Fixed typos and more tutorials
bzt
6 years ago
parent
22fc0181a3
commit
2fc348ba46
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#
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# Copyright (C) 2018 bzt (bztsrc@github)
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#
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# Permission is hereby granted, free of charge, to any person
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# obtaining a copy of this software and associated documentation
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# files (the "Software"), to deal in the Software without
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# restriction, including without limitation the rights to use, copy,
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# modify, merge, publish, distribute, sublicense, and/or sell copies
|
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# of the Software, and to permit persons to whom the Software is
|
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# furnished to do so, subject to the following conditions:
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#
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# The above copyright notice and this permission notice shall be
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# included in all copies or substantial portions of the Software.
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#
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# THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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# EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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# MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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# NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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# HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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# WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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# OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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# DEALINGS IN THE SOFTWARE.
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#
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#
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SRCS = $(wildcard *.c)
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OBJS = $(SRCS:.c=.o)
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CFLAGS = -Wall -O2 -ffreestanding -nostdinc -nostdlib -nostartfiles
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all: clean kernel8.img
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start.o: start.S
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aarch64-elf-gcc $(CFLAGS) -c start.S -o start.o
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%.o: %.c
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aarch64-elf-gcc $(CFLAGS) -c $< -o $@
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kernel8.img: start.o $(OBJS)
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aarch64-elf-ld -nostdlib -nostartfiles start.o $(OBJS) -T link.ld -o kernel8.elf
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aarch64-elf-objcopy -O binary kernel8.elf kernel8.img
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clean:
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rm kernel8.elf *.o >/dev/null 2>/dev/null || true
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@ -0,0 +1,46 @@
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Oktatóanyag 11 - Kivételkezelők
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===============================
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Legutóbb egy nagyon egyszerű címfordítási táblát használtunk, de a mindennapi életben többre van szükség.
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Nem könnyű vakon létrehozni ezt a táblát, ezért kivételkezelőket fogunk definiálni. Ez ki fogja dumpolni
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a fontos rendszer regisztereket, hogy azonosíthassuk és megtalálhassuk a problémát a címfordítási táblánkban.
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```sh
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$ qemu-system-aarch64 -M raspi3 -kernel kernel8.img -serial stdio
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Synchronous: Data abort, same EL, Translation fault at level 2:
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ESR_EL1 0000000096000006 ELR_EL1 0000000000080D7C
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SPSR_EL1 00000000200003C4 FAR_EL1 FFFFFFFFFF000000
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```
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Az ESR_EL1 elárulja, hogy Adathozzáférési probléma (Data Abort) lépett fel a táblázat második szintjén. Az
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utasítás, ami okozta, a 0x80D7C címen található, és a 0xFFFFFFFFFF000000 címet szerette volna elérni.
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A megadott vektor hasonló az AMD64 IDT-jéhez, két eltéréssel: először is, nincs külön utasítás (mint az sidt),
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hanem egy rendszer regiszter tárolja a címét. Másodszor, nem egy címeket tartalmazó táblázat címét adjuk meg,
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hanem a konkrét kód címét. Ezért minden "bejegyzés" a táblában nagyobb, kis programrészek amikkel be lehet
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állítani a paramétereket és meghívni egy közös kivételkezelőt.
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AMD64-en 32 belépési pont van, minden egyes kivételtípushoz egy. AArch-on ezzel szemben csak egy van, és egy
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rendszer regiszterből olvasható ki, melyik kivételtípusról van szó. Figyelembe véve, hogy minden OS úgyis csak
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átad egy kivételkódot egy közös kivételkezelőnek, ezzel megkönnyíti az életünket.
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Exc.c
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-----
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`exc_handler()` egy egyszerű kivételkezelő, ami kidumpolja a regisztereket és dekódolja az ESR_EL1-t (részben).
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Aztán megállítjuk a CPU-t, mert egyelőre nincs hova visszatérni a kivételkezelőből. A Kivétel Szindróma Regiszter
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(Exception Syndrome Register) részletes leírása megtalálható az ARM DDI0487B_b könyv D10.2.28 fejezetében.
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Start
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-----
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Mielőtt rendszerfelügyeleti módra váltanánk, beállítjuk a *vbar_el2*-t. Fontos, hogy az EL1 szinten fellépő
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kivételeket EL2 szinten futó kód kezeli le. Minden kezelőt megfelelően kell pozicionálni a memóriában. Qemu
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nem érzékeny annyira erre, de az igazi vas igen.
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`_vectors` kivételkezelők vektor táblája, kis assembly programokkal, mind az `exc_handler()` nevű C függvényt hívja.
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Main
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----
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Beállítjuk a címfordítást, majd szándékosan egy leképezetlen címre hivatkozunk, hogy kivételt idézzünk elő.
