├── .githooks └── pre-commit ├── .gitignore ├── .gitmodules ├── LICENSE.txt ├── README.md ├── TODO.txt ├── build.zig ├── fe310_g000.ld ├── flash ├── openocd.cfg ├── slipmux ├── coap.go ├── dispatcher.go ├── go.mod ├── go.sum ├── main.go ├── serial.go └── slow_writer.go └── src ├── clock.c ├── console.zig ├── crc.zig ├── gpio.zig ├── init.zig ├── irq.S ├── main.zig ├── periph.zig ├── plic.zig ├── slipmux.zig ├── start.S └── uart.zig /.githooks/pre-commit: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | 3 | # XXX: Unfourtunatly, it's difficult to differentiate between a 4 | # `zig fmt` usage error and an "found unformated file"-error. 5 | # To workaround this, we only check the output not the exit code. 6 | files=$(git diff-index --name-only --cached HEAD -- '*.zig' | \ 7 | xargs zig fmt --check 2>&1 | \ 8 | grep -v "expected at least one source file argument") 9 | 10 | if [ -n "$files" ]; then 11 | printf "The following files need to be formated with 'zig fmt':\n\n" 1>&2 12 | printf "%s\n" "$files" | sed 's/^/\t/g' 1>&2 13 | exit 1 14 | fi 15 | -------------------------------------------------------------------------------- /.gitignore: -------------------------------------------------------------------------------- 1 | zig-cache 2 | zig-out 3 | slipmux/slipmux 4 | -------------------------------------------------------------------------------- /.gitmodules: -------------------------------------------------------------------------------- 1 | [submodule "zoap"] 2 | path = zoap 3 | url = https://git.8pit.net/zoap.git 4 | -------------------------------------------------------------------------------- /LICENSE.txt: -------------------------------------------------------------------------------- 1 | GNU AFFERO GENERAL PUBLIC LICENSE 2 | Version 3, 19 November 2007 3 | 4 | Copyright (C) 2007 Free Software Foundation, Inc. 5 | Everyone is permitted to copy and distribute verbatim copies 6 | of this license document, but changing it is not allowed. 7 | 8 | Preamble 9 | 10 | The GNU Affero General Public License is a free, copyleft license for 11 | software and other kinds of works, specifically designed to ensure 12 | cooperation with the community in the case of network server software. 13 | 14 | The licenses for most software and other practical works are designed 15 | to take away your freedom to share and change the works. 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Limitation of Liability. 599 | 600 | IN NO EVENT UNLESS REQUIRED BY APPLICABLE LAW OR AGREED TO IN WRITING 601 | WILL ANY COPYRIGHT HOLDER, OR ANY OTHER PARTY WHO MODIFIES AND/OR CONVEYS 602 | THE PROGRAM AS PERMITTED ABOVE, BE LIABLE TO YOU FOR DAMAGES, INCLUDING ANY 603 | GENERAL, SPECIAL, INCIDENTAL OR CONSEQUENTIAL DAMAGES ARISING OUT OF THE 604 | USE OR INABILITY TO USE THE PROGRAM (INCLUDING BUT NOT LIMITED TO LOSS OF 605 | DATA OR DATA BEING RENDERED INACCURATE OR LOSSES SUSTAINED BY YOU OR THIRD 606 | PARTIES OR A FAILURE OF THE PROGRAM TO OPERATE WITH ANY OTHER PROGRAMS), 607 | EVEN IF SUCH HOLDER OR OTHER PARTY HAS BEEN ADVISED OF THE POSSIBILITY OF 608 | SUCH DAMAGES. 609 | 610 | 17. Interpretation of Sections 15 and 16. 611 | 612 | If the disclaimer of warranty and limitation of liability provided 613 | above cannot be given local legal effect according to their terms, 614 | reviewing courts shall apply local law that most closely approximates 615 | an absolute waiver of all civil liability in connection with the 616 | Program, unless a warranty or assumption of liability accompanies a 617 | copy of the Program in return for a fee. 618 | 619 | END OF TERMS AND CONDITIONS 620 | 621 | How to Apply These Terms to Your New Programs 622 | 623 | If you develop a new program, and you want it to be of the greatest 624 | possible use to the public, the best way to achieve this is to make it 625 | free software which everyone can redistribute and change under these terms. 626 | 627 | To do so, attach the following notices to the program. It is safest 628 | to attach them to the start of each source file to most effectively 629 | state the exclusion of warranty; and each file should have at least 630 | the "copyright" line and a pointer to where the full notice is found. 631 | 632 | 633 | Copyright (C) 634 | 635 | This program is free software: you can redistribute it and/or modify 636 | it under the terms of the GNU Affero General Public License as published by 637 | the Free Software Foundation, either version 3 of the License, or 638 | (at your option) any later version. 639 | 640 | This program is distributed in the hope that it will be useful, 641 | but WITHOUT ANY WARRANTY; without even the implied warranty of 642 | MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the 643 | GNU Affero General Public License for more details. 644 | 645 | You should have received a copy of the GNU Affero General Public License 646 | along with this program. If not, see . 647 | 648 | Also add information on how to contact you by electronic and paper mail. 649 | 650 | If your software can interact with users remotely through a computer 651 | network, you should also make sure that it provides a way for users to 652 | get its source. For example, if your program is a web application, its 653 | interface could display a "Source" link that leads users to an archive 654 | of the code. There are many ways you could offer source, and different 655 | solutions will be better for different programs; see section 13 for the 656 | specific requirements. 657 | 658 | You should also get your employer (if you work as a programmer) or school, 659 | if any, to sign a "copyright disclaimer" for the program, if necessary. 660 | For more information on this, and how to apply and follow the GNU AGPL, see 661 | . 662 | -------------------------------------------------------------------------------- /README.md: -------------------------------------------------------------------------------- 1 | # zig-riscv-embedded 2 | 3 | Experimental [Zig][zig website]-based [CoAP][rfc7252] node for the [HiFive1][hifive1 website] RISC-V board. 4 | 5 | ![World's first IoT-enabled Zig-based constrained node](https://gist.github.com/nmeum/9c921cac9e28e722a8415af3ff213e8c/raw/b936f1f05d5eda07a91a87efdaf5cb1552795ad1/output-2fps-960px.gif) 6 | 7 | ## Status 8 | 9 | This repository is intended to provide a simple sample application for 10 | experimenting with the Zig programming language on freestanding RISC-V. 11 | The application targets the [SiFive FE310-G000][fe310 manual] or more 12 | specifically the [HiFive 1][hifive1 website]. While possible to run the 13 | application on "real hardware", it can also be run using QEMU. In both 14 | cases it is possible to toggle an LED using [CoAP][rfc7252] over 15 | [SLIP][rfc1055]. 16 | 17 | ## CoAP over SLIP 18 | 19 | To experiment with external dependencies in Zig, this application 20 | provides a very bare bone implementation of [CoAP][rfc7252] using 21 | [zoap][zoap github]. Since implementing an entire UDP/IP stack from 22 | scratch is out-of-scope, this repository transports CoAP packets 23 | directly over [SLIP][rfc1055]. 24 | 25 | Unfortunately, the QFN48 package of the FE310-G000 (as used by the 26 | HiFive1) does not support the UART1. For this reason, the application 27 | multiplexes diagnostic messages and CoAP frames over the same UART 28 | (UART0) using [Slipmux][slipmux]. For this purpose, a Go-based 29 | multiplexer for the development system is available in the `./slipmux` 30 | subdirectory. 