Difference between revisions of "BeagleBoard/GSoC/2021 Proposal/bela on bbai"

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(Proposed method of Implementation and Timeline)
(Proposed method of Implementation and Timeline)
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; Workflow for building the PRU existing PRU code with clpru:
 
; Workflow for building the PRU existing PRU code with clpru:
 
Although this has already been done,it still needs some amount of testing.
 
Although this has already been done,it still needs some amount of testing.
# Build the .p file as is with pasm with `-V2 -b`. This generates a .bin file that contains the assembled program
+
# Build the .p file as is with pasm with ''-V2 -b''. This generates a .bin file that contains the assembled program
 
# I will be using the disassembler Giulio Moro put together hacking the one that was inside prudebug. (Find it [https://github.com/giuliomoro/prudebug/tree/disassembler here](built with ''gcc da.c -o prudis'') .
 
# I will be using the disassembler Giulio Moro put together hacking the one that was inside prudebug. (Find it [https://github.com/giuliomoro/prudebug/tree/disassembler here](built with ''gcc da.c -o prudis'') .
 
# Process the bin through the disassembelr and make it ready to be included inside an ''__asm__'' directive (i.e.: add quotes and prepend a space at the beginning of each line):
 
# Process the bin through the disassembelr and make it ready to be included inside an ''__asm__'' directive (i.e.: add quotes and prepend a space at the beginning of each line):
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# build main.c with the regular clpru toolchain
 
# build main.c with the regular clpru toolchain
  
I will need to change the MCASP addresses:
+
I will need to change the MCASP addresses as follows:
  
 
  #define MCASP0_BASE 0x48038000
 
  #define MCASP0_BASE 0x48038000

Revision as of 06:16, 12 April 2021


ProposalTemplate

{{#ev:youtube|https://www.youtube.com/watch?v=aVLRUyPBBJk}} About Student: Dhruva Gole
Mentors: Giulio Moro
Code: https://github.com/BelaPlatform/Bela
Wiki: https://learn.bela.io/get-started-guide/say-hello-to-bela/#what-is-bela
GSoC: GSoC entry

Status

This project is currently just a proposal.

Proposal

Please complete the requirements listed on the ideas page and fill out this template.

About you

IRC: dhruvag2000
Github: https://github.com/DhruvaG2000
School: Veermata Jijabai Technological Inst.
Country: India
Primary language : English, Marathi, Hindi
Typical work hours: 10AM - 7PM Indian Standard Time
Previous GSoC participation: I find embedded and IOT pretty interesting, given I have experience with ESP32, SIMCOM, ESP8266, Atmega, and many other microcontroller devices and I think I will be able to excel in this project. This is the first time i am participating in GSoC.

About your project

Project name: Bela support for the BeagleBone AI

Description

What is Bela?

As given on the official website, Bela is a hardware and software system for creating beautiful interaction with sensors and sound. Bela consists of a Bela cape on top of a BeagleBone Black computer (uptil now). Bela has a lot of analog and digital inputs and outputs for hooking up sensors and controlling other devices, and most importantly Bela has stereo audio i/o allowing you to interact with the world of sound.
Both Bela systems use the same Bela software. It uses a customised Debian distribution which - most notably - uses a Xenomai kernel instead of a stock kernel. Xenomai is co-kernel for Linux which allows to achieve hard real-time performance on Linux machines (http://xenomai.org/). It thus takes advantage of features of the BeagleBone computers and can achieve extremely fast audio and sensor processing times. Although the proposal Title mentions support for AI, I will try to develop a standardized setup that allows an easy jump across all TI chips.

Applications of Bela

Bela is ideal for creating anything interactive that uses sensors and sound. So far, Bela has been used to create:

  1. musical instruments and audio effects
  2. kinetic sculptures
  3. wearable devices
  4. interactive sound installations

and many more applications that are listed here

Why add support for BBAI/newer TI chips?

The Beagle Black and PocketBeagle are getting outdated by the day and also it would be better to have a more standardised setup that allows to more easily jump across TI chips, soon newer boards with different and more efficient chips like the AM5X and the TI C66x digital-signal-processor (DSP) cores in the BBAI are coming up that will need compatiblity with the Bela Software and Hardware. As part of the process we will try to offload peripheral initialisation to the mcasp and spi driver to in order to make it more portable for porting to other boards in the family, at present or future.

