netlink_register_notifier requires notify functions to not sleep.
nfc_stop_poll locks device mutex and must not be called from notifier.
Create workqueue that will handle this for all devices.

BUG: sleeping function called from invalid context at kernel/mutex.c:269
in_atomic(): 0, irqs_disabled(): 0, pid: 4497, name: neard
1 lock held by neard/4497:
Pid: 4497, comm: neard Not tainted 3.5.0-999-nfc+ #5
Call Trace:
[<ffffffff810952c5>] __might_sleep+0x145/0x200
[<ffffffff81743dde>] mutex_lock_nested+0x2e/0x50
[<ffffffff816ffd19>] nfc_stop_poll+0x39/0xb0
[<ffffffff81700a17>] nfc_genl_rcv_nl_event+0x77/0xc0
[<ffffffff8174aa8c>] notifier_call_chain+0x5c/0x120
[<ffffffff8174abd6>] __atomic_notifier_call_chain+0x86/0x140
[<ffffffff8174ab50>] ? notifier_call_chain+0x120/0x120
[<ffffffff815e1347>] ? skb_dequeue+0x67/0x90
[<ffffffff8174aca6>] atomic_notifier_call_chain+0x16/0x20
[<ffffffff8162119a>] netlink_release+0x24a/0x280
[<ffffffff815d7aa8>] sock_release+0x28/0xa0
[<ffffffff815d7be7>] sock_close+0x17/0x30
[<ffffffff811b2a7c>] __fput+0xcc/0x250
[<ffffffff811b2c0e>] ____fput+0xe/0x10
[<ffffffff81085009>] task_work_run+0x69/0x90
[<ffffffff8101b951>] do_notify_resume+0x81/0xd0
[<ffffffff8174ef22>] int_signal+0x12/0x17
Signed-off-by: NSzymon Janc <szymon.janc@tieto.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

It is a frequent mistake to confuse the netlink port identifier with a
process identifier.  Try to reduce this confusion by renaming fields
that hold port identifiers portid instead of pid.

I have carefully avoided changing the structures exported to
userspace to avoid changing the userspace API.

I have successfully built an allyesconfig kernel with this change.
Signed-off-by: N"Eric W. Biederman" <ebiederm@xmission.com>
Acked-by: NStephen Hemminger <shemminger@vyatta.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

We check for the polling flag before checking if the netlink PID caller
match.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

Using NLMSG_GOODSIZE results in multiple pages being used as
nlmsg_new() will automatically add the size of the netlink
header to the payload thus exceeding the page limit.

NLMSG_DEFAULT_SIZE takes this into account.
Signed-off-by: NThomas Graf <tgraf@suug.ch>
Cc: Jiri Pirko <jpirko@redhat.com>
Cc: Dmitry Eremin-Solenikov <dbaryshkov@gmail.com>
Cc: Sergey Lapin <slapin@ossfans.org>
Cc: Johannes Berg <johannes@sipsolutions.net>
Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Cc: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Reviewed-by: NJiri Pirko <jpirko@redhat.com>
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

That is needed for keeping backward compatibility with apps using the old
netlink polling API (NFC_ATTR_PROTOCOLS instead of NFC_ATTR_IM_PROTOCOLS).
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

Userspace gets a netlink event upon target mode activation.
The LLCP layer is also signaled when we get an ATR_REQ in order to get
the remote general bytes.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>

The variable 'nfc_genl_family' is only referenced in this file and
should be marked static to prevent it from being exposed globally.

Quites the sparse warning:

warning: symbol 'nfc_genl_family' was not declared. Should it be static?
Signed-off-by: NH Hartley Sweeten <hsweeten@visionengravers.com>
Cc: Lauro Ramos Venancio <lauro.venancio@openbossa.org>
Cc: Aloisio Almeida Jr <aloisio.almeida@openbossa.org>
Cc: Samuel Ortiz <sameo@linux.intel.com>
Cc: "David S. Miller" <davem@davemloft.net>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

It is now specified that nfc_target_found() and nfc_target_lost() core
functions must not be called from an atomic context. This allow us to
serialize calls and protect the targets table using the nfc device lock
instead of a spinlock.
Signed-off-by: NEric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Some chips are capable of detecting when a tag is out of the field, so
they could send a netlink event about it to userspace.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

These macros contain a hidden goto, and are thus extremely error
prone and make code hard to audit.
Signed-off-by: NDavid S. Miller <davem@davemloft.net>

Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

When calling nfc_dep_link_up, we implicitely are in initiator mode.
Which means we also can provide the general bytes as a function argument,
as all drivers will eventually request them.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

For user space to know if a device is up or down.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Export new attributes sensb_res for tech B and sensf_res
for tech F in the target info (returned as a response to
NFC_CMD_GET_TARGET).
The max size of the attributes nfcid1, sensb_res and sensf_res
is exported to user space though include/linux/nfc.
Signed-off-by: NIlan Elias <ilane@ti.com>
Acked-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The nfcid1 is the NFC-A identifier.
It is exported as an attribute of the target info
(returned as a response to NFC_CMD_GET_TARGET).
Signed-off-by: NIlan Elias <ilane@ti.com>
Acked-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

NFC-DEP (Data Exchange Protocol) is an NFC MAC layer.
This command allows to enable and disable the DEP link on to which e.g.
LLCP can run.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The netlink notifier is atomic so we must not sleep in that context.
Also we know that Any netlink packets arriving to us will be purged when
the notifier is called, so we don't need to take the mutex.
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Logging messages that mimic function tracer enter/exit
aren't necessary.  Just remove them.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Using the standard debugging mechanisms is better than
subsystem specific ones when the subsystem doesn't use
a specific struct.

Coalesce long formats.
Signed-off-by: NJoe Perches <joe@perches.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

Add 2 new nfc control operations:
dev_up to turn on the nfc device
dev_down to turn off the nfc device
Signed-off-by: NIlan Elias <ilane@ti.com>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>

The NFC generic netlink interface exports the NFC control operations
to the user space.
Signed-off-by: NLauro Ramos Venancio <lauro.venancio@openbossa.org>
Signed-off-by: NAloisio Almeida Jr <aloisio.almeida@openbossa.org>
Signed-off-by: NSamuel Ortiz <sameo@linux.intel.com>
Reviewed-by: NJohannes Berg <johannes@sipsolutions.net>
Signed-off-by: NJohn W. Linville <linville@tuxdriver.com>