31 | 32 | ## Dependencies 33 | 34 | For building the software and the associated Slipmux tooling, the 35 | following software is required: 36 | 37 | * Zig `0.9.1` 38 | * [Go][golang web] for compiling the `./slipmux` tool 39 | * A CoAP client, e.g. `coap-client(1)` from [libcoap][libcoap github] 40 | * QEMU (`qemu-system-riscv32`) for emulating a HiFive1 (optional) 41 | 42 | For flashing to real hardware, the following software is required: 43 | 44 | * [riscv-openocd][riscv-openocd] 45 | * [GDB][gdb web] with 32-bit RISC-V support 46 | 47 | ## Building 48 | 49 | The Zig build system is used for building the application, the 50 | configuration is available in `build.zig`. To build the application run: 51 | 52 | $ zig build 53 | 54 | This will create a freestanding RISC-V ELF binary `zig-out/bin/main`. 55 | If the image should be booted on real hardware, building in the 56 | `ReleaseSmall` [build mode][zig build modes] may be desirable: 57 | 58 | $ zig build -Drelease-small 59 | 60 | Furthermore, the Slipmux multiplexer needs to be compiled using the 61 | following commands in order to receive diagnostic messages from the 62 | device and send CoAP messages to the device: 63 | 64 | $ cd slipmux && go build -trimpath 65 | 66 | ## Booting in QEMU 67 | 68 | In order to simulate a serial device, which can be used with the 69 | `./slipmux` tool, QEMU must be started as follows: 70 | 71 | $ qemu-system-riscv32 -M sifive_e -nographic -kernel zig-out/bin/main -serial pty 72 | 73 | QEMU will print the allocated PTY path to standard output. In a separate 74 | terminal the `./slipmux` tool can then be started as follows: 75 | 76 | $ ./slipmux/slipmux :2342 77 | 78 | This will create a UDP Socket on `localhost:2342`, CoAP packets send to 79 | this socket are converted into Slipmux CoAP frames and forwarded to the 80 | emulated HiFive1 over the allocated PTY. CoAP packets can be send using 81 | any CoAP client, e.g. using `coap-client(1)` from [libcoap][libcoap github]: 82 | 83 | $ coap-client -N -m put coap://[::1]:2342/on 84 | $ coap-client -N -m put coap://[::1]:2342/off 85 | 86 | In QEMU, this will cause debug messages to appear in the terminal window 87 | were `./slipmux` is running. On real hardware, it will also cause the 88 | red LED to be toggled. 89 | 90 | ## Booting on real hardware 91 | 92 | The binary can be flashed to real hardware using OpenOCD and gdb. For 93 | this purpose, a shell script is provided. In order to flash a compiled 94 | binary run the following command: 95 | 96 | $ ./flash 97 | 98 | After flashing the device, interactions through CoAP are possible using 99 | the instructions given for QEMU above. However, with real hardware 100 | `./slipmux` needs to be passed the TTY device for the HiFive1 (i.e. 101 | `/dev/ttyUSB0`). 102 | 103 | To debug errors on real hardware start OpenOCD using `openocd -f 104 | openocd.cfg`. In a separate terminal start a gdb version with RISC-V 105 | support (e.g. [gdb-multiarch][gdb-multiarch alpine]) as follows: 106 | 107 | $ gdb-multiarch -ex 'target extended-remote :3333' zig-out/bin/main 108 | 109 | ## Development 110 | 111 | A pre-commit git hook for checking if files are properly formated is 112 | provided in `.githooks`. It can be activated using: 113 | 114 | $ git config --local core.hooksPath .githooks 115 | 116 | ## License 117 | 118 | The application uses slightly modified linker scripts and assembler 119 | startup code copied from the [RIOT][riot fe310] operating system. Unless 120 | otherwise noted code written by myself is licensed under 121 | `AGPL-3.0-or-later`. Refer to the license headers of the different files 122 | for more information. 123 | 124 | [zig website]: https://ziglang.org/ 125 | [zig build modes]: https://ziglang.org/documentation/master/#Build-Mode 126 | [qemu website]: https://www.qemu.org/ 127 | [fe310 manual]: https://static.dev.sifive.com/FE310-G000.pdf 128 | [hifive1 website]: https://www.sifive.com/boards/hifive1 129 | [riot fe310]: https://github.com/RIOT-OS/RIOT/tree/master/cpu/fe310 130 | [slipmux]: https://datatracker.ietf.org/doc/html/draft-bormann-t2trg-slipmux-03 131 | [rfc7252]: https://datatracker.ietf.org/doc/html/rfc7252 132 | [rfc1055]: https://datatracker.ietf.org/doc/html/rfc1055 133 | [libcoap github]: https://github.com/obgm/libcoap 134 | [golang web]: https://golang.org 135 | [zoap github]: https://github.com/nmeum/zoap 136 | [riscv-openocd]: https://github.com/riscv/riscv-openocd 137 | [gdb web]: https://www.gnu.org/software/gdb/ 138 | [gdb-multiarch alpine]: https://pkgs.alpinelinux.org/package/edge/main/x86_64/gdb-multiarch 139 | -------------------------------------------------------------------------------- /TODO.txt: -------------------------------------------------------------------------------- 1 | * Add abstraction for PRCI 2 | * Rewrite src/clock.c in Zig 3 | * Make LED handler read payload to determine desired LED status 4 | * Allow setting all three LEDs 5 | * Will likely require some sort of subdispatcher code in zoap 6 | * That is, a subdispatcher for /led 7 | * Debug occasional "bad checksum" Slipmux errors 8 | * Buffer incoming UART data in a linear FIFO 9 | * To reduce time spend in interrupt handler 10 | * Use RISC-V atomic instructions for MMIO 11 | * For example, atomic_or etc. (see RIOT code) 12 | * To-Do: Figure out how Zig abstracts these instructions 13 | -------------------------------------------------------------------------------- /build.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2020-2021 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public License 14 | // along with this program. If not, see . 15 | 16 | const std = @import("std"); 17 | const Target = std.Target; 18 | const Zig = std.zig; 19 | const FileSource = std.build.FileSource; 20 | const Builder = std.build.Builder; 21 | const FeatureSet = std.Target.Cpu.Feature.Set; 22 | 23 | pub fn build(b: *Builder) void { 24 | var fe310_cpu_feat = FeatureSet.empty; 25 | const m: std.Target.riscv.Feature = .m; 26 | const a: std.Target.riscv.Feature = .a; 27 | const c: std.Target.riscv.Feature = .c; 28 | fe310_cpu_feat.addFeature(@enumToInt(a)); 29 | fe310_cpu_feat.addFeature(@enumToInt(m)); 30 | fe310_cpu_feat.addFeature(@enumToInt(c)); 31 | 32 | const target = Zig.CrossTarget{ 33 | .cpu_arch = Target.Cpu.Arch.riscv32, 34 | .os_tag = Target.Os.Tag.freestanding, 35 | .abi = Target.Abi.none, 36 | .cpu_features_sub = std.Target.riscv.cpu.baseline_rv32.features, 37 | .cpu_features_add = fe310_cpu_feat, 38 | }; 39 | 40 | const mode = b.standardReleaseOptions(); 41 | 42 | const exe = b.addExecutable("main", "src/init.zig"); 43 | exe.setLinkerScriptPath(FileSource{ .path = "fe310_g000.ld" }); 44 | exe.setTarget(target); 45 | exe.setBuildMode(mode); 46 | 47 | exe.addCSourceFile("src/start.S", &[_][]const u8{}); 48 | exe.addCSourceFile("src/irq.S", &[_][]const u8{}); 49 | exe.addCSourceFile("src/clock.c", &[_][]const u8{}); 50 | 51 | exe.addPackage(std.build.Pkg{ 52 | .name = "zoap", 53 | .path = FileSource{ .path = "./zoap/src/zoap.zig" }, 54 | }); 55 | 56 | b.default_step.dependOn(&exe.step); 57 | b.installArtifact(exe); 58 | } 59 | -------------------------------------------------------------------------------- /fe310_g000.ld: -------------------------------------------------------------------------------- 1 | /* 2 | * Copyright (C) 2017, 2019 Ken Rabold 3 | * 4 | * This file is subject to the terms and conditions of the GNU Lesser 5 | * General Public License v2.1. See the file LICENSE in the top level 6 | * directory for more details. 7 | */ 8 | 9 | OUTPUT_ARCH( "riscv" ) 10 | 11 | ENTRY( _start ) 12 | 13 | PHDRS 14 | { 15 | flash PT_LOAD; 16 | ram_init PT_LOAD; 17 | ram PT_NULL; 18 | } 19 | 20 | MEMORY 21 | { 22 | flash (rx) : ORIGIN = 0x20400000, LENGTH = 0x1fc00000 23 | ram (rwx) : ORIGIN = 0x80000000, LENGTH = 0x00004000 24 | itim (rwx) : ORIGIN = 0x08000000, LENGTH = 0x00002000 25 | } 26 | 27 | SECTIONS 28 | { 29 | __stack_size = DEFINED(__stack_size) ? __stack_size : 256; 30 | 31 | .init : 32 | { 33 | KEEP (*(SORT_NONE(.init))) 34 | } >flash AT>flash :flash 35 | 36 | .text : 37 | { 38 | *(.text.unlikely .text.unlikely.