Add I3C target mode and tty over i3c func driver document. Signed-off-by: Frank Li <Frank.Li@xxxxxxx> --- Documentation/driver-api/i3c/index.rst | 1 + .../driver-api/i3c/target/i3c-target-cfs.rst | 109 ++++++++++ .../driver-api/i3c/target/i3c-target.rst | 189 ++++++++++++++++++ .../driver-api/i3c/target/i3c-tty-howto.rst | 109 ++++++++++ Documentation/driver-api/i3c/target/index.rst | 13 ++ 5 files changed, 421 insertions(+) create mode 100644 Documentation/driver-api/i3c/target/i3c-target-cfs.rst create mode 100644 Documentation/driver-api/i3c/target/i3c-target.rst create mode 100644 Documentation/driver-api/i3c/target/i3c-tty-howto.rst create mode 100644 Documentation/driver-api/i3c/target/index.rst diff --git a/Documentation/driver-api/i3c/index.rst b/Documentation/driver-api/i3c/index.rst index 783d6dad054b6..345a43c9f61b0 100644 --- a/Documentation/driver-api/i3c/index.rst +++ b/Documentation/driver-api/i3c/index.rst @@ -9,3 +9,4 @@ I3C subsystem protocol device-driver-api master-driver-api + target/index diff --git a/Documentation/driver-api/i3c/target/i3c-target-cfs.rst b/Documentation/driver-api/i3c/target/i3c-target-cfs.rst new file mode 100644 index 0000000000000..1fcf829dc4ae2 --- /dev/null +++ b/Documentation/driver-api/i3c/target/i3c-target-cfs.rst @@ -0,0 +1,109 @@ +.. SPDX-License-Identifier: GPL-2.0 + +======================================= +Configuring I3C Target Using CONFIGFS +======================================= + +:Author: Frank Li <Frank.Li@xxxxxxx> + +The I3C Target Core exposes configfs entry (i3c_target) to configure the I3C +target function and to bind the target function with the target controller. +(For introducing other mechanisms to configure the I3C Target Function refer to +[1]). + +Mounting configfs +================= + +The I3C Target Core layer creates i3c_target directory in the mounted configfs +directory. configfs can be mounted using the following command:: + + mount -t configfs none /sys/kernel/config + +Directory Structure +=================== + +The i3c_target configfs has two directories at its root: controllers and +functions. Every Controller device present in the system will have an entry in +the *controllers* directory and every Function driver present in the system will +have an entry in the *functions* directory. +:: + + /sys/kernel/config/i3c_target/ + .. controllers/ + .. functions/ + +Creating Function Device +=================== + +Every registered Function driver will be listed in controllers directory. The +entries corresponding to Function driver will be created by the Function core. +:: + + /sys/kernel/config/i3c_target/functions/ + .. <Function Driver1>/ + ... <Function Device 11>/ + ... <Function Device 21>/ + ... <Function Device 31>/ + .. <Function Driver2>/ + ... <Function Device 12>/ + ... <Function Device 22>/ + +In order to create a <Function device> of the type probed by <Function Driver>, +the user has to create a directory inside <Function DriverN>. + +Every <Function device> directory consists of the following entries that can be +used to configure the standard configuration header of the target function. +(These entries are created by the framework when any new <Function Device> is +created) +:: + + .. <Function Driver1>/ + ... <Function Device 11>/ + ... vendor_id + ... part_id + ... bcr + ... dcr + ... ext_id + ... instance_id + ... max_read_len + ... max_write_len + ... vendor_info + +Controller Device +========== + +Every registered Controller device will be listed in controllers directory. The +entries corresponding to Controller device will be created by the Controller +core. +:: + + /sys/kernel/config/i3c_target/controllers/ + .. <Controller Device1>/ + ... <Symlink Function Device11>/ + .. <Controller Device2>/ + ... <Symlink Function Device21>/ + +The <Controller Device> directory will have a list of symbolic links to +<Function Device>. These symbolic links should be created by the user to +represent the functions present in the target device. Only <Function Device> +that represents a physical function can be linked to a Controller device. + +:: + + | controllers/ + | <Directory: Controller name>/ + | <Symbolic Link: Function> + | functions/ + | <Directory: Function driver>/ + | <Directory: Function device>/ + | vendor_id + | part_id + | bcr + | dcr + | ext_id + | instance_id + | max_read_len + | max_write_len + | vendor_info + +[1] Documentation/I3C/target/pci-target.rst diff --git a/Documentation/driver-api/i3c/target/i3c-target.rst b/Documentation/driver-api/i3c/target/i3c-target.rst new file mode 100644 index 0000000000000..09ae26b1f311a --- /dev/null +++ b/Documentation/driver-api/i3c/target/i3c-target.rst @@ -0,0 +1,189 @@ +.. SPDX-License-Identifier: GPL-2.0 + +:Author: Frank Li <Frank.Li@xxxxxxx> + +This document is a guide to use the I3C Target Framework in order to create +target controller driver, target function driver, and using configfs interface +to bind the function driver to the controller driver. + +Introduction +============ + +Linux has a comprehensive I3C subsystem to support I3C controllers that +operates in master mode. The subsystem has capability to scan I3C bus,assign +i3c device address, load I3C driver (based on Manufacturer ID, part ID), +support other services like hot-join, In-Band Interrupt(IBI). + +However the I3C controller IP integrated in some SoCs is capable of operating +either in Master mode or Target mode. I3C Target Framework will add target mode +support in Linux. This will help to run Linux in an target system which can +have a wide variety of use cases from testing or validation, co-processor +accelerator, etc. + +I3C Target Core +================= + +The I3C Target Core layer comprises 3 components: the Target Controller +library, the Target Function library, and the configfs layer to bind the target +function with the target controller. + +I3C Target Controller Library +------------------------------------ + +The Controller library provides APIs to be used by the controller that can +operate in target mode. It also provides APIs to be used by function +driver/library in order to implement a particular target function. + +APIs for the I3C Target controller Driver +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This section lists the APIs that the I3C Target core provides to be used by the +I3C controller driver. + +* devm_i3c_target_ctrl_create()/i3c_target_ctrl_create() + + The I3C controller driver should implement the following ops: + + * set_config: ops to set i3c configuration + * enable: ops to enable controller + * disable: ops to disable controller + * raise_ibi: ops to raise IBI to master controller + * alloc_request: ops to alloc a transfer request + * free_request: ops to free a transfer request + * queue: ops to queue a request to transfer queue + * dequeue: ops to dequeue a request from transfer queue + * cancel_all_reqs: ops to cancel all request from transfer queue + * fifo_status: ops to get fifo status + * fifo_flush: ops to flush hardware fifo + * get_features: ops to get controller supported features + + The I3C controller driver can then create a new Controller device by + invoking devm_i3c_target_ctrl_create()/i3c_target_ctrl_create(). + +* devm_i3c_target_ctrl_destroy()/i3c_target_ctrl_destroy() + + The I3C controller driver can destroy the Controller device created by + either devm_i3c_target_ctrl_create() or i3c_target_ctrl_create() using + devm_i3c_target_ctrl_destroy() or i3c_target_ctrl_destroy(). + +I3C Target Controller APIs for the I3C Target Function Driver +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This section lists the APIs that the I3C Target core provides to be used by the +I3C target function driver. + +* i3c_target_ctrl_set_config() + + The I3C target function driver should use i3c_target_ctrl_set_config() to + write i3c configuration to the target controller. + +* i3c_target_ctrl_enable()/i3c_target_ctrl_disable() + + The I3C target function driver should use i3c_target_ctrl_enable()/ + i3c_target_ctrl_disable() to enable/disable i3c target controller. + +* i3c_target_ctrl_alloc_request()/i3c_target_ctrl_free_request() + + The I3C target function driver should usei3c_target_ctrl_alloc_request() / + i3c_target_ctrl_free_request() to alloc/free a i3c request. + +* i3c_target_ctrl_raise_ibi() + + The I3C target function driver should use i3c_target_ctrl_raise_ibi() to + raise IBI. + +* i3c_target_ctrl_queue()/i3c_target_ctrl_dequeue() + + The I3C target function driver should use i3c_target_ctrl_queue()/ + i3c_target_ctrl_dequeue(), to queue/dequeue I3C transfer to/from transfer + queue. + +* i3c_target_ctrl_get_features() + + The I3C target function driver should use i3c_target_ctrl_get_features() to + get I3C target controller supported features. + +Other I3C Target Controller APIs +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +There are other APIs provided by the Controller library. These are used for +binding the I3C Target Function device with Controlller device. i3c-cfs.c can +be used as reference for using these APIs. + +* i3c_target_ctrl_get() + + Get a reference to the I3C target controller based on the device name of + the controller. + +* i3c_target_ctrl_put() + + Release the reference to the I3C target controller obtained using + i3c_target_ctrl_get() + +* i3c_target_ctrl_add_func() + + Add a I3C target function to a I3C target controller. + +* i3c_target_ctrl_remove_func() + + Remove the I3C target function from I3C target controller. + +I3C Target Function Library +---------------------------------- + +The I3C Target Function library provides APIs to be used by the function driver +and the Controller library to provide target mode functionality. + +I3C Target Function APIs for the I3C Target Function Driver +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This section lists the APIs that the I3C Target core provides to be used +by the I3C target function driver. + +* i3c_target_func_register_driver() + + The I3C Target Function driver should implement the following ops: + * bind: ops to perform when a Controller device has been bound to + Function device + * unbind: ops to perform when a binding