net:nfc:digital: Fix a double free in digital_tg_recv_dep_req

In digital_tg_recv_dep_req, it calls nfc_tm_data_received(..,resp).
If nfc_tm_data_received() failed, the callee will free the resp via
kfree_skb() and return error. But in the exit branch, the resp
will be freed again.

My patch sets resp to NULL if nfc_tm_data_received() failed, to
avoid the double free.

Fixes: 1c7a4c24fbfd9 ("NFC Digital: Add target NFC-DEP support")
Signed-off-by: Lv Yunlong <lyl2019@mail.ustc.edu.cn>
Signed-off-by: David S. Miller <davem@davemloft.net>

net: nfc: Fix spelling errors in net/nfc module

These patches fix a series of spelling errors in net/nfc module.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Zheng Yongjun <zhengyongjun3@huawei.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

NFC: digital: Remove two unused macroes

DIGITAL_NFC_DEP_REQ_RES_TAILROOM is never used after it was introduced.
DIGITAL_NFC_DEP_REQ_RES_HEADROOM is no more used after below
commit e8e7f4217564 ("NFC: digital: Remove useless call to skb_reserve()")
Remove them.

Reported-by: Hulk Robot <hulkci@huawei.com>
Signed-off-by: Wang Hai <wanghai38@huawei.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

NFC: digital: Replace zero-length array with flexible-array member

The current codebase makes use of the zero-length array language
extension to the C90 standard, but the preferred mechanism to declare
variable-length types such as these ones is a flexible array member[1][2],
introduced in C99:

struct foo {
int stuff;
struct boo array[];
};

By making use of the mechanism above, we will get a compiler warning
in case the flexible array does not occur last in the structure, which
will help us prevent some kind of undefined behavior bugs from being
inadvertently introduced[3] to the codebase from now on.

Also, notice that, dynamic memory allocations won't be affected by
this change:

"Flexible array members have incomplete type, and so the sizeof operator
may not be applied. As a quirk of the original implementation of
zero-length arrays, sizeof evaluates to zero."[1]

This issue was found with the help of Coccinelle.

[1] https://gcc.gnu.org/onlinedocs/gcc/Zero-Length.html
[2] https://github.com/KSPP/linux/issues/21
[3] commit 76497732932f ("cxgb3/l2t: Fix undefined behaviour")

Signed-off-by: Gustavo A. R. Silva <gustavo@embeddedor.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 288

Based on 1 normalized pattern(s):

this program is free software you can redistribute it and or modify
it under the terms and conditions of the gnu general public license
version 2 as published by the free software foundation this program
is distributed in the hope it will be useful but without any
warranty without even the implied warranty of merchantability or
fitness for a particular purpose see the gnu general public license
for more details

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 263 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190529141901.208660670@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

NFC: digital: NFC-DEP Target WT(nfcdep,max) is now 14

Version 1.1 of the NFC Forum's NFC Digital Protocol Technical
Specification dated 2014-07-14 specifies that the NFC-DEP Protocol's
Target WT(nfcdep,max) value is 14. In version 1.0 it was 8 so change
the value in the Linux NFC-DEP Protocol code accordingly.

Signed-off-by: Mark Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

networking: add and use skb_put_u8()

Joe and Bjørn suggested that it'd be nicer to not have the
cast in the fairly common case of doing
*(u8 *)skb_put(skb, 1) = c;

Add skb_put_u8() for this case, and use it across the code,
using the following spatch:

@@
expression SKB, C, S;
typedef u8;
identifier fn = {skb_put};
fresh identifier fn2 = fn ## "_u8";
@@
- *(u8 *)fn(SKB, S) = C;
+ fn2(SKB, C);

Note that due to the "S", the spatch isn't perfect, it should
have checked that S is 1, but there's also places that use a
sizeof expression like sizeof(var) or sizeof(u8) etc. Turns
out that nobody ever did something like
*(u8 *)skb_put(skb, 2) = c;

which would be wrong anyway since the second byte wouldn't be
initialized.