*) 39 | *(.text.startup .text.startup.*) 40 | *(.text .text.*) 41 | *(.gnu.linkonce.t.*) 42 | 43 | KEEP(*(.eh_frame*)) 44 | } >flash AT>flash :flash 45 | 46 | .fini : 47 | { 48 | KEEP (*(SORT_NONE(.fini))) 49 | } >flash AT>flash :flash 50 | 51 | PROVIDE (__etext = .); 52 | PROVIDE (_etext = .); 53 | PROVIDE (etext = .); 54 | 55 | .rodata : 56 | { 57 | *(.rdata) 58 | *(.rodata .rodata.*) 59 | *(.gnu.linkonce.r.*) 60 | } >flash AT>flash :flash 61 | 62 | . = ALIGN(4); 63 | 64 | .preinit_array : 65 | { 66 | PROVIDE_HIDDEN (__preinit_array_start = .); 67 | KEEP (*(.preinit_array)) 68 | PROVIDE_HIDDEN (__preinit_array_end = .); 69 | } >flash AT>flash :flash 70 | 71 | .init_array : 72 | { 73 | PROVIDE_HIDDEN (__init_array_start = .); 74 | KEEP (*(SORT_BY_INIT_PRIORITY(.init_array.*) SORT_BY_INIT_PRIORITY(.ctors.*))) 75 | KEEP (*(.init_array EXCLUDE_FILE (*crtbegin.o *crtbegin?.o *crtend.o *crtend?.o ) .ctors)) 76 | PROVIDE_HIDDEN (__init_array_end = .); 77 | } >flash AT>flash :flash 78 | 79 | .fini_array : 80 | { 81 | PROVIDE_HIDDEN (__fini_array_start = .); 82 | KEEP (*(SORT_BY_INIT_PRIORITY(.fini_array.*) SORT_BY_INIT_PRIORITY(.dtors.*))) 83 | KEEP (*(.fini_array EXCLUDE_FILE (*crtbegin.o *crtbegin?.o *crtend.o *crtend?.o ) .dtors)) 84 | PROVIDE_HIDDEN (__fini_array_end = .); 85 | } >flash AT>flash :flash 86 | 87 | .ctors : 88 | { 89 | /* gcc uses crtbegin.o to find the start of 90 | the constructors, so we make sure it is 91 | first. Because this is a wildcard, it 92 | doesn't matter if the user does not 93 | actually link against crtbegin.o; the 94 | linker won't look for a file to match a 95 | wildcard. The wildcard also means that it 96 | doesn't matter which directory crtbegin.o 97 | is in. */ 98 | KEEP (*crtbegin.o(.ctors)) 99 | KEEP (*crtbegin?.o(.ctors)) 100 | /* We don't want to include the .ctor section from 101 | the crtend.o file until after the sorted ctors. 102 | The .ctor section from the crtend file contains the 103 | end of ctors marker and it must be last */ 104 | KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o ) .ctors)) 105 | KEEP (*(SORT(.ctors.*))) 106 | KEEP (*(.ctors)) 107 | } >flash AT>flash :flash 108 | 109 | .dtors : 110 | { 111 | KEEP (*crtbegin.o(.dtors)) 112 | KEEP (*crtbegin?.o(.dtors)) 113 | KEEP (*(EXCLUDE_FILE (*crtend.o *crtend?.o ) .dtors)) 114 | KEEP (*(SORT(.dtors.*))) 115 | KEEP (*(.dtors)) 116 | } >flash AT>flash :flash 117 | 118 | .lalign : 119 | { 120 | . = ALIGN(4); 121 | PROVIDE( _data_lma = . ); 122 | } >flash AT>flash :flash 123 | 124 | .dalign : 125 | { 126 | . = ALIGN(4); 127 | PROVIDE( _data = . ); 128 | } >ram AT>flash :ram_init 129 | 130 | .data : 131 | { 132 | *(.ramfunc .ramfunc.*) 133 | *(.data .data.*) 134 | *(.gnu.linkonce.d.*) 135 | . = ALIGN(8); 136 | PROVIDE( __global_pointer$ = . + 0x800 ); 137 | *(.sdata .sdata.*) 138 | *(.gnu.linkonce.s.*) 139 | . = ALIGN(8); 140 | *(.srodata.cst16) 141 | *(.srodata.cst8) 142 | *(.srodata.cst4) 143 | *(.srodata.cst2) 144 | *(.srodata .srodata.*) 145 | } >ram AT>flash :ram_init 146 | 147 | . = ALIGN(4); 148 | PROVIDE( _edata = . ); 149 | PROVIDE( edata = . ); 150 | 151 | PROVIDE( _fbss = . ); 152 | PROVIDE( __bss_start = . ); 153 | .bss : 154 | { 155 | *(.sbss*) 156 | *(.gnu.linkonce.sb.*) 157 | *(.bss .bss.*) 158 | *(.gnu.linkonce.b.*) 159 | *(COMMON) 160 | . = ALIGN(4); 161 | } >ram AT>ram :ram 162 | 163 | . = ALIGN(8); 164 | PROVIDE( _end = . ); 165 | PROVIDE( end = . ); 166 | PROVIDE( _heap_start = . ); 167 | 168 | __StackTop = ORIGIN(ram) + LENGTH(ram); 169 | __StackLimit = __StackTop - __stack_size; 170 | PROVIDE(__stack = __StackTop); 171 | } 172 | -------------------------------------------------------------------------------- /flash: -------------------------------------------------------------------------------- 1 | #!/bin/sh 2 | # From https://github.com/sifive/freedom-e-sdk/blob/c07ac84cbdd678963c4dc3ea34a68c47a8b53651/scripts/upload 3 | # 4 | # Copyright (c) 2019 SiFive, Inc. 5 | # Licensed under Apache2 and MIT licenses. 6 | 7 | set -e 8 | 9 | ELF_FILE=./zig-out/bin/main 10 | export GDB_PORT=3333 11 | 12 | openocd -f openocd.cfg & 13 | 14 | gdb-multiarch $ELF_FILE --batch -ex "set remotetimeout 240" \ 15 | -ex "target extended-remote localhost:${GDB_PORT}" \ 16 | -ex "monitor reset halt" \ 17 | -ex "monitor flash protect 0 64 last off" \ 18 | -ex "thread apply all set \$pc=_enter" \ 19 | -ex "load" \ 20 | -ex "monitor resume" \ 21 | -ex "monitor shutdown" -ex "quit" 22 | -------------------------------------------------------------------------------- /openocd.cfg: -------------------------------------------------------------------------------- 1 | # From https://github.com/sifive/freedom-e-sdk/blob/c07ac84cbdd678963c4dc3ea34a68c47a8b53651/bsp/sifive-hifive1/openocd.cfg 2 | # 3 | # Copyright (c) 2019 SiFive, Inc. 4 | # Licensed under Apache2 and MIT licenses. 5 | 6 | # JTAG adapter setup 7 | adapter_khz 10000 8 | 9 | set chain_length 5 10 | 11 | interface ftdi 12 | ftdi_device_desc "Dual RS232-HS" 13 | ftdi_vid_pid 0x0403 0x6010 14 | 15 | ftdi_layout_init 0x0008 0x001b 16 | ftdi_layout_signal nSRST -oe 0x0020 17 | ftdi_layout_signal LED -data 0x0020 18 | 19 | set _CHIPNAME riscv 20 | jtag newtap $_CHIPNAME cpu -irlen $chain_length 21 | 22 | set _TARGETNAME_0 $_CHIPNAME.cpu 23 | 24 | target create $_TARGETNAME_0 riscv -chain-position $_TARGETNAME_0 25 | 26 | $_TARGETNAME_0 configure -work-area-phys 0x80000000 -work-area-size 0x2710 -work-area-backup 1 27 | 28 | if { $chain_length == 6 } { 29 | riscv use_bscan_tunnel 5 30 | } 31 | 32 | flash bank spi0 fespi 0x20000000 0 0 0 $_TARGETNAME_0 0x10014000 33 | 34 | init 35 | if { [info exists authkey] } { 36 | riscv authdata_write $authkey 37 | } 38 | 39 | if {[ info exists pulse_srst]} { 40 | ftdi_set_signal nSRST 0 41 | ftdi_set_signal nSRST z 42 | sleep 1500 43 | } 44 | halt 45 | 46 | flash protect 0 64 last off 47 | 48 | echo "Ready for Remote Connections" 49 | -------------------------------------------------------------------------------- /slipmux/coap.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "net" 5 | ) 6 | 7 | type CoapEndpoint struct { 8 | conn net.PacketConn 9 | lastAddr *net.Addr 10 | // XXX: mutex? 11 | 12 | RX <-chan []byte 13 | TX chan<- []byte 14 | } 15 | 16 | func NewCoapEP(addr string) (*CoapEndpoint, error) { 17 | conn, err := net.ListenPacket("udp", addr) 18 | if err != nil { 19 | return nil, err 20 | } 21 | 22 | rx := make(chan []byte) 23 | tx := make(chan []byte) 24 | 25 | ep := &CoapEndpoint{ 26 | conn: conn, 27 | lastAddr: nil, 28 | RX: rx, 29 | TX: tx, 30 | } 31 | 32 | go ep.sndLoop(tx) 33 | go ep.rcvLoop(rx) 34 | 35 | return ep, nil 36 | } 37 | 38 | func (c *CoapEndpoint) sndLoop(ch <-chan []byte) { 39 | for { 40 | data := <-ch 41 | 42 | if c.lastAddr == nil { 43 | logger.Println("[CoapEndpoint] Unexpected CoAP send") 44 | continue 45 | } 46 | 47 | _, err := c.conn.WriteTo(data, *c.lastAddr) 48 | if err != nil { 49 | logger.Println("[CoapEndpoint] WriteTo failed", err) 50 | continue 51 | } 52 | } 53 | } 54 | 55 | func (c *CoapEndpoint) rcvLoop(ch chan<- []byte) { 56 | buf := make([]byte, bufSize) 57 | 58 | for { 59 | n, addr, err := c.conn.ReadFrom(buf) 60 | if err != nil { 61 | logger.Println("[CoapEndpoint] ReadFrom failed", err) 62 | continue 63 | } 64 | 65 | c.lastAddr = &addr 66 | ch <- buf[0:n] 67 | } 68 | } 69 | 70 | func (c *CoapEndpoint) Close() { 71 | // close(c.Chan) 72 | c.conn.Close() 73 | } 74 | -------------------------------------------------------------------------------- /slipmux/dispatcher.