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Are We Embedded Yet

=====================

## D7018E - Special Studies in Embedded Systems

Disclaimer: This document is in beta state!!!!! Just to give a hint how the course will look like.

The course will be given as a self study course with a set of introductional seminars and accompanying mandatory assignments, followed by a larger assignment (project). The project can be carried out individually or in groups depending on size. Grading will be individual, based on agreed requirements between the student and the teacher, showing understanding and abilities regarding:

The course will be given as a self study course with a set of introduction seminars and accompanying mandatory assignments, followed by a larger assignment (project). The project can be carried out individually or in groups depending on size. Grading will be individual, based on agreed requirements between the student and the teacher, showing understanding and abilities regarding:

1. The Rust ecosystem. [ecosystem](doc/Ecosystem.md)

8. Building and debugging embedded code in Rust

    Hardware abstractions using svd2rust (autogenerated from vendor-provided SVD specifications). Compiling using xargo. Setting up openocd and gdb.

    Hardware abstractions using svd2rust (auto-generated from vendor-provided SVD specifications). Compiling using xargo. Setting up openocd and gdb.

9. Pre-processing

    Custom build.rs build scripts, and the RTFM Concurrent Reactive Component model.

There will be two presentation rounds (at end of LP2 and LP3). Students taking (too many other) courses during LP2 may choose to present their project at end of LP3 (instead of LP2). Presentations will be oral, where the student(s), will present and demonstrate their work.

Projects should be related to embedded programming, either on the target side (some application using the RTFM-core or CRC model), or on the host side, communicating with an embedded target running Rust RTFM. E.g., two groups can work together with building a system, e.g., with back-end processing of data collected by the embedded system, or by providing a front-end to the embedded system. Alternatively, host side project could relate the development of the RTFM-core/ RTFM-CRC frameworks or related tools (e.g. LLWM-KLEE as a backend for analysis of Rust code).

Projects should be related to embedded programming, either on the target side (some application using the RTFM-core or CRC model), or on the host side, communicating with an embedded target running Rust RTFM. E.g., two groups can work together with building a system, e.g., with back-end processing of data collected by the embedded system, or by providing a front-end to the embedded system. Alternatively, host side project could relate the development of the RTFM-core/ RTFM-CRC frameworks or related tools (e.g. LLVM-KLEE as a back-end for analysis of Rust code).

## Resources

Students will carry out the assignments on their personal laptops (in case you don't have a working laptop we will try to lend you one). Tools used are available for Linux and OSX, but with a bit of trickery windows based installations should be possible (but you are on your own here). In case you don't run OSX/Linux native, virtual box or VMware is possible, though debugging of target MCUs are feasible it is a bit more tricky.

    * Topic [Memory](doc/Memory.md)

        In-depth discussion of underlying theory, linear types (relation to functional programming). The *Affine* type system of Rust, requirements on the programmer, and guarantees offered by the compiler. Lifetimes, of stack allocated and global variables. Relation to C++ `unique pointers`.

    * Assignment

    * Assignment 3

        a. Recall the D0013E course lab2/4, where you decrypted a message in assembler (lab2) and C (lab 4). Now, let's re-implement the lab in Rust (base your development on group number [1's](http://www.sm.luth.se/csee/courses/smd/D0013E/labs/lab1underlag/grupp_01.lab1_underlag.s ) lab assignment).

        The `seed`, `abc`,`coded` and `plain` should be stack allocated. The decoded string should be printed when decryption is finished.

        b. Make the `seed`, `abc`,`coded` and `plain` heap allocated. Accessing those will require some `unsafe` code. (Keep the unsafe blocks as local as possible, perhaps you can do all in *safe* Rust.)

        b. Make the `seed`, `abc`,`coded` and `plain` static (heap) allocated (i.e., as global variables). Accessing those will require some `unsafe` code. (Keep the unsafe blocks as local as possible.)

        c. Safety analysis. Provoke the implementation, by omitting the `'\0'` (null termination). Observe the result and motivate the behavior in terms of your understanding of the Rust memory model. Under which circumstances do you consider 3a and 3b to have same/different memory safety.

4. Cortex-M, are we embedded yet

    * Preparation

        Finish assignment 3. Bring a USB mini cable, and/or your Cortex M dev board of choice.

        Finish assignment 3. Bring a USB mini cable, and/or your Cortex M dev board of choice. We will provide Nucleo 64s (STM32f401re/STM32f411re if you do not have a board.)

    * Topic

        Embedded programming in Rust. 

