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authorMauro Carvalho Chehab <mchehab+samsung@kernel.org>2019-07-26 09:51:34 -0300
committerJonathan Corbet <corbet@lwn.net>2019-07-31 13:31:56 -0600
commite15d5a53ea3239e537d3a0c4bdfce8a4ea4e0da6 (patch)
tree0da73aa162c80b866bda4d67506ae37f09985889 /Documentation/networking/caif
parentdocs: nios2: add it to the main Documentation body (diff)
downloadlinux-dev-e15d5a53ea3239e537d3a0c4bdfce8a4ea4e0da6.tar.xz
linux-dev-e15d5a53ea3239e537d3a0c4bdfce8a4ea4e0da6.zip
docs: net: convert two README files to ReST format
There are two README files there with doesn't have a .txt extension nor are at ReST format. In order to help with the docs conversion to ReST, rename those and manually convert them to ReST format. As there are lot more to be done for networking to be part of the documentation body, for now mark those two files with :orphan:, in order to supress a build warning. Signed-off-by: Mauro Carvalho Chehab <mchehab+samsung@kernel.org> Signed-off-by: Jonathan Corbet <corbet@lwn.net>
Diffstat (limited to 'Documentation/networking/caif')
-rw-r--r--Documentation/networking/caif/caif.rst (renamed from Documentation/networking/caif/README)88
1 files changed, 60 insertions, 28 deletions
diff --git a/Documentation/networking/caif/README b/Documentation/networking/caif/caif.rst
index 757ccfaa1385..07afc8063d4d 100644
--- a/Documentation/networking/caif/README
+++ b/Documentation/networking/caif/caif.rst
@@ -1,18 +1,31 @@
-Copyright (C) ST-Ericsson AB 2010
-Author: Sjur Brendeland/ sjur.brandeland@stericsson.com
-License terms: GNU General Public License (GPL) version 2
----------------------------------------------------------
+:orphan:
-=== Start ===
-If you have compiled CAIF for modules do:
+.. SPDX-License-Identifier: GPL-2.0
+.. include:: <isonum.txt>
-$modprobe crc_ccitt
-$modprobe caif
-$modprobe caif_socket
-$modprobe chnl_net
+================
+Using Linux CAIF
+================
-=== Preparing the setup with a STE modem ===
+
+:Copyright: |copy| ST-Ericsson AB 2010
+
+:Author: Sjur Brendeland/ sjur.brandeland@stericsson.com
+
+Start
+=====
+
+If you have compiled CAIF for modules do::
+
+ $modprobe crc_ccitt
+ $modprobe caif
+ $modprobe caif_socket
+ $modprobe chnl_net
+
+
+Preparing the setup with a STE modem
+====================================
If you are working on integration of CAIF you should make sure
that the kernel is built with module support.
@@ -32,24 +45,30 @@ module parameter "ser_use_stx".
Normally Frame Checksum is always used on UART, but this is also provided as a
module parameter "ser_use_fcs".
-$ modprobe caif_serial ser_ttyname=/dev/ttyS0 ser_use_stx=yes
-$ ifconfig caif_ttyS0 up
+::
+
+ $ modprobe caif_serial ser_ttyname=/dev/ttyS0 ser_use_stx=yes
+ $ ifconfig caif_ttyS0 up
-PLEASE NOTE: There is a limitation in Android shell.
+PLEASE NOTE:
+ There is a limitation in Android shell.
It only accepts one argument to insmod/modprobe!
-=== Trouble shooting ===
+Trouble shooting
+================
There are debugfs parameters provided for serial communication.
/sys/kernel/debug/caif_serial/<tty-name>/
* ser_state: Prints the bit-mask status where
+
- 0x02 means SENDING, this is a transient state.
- 0x10 means FLOW_OFF_SENT, i.e. the previous frame has not been sent
- and is blocking further send operation. Flow OFF has been propagated
- to all CAIF Channels using this TTY.
+ and is blocking further send operation. Flow OFF has been propagated
+ to all CAIF Channels using this TTY.
* tty_status: Prints the bit-mask tty status information
+
- 0x01 - tty->warned is on.
- 0x02 - tty->low_latency is on.
- 0x04 - tty->packed is on.
@@ -58,13 +77,17 @@ There are debugfs parameters provided for serial communication.
- 0x20 - tty->stopped is on.
* last_tx_msg: Binary blob Prints the last transmitted frame.
- This can be printed with
+
+ This can be printed with::
+
$od --format=x1 /sys/kernel/debug/caif_serial/<tty>/last_rx_msg.
- The first two tx messages sent look like this. Note: The initial
- byte 02 is start of frame extension (STX) used for re-syncing
- upon errors.
- - Enumeration:
+ The first two tx messages sent look like this. Note: The initial
+ byte 02 is start of frame extension (STX) used for re-syncing
+ upon errors.
+
+ - Enumeration::
+
0000000 02 05 00 00 03 01 d2 02
| | | | | |
STX(1) | | | |
@@ -73,7 +96,9 @@ There are debugfs parameters provided for serial communication.
Command:Enumeration(1)
Link-ID(1)
Checksum(2)
- - Channel Setup:
+
+ - Channel Setup::
+
0000000 02 07 00 00 00 21 a1 00 48 df
| | | | | | | |
STX(1) | | | | | |
@@ -86,13 +111,18 @@ There are debugfs parameters provided for serial communication.
Checksum(2)
* last_rx_msg: Prints the last transmitted frame.
- The RX messages for LinkSetup look almost identical but they have the
- bit 0x20 set in the command bit, and Channel Setup has added one byte
- before Checksum containing Channel ID.
- NOTE: Several CAIF Messages might be concatenated. The maximum debug
+
+ The RX messages for LinkSetup look almost identical but they have the
+ bit 0x20 set in the command bit, and Channel Setup has added one byte
+ before Checksum containing Channel ID.
+
+ NOTE:
+ Several CAIF Messages might be concatenated. The maximum debug
buffer size is 128 bytes.
-== Error Scenarios:
+Error Scenarios
+===============
+
- last_tx_msg contains channel setup message and last_rx_msg is empty ->
The host seems to be able to send over the UART, at least the CAIF ldisc get
notified that sending is completed.
@@ -103,7 +133,9 @@ There are debugfs parameters provided for serial communication.
- if /sys/kernel/debug/caif_serial/<tty>/tty_status is non-zero there
might be problems transmitting over UART.
+
E.g. host and modem wiring is not correct you will typically see
tty_status = 0x10 (hw_stopped) and ser_state = 0x10 (FLOW_OFF_SENT).
+
You will probably see the enumeration message in last_tx_message
and empty last_rx_message.