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "os" 5 | 6 | "github.com/Lobaro/slip" 7 | ) 8 | 9 | type Dispatcher struct { 10 | coap *CoapEndpoint 11 | serial *SerialEndpoint 12 | } 13 | 14 | func (d *Dispatcher) handleCoap(data []byte) { 15 | d.serial.TX <- data 16 | } 17 | 18 | func (d *Dispatcher) handleSerial(pkt Packet) { 19 | switch pkt.FrameType { 20 | case slip.FRAME_DIAGNOSTIC: 21 | _, err := os.Stdout.WriteString(string(pkt.Data)) 22 | if err != nil { 23 | logger.Println("handleSerial:", err) 24 | } 25 | case slip.FRAME_COAP: 26 | d.coap.TX <- pkt.Data 27 | default: 28 | logger.Printf("handleSerial: Unsupported frame type: 0x%x\n", pkt.FrameType) 29 | } 30 | } 31 | 32 | func (d *Dispatcher) Run() { 33 | for { 34 | select { 35 | case data := <-d.coap.RX: 36 | d.handleCoap(data) 37 | case pkt := <-d.serial.RX: 38 | d.handleSerial(pkt) 39 | } 40 | } 41 | } 42 | -------------------------------------------------------------------------------- /slipmux/go.mod: -------------------------------------------------------------------------------- 1 | module github.com/nmeum/zig-riscv-embedded/slipmux 2 | 3 | go 1.17 4 | 5 | require ( 6 | github.com/Lobaro/slip v0.0.0-20170904164317-88dcb78414ea 7 | go.bug.st/serial v1.3.3 8 | ) 9 | 10 | require ( 11 | github.com/creack/goselect v0.1.2 // indirect 12 | golang.org/x/sys v0.0.0-20211004093028-2c5d950f24ef // indirect 13 | ) 14 | -------------------------------------------------------------------------------- /slipmux/go.sum: -------------------------------------------------------------------------------- 1 | github.com/Lobaro/slip v0.0.0-20170904164317-88dcb78414ea h1:lpHJkBxATbHlFRPGlD7/gU1LTyMNMkhpYKxCUT7Ynx0= 2 | github.com/Lobaro/slip v0.0.0-20170904164317-88dcb78414ea/go.mod h1:r5Qh0dZbKfQ+1KRK78WRCeStYKOIGr/cF/QrkjtH88s= 3 | github.com/creack/goselect v0.1.2 h1:2DNy14+JPjRBgPzAd1thbQp4BSIihxcBf0IXhQXDRa0= 4 | github.com/creack/goselect v0.1.2/go.mod h1:a/NhLweNvqIYMuxcMOuWY516Cimucms3DglDzQP3hKY= 5 | github.com/davecgh/go-spew v1.1.0 h1:ZDRjVQ15GmhC3fiQ8ni8+OwkZQO4DARzQgrnXU1Liz8= 6 | github.com/davecgh/go-spew v1.1.0/go.mod h1:J7Y8YcW2NihsgmVo/mv3lAwl/skON4iLHjSsI+c5H38= 7 | github.com/pmezard/go-difflib v1.0.0 h1:4DBwDE0NGyQoBHbLQYPwSUPoCMWR5BEzIk/f1lZbAQM= 8 | github.com/pmezard/go-difflib v1.0.0/go.mod h1:iKH77koFhYxTK1pcRnkKkqfTogsbg7gZNVY4sRDYZ/4= 9 | github.com/stretchr/objx v0.1.0/go.mod h1:HFkY916IF+rwdDfMAkV7OtwuqBVzrE8GR6GFx+wExME= 10 | github.com/stretchr/testify v1.4.0 h1:2E4SXV/wtOkTonXsotYi4li6zVWxYlZuYNCXe9XRJyk= 11 | github.com/stretchr/testify v1.4.0/go.mod h1:j7eGeouHqKxXV5pUuKE4zz7dFj8WfuZ+81PSLYec5m4= 12 | go.bug.st/serial v1.3.3 h1:lOSLGmZSB7qU6pSOaZqlRholjC8SmmFTGv4ib9oPwYo= 13 | go.bug.st/serial v1.3.3/go.mod h1:jDkjqASf/qSjmaOxHSHljwUQ6eHo/ZX/bxJLQqSlvZg= 14 | golang.org/x/sys v0.0.0-20210823070655-63515b42dcdf/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg= 15 | golang.org/x/sys v0.0.0-20211004093028-2c5d950f24ef h1:fPxZ3Umkct3LZ8gK9nbk+DWDJ9fstZa2grBn+lWVKPs= 16 | golang.org/x/sys v0.0.0-20211004093028-2c5d950f24ef/go.mod h1:oPkhp1MJrh7nUepCBck5+mAzfO9JrbApNNgaTdGDITg= 17 | gopkg.in/check.v1 v0.0.0-20161208181325-20d25e280405/go.mod h1:Co6ibVJAznAaIkqp8huTwlJQCZ016jof/cbN4VW5Yz0= 18 | gopkg.in/yaml.v2 v2.2.2 h1:ZCJp+EgiOT7lHqUV2J862kp8Qj64Jo6az82+3Td9dZw= 19 | gopkg.in/yaml.v2 v2.2.2/go.mod h1:hI93XBmqTisBFMUTm0b8Fm+jr3Dg1NNxqwp+5A1VGuI= 20 | -------------------------------------------------------------------------------- /slipmux/main.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "fmt" 5 | "log" 6 | "os" 7 | "path/filepath" 8 | ) 9 | 10 | const ( 11 | bufSize = 1024 12 | baudRate = 115200 13 | ) 14 | 15 | var ( 16 | out = os.Stdout 17 | err = os.Stderr 18 | ) 19 | 20 | var logger = log.New(err, "", log.Lshortfile) 21 | 22 | func main() { 23 | if len(os.Args) < 3 { 24 | fmt.Fprintf(os.Stderr, "USAGE: %s ADDR PATH\n", filepath.Base(os.Args[0])) 25 | os.Exit(1) 26 | } 27 | 28 | addr := os.Args[1] 29 | path := os.Args[2] 30 | 31 | cep, err := NewCoapEP(addr) 32 | if err != nil { 33 | logger.Fatal(err) 34 | } 35 | defer cep.Close() 36 | 37 | sep, err := NewSerialEP(path) 38 | if err != nil { 39 | logger.Fatal(err) 40 | } 41 | defer sep.Close() 42 | 43 | dispatcher := &Dispatcher{cep, sep} 44 | dispatcher.Run() 45 | } 46 | -------------------------------------------------------------------------------- /slipmux/serial.go: -------------------------------------------------------------------------------- 1 | package main 2 | 3 | import ( 4 | "bytes" 5 | "errors" 6 | 7 | "github.com/Lobaro/slip" 8 | "go.bug.st/serial" 9 | ) 10 | 11 | type Packet struct { 12 | FrameType byte 13 | Data []byte 14 | } 15 | 16 | type SerialEndpoint struct { 17 | port serial.Port 18 | 19 | RX <-chan Packet 20 | TX chan<- []byte 21 | } 22 | 23 | func NewSerialEP(path string) (*SerialEndpoint, error) { 24 | mode := &serial.Mode{ 25 | BaudRate: baudRate, 26 | DataBits: 8, 27 | Parity: serial.NoParity, 28 | StopBits: serial.OneStopBit, 29 | } 30 | 31 | port, err := serial.Open(path, mode) 32 | if err != nil { 33 | return nil, err 34 | } 35 | 36 | rx := make(chan Packet) 37 | tx := make(chan []byte) 38 | 39 | ep := &SerialEndpoint{ 40 | port: port, 41 | RX: rx, 42 | TX: tx, 43 | } 44 | 45 | go ep.rcvLoop(rx) 46 | go ep.sndLoop(tx) 47 | 48 | return ep, nil 49 | } 50 | 51 | func (s *SerialEndpoint) sndLoop(ch <-chan []byte) { 52 | writer := slip.NewSlipMuxWriter(NewSlowWriter(s.port)) 53 | 54 | for { 55 | data := <-ch 56 | 57 | err := writer.WritePacket(slip.FRAME_COAP, data) 58 | if err != nil { 59 | logger.Println("handleCoap:", err) 60 | continue 61 | } 62 | } 63 | } 64 | 65 | func (s *SerialEndpoint) rcvLoop(ch chan<- Packet) { 66 | reader := slip.NewSlipMuxReader(s.port) 67 | 68 | for { 69 | packet, frame, err := reader.ReadPacket() 70 | 71 | var perr *serial.PortError 72 | if errors.As(err, &perr) && perr.Code() == serial.PortClosed { 73 | logger.Fatal("[SerialEndpoint]", err) 74 | } else if err != nil { 75 | logger.Println("[SerialEndpoint]", err) 76 | continue 77 | } 78 | 79 | packet = bytes.TrimPrefix(packet, []byte{0}) 80 | ch <- Packet{frame, packet} 81 | } 82 | } 83 | 84 | func (s *SerialEndpoint) Close() { 85 | // close(s.Chan) 86 | // TODO: Close TTYIO 87 | } 88 | -------------------------------------------------------------------------------- /slipmux/slow_writer.go: -------------------------------------------------------------------------------- 1 | // This is a hacky workaround for the fact that the HiFive1 FTDI chip 2 | // doesn't do hardware flow control and the UART0 interrupt handler 3 | // takes an eternity to complete since it does CoAP message handling. 