lesson1 draft addded

docs/Contributions.md

@@ -0,0 +1,17 @@
+## Contributing to Raspberry Pi OS
+
+The general workflow is the following:
+
+1. Find an [issue](https://github.com/s-matyukevich/raspberry-pi-os/issues) that you want to start working on or create a new one.
+1. In the comments claim that you want to start working on the issue. The first person who did this will be assigned to the issue. In some circumstancies I may reasing the issue to somebody elase after contacting the original person.
+1. [Fork the repository](https://help.github.com/articles/fork-a-repo/).
+1. Make all necesary changes.
+1. [Send pull request](https://help.github.com/articles/about-pull-requests/). 
+1. After a review your changes will be merged.
+
+The following types of contributions are particulary helpfull for the project.
+
+1. Validating source code and text of the lessons for errors.
+1. Helping to make lessons content more accurate and easier to understand.
+1. Working on sorce code and description for new lessons.
+1. Anything else that can help the project to become a perfect starting point for OS developers.

docs/Prerequisites.md

@@ -1,11 +1,15 @@
 ## Prerequisites
 
-
 ### 1. [Raspberry Pi 3 model b](https://www.raspberrypi.org/products/raspberry-pi-3-model-b/) 
 
-Older versions of Raspberry Pi are not going to work with this tutorial, because all lessons are designed to use 64 bit processor that supports ARM.v8 architecture and such processor is only available in Raspberry Pi 3 model.
+Older versions of Raspberry Pi are not going to work with this tutorial, because all lessons are designed to use 64 bit processor that supports ARMv8 architecture and such processor is only available in Raspberry Pi 3 model.
 
 ### 2. [USB to TTL serial cable](https://www.amazon.com/s/ref=nb_sb_noss_2?url=search-alias%3Daps&field-keywords=usb+to+ttl+serial+cable&rh=i%3Aaps%2Ck%3Ausb+to+ttl+serial+cable) 
 
 After you get serial cable you need to test you connection. If you never done this before I recommend you to follow [this guide](https://cdn-learn.adafruit.com/downloads/pdf/adafruits-raspberry-pi-lesson-5-using-a-console-cable.pdf) It describes the process of connecting your raspberry Pi via serial cabel in great details. One thin that I can recomment you to do is to use your serial cable to power your Raspberry Pi. How to do this is described in the previous link.
 
+### 3. Docker
+
+Strictly speaking Docker is not a required dependency. It is just convinient to use docker to build source code of the lessons, especially for Mac and Windows users. Each lesson has `build.sh` script (or `build.bat` for windows users) This script uses docker to build source code of the lesson. Instructions how to install docker for you platform can be found on the [official docker website](https://docs.docker.com/engine/installation/)  
+
+If for some reasons you want to avoid using Docker, you can install [make utility](http://www.math.tau.ac.il/~danha/courses/software1/make-intro.html) as well as  `aarch64-linux-gnu` toolchain. If you are using ubuntu you just need  to install `gcc-aarch64-linux-gnu` and `build-essential` packages.

src/lesson01/Makefile

@@ -1,6 +1,7 @@
-ARMGNU ?= gcc-aarch64-linux-gnu
+ARMGNU ?= aarch64-linux-gnu
 
 COPS = -Wall -nostdlib -nostartfiles -ffreestanding -Iinclude -mgeneral-regs-only
+ASMOPS = -Iinclude 
 
 all : kernel7.img
 
@@ -11,7 +12,7 @@ src/%_c.o: src/%.c
 	$(ARMGNU)-gcc $(COPS) -c $< -o $@
 
 src/%_s.o: src/%.S
-	$(ARMGNU)-as $< -o $@
+	$(ARMGNU)-gcc $(ASMOPS) -c $< -o $@
 
 C_FILES = $(wildcard src/*.c)
 ASM_FILES = $(wildcard src/*.S)

src/lesson01/build.sh

@@ -0,0 +1,3 @@
+#!/bin/bash
+
+docker run -v $(pwd):/app -w /app smatyukevich/raspberry-pi-os-builder make $1

src/lesson01/include/mm.h

@@ -0,0 +1,17 @@
+#ifndef	_MM_H
+#define	_MM_H
+
+#define PAGE_SHIFT	 			12
+#define TABLE_SHIFT 			9
+#define SECTION_SHIFT			(PAGE_SHIFT + TABLE_SHIFT)
+
+#define PAGE_SIZE   			(1 << PAGE_SHIFT)	
+#define SECTION_SIZE			(1 << SECTION_SHIFT)	
+
+#ifndef __ASSEMBLER__
+
+void memzero(unsigned long src, unsigned long n);
+
+#endif
+
+#endif  /*_MM_H */

src/lesson01/include/utils.h

@@ -1,8 +1,8 @@
 #ifndef	_BOOT_H
 #define	_BOOT_H
 
-extern void DELAY ( unsigned int);
-extern void PUT32 ( unsigned int, unsigned int );
-extern unsigned int GET32 ( unsigned int );
+extern void delay ( unsigned long);
+extern void put32 ( unsigned long, unsigned int );
+extern unsigned int get32 ( unsigned long );
 