        Embedded programming in Rust. Check this [document](doc/Quickstart.md)

        * xargo for building non-`std` (bare metal) systems

        * [cortex-m-quickstart]

        * [cortex-m]

        * [bluepill/nucleo] crates

        * `cortex-m-quickstart`, project template

        * `cortex-m`, crate common to all Cortex-M devices

        * `stm32f103xx` and `stm32f40x`, device crates

        * `blue-pill` and `nucleo` board support crates

        * Building and debugging your first application.

    * Assignment

    * Assignment 4

        a. Backport assignment `3b` to your chosen target. Use semihosting in order to `write` the resulting string to the host. You may need to use `--release` for decoding the long (`coded`) message, as being deeply recursive unoptimized code may run out of stack memory.

        a. Backport assignment `3b` to your chosen target. Use semi-hosting in order to `write` the resulting string to the host. You may need to use `--release` for decoding the long (`coded`) message, as being deeply recursive unoptimized code may run out of stack memory.

        b. Discuss from a memory safety perspective the outcome.

        c. Compare for the short message (`abc`), the number of cycles required for `decode` in debug (standard) vs. `--release`. As a comparison my straightforword C implementation took 2200 cycles in best optimized mode using `gcc` (-o3), while my (transation) to Rust code took 1780 cycles. (Both executed on a bluepill board at 8MHz without (flash) memory wait states).

        c. Compare for the short message (`abc`), the number of cycles required for `decode` in debug (standard) vs. `--release`. As a comparison my straightforward C implementation took 2200 cycles in best optimized mode using `gcc` (-o3), while my (translation) to Rust code took 1780 cycles (--release). (Both executed on a bluepill board at 8MHz without (flash) memory wait states).

        Make a new git for your embedded development. Make three branches (`3a, 3b, 3c`) with updated documentation according to the above.

        Make a new git for your embedded development. Make three branches (`4a, 4b, 4c`) with updated documentation according to the above.

5. Advanced Rust Concepts

    * Preparation

        Be prepared to present the progress on assignment 3.

        Be prepared to present the progress on assignment 4.

    * Topic

        Advanced Rust features, trait system and closures.

        * [13 - Functional Language Features in Rust](https://doc.rust-lang.org/book/second-edition/ch13-00-functional-features.html).

    * Assignment

        Continue working on assignment 3.

        Continue working on assignment 4.

6. Memory Safe Concurrency

    * Preparation

        * Finish lab 3 and be prepared to show your solution.

        * Finish assignment 4 and be prepared to show your solution.

    * Topic

        * UnsafeCell, and synchronization in the RTFM model.

        * [cortex-m-rtfm](https://github.com/japaric/cortex-m-rtfm) The RTFM-core (task and resource model) in Rust for the Cortex-M family

        * [svd2rust](https://github.com/japaric/svd2rust) Generating

    * Assignment 4

    * Assignment 5

        Implement a simple system with 3 tasks

        Implement a simple system with two tasks

        * A periodic task executing each Xms (free of accumulated drift, and with minimal jitter), that blinks the on-board LED, and

        * A USART task receiving commands (pause, start, period 1-1000ms), received commands should be parsed and corresponding responses generated and sent over the USART. (Come up with a nice and simple user interface.)

        * A a logging task, run each second (period 1s), that prints statistics of CPU usage over the ITM port

        * Idle should gather statics on sleep/up time, (there is a sleep counter in the cortex core) 

        * Use shared resources (data structures) to ensure race free execution

        * a periodic task executing each 10ms, that blinks the onboard LED, and

        * USART task receiving commands (pause, start, period)

        * a shared resource (data structure) protecting the command and period

        You may use the core systic timer (relative) and the dwt cycle counter (absolute) in combination to achieve drift free timing. Alternative you look into the stm32f4xx timer peripheral. There is a support crate for the [STM32F3DISCOVERY](https://github.com/japaric/f3) board. Peripherals are similar so you may "borrow" code from there.

        Make a new git with the development and documentation.

7. Macros

    * Preparation

        Optional:

        Find a way to measure the power consumption. A possible solution is to power the board externally and use a power cube with current measuring capability. Alternative use an external power source with known charge (e.g., a "capacitor"), and measure the discharge time (start and residue charge at brown-out voltage), at least a precise relative measure is possible to obtain. 

        Be prepared to present the progress on assignment 4.

    * Topic

        Operation without being connected to the USB port: in this case the serial IO and ITM needs to be connected externally (e.g., using some ftdi serial-USB).