4 | package main 5 | 6 | import ( 7 | "io" 8 | "time" 9 | ) 10 | 11 | const ( 12 | pause = 1 * time.Second 13 | fifoDepth = 8 14 | ) 15 | 16 | type SlowWriter struct { 17 | w io.Writer 18 | } 19 | 20 | func NewSlowWriter(w io.Writer) SlowWriter { 21 | return SlowWriter{w: w} 22 | } 23 | 24 | func (w SlowWriter) Write(p []byte) (int, error) { 25 | var n int 26 | for i, c := range p { 27 | if i != 0 && i%fifoDepth == 0 { 28 | time.Sleep(pause) 29 | } 30 | 31 | written, err := w.w.Write([]byte{c}) 32 | if err != nil { 33 | return n, err 34 | } 35 | 36 | n += written 37 | } 38 | 39 | return n, nil 40 | } 41 | -------------------------------------------------------------------------------- /src/clock.c: -------------------------------------------------------------------------------- 1 | /* Copied from https://wiki.osdev.org/HiFive-1_Bare_Bones#The_kernel_source_code */ 2 | /* Should eventually be rewritten in Zig with proper abstraction for the PRCI. */ 3 | 4 | #include 5 | 6 | #define PRCI_CTRL_ADDR 0x10008000UL 7 | #define PRCI_HFROSCCFG (0x0000) 8 | #define PRCI_PLLCFG (0x0008) 9 | #define ROSC_EN(x) (((x) & 0x1) << 30) 10 | #define PLL_REFSEL(x) (((x) & 0x1) << 17) 11 | #define PLL_BYPASS(x) (((x) & 0x1) << 18) 12 | #define PLL_SEL(x) (((x) & 0x1) << 16) 13 | 14 | static inline uint32_t 15 | mmio_read_u32(unsigned long reg, unsigned int offset) 16 | { 17 | return (*(volatile uint32_t *) ((reg) + (offset))); 18 | } 19 | 20 | static inline void 21 | mmio_write_u32(unsigned long reg, unsigned int offset, uint32_t val) 22 | { 23 | (*(volatile uint32_t *) ((reg) + (offset))) = val; 24 | } 25 | 26 | void 27 | clock_init(void) 28 | { 29 | /* Make sure the HFROSC is on */ 30 | mmio_write_u32(PRCI_CTRL_ADDR, PRCI_HFROSCCFG, 31 | mmio_read_u32(PRCI_CTRL_ADDR, PRCI_HFROSCCFG) 32 | | ROSC_EN(1)); 33 | 34 | /* Run off 16 MHz Crystal for accuracy */ 35 | mmio_write_u32(PRCI_CTRL_ADDR, PRCI_PLLCFG, 36 | mmio_read_u32(PRCI_CTRL_ADDR, PRCI_PLLCFG) 37 | | (PLL_REFSEL(1) | PLL_BYPASS(1))); 38 | mmio_write_u32(PRCI_CTRL_ADDR, PRCI_PLLCFG, 39 | mmio_read_u32(PRCI_CTRL_ADDR, PRCI_PLLCFG) 40 | | (PLL_SEL(1))); 41 | 42 | /* Turn off HFROSC to save power */ 43 | mmio_write_u32(PRCI_CTRL_ADDR, PRCI_HFROSCCFG, 44 | mmio_read_u32(PRCI_CTRL_ADDR, PRCI_HFROSCCFG) 45 | & ~(ROSC_EN(1))); 46 | } 47 | -------------------------------------------------------------------------------- /src/console.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2021 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public License 14 | // along with this program. If not, see . 15 | 16 | const periph = @import("periph.zig"); 17 | const slipmux = @import("slipmux.zig"); 18 | 19 | pub fn getStdDbg() slipmux.Frame { 20 | const ftype = slipmux.FrameType.diagnostic; 21 | return periph.slipmux.newFrame(ftype); 22 | } 23 | 24 | // Write a Slipmux diagnostic message, unbuffered, to the UART. 25 | pub fn print(comptime fmt: []const u8, args: anytype) void { 26 | var stddbg = getStdDbg(); 27 | defer stddbg.close(); 28 | 29 | const w = stddbg.writer(); 30 | nosuspend w.print(fmt, args) catch return; 31 | } 32 | -------------------------------------------------------------------------------- /src/crc.zig: -------------------------------------------------------------------------------- 1 | // From https://github.com/lobaro/slip/blob/master/fcs.go 2 | 3 | const FCS_INIT: u16 = 0xffff; 4 | const FCS_GOOD: u16 = 0xf0b8; 5 | 6 | const fcstab = [256]u16{ 7 | 0x0000, 0x1189, 0x2312, 0x329b, 0x4624, 0x57ad, 0x6536, 0x74bf, 8 | 0x8c48, 0x9dc1, 0xaf5a, 0xbed3, 0xca6c, 0xdbe5, 0xe97e, 0xf8f7, 9 | 0x1081, 0x0108, 0x3393, 0x221a, 0x56a5, 0x472c, 0x75b7, 0x643e, 10 | 0x9cc9, 0x8d40, 0xbfdb, 0xae52, 0xdaed, 0xcb64, 0xf9ff, 0xe876, 11 | 0x2102, 0x308b, 0x0210, 0x1399, 0x6726, 0x76af, 0x4434, 0x55bd, 12 | 0xad4a, 0xbcc3, 0x8e58, 0x9fd1, 0xeb6e, 0xfae7, 0xc87c, 0xd9f5, 13 | 0x3183, 0x200a, 0x1291, 0x0318, 0x77a7, 0x662e, 0x54b5, 0x453c, 14 | 0xbdcb, 0xac42, 0x9ed9, 0x8f50, 0xfbef, 0xea66, 0xd8fd, 0xc974, 15 | 0x4204, 0x538d, 0x6116, 0x709f, 0x0420, 0x15a9, 0x2732, 0x36bb, 16 | 0xce4c, 0xdfc5, 0xed5e, 0xfcd7, 0x8868, 0x99e1, 0xab7a, 0xbaf3, 17 | 0x5285, 0x430c, 0x7197, 0x601e, 0x14a1, 0x0528, 0x37b3, 0x263a, 18 | 0xdecd, 0xcf44, 0xfddf, 0xec56, 0x98e9, 0x8960, 0xbbfb, 0xaa72, 19 | 0x6306, 0x728f, 0x4014, 0x519d, 0x2522, 0x34ab, 0x0630, 0x17b9, 20 | 0xef4e, 0xfec7, 0xcc5c, 0xddd5, 0xa96a, 0xb8e3, 0x8a78, 0x9bf1, 21 | 0x7387, 0x620e, 0x5095, 0x411c, 0x35a3, 0x242a, 0x16b1, 0x0738, 22 | 0xffcf, 0xee46, 0xdcdd, 0xcd54, 0xb9eb, 0xa862, 0x9af9, 0x8b70, 23 | 0x8408, 0x9581, 0xa71a, 0xb693, 0xc22c, 0xd3a5, 0xe13e, 0xf0b7, 24 | 0x0840, 0x19c9, 0x2b52, 0x3adb, 0x4e64, 0x5fed, 0x6d76, 0x7cff, 25 | 0x9489, 0x8500, 0xb79b, 0xa612, 0xd2ad, 0xc324, 0xf1bf, 0xe036, 26 | 0x18c1, 0x0948, 0x3bd3, 0x2a5a, 0x5ee5, 0x4f6c, 0x7df7, 0x6c7e, 27 | 0xa50a, 0xb483, 0x8618, 0x9791, 0xe32e, 0xf2a7, 0xc03c, 0xd1b5, 28 | 0x2942, 0x38cb, 0x0a50, 0x1bd9, 0x6f66, 0x7eef, 0x4c74, 0x5dfd, 29 | 0xb58b, 0xa402, 0x9699, 0x8710, 0xf3af, 0xe226, 0xd0bd, 0xc134, 30 | 0x39c3, 0x284a, 0x1ad1, 0x0b58, 0x7fe7, 0x6e6e, 0x5cf5, 0x4d7c, 31 | 0xc60c, 0xd785, 0xe51e, 0xf497, 0x8028, 0x91a1, 0xa33a, 0xb2b3, 32 | 0x4a44, 0x5bcd, 0x6956, 0x78df, 0x0c60, 0x1de9, 0x2f72, 0x3efb, 33 | 0xd68d, 0xc704, 0xf59f, 0xe416, 0x90a9, 0x8120, 0xb3bb, 0xa232, 34 | 0x5ac5, 0x4b4c, 0x79d7, 0x685e, 0x1ce1, 0x0d68, 0x3ff3, 0x2e7a, 35 | 0xe70e, 0xf687, 0xc41c, 0xd595, 0xa12a, 0xb0a3, 0x8238, 0x93b1, 36 | 0x6b46, 0x7acf, 0x4854, 0x59dd, 0x2d62, 0x3ceb, 0x0e70, 0x1ff9, 37 | 0xf78f, 0xe606, 0xd49d, 0xc514, 0xb1ab, 0xa022, 0x92b9, 0x8330, 38 | 0x7bc7, 0x6a4e, 0x58d5, 0x495c, 0x3de3, 0x2c6a, 0x1ef1, 0x0f78, 39 | }; 40 | 41 | pub const Incremental = struct { 42 | fcs: u16 = FCS_INIT, 43 | 44 | pub fn add(self: *Incremental, data: u8) void { 45 | self.fcs = (self.fcs >> 8) ^ fcstab[(self.fcs ^ @as(u16, data)) & 0xff]; 46 | } 47 | 48 | pub fn csum(self: *const Incremental) u16 { 49 | return self.fcs; 50 | } 51 | }; 52 | 53 | pub fn calcCsum(data: []const u8) u16 { 54 | var inc: Incremental = .{}; 55 | for (data) |b| 56 | inc.add(b); 57 | 58 | return inc.csum(); 59 | } 60 | 61 | pub fn validCsum(data: []const u8) bool { 62 | const trialfcs = calcCsum(data); 63 | return trialfcs == FCS_GOOD; 64 | } 65 | -------------------------------------------------------------------------------- /src/gpio.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2021 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public License 14 | // along with this program. If not, see . 15 | 16 | // Maximum of 32 pins -> 2**5 = 32. 17 | pub const Pin = u5; 18 | 19 | pub const Mode = enum { 20 | IN, 21 | OUT, 22 | }; 23 | 24 | pub fn pin(x: Pin, y: Pin) Pin { 25 | return x | y; 26 | } 27 | 28 | pub const Gpio = struct { 29 | base_addr: usize, 30 | 31 | const Reg = enum(usize) { 32 | input = 0x04, 33 | output_en = 0x08, 34 | output_val = 0x0c, 35 | pue = 0x10, 36 | iof_en = 0x38, 37 | iof_sel = 0x3c, 38 | }; 39 | 40 | fn readWord(self: Gpio, reg: Reg) u32 { 41 | const ptr = @intToPtr(*volatile u32, self.base_addr + @enumToInt(reg)); 42 | return ptr.*; 43 | } 44 | 45 | fn writeWord(self: Gpio, reg: Reg, value: u32) void { 46 | const ptr = @intToPtr(*volatile u32, self.base_addr + @enumToInt(reg)); 47 | ptr.* = value; 48 | } 49 | 50 | pub fn setRegister(self: Gpio, reg: Reg, x: Pin, val: u1) void { 51 | const regVal = self.readWord(reg); 52 | 53 | const mask = @as(u32, 1) << x; 54 | if (val == 0) { 55 | self.writeWord(reg, regVal & ~mask); 56 | } else { 57 | self.writeWord(reg, regVal | mask); 58 | } 59 | } 60 | 61 | // Configure a GPIO pin as IOF controlled (instead of software controlled). 62 | pub fn setIOFCtrl(self: Gpio, x: Pin, select: u1) void { 63 | // Select one of the two HW-Driven functions. 64 | self.setRegister(Reg.iof_sel, x, select); 65 | 66 | // Enable selected HW-Driven function. 67 | self.setRegister(Reg.iof_en, x, 1); 68 | } 69 | 70 | pub fn set(self: Gpio, x: Pin, v: u1) void { 71 | self.setRegister(Reg.output_val, x, v); 72 | } 73 | 74 | pub fn init(self: Gpio, x: Pin, mode: Mode) void { 75 | switch (mode) { 76 | Mode.IN => { 77 | self.setRegister(Reg.input, x, 1); 78 | self.setRegister(Reg.output_en, x, 0); 79 | self.setRegister(Reg.pue, x, 0); 80 | }, 81 | Mode.OUT => { 82 | self.setRegister(Reg.input, x, 0); 83 | self.setRegister(Reg.output_en, x, 1); 84 | self.setRegister(Reg.pue, x, 0); 85 | }, 86 | } 87 | 88 | // Disable HW-driven functions for Pin 89 | self.setRegister(Reg.iof_en, x, 0); 90 | self.setRegister(Reg.iof_sel, x, 0); 91 | } 92 | }; 93 | -------------------------------------------------------------------------------- /src/init.