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@ -0,0 +1,45 @@
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Tutorial 11 - Exceptions
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========================
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Last time we have used a very simple translation scheme, but in real life you often need more. And it is not
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easy to write the table blindly, so we're going to add exception handlers this time. This will print out some
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system registers to identify the problem with our translation tables.
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```sh
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$ qemu-system-aarch64 -M raspi3 -kernel kernel8.img -serial stdio
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Synchronous: Data abort, same EL, Translation fault at level 2:
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ESR_EL1 0000000096000006 ELR_EL1 0000000000080D7C
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SPSR_EL1 00000000200003C4 FAR_EL1 FFFFFFFFFF000000
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```
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Here ESR_EL1 tells us that it was a Data Abort, caused by a translation table error at level 2. The instruction
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triggered it is at address 0x80D7C which tried to access memory at 0xFFFFFFFFFF000000.
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The vector is very similar to AMD64's IDT, with two exceptions: first, there's no special instruction (like sidt),
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but a system register stores the address. Second, we don't pass a table with addresses rather the address of the
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actual code. Therefore each "entry" of the vector table is bigger, small stubs so that you can set up arguments
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and jump to a common handler.
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On AMD64 you have 32 entry points for each exception. On AArch, you only have one, and you can read the excpetion
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code from a system register. Considering that all OS sets a code for the exception and jumps to a common handler,
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this makes life easier.
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Exc.c
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-----
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`exc_handler()` a simple exception handler that dumps registers and decodes ESR_EL1 (partially). We simply stop
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the CPU for now, as we have no means to recover from an exception yet. The full comprehensive description of
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Exception Syndrome Register can be found in ARM DDI0487B_b chapter D10.2.28.
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Start
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-----
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Before we switch to supervisor mode, we set up *vbar_el2*. Note that exceptions triggered at EL1 will be handled
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by code at EL2. All handlers must be properly aligned. Qemu is not so picky, but real hardware is.
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`_vectors` the exception handler's vector table with small assembly stubs, each calling `exc_handler()` in C.
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Main
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----
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We set up page translations, and then we deliberatly reference an unmapped address to trigger an exception.
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@ -0,0 +1,88 @@
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/*
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* Copyright (C) 2018 bzt (bztsrc@github)
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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*/
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#include "uart.h"
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/**
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* common exception handler
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*/
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void exc_handler(unsigned long type, unsigned long esr, unsigned long elr, unsigned long spsr, unsigned long far)
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{
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// print out interruption type
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switch(type) {
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case 0: uart_puts("Synchronous"); break;
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case 1: uart_puts("IRQ"); break;
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case 2: uart_puts("FIQ"); break;
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case 3: uart_puts("SError"); break;
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}
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uart_puts(": ");
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// decode exception type (some, not all. See ARM DDI0487B_b chapter D10.2.28)
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switch(esr>>26) {
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case 0b000000: uart_puts("Unknown"); break;
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case 0b000001: uart_puts("Trapped WFI/WFE"); break;
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case 0b001110: uart_puts("Illegal execution"); break;
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case 0b010101: uart_puts("System call"); break;
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case 0b100000: uart_puts("Instruction abort, lower EL"); break;
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case 0b100001: uart_puts("Instruction abort, same EL"); break;
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case 0b100010: uart_puts("Instruction alignment fault"); break;
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case 0b100100: uart_puts("Data abort, lower EL"); break;
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case 0b100101: uart_puts("Data abort, same EL"); break;
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case 0b100110: uart_puts("Stack alignment fault"); break;
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case 0b101100: uart_puts("Floating point"); break;
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default: uart_puts("Unknown"); break;
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}
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// decode data abort cause
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if(esr>>26==0b100100 || esr>>26==0b100101) {
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uart_puts(", ");
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switch((esr>>2)&0x3) {
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case 0: uart_puts("Address size fault"); break;
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case 1: uart_puts("Translation fault"); break;
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case 2: uart_puts("Access flag fault"); break;
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case 3: uart_puts("Permission fault"); break;
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}
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switch(esr&0x3) {
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case 0: uart_puts(" at level 0"); break;
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case 1: uart_puts(" at level 1"); break;
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case 2: uart_puts(" at level 2"); break;
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case 3: uart_puts(" at level 3"); break;
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}
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}
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// dump registers
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uart_puts(":\n ESR_EL1 ");
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uart_hex(esr>>32);
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uart_hex(esr);
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uart_puts(" ELR_EL1 ");
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uart_hex(elr>>32);
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uart_hex(elr);
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uart_puts("\n SPSR_EL1 ");
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uart_hex(spsr>>32);
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uart_hex(spsr);
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uart_puts(" FAR_EL1 ");
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uart_hex(far>>32);
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uart_hex(far);
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uart_puts("\n");
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// no return from exception for now
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while(1);
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}
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@ -0,0 +1,45 @@
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/*
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* Copyright (C) 2018 bzt (bztsrc@github)