        Super optional:

        Try to minimize power consumption while maintaining desired operation. Lowering supply voltage and using aggressive power modes of the processor might be applied. (Not sure how USART/ITM communication can be made possible at sub 3.3v voltages. Also you have to make sure not to source the board over the communication interfaces.)

        We will cover the implementation of the RTFM-core crate.

        Special focus to `macro_rules` and `procedural macros`.

8. Concurrent Reactive Objects

7. Macros and Projects (Monday Nov. 20th)

    * Preparation 

        Be prepared to present assignment 4.

        Be prepared to present the progress on assignment 5.

    * Topic

        A component model for reactive real-time programming.

        We will cover the programming model and the implementation, including the `build.rs`, parsing of model files and generation of Rust code.

    * Assignment 5

        * port the assignment 4 to the RTFM-CRC model.

        - We will cover the implementation of the rtfm-core and the cortex-m-rtfm crates. For details see [RTFM](doc/RTFM.md).

        Make a new git for the development and documentation.

          Special focus to `macro_rules` and `procedural macros`.

        - RTFM-CRC A component model for reactive real-time programming.

9.  Presentation of project ideas

    * Preparation

          We will cover the programming model and the implementation, including the `build.rs`, parsing of model files and generation of Rust code.

        Be prepared to present progress of assignment 5.

    * Topic

        Discussion of projects

        - Discussion of project ideas

    * Assignment

        Write a project specification including individual grading assessment criteria.

10. Wrap-up 

8. Wrap-up (Monday Dec. 4th)

    * Preparation

        * Be prepared to present assignment 5.

        * Be prepared to present your project.

        * Be prepared to present your project, 10 minutes per project.

        * A good idea is to prepare a git for the project with a `README.md` and use that as supporting material for your presentation. Its advicable to have a section (or in a doc sub folder) where you collect references to the material you will use, i.e., links to data sheets, links to other related crates and projects of importance to your project. 

        This type of reference section will be largely helpful to both you (during the project and afterwards maintaining it, but also to other users and people interested in your work). Moreover, from a "course" perspective it shows that you have done the necessary background studies BEFORE you "hack away". Of corse this will be a living document, updated throughout the project, but its a very good thing to start out NOW, then it can be used for your 10 minutes of fame!

The [rustup](https://www.rustup.rs/), tool manager allows you to manage multiple tool chain installations. Rust is distributed in three channels (`stable`, `beta` and `nightly`). You may set the default toolchain:

```

rustup default nightly-2017-10-22-x86_64-unknown-linux-gnu 

rustup default nightly-2018-01-10-x86_64-unknown-linux-gnu 

```

and get information on the status of `rustup`

```

rustup show

```

Nightly tool chains allow for the development of libraries and applications including `unsafe` code using features not available on the `stable channel` (which will be necessary for the later exercises). For some tools to work (`rls/rustfmt`), you need to install additional components. For this to work, you should use a nightly toolchain for which all tools and components work (currently `nightly-2017-10-30` is the latest). Here is an example:

Nightly tool chains allow for the development of libraries and applications including `unsafe` code using features not available on the `stable channel` (which will be necessary for the later exercises). For some tools to work (`rls/rustfmt`), you need to install additional components. For this to work, you should use a nightly toolchain for which all tools and components work (currently `nightly-2018-01-10` is the latest). Here is an example:

```

rustup default nightly-2017-10-30

rustup default nightly-2018-01-10

rustup component add rls-preview

rustup component add rust-analysis

rustup component add rust-src

See [rls](https://marketplace.visualstudio.com/items?itemName=rust-lang.rust) for installing the RLS extension.

You will need to pin the specific toolchain version used, by setting the `"rust-client.channel": "nightly-2017-10-30"` in your `vscode` *user* settings (this will be stored in a file `~/.config/Code/User/settings.json` and used for all your `vscode` projects. Settings may be set individually for each *workspace*, overriding the defaults. Regarding the  `"rust-client.channel"` setting, a *workspace* setting would force the specific version (overriding the default), and may not work when the code is distributed (as other developers may be on other toolchains).

You will need to pin the specific toolchain version used, by setting the `"rust-client.channel": "nightly-2018-01-10"` in your `vscode` *user* settings (this will be stored in a file `~/.config/Code/User/settings.json` and used for all your `vscode` projects. Settings may be set individually for each *workspace*, overriding the defaults. Regarding the  `"rust-client.channel"` setting, a *workspace* setting would force the specific version (overriding the default), and may not work when the code is distributed (as other developers may be on other toolchains).

For RLS to work, `vscode` need a path to the `rls-preview` library (using the environment variable `LD_LIBRARY_PATH` (Linux), `DYLD_LIBRARY_PATH` (OSX ?)). 