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2020-2021 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public License 14 | // along with this program. If not, see . 15 | 16 | const console = @import("console.zig"); 17 | const periph = @import("periph.zig"); 18 | const main = @import("main.zig"); 19 | const StackTrace = @import("std").builtin.StackTrace; 20 | 21 | // Bitmasks for modifying mcause CSR 22 | const MCAUSE_EXPCODE = 0x0fff; 23 | const MCAUSE_INT = 0x80000000; 24 | 25 | // Exception codes 26 | const EXP_BREAKPOINT = 3; 27 | 28 | pub fn panic(msg: []const u8, error_return_trace: ?*StackTrace) noreturn { 29 | _ = error_return_trace; // unused 30 | 31 | // Copied from the default_panic implementation 32 | @setCold(true); 33 | 34 | // Write panic message, unbuffered to standard out 35 | console.print("PANIC: {s}\n", .{msg}); 36 | 37 | @breakpoint(); 38 | while (true) {} 39 | } 40 | 41 | export fn level1IRQHandler() void { 42 | const mcause = asm ("csrr %[ret], mcause" 43 | : [ret] "=r" (-> u32) 44 | ); 45 | 46 | const expcode: u32 = mcause & MCAUSE_EXPCODE; 47 | if ((mcause & MCAUSE_INT) == MCAUSE_INT) { 48 | periph.plic0.invokeHandler(); 49 | } else { 50 | if (expcode == EXP_BREAKPOINT) { 51 | while (true) {} 52 | } 53 | @panic("unexpected trap"); 54 | } 55 | } 56 | 57 | export fn init() void { 58 | periph.init(); 59 | console.print("Booting zig-riscv-embedded...\n", .{}); 60 | 61 | main.main() catch |err| { 62 | @panic(@errorName(err)); 63 | }; 64 | } 65 | -------------------------------------------------------------------------------- /src/irq.S: -------------------------------------------------------------------------------- 1 | // Based on https://github.com/agra-uni-bremen/riscv-vp/blob/f6e95b370cb6eab7024f1be26a2b8a8ae2c916be/sw/simple-sensor/bootstrap.S 2 | // 3 | // Copyright © 2017-2018, Group of Computer Architecture, University of Bremen 4 | // 5 | // Permission is hereby granted, free of charge, to any person obtaining a 6 | // copy of this software and associated documentation files (the 7 | // "Software"), to deal in the Software without restriction, including 8 | // without limitation the rights to use, copy, modify, merge, publish, 9 | // distribute, sublicense, and/or sell copies of the Software, and to 10 | // permit persons to whom the Software is furnished to do so, subject to 11 | // the following conditions: 12 | // 13 | // The above copyright notice and this permission notice shall be included 14 | // in all copies or substantial portions of the Software. 15 | // 16 | // THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS 17 | // OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF 18 | // MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. 19 | // IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY 20 | // CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN ACTION OF CONTRACT, 21 | // TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN CONNECTION WITH THE 22 | // SOFTWARE OR THE USE OR OTHER DEALINGS IN THE SOFTWARE. 23 | 24 | .globl register_handler 25 | .globl lvl0_handler 26 | 27 | lvl0_handler: 28 | # Store all register values on the stack 29 | addi sp, sp, -4 * 32 30 | sw x1, 0x0(sp) 31 | sw x4, 3 * 4(sp) 32 | sw x5, 4 * 4(sp) 33 | sw x6, 5 * 4(sp) 34 | sw x7, 6 * 4(sp) 35 | sw x10, 9 * 4(sp) 36 | sw x11, 10 * 4(sp) 37 | sw x12, 11 * 4(sp) 38 | sw x13, 12 * 4(sp) 39 | sw x14, 13 * 4(sp) 40 | sw x15, 14 * 4(sp) 41 | sw x16, 15 * 4(sp) 42 | sw x17, 16 * 4(sp) 43 | sw x28, 27 * 4(sp) 44 | sw x29, 28 * 4(sp) 45 | sw x30, 29 * 4(sp) 46 | sw x31, 30 * 4(sp) 47 | 48 | # Jump to the level 1 trap handler written in Zig 49 | jal level1IRQHandler 50 | 51 | # Load all register values from the stack and return 52 | lw x1, 0x0(sp) 53 | lw x4, 3 * 4(sp) 54 | lw x5, 4 * 4(sp) 55 | lw x6, 5 * 4(sp) 56 | lw x7, 6 * 4(sp) 57 | lw x10, 9 * 4(sp) 58 | lw x11, 10 * 4(sp) 59 | lw x12, 11 * 4(sp) 60 | lw x13, 12 * 4(sp) 61 | lw x14, 13 * 4(sp) 62 | lw x15, 14 * 4(sp) 63 | lw x16, 15 * 4(sp) 64 | lw x17, 16 * 4(sp) 65 | lw x28, 27 * 4(sp) 66 | lw x29, 28 * 4(sp) 67 | lw x30, 29 * 4(sp) 68 | lw x31, 30 * 4(sp) 69 | addi sp, sp, 4 * 32 70 | mret 71 | 72 | register_handler: 73 | # Use lvl0_handler as the trap handler 74 | la t0, lvl0_handler 75 | csrw mtvec, t0 76 | 77 | # Enable machine external interrupts (MIE bit) 78 | li t1, 0x800 79 | csrw mie, t1 80 | 81 | # Globally enable machine mode interrupts (MIE bit) 82 | li t1, 0x8 83 | csrw mstatus, t1 84 | 85 | # Return 86 | ret 87 | -------------------------------------------------------------------------------- /src/main.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2021 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public License 14 | // along with this program. If not, see . 15 | 16 | const console = @import("console.zig"); 17 | const slipmux = @import("slipmux.zig"); 18 | const periph = @import("periph.zig"); 19 | const zoap = @import("zoap"); 20 | const codes = zoap.codes; 21 | 22 | const resources = &[_]zoap.Resource{ 23 | .{ .path = "about", .handler = about }, 24 | .{ .path = "on", .handler = ledOn }, 25 | .{ .path = "off", .handler = ledOff }, 26 | }; 27 | var dispatcher = zoap.Dispatcher{ 28 | .resources = resources, 29 | }; 30 | 31 | pub fn about(resp: *zoap.Response, req: *zoap.Request) codes.Code { 32 | if (!req.header.code.equal(codes.GET)) 33 | return codes.BAD_METHOD; 34 | 35 | console.print("[coap] Received /about request\n", .{}); 36 | 37 | const w = resp.payloadWriter(); 38 | w.writeAll("zig-riscv-embedded licensed under AGPL3+") catch |err| { 39 | console.print("[coap] error in /about: {s}\n", .{@errorName(err)}); 40 | return codes.INTERNAL_ERR; 41 | }; 42 | 43 | return codes.CONTENT; 44 | } 45 | 46 | pub fn ledOn(resp: *zoap.Response, req: *zoap.Request) codes.Code { 47 | _ = resp; // Don't change response abort from code 48 | 49 | if (!req.header.code.equal(codes.PUT)) 50 | return codes.BAD_METHOD; 51 | 52 | console.print("[coap] Turning LED on\n", .{}); 53 | periph.gpio0.set(periph.led0, 0); 54 | 55 | return codes.CHANGED; 56 | } 57 | 58 | pub fn ledOff(resp: *zoap.Response, req: *zoap.Request) codes.Code { 59 | _ = resp; // Don't change response abort from code 60 | 61 | if (!req.header.code.equal(codes.PUT)) 62 | return codes.BAD_METHOD; 63 | 64 | console.print("[coap] Turning LED off\n", .{}); 65 | periph.gpio0.set(periph.led0, 1); 66 | 67 | return codes.CHANGED; 68 | } 69 | 70 | pub fn coapHandler(req: *zoap.Request) void { 71 | console.print("[coap] Incoming request\n", .{}); 72 | var resp = dispatcher.dispatch(req) catch |err| { 73 | console.print("[coap] Dispatch failed: {s}\n", .{@errorName(err)}); 74 | return; 75 | }; 76 | 77 | const ftype = slipmux.FrameType.coap; 78 | var frame = periph.slipmux.newFrame(ftype); 79 | 80 | try frame.writer().writeAll(resp.marshal()); 81 | frame.close(); 82 | } 83 | 84 | pub fn main() !void { 85 | try periph.slipmux.registerHandler(coapHandler); 86 | console.print("Waiting for incoming CoAP packets over UART0...\n", .{}); 87 | } 88 | -------------------------------------------------------------------------------- /src/periph.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2021 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public License 14 | // along with this program. If not, see . 15 | 16 | const gpio = @import("gpio.zig"); 17 | const plic = @import("plic.zig"); 18 | const uart = @import("uart.zig"); 19 | const smux = @import("slipmux.zig"); 20 | 21 | // Addresses of FE310 peripherals. 