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
|
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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*/
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#define MMIO_BASE 0x3F000000
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#define GPFSEL0 ((volatile unsigned int*)(MMIO_BASE+0x00200000))
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#define GPFSEL1 ((volatile unsigned int*)(MMIO_BASE+0x00200004))
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#define GPFSEL2 ((volatile unsigned int*)(MMIO_BASE+0x00200008))
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#define GPFSEL3 ((volatile unsigned int*)(MMIO_BASE+0x0020000C))
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#define GPFSEL4 ((volatile unsigned int*)(MMIO_BASE+0x00200010))
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#define GPFSEL5 ((volatile unsigned int*)(MMIO_BASE+0x00200014))
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#define GPSET0 ((volatile unsigned int*)(MMIO_BASE+0x0020001C))
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#define GPSET1 ((volatile unsigned int*)(MMIO_BASE+0x00200020))
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#define GPCLR0 ((volatile unsigned int*)(MMIO_BASE+0x00200028))
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#define GPLEV0 ((volatile unsigned int*)(MMIO_BASE+0x00200034))
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#define GPLEV1 ((volatile unsigned int*)(MMIO_BASE+0x00200038))
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#define GPEDS0 ((volatile unsigned int*)(MMIO_BASE+0x00200040))
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#define GPEDS1 ((volatile unsigned int*)(MMIO_BASE+0x00200044))
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#define GPHEN0 ((volatile unsigned int*)(MMIO_BASE+0x00200064))
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#define GPHEN1 ((volatile unsigned int*)(MMIO_BASE+0x00200068))
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#define GPPUD ((volatile unsigned int*)(MMIO_BASE+0x00200094))
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#define GPPUDCLK0 ((volatile unsigned int*)(MMIO_BASE+0x00200098))
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#define GPPUDCLK1 ((volatile unsigned int*)(MMIO_BASE+0x0020009C))
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Binary file not shown.
@ -0,0 +1,46 @@
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/*
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* Copyright (C) 2018 bzt (bztsrc@github)
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*
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* Permission is hereby granted, free of charge, to any person
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* obtaining a copy of this software and associated documentation
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* files (the "Software"), to deal in the Software without
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* restriction, including without limitation the rights to use, copy,
|
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* modify, merge, publish, distribute, sublicense, and/or sell copies
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* of the Software, and to permit persons to whom the Software is
|
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* furnished to do so, subject to the following conditions:
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*
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* The above copyright notice and this permission notice shall be
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* included in all copies or substantial portions of the Software.
|
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*
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* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
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* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
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* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
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* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
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* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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*/
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SECTIONS
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{
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. = 0x80000;
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.text : { KEEP(*(.text.boot)) *(.text .text.* .gnu.linkonce.t*) }
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.rodata : { *(.rodata .rodata.* .gnu.linkonce.r*) }
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. = ALIGN(4096);
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PROVIDE(_data = .);
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.data : { *(.data .data.* .gnu.linkonce.d*) }
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.bss (NOLOAD) : {
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. = ALIGN(16);
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__bss_start = .;
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*(.bss .bss.*)
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*(COMMON)
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__bss_end = .;
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}
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. = ALIGN(4096);
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_end = .;
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/DISCARD/ : { *(.comment) *(.gnu*) *(.note*) *(.eh_frame*) }
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}
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__bss_size = (__bss_end - __bss_start)>>3;
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@ -0,0 +1,48 @@
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/*
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* Copyright (C) 2018 bzt (bztsrc@github)
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*
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* Permission is hereby granted, free of charge, to any person
|
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* obtaining a copy of this software and associated documentation
|
||||
* files (the "Software"), to deal in the Software without
|
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* restriction, including without limitation the rights to use, copy,
|
||||
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
* of the Software, and to permit persons to whom the Software is
|
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* furnished to do so, subject to the following conditions:
|
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*
|
||||
* The above copyright notice and this permission notice shall be
|
||||
* included in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
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* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
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* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
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* DEALINGS IN THE SOFTWARE.
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*
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*/
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#include "uart.h"
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#include "mmu.h"
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void main()
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{
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unsigned int r;
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// set up serial console
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uart_init();
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// set up paging
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mmu_init();
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// generate a Data Abort with a bad address access
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r=*((volatile unsigned int*)0xFFFFFFFFFF000000);
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// make gcc happy about unused variables :-)
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r++;
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// echo everything back
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while(1) {
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uart_send(uart_getc());
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}
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}
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@ -0,0 +1,63 @@
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/*
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* Copyright (C) 2018 bzt (bztsrc@github)
|
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*
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* Permission is hereby granted, free of charge, to any person
|
||||
* obtaining a copy of this software and associated documentation
|
||||
* files (the "Software"), to deal in the Software without
|
||||
* restriction, including without limitation the rights to use, copy,
|
||||
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
* of the Software, and to permit persons to whom the Software is
|
||||
* furnished to do so, subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be
|
||||
* included in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
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* DEALINGS IN THE SOFTWARE.
