From 36c86c8566cec67924ae6f372d9066cc9e92ad0e Mon Sep 17 00:00:00 2001 From: Mat Martineau Date: Tue, 23 Oct 2012 15:24:20 -0700 Subject: [PATCH] Bluetooth: Configure appropriate timeouts for AMP controllers The L2CAP spec recommends specific retransmit and monitor timeouts for ERTM channels that are on AMP controllers. These timeouts are calculated from the AMP controller's best effort flush timeout. BR/EDR controllers use the default retransmit and monitor timeouts. Signed-off-by: Mat Martineau Acked-by: Marcel Holtmann Signed-off-by: Gustavo Padovan --- net/bluetooth/l2cap_core.c | 47 +++++++++++++++++++++++++++++++++----- 1 file changed, 41 insertions(+), 6 deletions(-) diff --git a/net/bluetooth/l2cap_core.c b/net/bluetooth/l2cap_core.c index 4eb3ca84de2f..6662ee34e754 100644 --- a/net/bluetooth/l2cap_core.c +++ b/net/bluetooth/l2cap_core.c @@ -2967,6 +2967,44 @@ static inline bool __l2cap_efs_supported(struct l2cap_chan *chan) return enable_hs && chan->conn->feat_mask & L2CAP_FEAT_EXT_FLOW; } +static void __l2cap_set_ertm_timeouts(struct l2cap_chan *chan, + struct l2cap_conf_rfc *rfc) +{ + if (chan->local_amp_id && chan->hs_hcon) { + u64 ertm_to = chan->hs_hcon->hdev->amp_be_flush_to; + + /* Class 1 devices have must have ERTM timeouts + * exceeding the Link Supervision Timeout. The + * default Link Supervision Timeout for AMP + * controllers is 10 seconds. + * + * Class 1 devices use 0xffffffff for their + * best-effort flush timeout, so the clamping logic + * will result in a timeout that meets the above + * requirement. ERTM timeouts are 16-bit values, so + * the maximum timeout is 65.535 seconds. + */ + + /* Convert timeout to milliseconds and round */ + ertm_to = DIV_ROUND_UP_ULL(ertm_to, 1000); + + /* This is the recommended formula for class 2 devices + * that start ERTM timers when packets are sent to the + * controller. + */ + ertm_to = 3 * ertm_to + 500; + + if (ertm_to > 0xffff) + ertm_to = 0xffff; + + rfc->retrans_timeout = cpu_to_le16((u16) ertm_to); + rfc->monitor_timeout = rfc->retrans_timeout; + } else { + rfc->retrans_timeout = __constant_cpu_to_le16(L2CAP_DEFAULT_RETRANS_TO); + rfc->monitor_timeout = __constant_cpu_to_le16(L2CAP_DEFAULT_MONITOR_TO); + } +} + static inline void l2cap_txwin_setup(struct l2cap_chan *chan) { if (chan->tx_win > L2CAP_DEFAULT_TX_WINDOW && @@ -3033,8 +3071,8 @@ done: case L2CAP_MODE_ERTM: rfc.mode = L2CAP_MODE_ERTM; rfc.max_transmit = chan->max_tx; - rfc.retrans_timeout = 0; - rfc.monitor_timeout = 0; + + __l2cap_set_ertm_timeouts(chan, &rfc); size = min_t(u16, L2CAP_DEFAULT_MAX_PDU_SIZE, chan->conn->mtu - L2CAP_EXT_HDR_SIZE - L2CAP_SDULEN_SIZE - @@ -3262,10 +3300,7 @@ done: rfc.max_pdu_size = cpu_to_le16(size); chan->remote_mps = size; - rfc.retrans_timeout = - __constant_cpu_to_le16(L2CAP_DEFAULT_RETRANS_TO); - rfc.monitor_timeout = - __constant_cpu_to_le16(L2CAP_DEFAULT_MONITOR_TO); + __l2cap_set_ertm_timeouts(chan, &rfc); set_bit(CONF_MODE_DONE, &chan->conf_state);