22 | const UART0_CTRL_ADDR: usize = 0x10013000; 23 | const UART1_CTRL_ADDR: usize = 0x10023000; 24 | const PLIC_CTRL_ADDR: usize = 0x0C000000; 25 | const GPIO_CTRL_ADDR: usize = 0x10012000; 26 | 27 | // LEDs. 28 | pub const led0 = gpio.pin(0, 22); 29 | pub const led1 = gpio.pin(0, 19); 30 | pub const led2 = gpio.pin(0, 21); 31 | 32 | pub const gpio0 = gpio.Gpio{ 33 | .base_addr = GPIO_CTRL_ADDR, 34 | }; 35 | pub const plic0 = plic.Plic{ 36 | .base_addr = PLIC_CTRL_ADDR, 37 | }; 38 | 39 | const uart0 = uart.Uart{ 40 | .base_addr = UART0_CTRL_ADDR, 41 | .rx_pin = gpio.pin(0, 16), 42 | .tx_pin = gpio.pin(0, 17), 43 | .irq = 3, 44 | }; 45 | var slip0 = smux.Slip{ 46 | .uart = &uart0, 47 | .plic = &plic0, 48 | }; 49 | pub var slipmux = smux.SlipMux{ 50 | .slip = &slip0, 51 | }; 52 | 53 | pub fn init() void { 54 | plic0.init(); 55 | uart0.init(gpio0, .{ .tx = true, .rx = true }); 56 | 57 | gpio0.init(led0, gpio.Mode.OUT); 58 | gpio0.init(led1, gpio.Mode.OUT); 59 | gpio0.init(led2, gpio.Mode.OUT); 60 | 61 | gpio0.set(led0, 1); 62 | gpio0.set(led1, 1); 63 | gpio0.set(led2, 1); 64 | } 65 | -------------------------------------------------------------------------------- /src/plic.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2020 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public License 14 | // along with this program. If not, see . 15 | 16 | const console = @import("console.zig"); 17 | 18 | // Type alias for IRQ values, largest possible IRQ on the FE310 is 19 | // 52 (see INTERRUPT_SOURCES below), thus representable by a u6. 20 | pub const Irq = u6; 21 | 22 | // Type alias for PLIC interrupt handler functions. 23 | pub const Handler = fn (args: ?*anyopaque) void; 24 | 25 | pub const Plic = struct { 26 | base_addr: usize, 27 | 28 | // Offsets for memory mapped PLIC control registers. 29 | const PLIC_PRIO_OFF: usize = 0x0000; 30 | const PLIC_PENDING_OFF: usize = 0x1000; 31 | const PLIC_ENABLE_OFF: usize = 0x2000; 32 | const PLIC_CONTEXT_OFF: usize = 0x200000; 33 | 34 | // Amount of interrupt sources supported by plic. 35 | const INTERRUPT_SOURCES: Irq = 52; 36 | 37 | // TODO: Get rid of anyopaque in the long run. 38 | var irq_handlers = [_]?Handler{null} ** INTERRUPT_SOURCES; 39 | var irq_contexts = [_]?*anyopaque{null} ** INTERRUPT_SOURCES; 40 | 41 | pub fn setThreshold(self: Plic, threshold: u3) void { 42 | const plic_thres = @intToPtr(*volatile u32, self.base_addr + PLIC_CONTEXT_OFF); 43 | plic_thres.* = threshold; 44 | } 45 | 46 | fn setPriority(self: Plic, irq: Irq, prio: u3) void { 47 | // Set PLIC priority for IRQ 48 | const plic_prio = @intToPtr(*volatile u32, self.base_addr + 49 | PLIC_PRIO_OFF + (@as(u32, irq) * @sizeOf(u32))); 50 | plic_prio.* = @as(u32, prio); 51 | } 52 | 53 | fn setEnable(self: Plic, irq: Irq, enable: bool) void { 54 | const idx = irq / 32; 55 | 56 | const enable_addr: usize = self.base_addr + PLIC_ENABLE_OFF; 57 | const plic_enable = @intToPtr(*volatile u32, enable_addr + (idx * @sizeOf(u32))); 58 | 59 | const off = @intCast(u5, irq % 32); 60 | if (enable) { 61 | plic_enable.* |= @intCast(u32, 1) << off; 62 | } else { 63 | plic_enable.* &= ~(@intCast(u32, 1) << off); 64 | } 65 | } 66 | 67 | pub fn registerHandler(self: Plic, irq: Irq, func: Handler, ctx: ?*anyopaque) !void { 68 | if (irq >= irq_handlers.len) 69 | return error.OutOfBounds; 70 | 71 | irq_handlers[irq] = func; 72 | irq_contexts[irq] = ctx; 73 | 74 | self.setPriority(irq, 1); 75 | self.setEnable(irq, true); 76 | } 77 | 78 | pub fn invokeHandler(self: Plic) void { 79 | const claim_reg = @intToPtr(*volatile u32, self.base_addr + PLIC_CONTEXT_OFF + @sizeOf(u32)); 80 | const irq = @intCast(Irq, claim_reg.*); 81 | 82 | if (irq_handlers[irq]) |handler| 83 | handler(irq_contexts[irq]); 84 | 85 | // Mark interrupt as completed 86 | claim_reg.* = irq; 87 | } 88 | 89 | pub fn init(self: Plic) void { 90 | // Threshold is uninitialized by default. 91 | self.setThreshold(0); 92 | 93 | var i: Irq = 1; 94 | while (i <= INTERRUPT_SOURCES) : (i += 1) { 95 | self.setEnable(i, false); 96 | self.setPriority(i, 0); 97 | } 98 | } 99 | }; 100 | -------------------------------------------------------------------------------- /src/slipmux.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2021 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public License 14 | // along with this program. If not, see . 15 | 16 | const zoap = @import("zoap"); 17 | const crc = @import("crc.zig"); 18 | const std = @import("std"); 19 | const console = @import("console.zig"); 20 | 21 | const Plic = @import("plic.zig").Plic; 22 | const Uart = @import("uart.zig").Uart; 23 | 24 | const FrameHandler = fn (ctx: ?*anyopaque, buf: []const u8) void; 25 | const CoapHandler = fn (req: *zoap.Request) void; 26 | 27 | pub const Slip = struct { 28 | uart: *const Uart, 29 | plic: *const Plic, 30 | handler: ?FrameHandler = null, 31 | context: ?*anyopaque = null, 32 | rcvbuf: [MTU]u8 = undefined, 33 | rcvpos: usize = 0, 34 | prev_esc: bool = false, 35 | 36 | // SLIP control bytes from RFC 1055. 37 | const END: u8 = 0o300; 38 | const ESC: u8 = 0o333; 39 | const ESC_END: u8 = 0o334; 40 | const ESC_ESC: u8 = 0o335; 41 | 42 | // SLIP (as defined in RFC 1055) doesn't specify an MTU. 43 | const MTU: u32 = 1500; 44 | 45 | fn writeByte(self: *Slip, byte: u8) void { 46 | self.rcvbuf[self.rcvpos] = byte; 47 | self.rcvpos += 1; 48 | } 49 | 50 | fn handleByte(self: *Slip, byte: u8) !void { 51 | if (self.rcvpos >= self.rcvbuf.len) { 52 | self.prev_esc = false; 53 | return error.FrameTooLarge; 54 | } 55 | 56 | switch (byte) { 57 | ESC => { 58 | self.prev_esc = true; 59 | return; 60 | }, 61 | END => { 62 | if (self.handler != null) 63 | self.handler.?(self.context, self.rcvbuf[0..self.rcvpos]); 64 | self.rcvpos = 0; 65 | }, 66 | ESC_END, ESC_ESC => { 67 | var c: u8 = undefined; 68 | if (self.prev_esc) { 69 | switch (byte) { 70 | ESC_END => c = END, 71 | ESC_ESC => c = ESC, 72 | else => return error.UnknownEscapeSequence, 73 | } 74 | } else { 75 | c = byte; 76 | } 77 | 78 | self.writeByte(c); 79 | }, 80 | else => { 81 | self.writeByte(byte); 82 | }, 83 | } 84 | 85 | self.prev_esc = false; 86 | } 87 | 88 | fn rxIrqHandler(self: *Slip) !void { 89 | while (self.uart.readByte()) |byte| { 90 | try self.handleByte(byte); 91 | } 92 | } 93 | 94 | fn irqHandler(ctx: ?*anyopaque) void { 95 | var self: *Slip = @ptrCast(*Slip, @alignCast(@alignOf(*Slip), ctx.?)); 96 | 97 | const ip = self.uart.readIp(); 98 | if (ip.rxwm) { 99 | rxIrqHandler(self) catch { 100 | @panic("rx handler failed"); 101 | }; 102 | } 103 | } 104 | 105 | pub fn registerHandler(self: *Slip, func: FrameHandler, ctx: ?*anyopaque) !void { 106 | // Enable RX interrupt, dissable TX interrupt. 107 | self.uart.writeIe(false, true); 108 | 109 | self.handler = func; 110 | self.context = ctx; 111 | 112 | try self.plic.registerHandler(self.uart.irq, irqHandler, self); 113 | } 114 | }; 115 | 116 | pub const FrameType = enum(u8) { 117 | diagnostic = 0x0a, 118 | coap = 0xa9, 119 | }; 120 | 121 | pub const Frame = struct { 122 | slip: *const Slip, 123 | ftype: FrameType, 124 | csum: crc.Incremental, 125 | 126 | const WriteError = error{}; 127 | const FrameWriter = std.io.Writer(*Frame, WriteError, write); 128 | 129 | fn init(slip: *const Slip, ftype: FrameType) Frame { 130 | var frame = Frame{ 131 | .slip = slip, 132 | .ftype = ftype, 133 | .csum = .{}, 134 | }; 135 | 136 | frame.pushByte(@enumToInt(ftype)); 137 | return frame; 138 | } 139 | 140 | fn pushByteRaw(self: *Frame, byte: u8) void { 141 | const uart = self.slip.uart; 142 | 143 | // Busy wait for TX fifo to empty. 