Re: [PATCH v7 1/7] i3c: master: secondary master initialization document

Boris Brezillon
2020-05-11T16:05:10Z

On Mon, 11 May 2020 15:12:39 +0200
Parshuram Thombare <pthombar@cadence.com> wrote:

> Document describing secondary master initialization,
> mastership handover and DEFSLVS handling processes.

Thanks for doing that, but you probably didn't try to compile the doc
(the formatting is all messed up).

# make htmldocs

and then check the output in Documentation/output/ (open index.html
with a web-browser and go to the i3c section).

>
> Signed-off-by: Parshuram Thombare <pthombar@cadence.com>
> ---
> Documentation/driver-api/i3c/index.rst | 1 +
> .../i3c/secondary-master-initialization.rst | 118 ++++++++++++++++++
> 2 files changed, 119 insertions(+)
> create mode 100644 Documentation/driver-api/i3c/secondary-master-initialization.rst
>
> diff --git a/Documentation/driver-api/i3c/index.rst b/Documentation/driver-api/i3c/index.rst
> index 783d6dad054b..af2a0aa68f5b 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
> + secondary-master-initialization
> diff --git a/Documentation/driver-api/i3c/secondary-master-initialization.rst b/Documentation/driver-api/i3c/secondary-master-initialization.rst
> new file mode 100644
> index 000000000000..9d1869550807
> --- /dev/null
> +++ b/Documentation/driver-api/i3c/secondary-master-initialization.rst
> @@ -0,0 +1,118 @@
> +.. SPDX-License-Identifier: GPL-2.0
> +
> +===================================
> +I3C Secondary Master Initialization
> +===================================
> +
> ++-----------------------------------------+-------------------------------------------+
> +| **Main master** | **Secondary master** |
> ++=========================================+===========================================+
> +| | |
> +| | Do I3C master controller specific | | Do I3C master controller specefic |
> +| initialization. | initialization, except enabling |
> +| | the DEFSLVS interrupt. |
> +| | Call i3c_master_register | | Call i3c_secondary_master_register |
> +| | |
> +| *i3c_master_register* | *i3c_secondary_master_register* |
> +| | Initialize I3C master controller | | Initialize I3C master controller |
> +| object. | object. |
> +| | Scan I3C and I2C devices from DTS. | | Scan I2C devices from DTS. |
> +| | Set appropriate bus mode based on | | Set appropriate bus mode based on |
> +| I2C devices information. | I3C and I2C devices information. |
> +| | Create a work queue. | | Create a work queue. |
> +| | Call i3c_master_bus_init | | Call i3c_secondary_master_bus_init |
> +| | |
> +| *i3c_master_bus_init* | *i3c_secondary_master_bus_init* |
> +| | Call bus_init to do controller | | Call bus_init to do controller |
> +| specific bus initialization and | specific bus initialization and |
> +| enabling the controller. | enabling the controller. |
> +| | Create I3C device representing a| | Create I3C device representing a |
> +| master and add it to the I3C | master and add it to the I3C |
> +| device list. | device list. |
> +| | Set current master to the device| |
> +| created to represent I3C master | | Allocate memory for 'defslvs_data', |
> +| device. | that will be used to pass I3C |
> +| | Reset all dynamic address that | device list received in DEFSLVS |
> +| may have been assigned before. | to I3C core DEFSLVS processing |
> +| | Disable all slave events before | | Add I3C device representing this |
> +| starting DAA. | master to the system. |
> +| | Pre-assign dynamic address and | | Expose our I3C bus as an I2C adapter |
> +| retrieve device information if | so that I2C devices are exposed |
> +| needed. | through the I2C subsystem. |
> +| | Do dynamic address assignment to| |
> +| all I3C devices currenly present| | Enable DEFSLVS interrupt. |
> +| on the bus. | |
> +| | Create I3C devices representing | |
> +| those found during DAA. +-------------------------------------------+
> +| | Send DEFSVLS message | | *DEFSLVS interrupt* |
> +| containing information about all| | Controller driver can chose how to |
> +| known I3C and I2C devices. | to handle I2C devices received in |
> +| | DEFSLVS e.g. Cadence's controller |
> +| | driver ignore I2C devices from |
> +| | DEFSLVS and only uses I2C device |
> +| | information from DTS. |
> +| | | Read all I3C devices information |
> +| | from DEFSLVS message in hardware to |
> +| | defslvs_data in master object. |
> +| | | Call i3c_master_process_defslvs |
> +| | |
> +| | *i3c_master_process_defslvs* |
> +| | | Acquire I3c bus |
> +| | |
> +| | *i3c_master_acquire_bus* |
> +| | Add I3C device representing this | | If device is already holding the |
> +| master to the system. | mastership, just broadcast DISEC |
> +| | Expose our I3C bus as an I2C | MR, HJ message and return. |
> +| adapter so that I2C devices are | | Check if device has got a address |
> +| exposed through the I2C subsystem. | by polling with a timeout. |
> +| | Register all I3C devices. | |
> +| | | Send MR request: Controller driver|
> +| | should check if it is already in |
> +| | master mode, to handle the case |
> +| | of mastership yielded but due to |
> +| | poll timeout acquire failed. |
> +| | | If not a master, wait until MR |
> +| | ENEC is received if currently it |
> +| | is disabled. |
> +| | Broadcast ENEC MR, HJ message. | | Send MR request. |
> ++-----------------------------------------+ |
> +| | *MR request interrupt* | |
> +| | |
> +| *i3c_master_yield_bus* | |
> +| | Check if this device is still a | |
> +| master to handle a case of | |
> +| multiple MR requests from different| |
> +| devices at a same time. | |
> +| | Broadcast DISEC MR, HJ message. | |
> +| New master should broadcast ENEC | |
> +| MR, HJ once it's usage of bus is | |
> +| done. | |
> +| | Get accept mastership acknowldege | |
> +| from requesting master. | |
> +| | Mastership hand over is done. | | Check if device enter master |
> +| | In case of failure reenable | mode by polling with a timeout. |
> +| MR requests by broadcasting ENEC | |
> +| MR, HJ. | Handle I3C device list from DEFSLVS. |
> +| | |
> +| | *i3c_master_populate_bus* |
> +| | | Free up all I3C addresses to handle |
> +| | address re assignment by main |
> +| | master. |
> +| | | Move all devices from I3C list to a |
> +| | temporary list. |
> +| | | For every device from defslvs_data |
> +| | list except the receiving master |
> +| | device, retrieve pid and compare it |
> +| | with already known I3C devices from |
> +| | I3C list. If match is found, |
> +| | allocate new address and move the |
> +| | device to the original I3C device |
> +| | list. If no match is found, it is a |
> +| | new device. Register and add it to |
> +| | the original I3C list. |
> +| | | At the end if temporary list is not |
> +| | empty, it contains unplugged I3C |
> +| | device. Deregister and delete them. |
> +| | |
> +| | Broadcast ENEC MR, HJ message. |
> ++-----------------------------------------+-------------------------------------------+