Hi Mat,
> 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 <mathewm@xxxxxxxxxxxxxx>
> ---
> 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 cf1dc4e..dbcd1e3 100644
> --- a/net/bluetooth/l2cap_core.c
> +++ b/net/bluetooth/l2cap_core.c
> @@ -2965,6 +2965,44 @@ 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_u64(ertm_to + 999, 1000);
don't we have a proper ROUND function for this?
> +
> + /* 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 &&
> @@ -3031,8 +3069,8 @@ 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 -
> @@ -3260,10 +3298,7 @@ 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);
>
Otherwise, looks good.
Acked-by: Marcel Holtmann <marcel@xxxxxxxxxxxx>
Regards
Marcel
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