144 | while (uart.isTxFull()) {} 145 | uart.writeByte(byte); 146 | } 147 | 148 | fn pushByte(self: *Frame, byte: u8) void { 149 | self.pushByteRaw(byte); 150 | if (self.ftype == FrameType.coap) 151 | self.csum.add(byte); 152 | } 153 | 154 | fn write(self: *Frame, data: []const u8) WriteError!usize { 155 | for (data) |c| { 156 | switch (c) { 157 | Slip.END => { 158 | self.pushByte(Slip.ESC); 159 | self.pushByte(Slip.ESC_END); 160 | }, 161 | Slip.ESC => { 162 | self.pushByte(Slip.ESC); 163 | self.pushByte(Slip.ESC_ESC); 164 | }, 165 | else => { 166 | self.pushByte(c); 167 | }, 168 | } 169 | } 170 | 171 | return data.len; 172 | } 173 | 174 | pub fn close(self: *Frame) void { 175 | if (self.ftype == FrameType.coap) { 176 | var fcs16 = self.csum.csum(); 177 | fcs16 ^= 0xffff; // complement 178 | 179 | // XXX: Use @truncate instead? 180 | self.pushByteRaw(@intCast(u8, fcs16 & @as(u16, 0x00ff))); 181 | self.pushByteRaw(@intCast(u8, fcs16 >> 8 & @as(u16, 0x00ff))); 182 | } 183 | 184 | self.pushByteRaw(Slip.END); 185 | } 186 | 187 | pub fn writer(self: *Frame) FrameWriter { 188 | return .{ .context = self }; 189 | } 190 | }; 191 | 192 | pub const SlipMux = struct { 193 | slip: *Slip, 194 | handler: ?CoapHandler = null, 195 | 196 | fn handleCoAP(self: *SlipMux, buf: []const u8) !void { 197 | // 1 byte (frame type) + 4 byte (coap message) + 2 byte CRC 198 | if (buf.len <= 7) 199 | return error.CoAPFrameTooShort; 200 | if (!crc.validCsum(buf)) 201 | return error.InvalidChecksum; 202 | 203 | // Strip frame identifier and 16-bit CRC FCS. 204 | const msgBuf = buf[1..(buf.len - @sizeOf(u16))]; 205 | 206 | var req = try zoap.Request.init(msgBuf); 207 | self.handler.?(&req); 208 | } 209 | 210 | fn dispatchFrame(self: *SlipMux, buf: []const u8) !void { 211 | switch (buf[0]) { 212 | @enumToInt(FrameType.diagnostic) => { 213 | return error.NoDiagnosticSupport; 214 | }, 215 | @enumToInt(FrameType.coap) => { 216 | try self.handleCoAP(buf); 217 | }, 218 | else => { 219 | return error.UnsupportedFrameType; 220 | }, 221 | } 222 | } 223 | 224 | fn handleFrame(ctx: ?*anyopaque, buf: []const u8) void { 225 | var self: *SlipMux = @ptrCast(*SlipMux, @alignCast(@alignOf(*SlipMux), ctx.?)); 226 | if (buf.len == 0) 227 | return; 228 | 229 | self.dispatchFrame(buf) catch |err| { 230 | console.print("handleFrame failed: {s}\n", .{@errorName(err)}); 231 | }; 232 | } 233 | 234 | pub fn newFrame(self: *SlipMux, ftype: FrameType) Frame { 235 | return Frame.init(self.slip, ftype); 236 | } 237 | 238 | pub fn registerHandler(self: *SlipMux, handler: CoapHandler) !void { 239 | self.handler = handler; 240 | try self.slip.registerHandler(handleFrame, self); 241 | } 242 | }; 243 | -------------------------------------------------------------------------------- /src/start.S: -------------------------------------------------------------------------------- 1 | /* 2 | * Copyright (C) 2017 JP Bonn, Ken Rabold 3 | * 4 | * This file is subject to the terms and conditions of the GNU Lesser 5 | * General Public License v2.1. See the file LICENSE in the top level 6 | * directory for more details. 7 | */ 8 | 9 | .section .init 10 | .globl _start 11 | .type _start,@function 12 | 13 | _start: 14 | .cfi_startproc 15 | .cfi_undefined ra 16 | .option push 17 | .option norelax 18 | la gp, __global_pointer$ 19 | .option pop 20 | la sp, __StackTop 21 | 22 | 23 | /* Load data section */ 24 | la a0, _data_lma 25 | la a1, _data 26 | la a2, _edata 27 | bgeu a1, a2, 2f 28 | 1: 29 | lw t0, (a0) 30 | sw t0, (a1) 31 | addi a0, a0, 4 32 | addi a1, a1, 4 33 | bltu a1, a2, 1b 34 | 2: 35 | 36 | /* Clear bss section */ 37 | la a0, __bss_start 38 | la a1, _end 39 | bgeu a0, a1, 2f 40 | 1: 41 | sw zero, (a0) 42 | addi a0, a0, 4 43 | bltu a0, a1, 1b 44 | 2: 45 | call register_handler 46 | call clock_init 47 | call init 48 | 49 | /* Loop forever */ 50 | 1: 51 | wfi 52 | j 1b 53 | 54 | .cfi_endproc 55 | -------------------------------------------------------------------------------- /src/uart.zig: -------------------------------------------------------------------------------- 1 | // Copyright © 2020-2021 Sören Tempel 2 | // 3 | // This program is free software: you can redistribute it and/or modify 4 | // it under the terms of the GNU Affero General Public License as 5 | // published by the Free Software Foundation, either version 3 of the 6 | // License, or (at your option) any later version. 7 | // 8 | // This program is distributed in the hope that it will be useful, but 9 | // WITHOUT ANY WARRANTY; without even the implied warranty of 10 | // MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU 11 | // Affero General Public License for more details. 12 | // 13 | // You should have received a copy of the GNU Affero General Public 14 | // License along with this program. If not, see . 15 | 16 | const gpio = @import("gpio.zig"); 17 | const plic = @import("plic.zig"); 18 | 19 | // TODO: Extract this value using the PRCI. 20 | const CLK_FREQ = 16 * 1000 * 1000; // 16 MHZ 21 | 22 | pub const ConfFlags = struct { 23 | tx: bool, 24 | rx: bool, 25 | cnt: u3 = 0, 26 | baud: u32 = 115200, 27 | }; 28 | 29 | fn ctrlCount(watermark: u3) u32 { 30 | return (@as(u32, watermark) & 0x07) << 16; 31 | } 32 | 33 | pub const Uart = struct { 34 | base_addr: usize, 35 | rx_pin: gpio.Pin, 36 | tx_pin: gpio.Pin, 37 | irq: plic.Irq, 38 | 39 | const Reg = enum(usize) { 40 | txfifo = 0x00, 41 | rxfifo = 0x04, 42 | txctrl = 0x08, 43 | rxctrl = 0x0c, 44 | ie = 0x10, 45 | ip = 0x14, 46 | div = 0x18, 47 | }; 48 | 49 | pub const ie = struct { 50 | txwm: bool, 51 | rxwm: bool, 52 | }; 53 | 54 | pub const FIFO_DEPTH: usize = 8; 55 | pub const TXCTRL_ENABLE: u32 = 1; 56 | pub const RXCTRL_ENABLE: u32 = 1; 57 | pub const EMPTY_MASK: u32 = 1 << 31; // for txdata/rxdata 58 | pub const IE_TXWM: u32 = 1 << 0; 59 | pub const IE_RXWM: u32 = 1 << 1; 60 | 61 | fn writeWord(self: Uart, reg: Reg, value: u32) void { 62 | const ptr = @intToPtr(*volatile u32, self.base_addr + @enumToInt(reg)); 63 | ptr.* = value; 64 | } 65 | 66 | fn readWord(self: Uart, reg: Reg) u32 { 67 | const ptr = @intToPtr(*volatile u32, self.base_addr + @enumToInt(reg)); 68 | return ptr.*; 69 | } 70 | 71 | pub fn confTx(self: Uart, watermark: u3) void { 72 | self.writeWord(Reg.txctrl, TXCTRL_ENABLE | ctrlCount(watermark)); 73 | } 74 | 75 | pub fn confRx(self: Uart, watermark: u3) void { 76 | self.writeWord(Reg.rxctrl, RXCTRL_ENABLE | ctrlCount(watermark)); 77 | } 78 | 79 | pub fn readIp(self: Uart) ie { 80 | const r = self.readWord(Reg.ip); 81 | return .{ 82 | .txwm = (r & IE_TXWM) != 0, 83 | .rxwm = (r & IE_RXWM) != 0, 84 | }; 85 | } 86 | 87 | pub fn writeIe(self: Uart, txwm: bool, rxwm: bool) void { 88 | var r: u32 = 0; 89 | if (txwm) 90 | r |= IE_TXWM; 91 | if (rxwm) 92 | r |= IE_RXWM; 93 | 94 | self.writeWord(Reg.ie, r); 95 | } 96 | 97 | pub fn writeByte(self: Uart, value: u8) void { 98 | self.writeWord(Reg.txfifo, value); 99 | } 100 | 101 | fn drainInput(self: Uart) void { 102 | // Read until self.readByte() returns null 103 | while (self.readByte()) |_| {} 104 | } 105 | 106 | pub fn readByte(self: Uart) ?u8 { 107 | const rxdata = self.readWord(Reg.rxfifo); 108 | if ((rxdata & EMPTY_MASK) != 0) 109 | return null; 110 | return @truncate(u8, rxdata); 111 | } 112 | 113 | pub fn isTxFull(self: Uart) bool { 114 | const txdata = self.readWord(Reg.txfifo); 115 | return (txdata & EMPTY_MASK) != 0; 116 | } 117 | 118 | pub fn init(self: Uart, ugpio: gpio.Gpio, conf: ConfFlags) void { 119 | // Enable the UART at the given baud rate 120 | self.writeWord(Reg.div, CLK_FREQ / conf.baud); 121 | 122 | if (conf.tx) 123 | self.confTx(conf.cnt); 124 | if (conf.rx) 125 | self.confRx(conf.cnt); 126 | 127 | if (conf.tx) 128 | ugpio.setIOFCtrl(self.tx_pin, 0); 129 | if (conf.rx) 130 | ugpio.setIOFCtrl(self.rx_pin, 0); 131 | 132 | if (conf.rx) 133 | self.drainInput(); 134 | } 135 | }; 136 | --------------------------------------------------------------------------------