|
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*
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*/
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#include "gpio.h"
|
||||
|
||||
/* mailbox message buffer */
|
||||
volatile unsigned int __attribute__((aligned(16))) mbox[36];
|
||||
|
||||
#define VIDEOCORE_MBOX (MMIO_BASE+0x0000B880)
|
||||
#define MBOX_READ ((volatile unsigned int*)(VIDEOCORE_MBOX+0x0))
|
||||
#define MBOX_POLL ((volatile unsigned int*)(VIDEOCORE_MBOX+0x10))
|
||||
#define MBOX_SENDER ((volatile unsigned int*)(VIDEOCORE_MBOX+0x14))
|
||||
#define MBOX_STATUS ((volatile unsigned int*)(VIDEOCORE_MBOX+0x18))
|
||||
#define MBOX_CONFIG ((volatile unsigned int*)(VIDEOCORE_MBOX+0x1C))
|
||||
#define MBOX_WRITE ((volatile unsigned int*)(VIDEOCORE_MBOX+0x20))
|
||||
#define MBOX_RESPONSE 0x80000000
|
||||
#define MBOX_FULL 0x80000000
|
||||
#define MBOX_EMPTY 0x40000000
|
||||
|
||||
/**
|
||||
* Make a mailbox call. Returns 0 on failure, non-zero on success
|
||||
*/
|
||||
int mbox_call(unsigned char ch)
|
||||
{
|
||||
unsigned int r;
|
||||
/* wait until we can write to the mailbox */
|
||||
do{asm volatile("nop");}while(*MBOX_STATUS & MBOX_FULL);
|
||||
/* write the address of our message to the mailbox with channel identifier */
|
||||
*MBOX_WRITE = (((unsigned int)((unsigned long)&mbox)&~0xF) | (ch&0xF));
|
||||
/* now wait for the response */
|
||||
while(1) {
|
||||
/* is there a response? */
|
||||
do{asm volatile("nop");}while(*MBOX_STATUS & MBOX_EMPTY);
|
||||
r=*MBOX_READ;
|
||||
/* is it a response to our message? */
|
||||
if((unsigned char)(r&0xF)==ch && (r&~0xF)==(unsigned int)((unsigned long)&mbox))
|
||||
/* is it a valid successful response? */
|
||||
return mbox[1]==MBOX_RESPONSE;
|
||||
}
|
||||
return 0;
|
||||
}
|
||||
@ -0,0 +1,47 @@
|
||||
/*
|
||||
* Copyright (C) 2018 bzt (bztsrc@github)
|
||||
*
|
||||
* Permission is hereby granted, free of charge, to any person
|
||||
* obtaining a copy of this software and associated documentation
|
||||
* files (the "Software"), to deal in the Software without
|
||||
* restriction, including without limitation the rights to use, copy,
|
||||
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
* of the Software, and to permit persons to whom the Software is
|
||||
* furnished to do so, subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be
|
||||
* included in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS IN THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
/* a properly aligned buffer */
|
||||
extern volatile unsigned int mbox[36];
|
||||
|
||||
#define MBOX_REQUEST 0
|
||||
|
||||
/* channels */
|
||||
#define MBOX_CH_POWER 0
|
||||
#define MBOX_CH_FB 1
|
||||
#define MBOX_CH_VUART 2
|
||||
#define MBOX_CH_VCHIQ 3
|
||||
#define MBOX_CH_LEDS 4
|
||||
#define MBOX_CH_BTNS 5
|
||||
#define MBOX_CH_TOUCH 6
|
||||
#define MBOX_CH_COUNT 7
|
||||
#define MBOX_CH_PROP 8
|
||||
|
||||
/* tags */
|
||||
#define MBOX_TAG_GETSERIAL 0x10004
|
||||
#define MBOX_TAG_SETCLKRATE 0x38002
|
||||
#define MBOX_TAG_LAST 0
|
||||
|
||||
int mbox_call(unsigned char ch);
|
||||
@ -0,0 +1,177 @@
|
||||
/*
|
||||
* Copyright (C) 2018 bzt (bztsrc@github)
|
||||
*
|
||||
* Permission is hereby granted, free of charge, to any person
|
||||
* obtaining a copy of this software and associated documentation
|
||||
* files (the "Software"), to deal in the Software without
|
||||
* restriction, including without limitation the rights to use, copy,
|
||||
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
* of the Software, and to permit persons to whom the Software is
|
||||
* furnished to do so, subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be
|
||||