Suggested-by: Joe Perches <joe@perches.com>
Suggested-by: Bjørn Mork <bjorn@mork.no>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

networking: make skb_push & __skb_push return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions return void * and remove all the casts across
the tree, adding a (u8 *) cast only where the unsigned char pointer
was used directly, all done with the following spatch:

@@
expression SKB, LEN;
typedef u8;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
@@
- *(fn(SKB, LEN))
+ *(u8 *)fn(SKB, LEN)

@@
expression E, SKB, LEN;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
type T;
@@
- E = ((T *)(fn(SKB, LEN)))
+ E = fn(SKB, LEN)

@@
expression SKB, LEN;
identifier fn = { skb_push, __skb_push, skb_push_rcsum };
@@
- fn(SKB, LEN)[0]
+ *(u8 *)fn(SKB, LEN)

Note that the last part there converts from push(...)[0] to the
more idiomatic *(u8 *)push(...).

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

networking: make skb_put & friends return void pointers

It seems like a historic accident that these return unsigned char *,
and in many places that means casts are required, more often than not.

Make these functions (skb_put, __skb_put and pskb_put) return void *
and remove all the casts across the tree, adding a (u8 *) cast only
where the unsigned char pointer was used directly, all done with the
following spatch:

@@
expression SKB, LEN;
typedef u8;
identifier fn = { skb_put, __skb_put };
@@
- *(fn(SKB, LEN))
+ *(u8 *)fn(SKB, LEN)

@@
expression E, SKB, LEN;
identifier fn = { skb_put, __skb_put };
type T;
@@
- E = ((T *)(fn(SKB, LEN)))
+ E = fn(SKB, LEN)

which actually doesn't cover pskb_put since there are only three
users overall.

A handful of stragglers were converted manually, notably a macro in
drivers/isdn/i4l/isdn_bsdcomp.c and, oddly enough, one of the many
instances in net/bluetooth/hci_sock.c. In the former file, I also
had to fix one whitespace problem spatch introduced.

Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

networking: introduce and use skb_put_data()

A common pattern with skb_put() is to just want to memcpy()
some data into the new space, introduce skb_put_data() for
this.

An spatch similar to the one for skb_put_zero() converts many
of the places using it:

@@
identifier p, p2;
expression len, skb, data;
type t, t2;
@@
(
-p = skb_put(skb, len);
+p = skb_put_data(skb, data, len);
|
-p = (t)skb_put(skb, len);
+p = skb_put_data(skb, data, len);
)
(
p2 = (t2)p;
-memcpy(p2, data, len);
|
-memcpy(p, data, len);
)

@@
type t, t2;
identifier p, p2;
expression skb, data;
@@
t *p;
...
(
-p = skb_put(skb, sizeof(t));
+p = skb_put_data(skb, data, sizeof(t));
|
-p = (t *)skb_put(skb, sizeof(t));
+p = skb_put_data(skb, data, sizeof(t));
)
(
p2 = (t2)p;
-memcpy(p2, data, sizeof(*p));
|
-memcpy(p, data, sizeof(*p));
)

@@
expression skb, len, data;
@@
-memcpy(skb_put(skb, len), data, len);
+skb_put_data(skb, data, len);

(again, manually post-processed to retain some comments)

Reviewed-by: Stephen Hemminger <stephen@networkplumber.org>
Signed-off-by: Johannes Berg <johannes.berg@intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

NFC: digital: Fix RTOX supervisor PDU handling

When the target needs more time to process the received PDU, it sends
Response Timeout Extension (RTOX) PDU.

When the initiator receives a RTOX PDU, it must reply with a RTOX PDU
and extends the current rwt value with the formula:
rwt_int = rwt * rtox

This patch takes care of the rtox value passed by the target in the RTOX
PDU and extends the timeout for the next response accordingly.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add support for NFC DEP Response Waiting Time

When sending an ATR_REQ, the initiator must wait for the ATR_RES at
least 'RWT(nfcdep,activation) + dRWT(nfcdep)' and no more than
'RWT(nfcdep,activation) + dRWT(nfcdep) + dT(nfcdep,initiator)'. This
gives a timeout value between 1237 ms and 1337 ms. This patch defines
DIGITAL_ATR_RES_RWT to 1337 used for the timeout value of ATR_REQ
command.

For other DEP PDUs, the initiator must wait between 'RWT + dRWT(nfcdep)'
and 'RWT + dRWT(nfcdep) + dT(nfcdep,initiator)' where RWT is given by
the following formula: '(256 * 16 / f(c)) * 2^wt' where wt is the value
of the TO field in the ATR_RES response and is in the range between 0
and 14. This patch declares a mapping table for wt values and gives RWT
max values between 100 ms and 5049 ms.