 #endif  /*_BOOT_H */

src/lesson01/src/boot.S

@@ -1,15 +1,24 @@
+#include "mm.h"
+
 .section ".text.boot"
 
 .globl _start
 _start:
 	mrs	x0, mpidr_el1		
 	and	x0, x0,#0xFF		// Check processor id
 	cbz	x0, master		// Hang for all non-primary CPU
-	b	hang
+	b	proc_hang
+
+proc_hang: 
+	b proc_hang
 
 master:
-	mov	sp,#0x00400000
+	adr	x0, bss_begin
+	adr	x1, bss_end
+	sub	x1, x1, x0
+	bl 	memzero
+
+	mov	sp, #(2 * SECTION_SIZE) 
 	bl	kernel_main
 
-hang: b hang
 

src/lesson01/src/kernel.c

@@ -1,7 +1,3 @@
-#include <stddef.h>
-#include <stdint.h>
-
-#include "utils.h"
 #include "mini_uart.h"
 
 void kernel_main(void)

src/lesson01/src/linker.ld

@@ -1,12 +1,11 @@
 SECTIONS
 {
-    .text :
-    {
-        KEEP(*(.text.boot))
-        *(.text)
-    }
-    .rodata :{ *(.rodata) }
-    .data :{ *(.data) }
+    .text.boot : { *(.text.boot) }
+    .text :  { *(.text) }
+    .rodata : { *(.rodata) }
+    .data : { *(.data) }
+    . = ALIGN(0x8);
+    bss_begin = .;
     .bss : { *(.bss*) } 
+    bss_end = .;
 }
-

src/lesson01/src/mini_uart.c

@@ -1,6 +1,3 @@
-#include <stddef.h>
-#include <stdint.h>
-
 #include "utils.h"
 #include "peripherals/mini_uart.h"
 #include "peripherals/gpio.h"
@@ -9,18 +6,18 @@ void uart_send ( char c )
 {
 	while(1)
 	{
-		if(GET32(AUX_MU_LSR_REG)&0x20) break;
+		if(get32(AUX_MU_LSR_REG)&0x20) break;
 	}
-	PUT32(AUX_MU_IO_REG,c);
+	put32(AUX_MU_IO_REG,c);
 }
 
 char uart_recv ( void )
 {
 	while(1)
 	{
-		if(GET32(AUX_MU_LSR_REG)&0x01) break;
+		if(get32(AUX_MU_LSR_REG)&0x01) break;
 	}
-	return(GET32(AUX_MU_IO_REG)&0xFF);
+	return(get32(AUX_MU_IO_REG)&0xFF);
 }
 
 void uart_send_string(char* str)
@@ -33,14 +30,15 @@ void uart_send_string(char* str)
 
 void uart_init ( void )
 {
-	uint32_t ra;
+	unsigned int selector;
 
-	ra=GET32(GPFSEL1);
-	ra&=~(7<<12); //gpio14
-	ra|=2<<12;    //alt5
-	ra&=~(7<<15); //gpio15
-	ra|=2<<15;    //alt5
+	selector = GET32(GPFSEL1);
+	selector &= ~(7<<12);                   // clean gpio14
+	selector |= 2<<12;                      // set alt5 for gpio14
+	selector &= ~(7<<15);                   // clean gpio15
+	selector |= 2<<15;                      // set alt5 for gpio 15
 	PUT32(GPFSEL1,ra);
+
 	PUT32(GPPUD,0);
 	DELAY(150);
 	PUT32(GPPUDCLK0,(1<<14)|(1<<15));

src/lesson01/src/mm.S

@@ -0,0 +1,6 @@
+.globl memzero
+memzero:
+	str xzr, [x0], #8
+	subs x1, x1, #8
+	b.gt memzero
+	ret

src/lesson01/src/utils.S

@@ -1,15 +1,15 @@
-.globl PUT32
-PUT32:
+.globl put32
+put32:
 	str w1,[x0]
 	ret
 
-.globl GET32
-GET32:
+.globl get32
+get32:
 	ldr w0,[x0]
 	ret
 
-.globl DELAY
-DELAY:
+.globl delay
+delay:
 	subs x0, x0, #1
-	bne DELAY
+	bne delay
 	ret

src/lesson06/src/boot.S

@@ -10,7 +10,7 @@ _start:
 	mrs	x0, mpidr_el1		
 	and	x0, x0,#0xFF		// Check processor id
 	cbz	x0, master		// Hang for all non-primary CPU
-	b	hang
+	b	proc_hang
 
 proc_hang: 
 	b proc_hang