* included in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS IN THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
#include "gpio.h" // get MMIO_BASE
|
||||
#include "uart.h"
|
||||
|
||||
#define PAGESIZE 4096
|
||||
|
||||
// granularity
|
||||
#define PT_PAGE 0b11 // 4k granule
|
||||
#define PT_BLOCK 0b01 // 2M granule
|
||||
// accessibility
|
||||
#define PT_KERNEL (0<<6) // privileged, supervisor EL1 access only
|
||||
#define PT_USER (1<<6) // unprivileged, EL0 access allowed
|
||||
#define PT_RW (0<<7) // read-write
|
||||
#define PT_RO (1<<7) // read-only
|
||||
#define PT_AF (1<<10) // accessed flag
|
||||
#define PT_NX (1UL<<54) // no execute
|
||||
// shareability
|
||||
#define PT_OSH (2<<8) // outter shareable
|
||||
#define PT_ISH (3<<8) // inner shareable
|
||||
// defined in MAIR register
|
||||
#define PT_MEM (0<<2) // normal memory
|
||||
#define PT_DEV (1<<2) // device MMIO
|
||||
#define PT_NC (2<<2) // non-cachable
|
||||
|
||||
#define TTBR_ENABLE 1
|
||||
|
||||
// get addresses from linker
|
||||
extern volatile unsigned char _data;
|
||||
extern volatile unsigned char _end;
|
||||
|
||||
/**
|
||||
* Set up page translation tables and enable virtual memory
|
||||
*/
|
||||
void mmu_init()
|
||||
{
|
||||
unsigned long r, b, *paging=(unsigned long*)&_end;
|
||||
|
||||
/* create MMU translation tables at _end */
|
||||
|
||||
// TTBR0, identity L1
|
||||
paging[0]=(unsigned long)((unsigned char*)&_end+2*PAGESIZE) | // physical address
|
||||
PT_PAGE | // it has the "Present" flag, which must be set, and we have area in it mapped by pages
|
||||
PT_AF | // accessed flag. Without this we're going to have a Data Abort exception
|
||||
PT_USER | // non-privileged
|
||||
PT_ISH | // inner shareable
|
||||
PT_MEM; // normal memory
|
||||
|
||||
// identity L2, first 2M block
|
||||
paging[2*512]=(unsigned long)((unsigned char*)&_end+3*PAGESIZE) | // physical address
|
||||
PT_PAGE | // we have area in it mapped by pages
|
||||
PT_AF | // accessed flag
|
||||
PT_USER | // non-privileged
|
||||
PT_ISH | // inner shareable
|
||||
PT_MEM; // normal memory
|
||||
|
||||
// identity L2 2M blocks
|
||||
b=MMIO_BASE>>21;
|
||||
// skip 0th, as we're about to map it by L3
|
||||
for(r=1;r<512;r++)
|
||||
paging[2*512+r]=(unsigned long)((r<<21)) | // physical address
|
||||
PT_BLOCK | // map 2M block
|
||||
PT_AF | // accessed flag
|
||||
PT_NX | // no execute
|
||||
PT_USER | // non-privileged
|
||||
(r>=b? PT_OSH|PT_DEV : PT_ISH|PT_MEM); // different attributes for device memory
|
||||
|
||||
// identity L3
|
||||
for(r=0;r<512;r++)
|
||||
paging[3*512+r]=(unsigned long)(r*PAGESIZE) | // physical address
|
||||
PT_PAGE | // map 4k
|
||||
PT_AF | // accessed flag
|
||||
PT_USER | // non-privileged
|
||||
PT_ISH | // inner shareable
|
||||
((r<0x80||r>(unsigned long)&_data/PAGESIZE)? PT_RW|PT_NX : PT_RO); // different for code and data
|
||||
|
||||
// TTBR1, kernel L1
|
||||
paging[512+511]=(unsigned long)((unsigned char*)&_end+4*PAGESIZE) | // physical address
|
||||
PT_PAGE | // we have area in it mapped by pages
|
||||
PT_AF | // accessed flag
|
||||
PT_KERNEL | // privileged
|
||||
PT_ISH | // inner shareable
|
||||
PT_MEM; // normal memory
|
||||
|
||||
// kernel L2
|
||||
paging[4*512+511]=(unsigned long)((unsigned char*)&_end+5*PAGESIZE) | // physical address
|
||||
PT_PAGE | // we have area in it mapped by pages
|
||||
PT_AF | // accessed flag
|
||||
PT_KERNEL | // privileged
|
||||
PT_ISH | // inner shareable
|
||||
PT_MEM; // normal memory
|
||||
|
||||
// kernel L3
|
||||
paging[5*512]=(unsigned long)(MMIO_BASE+0x00201000) | // physical address
|
||||
PT_PAGE | // map 4k
|
||||
PT_AF | // accessed flag
|
||||
PT_NX | // no execute
|
||||
PT_KERNEL | // privileged
|
||||
PT_OSH | // outter shareable
|
||||
PT_DEV; // device memory
