net: fill in MODULE_DESCRIPTION()s for NFC

W=1 builds now warn if module is built without a MODULE_DESCRIPTION().
Add descriptions to all NFC Controller Interface (NCI) modules.

Signed-off-by: Breno Leitao <leitao@debian.org>
Reviewed-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Link: https://lore.kernel.org/r/20240108181610.2697017-5-leitao@debian.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

nfc: nci: fix possible NULL pointer dereference in send_acknowledge()

Handle memory allocation failure from nci_skb_alloc() (calling
alloc_skb()) to avoid possible NULL pointer dereference.

Reported-by: 黄思聪 <huangsicong@iie.ac.cn>
Fixes: 391d8a2da787 ("NFC: Add NCI over SPI receive")
Cc: <stable@vger.kernel.org>
Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@linaro.org>
Reviewed-by: Simon Horman <horms@kernel.org>
Link: https://lore.kernel.org/r/20231013184129.18738-1-krzysztof.kozlowski@linaro.org
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

nfc: nci: constify several pointers to u8, sk_buff and other structs

Several functions receive pointers to u8, sk_buff or other structs but
do not modify the contents so make them const. This allows doing the
same for local variables and in total makes the code a little bit safer.

This makes const also data passed as "unsigned long opt" argument to
nci_request() function. Usual flow for such functions is:
1. Receive "u8 *" and store it (the pointer) in a structure
allocated on stack (e.g. struct nci_set_config_param),
2. Call nci_request() or __nci_request() passing a callback function an
the pointer to the structure via an "unsigned long opt",
3. nci_request() calls the callback which dereferences "unsigned long
opt" in a read-only way.

This converts all above paths to use proper pointer to const data, so
entire flow is safer.

Signed-off-by: Krzysztof Kozlowski <krzysztof.kozlowski@canonical.com>
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

NFC: NCI: use new `delay` structure for SPI transfer delays

In a recent change to the SPI subsystem [1], a new `delay` struct was added
to replace the `delay_usecs`. This change replaces the current `delay_secs`
with `delay` for this driver.

The `spi_transfer_delay_exec()` function [in the SPI framework] makes sure
that both `delay_usecs` & `delay` are used (in this order to preserve
backwards compatibility).

[1] commit bebcfd272df6485 ("spi: introduce `delay` field for
`spi_transfer` + spi_transfer_delay_exec()")

Signed-off-by: Alexandru Ardelean <alexandru.ardelean@analog.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 335

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 you should have received a copy of the gnu general
public license along with this program if not write to the free
software foundation inc 51 franklin st fifth floor boston ma 02110
1301 usa

extracted by the scancode license scanner the SPDX license identifier

GPL-2.0-only

has been chosen to replace the boilerplate/reference in 111 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Alexios Zavras <alexios.zavras@intel.com>
Reviewed-by: Allison Randal <allison@lohutok.net>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190530000436.567572064@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

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>

NFC: NCI: allow spi driver to choose transfer clock

In some cases low level drivers might want to update the
SPI transfer clock (e.g. during firmware download).

This patch adds this support. Without any modification the
driver will use the default SPI clock (from pdata or device tree).

Signed-off-by: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: move generic spi driver to a module

SPI driver should be a module.

Signed-off-by: Vincent Cuissard <cuissard@marvell.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: Use reinit_completion() at appropriate places

Calling init_completion() once is enough.
Then use reinit_completion() instead in __nci_request() and nci_spi_send().

Signed-off-by: Axel Lin <axel.lin@ingics.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: Modify NCI SPI to implement CS/INT handshake per the spec

The NFC Forum NCI specification defines both a hardware and software
protocol when using a SPI physical transport to connect an NFC NCI
Chipset. The hardware requirement is that, after having raised the chip
select line, the SPI driver must wait for an INT line from the NFC
chipset to raise before it sends the data. The chip select must be
raised first though, because this is the signal that the NFC chipset
will detect to wake up and then raise its INT line. If the INT line
doesn't raise in a timely fashion, the SPI driver should abort
operation.

When data is transferred from Device host (DH) to NFC Controller (NFCC),
the signaling sequence is the following:

Data Transfer from DH to NFCC
• 1-Master asserts SPI_CSN
• 2-Slave asserts SPI_INT
• 3-Master sends NCI-over-SPI protocol header and payload data
• 4-Slave deasserts SPI_INT
• 5-Master deasserts SPI_CSN

When data must be transferred from NFCC to DH, things are a little bit
different.

Data Transfer from NFCC to DH
• 1-Slave asserts SPI_INT -> NFC chipset irq handler called -> process
reading from SPI
• 2-Master asserts SPI_CSN
• 3-Master send 2-octet NCI-over-SPI protocol header
• 4-Slave sends 2-octet NCI-over-SPI protocol payload length
• 5-Slave sends NCI-over-SPI protocol payload
• 6-Master deasserts SPI_CSN

In this case, SPI driver should function normally as it does today. Note
that the INT line can and will be lowered anytime between beginning of
step 3 and end of step 5. A low INT is therefore valid after chip select
has been raised.