This patch also defines DIGITAL_ATR_RES_TO_WT, the maximum wt value in
target mode, to 8.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Free supervisor PDUs

This patch frees the RTOX resp sk_buff in initiator mode. It also makes
use of the free_resp exit point for ATN supervisor PDUs in both
initiator and target mode.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Rework ACK PDU handling in initiator mode

With this patch, ACK PDU sk_buffs are now freed and code has been
refactored for better errors handling.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Fix ACK & NACK PDUs handling in target mode

When the target receives a NACK PDU, it re-sends the last sent PDU.

ACK PDUs are received by the target as a reply from the initiator to
chained I-PDUs. There are 3 cases to handle:
- If the target has previously received 1 or more ATN PDUs and the PNI
in the ACK PDU is equal to the target PNI - 1, then it means that the
initiator did not received the last issued PDU from the target. In
this case it re-sends this PDU.
- If the target has received 1 or more ATN PDUs but the ACK PNI is not
the target PNI - 1, then this means that this ACK is the reply of the
previous chained I-PDU sent by the target. The target did not received
it on the first attempt and it is being re-sent by the initiator. The
process continues as usual.
- No ATN PDU received before this ACK PDU. This is the reply of a
chained I-PDU. The target keeps on processing its chained I-PDU.

The code has been refactored to avoid too many indentation levels.

Also, ACK and NACK PDUs were not freed. This is now fixed.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Fix target DEP_REQ I-PDU handling after ATN PDU

When the initiator sends a DEP_REQ I-PDU, the target device may not
reply in a timely manner. In this case the initiator device must send an
attention PDU (ATN) and if the recipient replies with an ATN PDU in
return, then the last I-PDU must be sent again by the initiator.

This patch fixes how the target handles I-PDU received after an ATN PDU
has been received.

There are 2 possible cases:
- The target has received the initial DEP_REQ and sends back the DEP_RES
but the initiator did not receive it. In this case, after the
initiator has sent an ATN PDU and the target replied it (with an ATN
as well), the initiator sends the saved skb of the initial DEP_REQ
again and the target replies with the saved skb of the initial
DEP_RES.
- Or the target did not even received the initial DEP_REQ. In this case,
after the ATN PDUs exchange, the initiator sends the saved skb and the
target simply passes it up, just as usual.

This behavior is controlled using the atn_count and the PNI field of the
digital device structure.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Remove useless call to skb_reserve()

When allocating chained I-PDUs, there is no need to call skb_reserve()
since it's already done by digital_alloc_skb() and contains enough room
for the driver head and tail data.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Fix handling of saved PDU sk_buff pointers

This patch fixes the way an I-PDU is saved in case it needs to be sent
again. It is now copied using pskb_copy() and not simply referenced
using skb_get() since it could be modified by the driver.

digital_in_send_saved_skb() and digital_tg_send_saved_skb() still get a
reference on the saved skb which is re-sent but release it if the send
operation fails. That way the caller doesn't have to take care about skb
ref in case of error.

RTOX supervisor PDU must not be saved as this can override a previously
saved I-PDU that should be re-sent later on.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Rework error handling in DEP_RES response

The Digital Protocol stack used to send a NACK frame whatever the error
type it receives in digital_in_recv_dep_res(). It actually should only
send a NACK frame on CRC or parity check errors or on any transmission
error if a NACK frame was previously sent. Existing drivers used to send
EIO error for this kind of issues so this patch limits sending of NACK
frames on EIO errors. All other errors will be reported to the upper
layers.

Signed-off-by: Thierry Escande <thierry.escande@collabora.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add NFC-DEP Target-side ATN Support

When an NFC-DEP target receives an ATN PDU, its
supposed to respond with a similar ATN PDU.
When the Target receives an I PDU with the PNI
one less than the current PNI and the last PDU
sent was an ATN PDU, the Target is to resend the
last non-ATN PDU that it has sent. This is
described in section 14.12.3.4 of the NFC Digital
Protocol Spec.

The digital layer's NFC-DEP code doesn't implement
this so add that support.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add NFC-DEP Initiator-side ATN Support

When an NFC-DEP Initiator times out when waiting for
a DEP_RES from the Target, its supposed to send an
ATN to the Target. The Target should respond to the
ATN with a similar ATN PDU and the Initiator can then
resend the last non-ATN PDU that it sent. No more
than 'N(retry,atn)' are to be send where
2 <= 'N(retry,atn)' <= 5. If the Initiator had just
sent a NACK PDU when the timeout occurred, it is to
continue sending NACKs until 'N(retry,nack)' NACKs
have been send. This is described in section
14.12.5.6 of the NFC-DEP Digital Protocol Spec.