|
||||
|
||||
/* okay, now we have to set system registers to enable MMU */
|
||||
|
||||
// check for 4k granule and at least 36 bits physical address bus */
|
||||
asm volatile ("mrs %0, id_aa64mmfr0_el1" : "=r" (r));
|
||||
b=r&0xF;
|
||||
if(r&(0xF<<28)/*4k*/ || b<1/*36 bits*/) {
|
||||
uart_puts("ERROR: 4k granule or 36 bit address space not supported\n");
|
||||
return;
|
||||
}
|
||||
|
||||
// first, set Memory Attributes array, indexed by PT_MEM, PT_DEV, PT_NC in our example
|
||||
r= (0xFF << 0) | // AttrIdx=0: normal, IWBWA, OWBWA, NTR
|
||||
(0x04 << 8) | // AttrIdx=1: device, nGnRE (must be OSH too)
|
||||
(0x44 <<16); // AttrIdx=2: non cacheable
|
||||
asm volatile ("msr mair_el1, %0" : : "r" (r));
|
||||
|
||||
// next, specify mapping characteristics in translate control register
|
||||
r= (0b00LL << 37) | // TBI=0, no tagging
|
||||
(b << 32) | // IPS=autodetected
|
||||
(0b10LL << 30) | // TG1=4k
|
||||
(0b11LL << 28) | // SH1=3 inner
|
||||
(0b01LL << 26) | // ORGN1=1 write back
|
||||
(0b01LL << 24) | // IRGN1=1 write back
|
||||
(0b0LL << 23) | // EPD1 enable higher half
|
||||
(25LL << 16) | // T1SZ=25, 3 levels (512G)
|
||||
(0b00LL << 14) | // TG0=4k
|
||||
(0b11LL << 12) | // SH0=3 inner
|
||||
(0b01LL << 10) | // ORGN0=1 write back
|
||||
(0b01LL << 8) | // IRGN0=1 write back
|
||||
(0b0LL << 7) | // EPD0 enable lower half
|
||||
(25LL << 0); // T0SZ=25, 3 levels (512G)
|
||||
asm volatile ("msr tcr_el1, %0; isb" : : "r" (r));
|
||||
|
||||
// tell the MMU where our translation tables are. TTBR_ENABLE bit not documented, but required
|
||||
// lower half, user space
|
||||
asm volatile ("msr ttbr0_el1, %0" : : "r" ((unsigned long)&_end + TTBR_ENABLE));
|
||||
// upper half, kernel space
|
||||
asm volatile ("msr ttbr1_el1, %0" : : "r" ((unsigned long)&_end + TTBR_ENABLE + PAGESIZE));
|
||||
|
||||
// finally, toggle some bits in system control register to enable page translation
|
||||
asm volatile ("dsb ish; isb; mrs %0, sctlr_el1" : "=r" (r));
|
||||
r|=0xC00800; // set mandatory reserved bits
|
||||
r&=~((1<<25) | // clear EE, little endian translation tables
|
||||
(1<<24) | // clear E0E
|
||||
(1<<19) | // clear WXN
|
||||
(1<<12) | // clear I, no instruction cache
|
||||
(1<<4) | // clear SA0
|
||||
(1<<3) | // clear SA
|
||||
(1<<2) | // clear C, no cache at all
|
||||
(1<<1)); // clear A, no aligment check
|
||||
r|= (1<<0); // set M, enable MMU
|
||||
asm volatile ("msr sctlr_el1, %0; isb" : : "r" (r));
|
||||
}
|
||||
@ -0,0 +1,26 @@
|
||||
/*
|
||||
* Copyright (C) 2018 bzt (bztsrc@github)
|
||||
*
|
||||
* Permission is hereby granted, free of charge, to any person
|
||||
* obtaining a copy of this software and associated documentation
|
||||
* files (the "Software"), to deal in the Software without
|
||||
* restriction, including without limitation the rights to use, copy,
|
||||
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
* of the Software, and to permit persons to whom the Software is
|
||||
* furnished to do so, subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be
|
||||
* included in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS IN THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
void mmu_init();
|
||||
@ -0,0 +1,123 @@
|
||||
/*
|
||||
* Copyright (C) 2018 bzt (bztsrc@github)
|
||||
*
|
||||
* Permission is hereby granted, free of charge, to any person
|
||||
* obtaining a copy of this software and associated documentation
|
||||
* files (the "Software"), to deal in the Software without
|
||||
* restriction, including without limitation the rights to use, copy,
|
||||
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
* of the Software, and to permit persons to whom the Software is
|
||||