has been lost between a + Controller device and Function device + + The I3C Function driver can then register the I3C Function driver by using + i3c_target_func_register_driver(). + +* i3c_target_func_unregister_driver() + + The I3C Function driver can unregister the I3C Function driver by using + i3c_epf_unregister_driver(). + +APIs for the I3C Target Controller Library +~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~~ + +This section lists the APIs that the I3C Target core provides to be used by the +I3C target controller library. + +Other I3C Target APIs +~~~~~~~~~~~~~~~~~~~~ + +There are other APIs provided by the Function library. These are used to notify +the function driver when the Function device is bound to the EPC device. +i3c-cfs.c can be used as reference for using these APIs. + +* i3c_target_func_create() + + Create a new I3C Function device by passing the name of the I3C EPF device. + This name will be used to bind the Function device to a Function driver. + +* i3c_target_func_destroy() + + Destroy the created I3C Function device. + +* i3c_target_func_bind() + + i3c_target_func_bind() should be invoked when the EPF device has been bound + to a Controller device. + +* i3c_target_func_unbind() + + i3c_target_func_unbind() should be invoked when the binding between EPC + device and function device is lost. diff --git a/Documentation/driver-api/i3c/target/i3c-tty-howto.rst b/Documentation/driver-api/i3c/target/i3c-tty-howto.rst new file mode 100644 index 0000000000000..43a129b18e938 --- /dev/null +++ b/Documentation/driver-api/i3c/target/i3c-tty-howto.rst @@ -0,0 +1,109 @@ +.. SPDX-License-Identifier: GPL-2.0 + +=================== +I3C TTY User Guide +=================== + +:Author: Frank Li <Frank.Li@xxxxxxx> + +This document is a guide to help users use i3c-target-tty function driver and +i3ctty master driver for testing I3C. The list of steps to be followed in the +master side and target side is given below. + +Endpoint Device +=============== + +Endpoint Controller Devices +--------------------------- + +To find the list of target controller devices in the system:: + + # ls /sys/class/i3c_target/ + 44330000.i3c-target + +If CONFIG_I3C_SLAVE_CONFIGFS is enabled:: + + # ls /sys/kernel/config/i3c_target/controllers/ + 44330000.i3c-target + + +Endpoint Function Drivers +------------------------- + +To find the list of target function drivers in the system:: + + # ls /sys/bus/i3c_target_func/drivers + tty + +If CONFIG_I3C_SLAVE_CONFIGFS is enabled:: + + # ls /sys/kernel/config/i3c_target/functions + tty + + +Creating i3c-target-tty Device +---------------------------- + +I3C target function device can be created using the configfs. To create +i3c-target-tty device, the following commands can be used:: + + # mount -t configfs none /sys/kernel/config + # cd /sys/kernel/config/i3c_target/ + # mkdir functions/tty/func1 + +The "mkdir func1" above creates the i3c-target-tty function device that will +be probed by i3c tty driver. + +The I3C target framework populates the directory with the following +configurable fields:: + + # ls functions/tty/func1 + bcr dcr ext_id instance_id max_read_len max_write_len + part_id vendor_id vendor_info + +The I3C target function driver populates these entries with default values when +the device is bound to the driver. The i3c-target-tty driver populates vendorid +with 0xffff and interrupt_pin with 0x0001:: + + # cat functions/tty/func1/vendor_id + 0x0 + +Configuring i3c-target-tty Device +------------------------------- + +The user can configure the i3c-target-tty device using configfs entry. In order +to change the vendorid, the following commands can be used:: + + # echo 0x011b > functions/tty/func1/vendor_id + # echo 0x1000 > functions/tty/func1/part_id + # echo 0x6 > functions/tty/t/bcr + +Binding i3c-target-tty Device to target Controller +------------------------------------------------ + +In order for the target function device to be useful, it has to be bound to a +I3C target controller driver. Use the configfs to bind the function device to +one of the controller driver present in the system:: + + # ln -s functions/tty/func1 controllers/44330000.i3c-target/ + +I3C Master Device +================ + +Check I3C tty device is probed + + # ls /sys/bus/i3c/devices/0-23610000000 + 0-23610000000:0 bcr dcr driver dynamic_address hdrcap + modalias pid power subsystem tty uevent + +Using Target TTY function Device +----------------------------------- + +Host side: + cat /dev/ttyI3C0 +Target side + echo abc >/dev/ttyI3C0 + +You will see "abc" show at console. + +You can use other tty tool to test I3C target tty device. diff --git a/Documentation/driver-api/i3c/target/index.rst b/Documentation/driver-api/i3c/target/index.rst new file mode 100644 index 0000000000000..56eabfae83aa4 --- /dev/null +++ b/Documentation/driver-api/i3c/target/index.rst @@ -0,0 +1,13 @@ +.. SPDX-License-Identifier: GPL-2.0 + +====================== +I3C Target Framework +====================== + +.. toctree:: + :maxdepth: 2 + + i3c-target + i3c-target-cfs + i3c-tty-howto + -- 2.34.1