```

In short, the complilation process can be broken down to the following steps:

1. Parsing input

    * this processes the .rs files and produces the AST ("abstract syntax tree")

    * the AST is defined in syntax/ast.rs. It is intended to match the lexical syntax of the Rust language quite closely.

2. Name resolution, macro expansion, and configuration

    * once parsing is complete, we process the AST recursively,     resolving paths and expanding macros. This same process         also processes `#[cfg]` nodes, and hence may strip thingsout of the AST as well.

3. Lowering to HIR

    * Once name resolution completes, we convert the AST into the HIR, or "high-level IR". 

    * The HIR is a lightly desugared variant of the AST. It is more processed than the AST and more suitable for the analyses that follow. 

4. Type-checking and subsequent analyses

    * An important step in processing the HIR is to perform type checking. This process assigns types to every HIR expression, and also is responsible for resolving some "type-dependent" paths, such as field accesses (`x.f`)

5. Lowering to MIR and post-processing

    * Once type-checking is done, we can lower the HIR into MIR ("middle IR"), which is a very desugared version of Rust.

    Here is where the borrow checking is done!!!!

6. Translation to LLVM and LLVM optimizations

    * From MIR, we can produce LLVM IR.

    LLVM then runs its various optimizations, which produces a number of .o files (one for each "codegen unit").

7. Linking

    Finally, those .o files are linked together.

### LLVM

# Nucleo 64

A collection of documentation, tricks and tips regarding the ST Nucleo 64 development kit.

# STM32 Nucleo-64 Board

A collection of documentation, tricks and tips regarding the STM32 Nucleo-64 Board (development kit).

We will mainly cover the `stm32f401re` and `stm32f411re` as these models.

We will mainly cover the `stm32f401re` and `stm32f411re` as these models (main difference is the higher maximum clock frequency of the `stm32f411re`).

---

## Stlink inteface

The nucleo-64 platform has an onboard `stlink-v2.1` SWD interface (programmer) supported by `openocd`. By default the programmer is connected to the target (`stm32f401re` or similar). 

---

### Programming external targets

You may use the board as a programmer (connector `CN4` SWD), in that case you should remove the `CN3` jumpers, and optionally desolder `SB15` (SWO) and `SB12` (NRST). See board documentation for details. 

## Links

* [Nucleo-64 board](http://www.st.com/content/ccc/resource/technical/document/user_manual/98/2e/fa/4b/e0/82/43/b7/DM00105823.pdf/files/DM00105823.pdf/jcr:content/translations/en.DM00105823.pdf) 

    Board documentation.

* [Firmware Upgrade](http://www.st.com/en/development-tools/stsw-link007.html)

    Standalone java program.

# Clocking

* [Note on Overclocking](https://stm32f4-discovery.net/2014/11/overclock-stm32f4-device-up-to-250mhz/)

# Course description

In order to be officially enrolled for the course each student need to write (and submit) an individual course plan including grading goals and assessments based on this document. 

Assignments are mandatory (as detailed in the README.md). 

- Each student should for each assigment 2, .., 5 comment (make an `issue` and/or `pull request` to one other `git`). Comments should be meaningful and constructive. For the assigment 2, .., 5 you should comment on different groups. Strive to spread comments so that each group will get at least one comment for each assignment.

- Each student/group should attend `issues`/`pull request`

Projects should aim to further cover the learning goals as stated in the README.md. 

## Blooms taxonomy 

Blooms taxonomy assess the (increasing) level of understanding as:

- Remember

- Understand

- Apply

- Evaluate

- Create.

(In the original taxonomy Evaluate was set at a higher level than Create.)

 Well its not the only one. 

 ## The SOLO taxonomy

 The SOLO taxonomy can be summarised:

-   Prestructural - Incompetence: fail, incompetent, missing the point 

-   Unistructural - One relevant aspect: identify, name, follow simple procedure

-    Multistructural - Several relevant inedendent aspects: combine, describe, enumerate, perform serial skills, list

-    Relational - Aspects integrated into a structure: analyze, apply, argue, compare/contrast, critisze, explain causes, relate, justify,

-    Extended Abstract - Asprects generalized to new domain: create, formulate, generate, hypothesize, reflect, theorize

The advantage of the SOLO taxonomy is that you have progression towards generalization (while the Bloom taxonomy allows progression in isolation). 