The digital layer's NFC-DEP code doesn't implement
this so add that support.

The value chosen for 'N(retry,atn)' is 2.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add NFC-DEP Target-side NACK Support

When an NFC-DEP Target receives a NACK PDU with
a PNI equal to 1 less than the current PNI, it
is supposed to re-send the last PDU. This is
implied in section 14.12.5.4 of the NFC Digital
Protocol Spec.

The digital layer's NFC-DEP code doesn't implement
Target-side NACK handing so add it. The last PDU
that was sent is saved in the 'nfc_digital_dev'
structure's 'saved_skb' member. The skb will have
an additional reference taken to ensure that the skb
isn't freed when the driver performs a kfree_skb()
on the skb. The length of the skb/PDU is also saved
so the length can be restored when re-sending the PDU
in the skb (the driver will perform an skb_pull() so
an skb_push() needs to be done to restore the skb's
data pointer/length).

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add NFC-DEP Initiator-side NACK Support

When an NFC-DEP Initiator receives a frame with
an incorrect CRC or with a parity error, and the
frame is at least 4 bytes long, its supposed to
send a NACK to the Target. The Initiator can
send up to 'N(retry,nack)' consecutive NACKs
where 2 <= 'N(retry,nack)' <= 5. When the limit
is exceeded, a PROTOCOL EXCEPTION is raised.
Any other type of transmission error is to be
ignored and the Initiator should continue
waiting for a new frame. This is described
in section 14.12.5.4 of the NFC Digital Protocol
Spec.

The digital layer's NFC-DEP code doesn't implement
any of this so add it. This support diverges from
the spec in two significant ways:

a) NACKs will be sent for ANY error reported by the
driver except a timeout. This is done because
there is currently no way for the digital layer
to distinguish a CRC or parity error from any
other type of error reported by the driver.

b) All other errors will cause a PROTOCOL EXCEPTION
even frames with CRC errors that are less than 4
bytes.

The value chosen for 'N(retry,nack)' is 2.

Targets do not send NACK PDUs.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add NFC-DEP Receive Chaining Support

When the peer in an NFC-DEP exchange has a
packet to send that is larger than the local
maximum payload, it sets the 'MI' bit in the
'I' PDU. This indicates that NFC-DEP chaining
is to occur.

When such a PDU is received, the local side
responds with an 'ACK' PDU and this continues
until the peer sends an 'I' PDU with the 'MI'
bit cleared. This indicates that the chaining
sequence is complete and the entire packet has
been transferred.

Receiving chained PDUs is currently not supported
by the digital layer so add that support. When a
chaining sequence is initiated by the peer, the
digital layer will allocate an skb large enough
to hold 8 maximum sized frame payloads. The maximum
payload can range from 64 to 254 bytes so 8 * 254 =
2032 seems like a reasonable compromise between
potentially wasting memory and constantly reallocating
new, larger skbs.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add NFC-DEP Send Chaining Support

When the NFC-DEP code is given a packet to send
that is larger than the peer's maximum payload,
its supposed to set the 'MI' bit in the 'I' PDU's
Protocol Frame Byte (PFB). Setting this bit
indicates that NFC-DEP chaining is to occur.

When NFC-DEP chaining is progress, sender 'I' PDUs
are acknowledged with 'ACK' PDUs until the last 'I'
PDU in the chain (which has the 'MI' bit cleared)
is responded to with a normal 'I' PDU. This can
occur while in Initiator mode or in Target mode.

Sender NFC-DEP chaining is currently not implemented
in the digital layer so add that support. Unfortunately,
since sending a frame may require writing the CRC to the
end of the data, the relevant data part of the original
skb must be copied for each intermediate frame.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Implement NFC-DEP max payload lengths

The maximum payload for NFC-DEP exchanges (i.e., the
number of bytes between SoD and EoD) is negotiated
using the ATR_REQ, ATR_RES, and PSL_REQ commands.
The valid maximum lengths are 64, 128, 192, and 254
bytes.

