Bluetooth: Add BT_POWER L2CAP socket option.

Add BT_POWER socket option used to control the power
characteristics of the underlying ACL link. When the remote end
has put the link in sniff mode and the host stack wants to send
data we need need to explicitly exit sniff mode to work well with
certain devices (For example, A2DP on Plantronics Voyager 855).
However, this causes problems with HID devices.

Hence, moving into active mode when sending data, irrespective
of who set the sniff mode has been made as a socket option. By
default, we will move into active mode. HID devices can set the
L2CAP socket option to prevent this from happening.

Currently, this has been implemented for L2CAP sockets. This has been
tested with incoming and outgoing L2CAP sockets for HID and A2DP.

Based on discussions on linux-bluetooth and patches submitted by
Andrei Emeltchenko.

Signed-off-by: Jaikumar Ganesh <jaikumar@google.com>
Signed-off-by: Gustavo F. Padovan <padovan@profusion.mobi>

1 files changed, 36 insertions, 0 deletions

diff --git a/net/bluetooth/l2cap_sock.c b/net/bluetooth/l2cap_sock.c
index b79fb7561836..bec3e043b254 100644
--- a/net/bluetooth/l2cap_sock.c
+++ b/net/bluetooth/l2cap_sock.c
@@ -390,6 +390,7 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname, ch
         struct sock *sk = sock->sk;
         struct l2cap_chan *chan = l2cap_pi(sk)->chan;
         struct bt_security sec;
+        struct bt_power pwr;
         int len, err = 0;
 
         BT_DBG("sk %p", sk);
@@ -438,6 +439,21 @@ static int l2cap_sock_getsockopt(struct socket *sock, int level, int optname, ch
 
                 break;
 
+        case BT_POWER:
+                if (sk->sk_type != SOCK_SEQPACKET && sk->sk_type != SOCK_STREAM
+                                && sk->sk_type != SOCK_RAW) {
+                        err = -EINVAL;
+                        break;
+                }
+
+                pwr.force_active = chan->force_active;
+
+                len = min_t(unsigned int, len, sizeof(pwr));
+                if (copy_to_user(optval, (char *) &pwr, len))
+                        err = -EFAULT;
+
+                break;
+
         default:
                 err = -ENOPROTOOPT;
                 break;
@@ -538,6 +554,7 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, ch
         struct sock *sk = sock->sk;
         struct l2cap_chan *chan = l2cap_pi(sk)->chan;
         struct bt_security sec;
+        struct bt_power pwr;
         int len, err = 0;
         u32 opt;
 
@@ -614,6 +631,23 @@ static int l2cap_sock_setsockopt(struct socket *sock, int level, int optname, ch
                 chan->flushable = opt;
                 break;
 
+        case BT_POWER:
+                if (chan->chan_type != L2CAP_CHAN_CONN_ORIENTED &&
+                                        chan->chan_type != L2CAP_CHAN_RAW) {
+                        err = -EINVAL;
+                        break;
+                }
+
+                pwr.force_active = BT_POWER_FORCE_ACTIVE_ON;
+
+                len = min_t(unsigned int, sizeof(pwr), optlen);
+                if (copy_from_user((char *) &pwr, optval, len)) {
+                        err = -EFAULT;
+                        break;
+                }
+                chan->force_active = pwr.force_active;
+                break;
+
         default:
                 err = -ENOPROTOOPT;
                 break;
@@ -771,6 +805,7 @@ void l2cap_sock_init(struct sock *sk, struct sock *parent)
                 chan->role_switch = pchan->role_switch;
                 chan->force_reliable = pchan->force_reliable;
                 chan->flushable = pchan->flushable;
+                chan->force_active = pchan->force_active;
         } else {
 
                 switch (sk->sk_type) {
@@ -801,6 +836,7 @@ void l2cap_sock_init(struct sock *sk, struct sock *parent)
                 chan->role_switch = 0;
                 chan->force_reliable = 0;
                 chan->flushable = BT_FLUSHABLE_OFF;
+                chan->force_active = BT_POWER_FORCE_ACTIVE_ON;
         }
 
         /* Default config options */