Programming languages and tools to be used

C, PRU, dtb, uboot, make

Proposed method of Implementation and Timeline

The Bela cape is working on the BB AI using ALSA (although one of the clocks seems to be of the wrong frequency), so we can confirm the pinout and pin settings are OK. We have not tried running the Bela code on the PRU yet. I will be learning and using pinmuxing, uboot, PRU assembly and reading about the Sitara family of SoCs and the McASP audio port. (ref. here)

Syntax Analysis

Compatibility is checked here in the form of

bool Bela_checkHwCompatibility(BelaHw userHw, BelaHw detectedHw);

Come the BBAI, as seen here

int cs_pin = 2 * 32 + 12; // P9.15a on BB AI

Two lines below this have been commented out for the older BB boards, which means this code won't really work for BB Black or pocketbeagle. This ofcourse is not the ideal workflow, which is why when I will start working I will add the necessary conditional statements to avoid this and provide easier identification and execution that is processor specific
To explain in short how I aim to establish a common code base for supporting all boards, I will start off by enumerating different boards once we detect which board it is. Then in the libraries, the constants (like pin numbers and their symlinks) will be set accordingly and the rest of the code base will become much easier to use without the need to hard code anything.

PRU
  1. It is better to minimise PRU code changes
  2. Preferably changing the PRU code will not be changed in such a way that it stops working on current Bela images (which currently use pasm / uio). In particular, we do not want to force Bela on BBB/PB to move to using clpru / rproc.

The Solution to run the current PRU assembly (designed for pasm/uio) using clpru/rproc (as for the AI) is:

  1. No PRU code changes (at least not yet, we'll need to change the MCASP addresses at the very least, but at least there is no massive rewrite to do just to be able to run the code)
  2. The same code that is built with pasm to run with uio can be translated automatically into code that builds with clpru and runs with rproc. So any changes made to that code can be back/fwd ported between BBB and BBAI.
Workflow for building the PRU existing PRU code with clpru

Although this has already been done,it still needs some amount of testing.

  1. Build the .p file as is with pasm with -V2 -b. This generates a .bin file that contains the assembled program
  2. I will be using the disassembler Giulio Moro put together hacking the one that was inside prudebug. (Find it here(built with gcc da.c -o prudis) .
  3. Process the bin through the disassembelr and make it ready to be included inside an __asm__ directive (i.e.: add quotes and prepend a space at the beginning of each line):
   prudis file.bin | sed 's/^\(.*\)$/" \1\\n"/' > included_assembly.h
  1. have the following in main.c:
void main()
{
     __asm__ __volatile__
     (
#include "included_assembly.h"
     );
}
  1. build main.c with the regular clpru toolchain

I will need to change the MCASP addresses as follows:

#define MCASP0_BASE 0x48038000
#define MCASP1_BASE 0x4803C000
#define MCASP0_DATAPORT 0x46000000
#define MCASP1_DATAPORT 0x46400000
#define MCASP_BASE  MCASP0_BASE
#define MCASP_DATAPORT  MCASP0_DATAPORT
PINMUXING

I am yet to figure out pinmuxing to make sure the relevant pins are set to the correct function (they are NOT by default). I will see here https://elinux.org/BeagleBoard/GSoC/2020_Projects/Cape_Compatibility and/or ask on the BB slack about for the best way to go about it.

PRU->ARM INTERRUPTS

Bela can work with a PRU->ARM interrupt, which is default these days, but requires an rtdm driver, which is another layer of complications. To start off, I will try to run it without the PRU->ARM interrupt by adding BELA_USE_DEFINE=BELA_USE_POLL to my make command line.

PRU transitioning from libprussdrv to rproc

The Remote Processor Framework (rproc) allows different platforms/architectures to control (power on, load firmware, power off) those remote processors while abstracting the hardware differences, so the entire driver doesn't need to be duplicated. I will need to change the initialization code in PRU.cpp that is currently relying on lib prussdrv and move to rproc . Not sure if rproc provides some functionalities to access the PRU's RAM the way prussdrv_map_prumem() used to, but that essentially gives access to a previously mmap'ed area of memory , so it should be easy to replace, as long as I am able to find the correct addresses in the TRM. On the latest Bela code there's a Mmap class which can make this somehow simpler ref. here.

XENOMAI kernel

I would need to install a xenomai kernel through whatever the default procedure to update kernel is on the BBAI. I will also need to install the user-space Xenomai library as well. That MAY be available through apt-get (Xenomai >= 3.0), or it can be easily built from source.

Hardware required

The hardware listed below will be necessary for testing if my code implementation works correctly on the hardware.