How can such "mumbo jumbo" be useful towards setting the goals and assessment criteria for Your project? Project assessment is not an easy task and there is no single correct answer to it, so let's study an example.

---

## Example HW AES Support for cortex-m.

- Grade 5. The project aims to `create` an API and library allowing end user memory safe access to the underlying AES hardware of the target platform. The API will provide the features A, B, C, and D, with correcness argued from the evaluation.

- Grade 4. The API/library will be based on an `evalution` (analysis) or requirements and possible solutions based on the Rust Memory model and the `cortex-m-rtfm` task/resource model. 

- Grade 3. Low level access to the AES hardware, by `applying`, provided primitives by the Rust language and the `cortex-m-rtfm` library. 

---

## Grading

So basically for grade 3 you show that you understand and can apply known methods and provided material. For grade 4, you show that you can make judgements on designs choices. And for grade 5, you put it all together, practical understaning and theoretical judgements. For the example for grade 5, you will show to combine knowledge and understanding of both software and hardware architecture and the theoretical concerns of a sound implementation.

Assessment/evalutation is individual. If you work together in a group, you should detail the description, e.g., student X will focus on the features A and B, while studen Y will focucs C and D.

## Amount versus quality. 

The amount of work required to make a complete solution is VERY hard to predict (even industry stuggles with such questions). However in industry a track record of previous projects serves as a baseline, here we face a much harder problem, You are likely new to the topic.

Thus, if you along the project see that covering a complete solution (in this case features A-D) is out of reach (or that when doing the grade 3 you find that B and D is not possible for some reason) you are free to make restrictions (meaning that its ok to drop features provided a motivation). However quality is not to be compromised. Shortcutting the design/evaluation in favour of more features is NOT getting you a higher grade. Ultimatetely, you can still get a grade 5, even if the project fails to meet its goals (provided that the quality of the work done holds up). This is where industry and academia largly differs!

## Engineering

You are becoming engineers, to that end I believe Bloom's taxonomy to a good fit (simle to apply), you will become experts at engineering in your field. Of course this does not prohibit generalization, but the point here is NOT to show the socioeconamical impact and political issues of AES encryption, but rather to engineer a solution. (Actually, we are subject to political issues regarding AES - due to US export restrictions the Nucleo boards are shipped without HW AES, but thats another story.)

# Instructions, what to turn in

For each student

Create a git with a README.md with

- Course name : "d7018e - special studies in embedded systems"

- name, mail address and personal number

- title of your project

- project description (here you may share text with your partner) and grading goals (individual)

I will give feedback to the git (an issue). When we have an agreement you will print the READE.md as a `pdf` and send to edusrt@ltu.se (with the title "d7018e - special studies in embedded systems", so you can be officially admitted and enrolled.

# Suggested projects

---

## Printing device (William)

- Rotating stick with LEDs at the end of the stick that can "print" text by switching the LEDs on and off with the right timings.

---

## Seer (Nils)

Symbolic execution engine for MIR internal format

- Study and understand the Z3 API

- Study and understand the user API (maybe add more functionalty)

- Study outsets for program verification based on seer

---

## LED Audio (John)

- Modulate LED colors and intensity according to audio input

---

## Drivers for NXP (Axel)

---

## WCET analysis for RTFM models using KLEE (Henrik)

- Automated testebed, integrated as cargo sub-command

---

## USB-Hid (Johannes)

---

## ETM Tracing 

- Develop an API for setting up ETM trace

[ARM](https://www.arm.com/files/pdf/AT_-_Advanced_Debug_of_Cortex-M_Systems.pdf)

---

## AES Encryption in hardware (Viktor)

- Develop on API for hardware supported AES encryption

---

## CAN bus API and Wheel Sensor implementation

- Develop a CAN bus API for cortex-m0

- Implement a wheel sensor for existing model car

---

## Stack Memory Analysis

- Seer or KLEE based path/call graph extraction

- Target code analysis, per function stack usage

- Static worst case stack analysis for RTFM and/or RTFM-TTA

---

## Ethernet driver for TCP/UDP/IP stack (Jonas)

- Develop driver and integrate to existing TCP/UDP/IP stack

---

## Nucleo 64 support crate

- Drivers for the Nucleo 64, stm32f401re/stm32f411re, similar to the f3/bluepill support crates

---

## Time Triggered Architecture (RTFM-TTA) 

- Periodic timers

- Communication channels/message buffers 

- Static analysis (for safely bound buffers)

- Static analysis for data aging (opitmal ordering?)

---

## Your ideas...

 No newline at end of file