* furnished to do so, subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be
|
||||
* included in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS IN THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
.section ".text.boot"
|
||||
|
||||
.global _start
|
||||
|
||||
_start:
|
||||
// read cpu id, stop slave cores
|
||||
mrs x1, mpidr_el1
|
||||
and x1, x1, #3
|
||||
cbz x1, 2f
|
||||
// cpu id > 0, stop
|
||||
1: wfe
|
||||
b 1b
|
||||
2: // cpu id == 0
|
||||
|
||||
// set stack before our code
|
||||
ldr x1, =_start
|
||||
|
||||
// set up EL1
|
||||
mrs x0, CurrentEL
|
||||
cmp x0, #4
|
||||
beq 5f
|
||||
msr sp_el1, x1
|
||||
// enable CNTP for EL1
|
||||
mrs x0, cnthctl_el2
|
||||
orr x0, x0, #3
|
||||
msr cnthctl_el2, x0
|
||||
msr cntvoff_el2, xzr
|
||||
// Setup SCTLR access
|
||||
mov x0, #(1 << 31) // AArch64
|
||||
orr x0, x0, #(1 << 1) // SWIO hardwired on Pi3
|
||||
msr hcr_el2, x0
|
||||
mrs x0, hcr_el2
|
||||
mov x2, #0x0800
|
||||
movk x2, #0x30d0, lsl #16
|
||||
msr sctlr_el1, x2
|
||||
// set up exception handlers
|
||||
ldr x1, =_vectors
|
||||
msr vbar_el1, x1
|
||||
// change execution level to EL1
|
||||
mov x2, #0x3c4
|
||||
msr spsr_el2, x2
|
||||
adr x2, 5f
|
||||
msr elr_el2, x2
|
||||
eret
|
||||
|
||||
5: mov sp, x1
|
||||
|
||||
// clear bss
|
||||
ldr x1, =__bss_start
|
||||
ldr w2, =__bss_size
|
||||
3: cbz w2, 4f
|
||||
str xzr, [x1], #8
|
||||
sub w2, w2, #1
|
||||
cbnz w2, 3b
|
||||
|
||||
// jump to C code, should not return
|
||||
4: bl main
|
||||
// for failsafe, halt this core too
|
||||
b 1b
|
||||
|
||||
// important, code has to be properly aligned
|
||||
.align 11
|
||||
_vectors:
|
||||
// synchronous
|
||||
.align 7
|
||||
mov x0, #0
|
||||
mrs x1, esr_el1
|
||||
mrs x2, elr_el1
|
||||
mrs x3, spsr_el1
|
||||
mrs x4, far_el1
|
||||
b exc_handler
|
||||
|
||||
// IRQ
|
||||
.align 7
|
||||
mov x0, #1
|
||||
mrs x1, esr_el1
|
||||
mrs x2, elr_el1
|
||||
mrs x3, spsr_el1
|
||||
mrs x4, far_el1
|
||||
b exc_handler
|
||||
|
||||
// FIQ
|
||||
.align 7
|
||||
mov x0, #2
|
||||
mrs x1, esr_el1
|
||||
mrs x2, elr_el1
|
||||
mrs x3, spsr_el1
|
||||
mrs x4, far_el1
|
||||
b exc_handler
|
||||
|
||||
// SError
|
||||
.align 7
|
||||
mov x0, #3
|
||||
mrs x1, esr_el1
|
||||
mrs x2, elr_el1
|
||||
mrs x3, spsr_el1
|
||||
mrs x4, far_el1
|
||||
b exc_handler
|
||||
@ -0,0 +1,126 @@
|
||||
/*
|
||||
* Copyright (C) 2018 bzt (bztsrc@github)
|
||||
*
|
||||
* Permission is hereby granted, free of charge, to any person
|
||||
* obtaining a copy of this software and associated documentation
|
||||
* files (the "Software"), to deal in the Software without
|
||||
* restriction, including without limitation the rights to use, copy,
|
||||
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
* of the Software, and to permit persons to whom the Software is
|
||||
* furnished to do so, subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be
|
||||
* included in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS IN THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
#include "gpio.h"
|
||||
#include "mbox.h"
|
||||
|
||||
/* PL011 UART registers */
|
||||
#define UART0_DR ((volatile unsigned int*)(MMIO_BASE+0x00201000))
|
||||
#define UART0_FR ((volatile unsigned int*)(MMIO_BASE+0x00201018))
|
||||
#define UART0_IBRD ((volatile unsigned int*)(MMIO_BASE+0x00201024))
|
||||
#define UART0_FBRD ((volatile unsigned int*)(MMIO_BASE+0x00201028))
|
||||
#define UART0_LCRH ((volatile unsigned int*)(MMIO_BASE+0x0020102C))
|
||||
#define UART0_CR ((volatile unsigned int*)(MMIO_BASE+0x00201030))
|
||||
#define UART0_IMSC ((volatile unsigned int*)(MMIO_BASE+0x00201038))
|
||||
#define UART0_ICR ((volatile unsigned int*)(MMIO_BASE+0x00201044))
|
||||
|
||||
/**
|
||||
* Set baud rate and characteristics (115200 8N1) and map to GPIO