This would be easily implemented in a single driver. Unfortunately, we
don't write the SPI driver and I had to imagine some workaround trick to
get the SPI and NFC drivers to work in a synchronized fashion. The trick
is the following:

- send an empty spi message: this will raise the chip select line, and
send nothing. We expect the /CS line will stay arisen because we asked
for it in the spi_transfer cs_change field
- wait for a completion, that will be completed by the NFC driver IRQ
handler when it knows we are in the process of sending data (NFC spec
says that we use SPI in a half duplex mode, so we are either sending or
receiving).
- when completed, proceed with the normal data send.

This has been tested and verified to work very consistently on a Nexus
10 (spi-s3c64xx driver). It may not work the same with other spi
drivers.

The previously defined nci_spi_ops{} whose intended purpose were to
address this problem are not used anymore and therefore totally removed.

The nci_spi_send() takes a new optional write_handshake_completion
completion pointer. If non NULL, the nci spi layer will run the above
trick when sending data to the NFC Chip. If NULL, the data is sent
normally all at once and it is then the NFC driver responsibility to
know what it's doing.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: nci_spi_recv_frame() now returns (not forward) the read frame

Previously, nci_spi_recv_frame() would directly transmit incoming frames
to the NCI Core. However, it turns out that some NFC NCI Chips will add
additional proprietary headers that must be handled/removed before NCI
Core gets a chance to handle the frame. With this modification, the chip
phy or driver are now responsible to transmit incoming frames to NCI
Core after proper treatment, and NCI SPI becomes a driver helper instead
of sitting between the NFC driver and NCI Core.

As a general rule in NFC, *_recv_frame() APIs are used to deliver an
incoming frame to an upper layer. To better suit the actual purpose of
nci_spi_recv_frame(), and go along with its nci_spi_send()
counterpart, the function is renamed to nci_spi_read()

The skb is returned as the function result

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: zero struct spi_transfer variables before usage

Using ARM compiler, and without zero-ing spi_transfer, spi-s3c64xx
driver would issue abnormal errors due to bpw field value being set to
unexpected value. This structure MUST be set to all zeros except for
those field specifically used.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: Store the spi device pointer from the spi instance

Storing the spi device was forgotten in the original implementation,
which would pretty obviously cause some kind of serious crash when
actually trying to send something through that device.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: Simplify NCI SPI to become a simple framing/checking layer

NCI SPI layer should not manage the nci dev, this is the job of the nci
chipset driver. This layer should be limited to frame/deframe nci
packets, and optionnaly check integrity (crc) and manage the ack/nak
protocol.

The NCI SPI must not be mixed up with an NCI dev. spi_[dev|device] are
therefore renamed to a simple spi for more clarity.
The header and crc sizes are moved to nci.h so that drivers can use
them to reserve space in outgoing skbs.
nci_spi_send() is exported to be accessible by drivers.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: Rename spi ndev -> nsdev and nci_dev -> ndev for consistency

An hci dev is an hdev. An nci dev is an ndev. Calling an nci spi dev an
ndev is misleading since it's not the same thing. The nci dev contained
in the nci spi dev is also named inconsistently.

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: NCI: Fix wrong allocation size in nci_spi_allocate_device()

Signed-off-by: Eric Lapuyade <eric.lapuyade@intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: Remove the static supported_se field

Supported secure elements are typically found during a discovery process
initiated when the NFC controller is up and running. For a given NFC
chipset there can be many configurations (embedded SE or not, with or
without a SIM card wired to the NFC controller SWP interface, etc...) and
thus driver code will never know before hand which SEs are available.
So we remove this field, it will be replaced by a real SE discovery
mechanism.

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

NFC: Add NCI over SPI receive

Before any operation, driver interruption is de-asserted to prevent
race condition between TX and RX.

Transaction starts by emitting "Direct read" and acknowledged mode
bytes. Then packet length is read allowing to allocate correct NCI
socket buffer. After that payload is retrieved.

A delay after the transaction can be added.
This delay is determined by the driver during nci_spi_allocate_device()
call and can be 0.

If acknowledged mode is set:
- CRC of header and payload is checked
- if frame reception fails (CRC error): NACK is sent
- if received frame has ACK or NACK flag: unblock nci_spi_send()

Payload is passed to NCI module.

At the end, driver interruption is re asserted.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: Add NCI over SPI send

Before any operation, driver interruption is de-asserted to prevent
race condition between TX and RX.

The NCI over SPI header is added in front of NCI packet.
If acknowledged mode is set, CRC-16-CCITT is added to the packet.
Then the packet is forwarded to SPI module to be sent.

A delay after the transaction is added.
This delay is determined by the driver during nci_spi_allocate_device()
call and can be 0.

After data has been sent, driver interruption is re-asserted.

If acknowledged mode is set, nci_spi_send will block until
acknowledgment is received.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>

NFC: Add basic NCI over SPI

The NFC Forum defines a transport interface based on
Serial Peripheral Interface (SPI) for the NFC Controller
Interface (NCI).

This module implements the SPI transport of NCI, calling SPI module
directly to read/write data to NFC controller (NFCC).

NFCC driver should provide functions performing device open and close.
It should also provide functions asserting/de-asserting interruption
to prevent TX/RX race conditions.
NFCC driver can also fix a delay between transactions if needed by
the hardware.

Signed-off-by: Frederic Danis <frederic.danis@linux.intel.com>
Signed-off-by: Samuel Ortiz <sameo@linux.intel.com>