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| author | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
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| committer | Linus Torvalds <torvalds@linux-foundation.org> | 2026-08-24 08:46:03 -0700 |
| commit | cf9610f9116d55c5a66ef9f1faecacabd93a9322 (patch) | |
| tree | 757a3d280760c654767631cab5ad8af2d86d1848 /Documentation/networking/lapb-module.rst | |
| download | linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.tar.gz linux-stable-cf9610f9116d55c5a66ef9f1faecacabd93a9322.zip | |
Merge tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrlgrafted
Pull pin control updates from Linus Walleij:
"Core changes:
- Use the non-blocking mux_state_try_select() in the generic MUX pin
control back-end
- Free pin maps on pinctrl_generic_to_map() failure in the core
helpers
New hardware pin control:
- Qualcomm Maili TLMM SoC, PMG1110 PMIC, and Eliza LPASS LPI TLMM SoC
(this is for the low power audio, LPASS = Low Power Audio SubSystem
portions)
- Upboard support on top of the Intel pin controller
- Apple T6030 and T6031 support (just compatible strings)
- Samsung Exynos 8855 SoC
- Mediatek MT6858 SoC
- Rockchip RK3308B and RV1106 SoCs
- Airoha EN7523 and AN7563 SoCs
Improvements:
- Qualcomm TLMM GPIOs are unconditionally marked as wakeup capable
- Qualcomm improvements on top of the Qualcomm PDC (power domain
controller) irqchip improvements from tglx:s tree
- Qualcomm IPQ806x and IPQ9650 non-urgent pin grop fixups
- The NPCM8xx driver has been put into shape fixing many pin and
group definitions
- Some non-urgent Tegra 264 pin assignments are fixed up
- Some non-urgent fixups to Airoha AN7581 and AN7583 registers and
pin assignments, missing features etc"
* tag 'pinctrl-v7.3-1' of git://git.kernel.org/pub/scm/linux/kernel/git/linusw/linux-pinctrl: (130 commits)
dt-bindings: pinctrl: Convert TI DA850 pupd to DT schema
pinctrl: meson: sync some modify from A4
pinctrl: meson: a4: Add input enable pin configuration
pinctrl: realtek: rtd1625: remove unused group name spdif_sel
pinctrl: realtek: rtd1625: fix base_bit for VE4 GPIO 13
dt-bindings: pinctrl: microchip,pic32mzda-pinctrl: Convert to DT schema
Revert "Merge branch 'ib-rsk7204' into devel"
pinctrl: rockchip: Add RV1106 pinctrl support
dt-bindings: pinctrl: rockchip: Add RV1106 compatible
pinctrl: rockchip: Decode drive strength in the get function
pinctrl: fix PINCTRL_GENERIC_MUX not always being selectable
pinctrl: airoha: add support of an7563 SoC
dt-bindings: pinctrl: airoha: add support of an7563 pin controller
pinctrl: airoha: try to find chip scu node by phandle first
pinctrl: airoha: add support of en7523 SoC
dt-bindings: pinctrl: airoha: add support of en7523 pin controller
pinctrl: airoha: an7583: add support for olt pinmux
pinctrl: airoha: an7583: add support for pon_alt pinmux
pinctrl: airoha: an7583: add support for npu_uart pinmux
dt-bindings: pinctrl: airoha: an7583: add missed features
...