  1. BeagleBone AI.
  2. Bela cape: The original Bela board.


Timeline
Mar 29 Applications open Students register with GSoC, work on proposal with mentors.
Apr 13 Proposal complete Submitted to https://summerofcode.withgoogle.com
May 17 Proposal accepted or rejected
  1. Community Bonding Period and discussion on the project and resources available.
  2. Setting up beaglebone-ai i.e flashing up to date Linux image and connect to local area network (LAN) via either Ethernet or WiFi and try to run bare_minimum code from this repository to test basic stuff is working.
Jun 07 Pre-work complete, Coding officially begins!
  1. All the boards and additional hardware will be available to me at this period of time and I should have set up my BeagleBone Black and Ai boards i.e flashing up to date Linux image and Testing user-led blink code :)
  2. Initial checks for hardware like audio ports and other peripheral devices will be completed and all the soldering related work will be done.
  3. A detailed spreadsheet will be created if not already available for cape pin mapping and referencing for further use during BeagleBone AI software development ease.

(above ref. from here )

Jun 17 Milestone #1,
  1. Introductory YouTube video
  2. Setting pinmux values appropriately and fix the dtb to get the correct clock on the McASP MCLK pin.
  3. verify it works running with ALSA using the BB-BONE-AUDI overlay.
June 24 Milestone #2
  1. test and debug running Bela's PRU code on BBAI
June 30 Milestone #3
  1. Try to run Bela without Xenomai (This requires changing a few calls to __wrap_pthread_...() in the Bela core code to pthread_...() and minor changes.)
  2. run Bela with Xenomai, without rtdm(Real-time data monitoring) ie. generate (PRU->ARM interrupts)
  3. Document everything done so far and make READMEs for undocumented but pre-existing codes(for eg: this) .
July 12 18:00 UTC Milestone #4

Mentors and students can begin submitting Phase 1 evaluations

July 16 18:00 UTC Phase 1 Evaluation deadline
July 23 Milestone #5
  1. run Bela with Xenomai, with (PRU->ARM interrupts)
  2. Try to run all the stock tutorials
July 30 Milestone #6
  1. Validate existing work with some functional tests.
  2. Test and debug if any errors occur while running the stock tutorials and functional tests.
  3. Start organizing the codes so far by adding comments and making variable readable.
Aug 06 Milestone #7
  1. Create detailed Documentation about the above implementation.
  2. Provide guides on how to provide support for upcoming TI processors into the existing code base.
August 10 Milestone #8
  1. Writing the overall project summary and outcomes.
  2. Start making the Completion YouTube video.
August 16 - 26 18:00 UTC Final week: Students submit their final work product and their final mentor evaluation
August 23 - 30 18:00 UTC Mentors submit final student evaluations

Experience and approach

  1. I have used C++, C and Python programming languages over the past 3 years in a variety of projects involving embedded systems using the ESP32, Arduino UNO, ESP8266 and am also well-versed with freeRTOS.
  2. I have an aptitude for writing good reports and blogs, and have written a small blog on how to use a debugger.
  3. I recently did a project using ESP32, in which I used the DHT11 sensor to display humidity and temperature on a local HTML server . Other than that I have worked on developing hardware and making documentation for a 3 DOF arm based on an ESP32 custom board.
  4. I also interned at an embedded device startup where I
    1. Interfaced ADS1115 ADC with the ESP32 and used it to read battery voltage.
    2. Used UART for ESP32 and SIMCOM SIM 7600IE communication to gain LTE support.
    3. Published local sensor data to the cloud via LTE.
  5. I actively contribute to open source (most recently, I contributed to the ADS1115 library for ESP32 on the unclerus repo and can be seen here).
  6. Currently I am working on designing a Development board for the Raspberry Pico (RP2040) using KiCAD.
  7. I also do a lot of mini projects throughout the year, you can find my several more interesting projects at my github page

Contingency

I believe that if I get stuck on my project and my mentor isn’t around, I will use the resources that are available to me. Some of those information portals are listed below.

  1. Derek Molloy's beagle bone guide provides all the information needed for getting up and running with my beagle.
  2. Content on e-ALE.org is very useful for information that ranges from tutorials and walkthroughs to the level of very advanced stuff.
  3. https://credentiality2.blogspot.com/2015/09/beaglebone-pru-gpio-example.html

Benefit

If successfully completed, this project will add support for the Bela cape + Xenomai + PRU on the BeagleBone AI, and also the code will be easier to port to other Texas Instruments systems-on-chip.

By going through the steps needed to have the Bela environment running on BBAI, we will go through refactoring and rationalisation, using mainline drivers and APIs where possible. This will make Bela easier to maintain and to port to new platforms, benefiting the project's longevity and allowing it to expand its user base. -Giulio Moro

Misc

Completed all the requirements listed on the ideas page.
The code for the cross-compilation task can be found here submitted through pull request #149.