Currently, NFC-DEP code assumes that both sides are
always using 254 byte maximums and ignores attempts
by the peer to change it. Instead, implement the
negotiation code, enforce the local maximum when
receiving data from the peer, and don't send payloads
that exceed the remote's maximum. The default local
maximum is 254 bytes.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Enforce NFC-DEP PNI sequencing

NFC-DEP DEP_REQ and DEP_RES exchanges using 'I'
and 'ACK/NACK' PDUs have a sequence number called
the Packet Number Information (PNI). The PNI
is incremented (modulo 4) after every DEP_REQ/
DEP_RES pair and should be verified by the digital
layer code. That verification isn't always done,
though, so add code to make sure that it is done.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Ensure no NAD byte in DEP_REQ and DEP_RES frames

According to chapter 14 of the NFC-DEP Digital
Protocol Spec., the NAD byte should never be
present in DEP_REQ or DEP_RES frames. However,
this is not enforced so add that enforcement code.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add Target-mode NFC-DEP DID Support

When in Target mode, the Initiator specifies whether
subsequent DEP_REQ and DEP_RES frames will include
a DID byte by the value passed in the ATR_REQ. If
the DID value in the ATR_REQ is '0' then no DID
byte will be included. If the DID value is between
'1' and '14' then a DID byte containing the same
value must be included in subsequent DEP_REQ and
DEP_RES frames. Any other DID value is invalid.
This is specified in sections 14.8.1.2 and 14.8.2.2
of the NFC Digital Protocol Spec.

Checking the DID value (if it should be there at all),
is not currently supported by the digital layer's
NFC-DEP code. Add this support by remembering the
DID value in the ATR_REQ, checking the DID value of
received DEP_REQ frames (if it should be there at all),
and including the remembered DID value in DEP_RES
frames when appropriate.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Ensure no DID in NFC-DEP responses

When in Initiator mode, the digital layer's
NFC-DEP code always sets the Device ID (DID)
value in the ATR_REQ to '0'. This means that
subsequent DEP_REQ and DEP_RES frames must
never include a DID byte. This is specified
in sections 14.8.1.1 and 14.8.2.1 of the NFC
Digital Protocol Spec.

Currently, the digital layer's NFC-DEP code
doesn't enforce this rule so add code to ensure
that there is no DID byte in DEP_RES frames.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Rearrange NFC-DEP DEP_REQ/DEP_RES Code

Rearrange some of the code in digital_in_recv_dep_res()
and digital_tg_recv_dep_req() so the initial code looks
similar. The real reason is prepare the code for some
upcoming patches that require these changes.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Fix potential skb leaks in NFC-DEP code

When digital_in_send_cmd() or digital_tg_send_cmd()
fail, they do not free the skb that was passed to
them so the routine that allocated the skb should
free it. Currently, there are several routines in
the NFC-DEP code that don't do this so make them.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Add Inititor-side PSL support

In order to operate at the fasted bit rate
possible, add initiator-side support for
PSL REQ while in P2P mode. The PSL REQ
will switch the RF technology to 424F
whenever possible.

Reviewed-by: Thierry Escande <thierry.escande@linux.intel.com>
Tested-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Clear poll_tech_count before activating target

Currently, digital_target_found() has a race between
the events started by calling nfc_targets_found()
(which ultimately expect ddev->poll_tech_count to be
zero) and setting ddev->poll_tech_count to zero after
the call to nfc_targets_found(). When the race is
"lost" (i.e., ddev->poll_tech_count is found to not
be zero by the events started by nfc_targets_found()),
an error message is printed and the target is not found.
A similar race exists when digital_tg_recv_atr_req()
calls nfc_tm_activated().

Fix this by first saving the current value of
ddev->poll_tech_count and then clearing it before
calling nfc_targets_found()/nfc_tm_activated().
Clearing ddev->poll_tech_count before calling
nfc_targets_found()/nfc_tm_activated() eliminates
the race. Saving the value is required so it can be
restored when nfc_targets_found()/nfc_tm_activated()
fails and polling needs to continue.

Acked-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Mark A. Greer <mgreer@animalcreek.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: remove unnecessary break after goto

Signed-off-by: Fabian Frederick <fabf@skynet.be>
Signed-off-by: David S. Miller <davem@davemloft.net>

NFC: digital: Return proper error code when sending ATR_REQ

The error code returned by digital_in_send_cmd() was not returned by
digital_in_send_atr_req().

