ( active )
 		net80211_add_channels ( dev, 1, 11, NET80211_REG_TXPOWER );
 	else {
-		if ( band & NET80211_BAND_2GHZ )
+		if ( band & NET80211_BAND_BIT_2GHZ )
 			net80211_add_channels ( dev, 1, 14,
 						NET80211_REG_TXPOWER );
-		if ( band & NET80211_BAND_5GHZ )
+		if ( band & NET80211_BAND_BIT_5GHZ )
 			net80211_add_channels ( dev, 36, 8,
 						NET80211_REG_TXPOWER );
 	}
 
+	net80211_filter_hw_channels ( dev );
+
 	/* Use channel 1 for now */
 	dev->channel = 0;
 	dev->op->config ( dev, NET80211_CFG_CHANNEL );
 
-	/* Always do active probes at 1Mbps */
+	/* Always do active probes at lowest (presumably first) speed */
 	dev->rate = 0;
 	dev->nr_rates = 1;
-	dev->rates[0] = 10;
+	dev->rates[0] = dev->hw->rates[dev->channels[0].band][0];
 	dev->op->config ( dev, NET80211_CFG_RATE );
 
 	return 0;