Diffstat (limited to 'Documentation/networking/lapb-module.rst')
| -rw-r--r-- | Documentation/networking/lapb-module.rst | 305 |
1 files changed, 305 insertions, 0 deletions
diff --git a/Documentation/networking/lapb-module.rst b/Documentation/networking/lapb-module.rst new file mode 100644 index 000000000..ff586bc9f --- /dev/null +++ b/Documentation/networking/lapb-module.rst @@ -0,0 +1,305 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=============================== +The Linux LAPB Module Interface +=============================== + +Version 1.3 + +Jonathan Naylor 29.12.96 + +Changed (Henner Eisen, 2000-10-29): int return value for data_indication() + +The LAPB module will be a separately compiled module for use by any parts of +the Linux operating system that require a LAPB service. This document +defines the interfaces to, and the services provided by this module. The +term module in this context does not imply that the LAPB module is a +separately loadable module, although it may be. The term module is used in +its more standard meaning. + +The interface to the LAPB module consists of functions to the module, +callbacks from the module to indicate important state changes, and +structures for getting and setting information about the module. + +Structures +---------- + +Probably the most important structure is the skbuff structure for holding +received and transmitted data, however it is beyond the scope of this +document. + +The two LAPB specific structures are the LAPB initialisation structure and +the LAPB parameter structure. These will be defined in a standard header +file, <linux/lapb.h>. The header file <net/lapb.h> is internal to the LAPB +module and is not for use. + +LAPB Initialisation Structure +----------------------------- + +This structure is used only once, in the call to lapb_register (see below). +It contains information about the device driver that requires the services +of the LAPB module:: + + struct lapb_register_struct { + void (*connect_confirmation)(int token, int reason); + void (*connect_indication)(int token, int reason); + void (*disconnect_confirmation)(int token, int reason); + void (*disconnect_indication)(int token, int reason); + int (*data_indication)(int token, struct sk_buff *skb); + void (*data_transmit)(int token, struct sk_buff *skb); + }; + +Each member of this structure corresponds to a function in the device driver +that is called when a particular event in the LAPB module occurs. These will +be described in detail below. If a callback is not required (!!) then a NULL +may be substituted. + + +LAPB Parameter Structure +------------------------ + +This structure is used with the lapb_getparms and lapb_setparms functions +(see below). They are used to allow the device driver to get and set the +operational parameters of the LAPB implementation for a given connection:: + + struct lapb_parms_struct { + unsigned int t1; + unsigned int t1timer; + unsigned int t2; + unsigned int t2timer; + unsigned int n2; + unsigned int n2count; + unsigned int window; + unsigned int state; + unsigned int mode; + }; + +T1 and T2 are protocol timing parameters and are given in units of 100ms. N2 +is the maximum number of tries on the link before it is declared a failure. +The window size is the maximum number of outstanding data packets allowed to +be unacknowledged by the remote end, the value of the window is between 1 +and 7 for a standard LAPB link, and between 1 and 127 for an extended LAPB +link. + +The mode variable is a bit field used for setting (at present) three values. +The bit fields have the following meanings: + +====== ================================================= +Bit Meaning +====== ================================================= +0 LAPB operation (0=LAPB_STANDARD 1=LAPB_EXTENDED). +1 [SM]LP operation (0=LAPB_SLP 1=LAPB=MLP). +2 DTE/DCE operation (0=LAPB_DTE 1=LAPB_DCE) +3-31 Reserved, must be 0. +====== ================================================= + +Extended LAPB operation indicates the use of extended sequence numbers and +consequently larger window sizes, the default is standard LAPB operation. +MLP operation is the same as SLP operation except that the addresses used by +LAPB are different to indicate the mode of operation, the default is Single +Link Procedure. The difference between DCE and DTE operation is (i) the +addresses used for commands and responses, and (ii) when the DCE is not +connected, it sends DM without polls set, every T1. The upper case constant +names will be defined in the public LAPB header file. + + +Functions +--------- + +The LAPB module provides a number of function entry points. + +:: + + int lapb_register(void *token, struct lapb_register_struct); + +This must be called before the LAPB module may be used. If the call is +successful then LAPB_OK is returned. The token must be a unique identifier +generated by the device driver to allow for the unique identification of the +instance of the LAPB link. It is returned by the LAPB module in all of the +callbacks, and is used by the device driver in all calls to the LAPB module. +For multiple LAPB links in a single device driver, multiple calls to +lapb_register must be made. The format of the lapb_register_struct is given +above. The return values are: + +============= ============================= +LAPB_OK LAPB registered successfully. +LAPB_BADTOKEN Token is already registered. +LAPB_NOMEM Out of memory +============= ============================= + +:: + + int lapb_unregister(void *token); + +This releases all the resources associated with a LAPB link. Any current +LAPB link will be abandoned without further messages being passed. After +this call, the value of token is no longer valid for any calls to the LAPB +function. The valid return values are: + +============= =============================== +LAPB_OK LAPB unregistered successfully. +LAPB_BADTOKEN Invalid/unknown LAPB token. +============= =============================== + +:: + + int