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Set rf tech and crc functions when receiving a PSL_REQ

This patch sets the correct rf tech value and crc functions in target
mode when receiving a PSL_REQ, as done when receiving an ATR_REQ.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Set current target active on activate_target() call

The curr_protocol field of nfc_digital_dev structure used to determine
if a target is currently active was set too soon, immediately when a
target is found. This is not good since there is no other way than
deactivate_target() to reset curr_protocol and if activate_target() is
not called, the target remains active and it's not possible to put the
device in poll mode anymore.

With this patch curr_protocol is set when nfc core activates a target,
puts a device up, or when an ATR_REQ is received in target mode.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Use NFC_NFCID3_MAXSIZE from nfc.h

This removes the declaration of NFCID3 size in digital_dep.c and now
uses the one from nfc.h.

This also removes a faulty and unneeded call to max().

Reported-by: Dan Carpenter <dan.carpenter@oracle.com>
Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: digital: Fix incorrect use of ERR_PTR and PTR_ERR macros

It's bad to use these macros when not dealing with error code. this
patch changes calls to these macros with correct casts.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

treewide: Fix typos in printk

Correct spelling typo in various part of kernel

Signed-off-by: Masanari Iida <standby24x7@gmail.com>
Acked-by: Randy Dunlap <rdunlap@infradead.org>
Signed-off-by: Jiri Kosina <jkosina@suse.cz>

NFC: digital: Add newline to pr_* calls

We do not add the newline to the pr_fmt macro, in order to give more
flexibility to the caller and to keep the logging style consistent with
the rest of the NFC and kernel code.

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

NFC: digital: Remove PR_ERR and PR_DBG macros

They can be replaced by the standard pr_err and pr_debug one after
defining the right pr_fmt macro.

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

NFC Digital: Add target NFC-DEP support

This adds support for NFC-DEP target mode for NFC-A and NFC-F
technologies.

If the driver provides it, the stack uses an automatic mode for
technology detection and automatic anti-collision. Otherwise the stack
tries to use non-automatic synchronization and listens for SENS_REQ and
SENSF_REQ commands.

The detection, activation, and data exchange procedures work exactly
the same way as in initiator mode, as described in the previous
commits, except that the digital stack waits for commands and sends
responses back to the peer device.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC Digital: Add initiator NFC-DEP support

This adds support for NFC-DEP protocol in initiator mode for NFC-A and
NFC-F technologies.

When a target is detected, the process flow is as follow:

For NFC-A technology:
1 - The digital stack receives a SEL_RES as the reply of the SEL_REQ
command.
2 - If b7 of SEL_RES is set, the peer device is configure for NFC-DEP
protocol. NFC core is notified through nfc_targets_found().
Execution continues at step 4.
3 - Otherwise, it's a tag and the NFC core is notified. Detection
ends.
4 - The digital stacks sends an ATR_REQ command containing a randomly
generated NFCID3 and the general bytes obtained from the LLCP layer
of NFC core.

For NFC-F technology:
1 - The digital stack receives a SENSF_RES as the reply of the
SENSF_REQ command.
2 - If B1 and B2 of NFCID2 are 0x01 and 0xFE respectively, the peer
device is configured for NFC-DEP protocol. NFC core is notified
through nfc_targets_found(). Execution continues at step 4.
3 - Otherwise it's a type 3 tag. NFC core is notified. Detection
ends.
4 - The digital stacks sends an ATR_REQ command containing the NFC-F
NFCID2 as NFCID3 and the general bytes obtained from the LLCP layer
of NFC core.

For both technologies:
5 - The digital stacks receives the ATR_RES response containing the
NFCID3 and the general bytes of the peer device.
6 - The digital stack notifies NFC core that the DEP link is up through
nfc_dep_link_up().
7 - The NFC core performs data exchange through tm_transceive().
8 - The digital stack sends a DEP_REQ command containing an I PDU with
the data from NFC core.
9 - The digital stack receives a DEP_RES command
10 - If the DEP_RES response contains a supervisor PDU with timeout
extension request (RTOX) the digital stack sends a DEP_REQ
command containing a supervisor PDU acknowledging the RTOX
request. The execution continues at step 9.
11 - If the DEP_RES response contains an I PDU, the response data is
passed back to NFC core through the response callback. The
execution continues at step 8.

Signed-off-by: Thierry Escande <thierry.escande@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>