|
||||
*/
|
||||
void uart_init()
|
||||
{
|
||||
register unsigned int r;
|
||||
|
||||
/* initialize UART */
|
||||
*UART0_CR = 0; // turn off UART0
|
||||
|
||||
/* set up clock for consistent divisor values */
|
||||
mbox[0] = 8*4;
|
||||
mbox[1] = MBOX_REQUEST;
|
||||
mbox[2] = MBOX_TAG_SETCLKRATE; // set clock rate
|
||||
mbox[3] = 12;
|
||||
mbox[4] = 8;
|
||||
mbox[5] = 2; // UART clock
|
||||
mbox[6] = 4000000; // 4Mhz
|
||||
mbox[7] = MBOX_TAG_LAST;
|
||||
mbox_call(MBOX_CH_PROP);
|
||||
|
||||
/* map UART0 to GPIO pins */
|
||||
r=*GPFSEL1;
|
||||
r&=~((7<<12)|(7<<15)); // gpio14, gpio15
|
||||
r|=(2<<12)|(2<<15); // alt5
|
||||
*GPFSEL1 = r;
|
||||
*GPPUD = 0; // enable pins 14 and 15
|
||||
r=150; while(r--) { asm volatile("nop"); }
|
||||
*GPPUDCLK0 = (1<<14)|(1<<15);
|
||||
r=150; while(r--) { asm volatile("nop"); }
|
||||
*GPPUDCLK0 = 0; // flush GPIO setup
|
||||
|
||||
*UART0_ICR = 0x7FF; // clear interrupts
|
||||
*UART0_IBRD = 2; // 115200 baud
|
||||
*UART0_FBRD = 0xB;
|
||||
*UART0_LCRH = 0b11<<5; // 8n1
|
||||
*UART0_CR = 0x301; // enable Tx, Rx, FIFO
|
||||
}
|
||||
|
||||
/**
|
||||
* Send a character
|
||||
*/
|
||||
void uart_send(unsigned int c) {
|
||||
/* wait until we can send */
|
||||
do{asm volatile("nop");}while(*UART0_FR&0x20);
|
||||
/* write the character to the buffer */
|
||||
*UART0_DR=c;
|
||||
}
|
||||
|
||||
/**
|
||||
* Receive a character
|
||||
*/
|
||||
char uart_getc() {
|
||||
char r;
|
||||
/* wait until something is in the buffer */
|
||||
do{asm volatile("nop");}while(*UART0_FR&0x10);
|
||||
/* read it and return */
|
||||
r=(char)(*UART0_DR);
|
||||
/* convert carrige return to newline */
|
||||
return r=='\r'?'\n':r;
|
||||
}
|
||||
|
||||
/**
|
||||
* Display a string
|
||||
*/
|
||||
void uart_puts(char *s) {
|
||||
while(*s) {
|
||||
/* convert newline to carrige return + newline */
|
||||
if(*s=='\n')
|
||||
uart_send('\r');
|
||||
uart_send(*s++);
|
||||
}
|
||||
}
|
||||
|
||||
/**
|
||||
* Display a binary value in hexadecimal
|
||||
*/
|
||||
void uart_hex(unsigned int d) {
|
||||
unsigned int n;
|
||||
int c;
|
||||
for(c=28;c>=0;c-=4) {
|
||||
// get highest tetrad
|
||||
n=(d>>c)&0xF;
|
||||
// 0-9 => '0'-'9', 10-15 => 'A'-'F'
|
||||
n+=n>9?0x37:0x30;
|
||||
uart_send(n);
|
||||
}
|
||||
}
|
||||
@ -0,0 +1,30 @@
|
||||
/*
|
||||
* Copyright (C) 2018 bzt (bztsrc@github)
|
||||
*
|
||||
* Permission is hereby granted, free of charge, to any person
|
||||
* obtaining a copy of this software and associated documentation
|
||||
* files (the "Software"), to deal in the Software without
|
||||
* restriction, including without limitation the rights to use, copy,
|
||||
* modify, merge, publish, distribute, sublicense, and/or sell copies
|
||||
* of the Software, and to permit persons to whom the Software is
|
||||
* furnished to do so, subject to the following conditions:
|
||||
*
|
||||
* The above copyright notice and this permission notice shall be
|
||||
* included in all copies or substantial portions of the Software.
|
||||
*
|
||||
* THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
|
||||
* EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
|
||||
* MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
|
||||
* NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT
|
||||
* HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY,
|
||||
* WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
|
||||
* OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER
|
||||
* DEALINGS IN THE SOFTWARE.
|
||||
*
|
||||
*/
|
||||
|
||||
void uart_init();
|
||||
void uart_send(unsigned int c);
|
||||
char uart_getc();
|
||||
void uart_puts(char *s);
|
||||
void uart_hex(unsigned int d);
|
||||
Loading…
Reference in New Issue