lapb_getparms(void *token, struct lapb_parms_struct *parms); + +This allows the device driver to get the values of the current LAPB +variables, the lapb_parms_struct is described above. The valid return values +are: + +============= ============================= +LAPB_OK LAPB getparms was successful. +LAPB_BADTOKEN Invalid/unknown LAPB token. +============= ============================= + +:: + + int lapb_setparms(void *token, struct lapb_parms_struct *parms); + +This allows the device driver to set the values of the current LAPB +variables, the lapb_parms_struct is described above. The values of t1timer, +t2timer and n2count are ignored, likewise changing the mode bits when +connected will be ignored. An error implies that none of the values have +been changed. The valid return values are: + +============= ================================================= +LAPB_OK LAPB getparms was successful. +LAPB_BADTOKEN Invalid/unknown LAPB token. +LAPB_INVALUE One of the values was out of its allowable range. +============= ================================================= + +:: + + int lapb_connect_request(void *token); + +Initiate a connect using the current parameter settings. The valid return +values are: + +============== ================================= +LAPB_OK LAPB is starting to connect. +LAPB_BADTOKEN Invalid/unknown LAPB token. +LAPB_CONNECTED LAPB module is already connected. +============== ================================= + +:: + + int lapb_disconnect_request(void *token); + +Initiate a disconnect. The valid return values are: + +================= =============================== +LAPB_OK LAPB is starting to disconnect. +LAPB_BADTOKEN Invalid/unknown LAPB token. +LAPB_NOTCONNECTED LAPB module is not connected. +================= =============================== + +:: + + int lapb_data_request(void *token, struct sk_buff *skb); + +Queue data with the LAPB module for transmitting over the link. If the call +is successful then the skbuff is owned by the LAPB module and may not be +used by the device driver again. The valid return values are: + +================= ============================= +LAPB_OK LAPB has accepted the data. +LAPB_BADTOKEN Invalid/unknown LAPB token. +LAPB_NOTCONNECTED LAPB module is not connected. +================= ============================= + +:: + + int lapb_data_received(void *token, struct sk_buff *skb); + +Queue data with the LAPB module which has been received from the device. It +is expected that the data passed to the LAPB module has skb->data pointing +to the beginning of the LAPB data. If the call is successful then the skbuff +is owned by the LAPB module and may not be used by the device driver again. +The valid return values are: + +============= =========================== +LAPB_OK LAPB has accepted the data. +LAPB_BADTOKEN Invalid/unknown LAPB token. +============= =========================== + +Callbacks +--------- + +These callbacks are functions provided by the device driver for the LAPB +module to call when an event occurs. They are registered with the LAPB +module with lapb_register (see above) in the structure lapb_register_struct +(see above). + +:: + + void (*connect_confirmation)(void *token, int reason); + +This is called by the LAPB module when a connection is established after +being requested by a call to lapb_connect_request (see above). The reason is +always LAPB_OK. + +:: + + void (*connect_indication)(void *token, int reason); + +This is called by the LAPB module when the link is established by the remote +system. The value of reason is always LAPB_OK. + +:: + + void (*disconnect_confirmation)(void *token, int reason); + +This is called by the LAPB module when an event occurs after the device +driver has called lapb_disconnect_request (see above). The reason indicates +what has happened. In all cases the LAPB link can be regarded as being +terminated. The values for reason are: + +================= ==================================================== +LAPB_OK The LAPB link was terminated normally. +LAPB_NOTCONNECTED The remote system was not connected. +LAPB_TIMEDOUT No response was received in N2 tries from the remote + system. +================= ==================================================== + +:: + + void (*disconnect_indication)(void *token, int reason); + +This is called by the LAPB module when the link is terminated by the remote +system or another event has occurred to terminate the link. This may be +returned in response to a lapb_connect_request (see above) if the remote +system refused the request. The values for reason are: + +================= ==================================================== +LAPB_OK The LAPB link was terminated normally by the remote + system. +LAPB_REFUSED The remote system refused the connect request. +LAPB_NOTCONNECTED The remote system was not connected. +LAPB_TIMEDOUT No response was received in N2 tries from the remote + system. +================= ==================================================== + +:: + + int (*data_indication)(void *token, struct sk_buff *skb); + +This is called by the LAPB module when data has been received from the +remote system that should be passed onto the next layer in the protocol +stack. The skbuff becomes the property of the device driver and the LAPB +module will not perform any more actions on it. The skb->data pointer will +be pointing to the first byte of data after the LAPB header. + +This method should return NET_RX_DROP (as defined in the header +file include/linux/netdevice.h) if and only if the frame was dropped +before it could be delivered to the upper layer. + +:: + + void (*data_transmit)(void *token, struct sk_buff *skb); + +This is called by the LAPB module when data is to be transmitted to the +remote system by the device driver. The skbuff becomes the property of the +device driver and the LAPB module will not perform any more actions on it. +The skb->data pointer will be pointing to the first byte of the LAPB header. |
