From 23c4f42eb4c8a445b59801a9ce35a3a487d3355f Mon Sep 17 00:00:00 2001 From: ProtoByter Date: Sun, 11 Dec 2022 22:01:27 +0000 Subject: [PATCH] Actually get it working --- .gitmodules | 4 +- Makefile | 103 ++++++++++++++++++------- include/mini_uart.h | 9 +++ include/mm.h | 19 +++++ {src => include}/mmio.h | 0 include/peripherals/base.h | 6 ++ include/peripherals/gpio.h | 12 +++ include/peripherals/mini_uart.h | 19 +++++ {src => include}/uart.h | 0 include/utils.h | 8 ++ src/boot.S | 45 +++++------ src/config.txt | 3 + src/kernel.c | 48 ++---------- src/linker.ld | 48 ++---------- src/mini_uart.c | 56 ++++++++++++++ src/mm.S | 6 ++ src/utils.S | 15 ++++ raspi_fw => third-party/raspi-firmware | 0 18 files changed, 262 insertions(+), 139 deletions(-) create mode 100644 include/mini_uart.h create mode 100644 include/mm.h rename {src => include}/mmio.h (100%) create mode 100644 include/peripherals/base.h create mode 100644 include/peripherals/gpio.h create mode 100644 include/peripherals/mini_uart.h rename {src => include}/uart.h (100%) create mode 100644 include/utils.h create mode 100644 src/config.txt create mode 100644 src/mini_uart.c create mode 100644 src/mm.S create mode 100644 src/utils.S rename raspi_fw => third-party/raspi-firmware (100%) diff --git a/.gitmodules b/.gitmodules index 3162054..7c1e3cd 100644 --- a/.gitmodules +++ b/.gitmodules @@ -1,3 +1,3 @@ -[submodule "raspi_fw"] - path = raspi_fw +[submodule "third-party/raspi-firmware"] + path = third-party/raspi-firmware url = https://github.com/raspberrypi/firmware diff --git a/Makefile b/Makefile index 6d42cc3..94b0924 100644 --- a/Makefile +++ b/Makefile @@ -1,38 +1,83 @@ -CC := $(PREFIX)gcc -AS := $(PREFIX)as -OBJCPY := $(PREFIX)objcopy -boot.o: src/boot.S - $(AS) -c src/boot.S -o boot.o +CC := clang +OBJCPY := llvm-objcopy +LD := ld.lld -kernel.o: src/kernel.c - $(CC) -ffreestanding -c src/kernel.c -o kernel.o -O2 -Wall -Wextra +BUILD_DIR = build +SRC_DIR = src -os.elf: boot.o kernel.o src/linker.ld - $(CC) -T src/linker.ld -o os.elf -ffreestanding -O2 -nostdlib boot.o kernel.o -lgcc +GENERAL_OPTIONS = -kernel8.img: os.elf - $(OBJCPY) os.elf -O binary kernel8.img +CLANGOPS = -Wall -nostdlib -ffreestanding -mgeneral-regs-only -Iinclude -mcpu=cortex-a72+nosimd --target=aarch64-elf +ASMOPS = $(CLANGOPS) +COPS = $(CLANGOPS) -.PHONY: image kernel +C_FILES = $(wildcard $(SRC_DIR)/*.c) +ASM_FILES = $(wildcard $(SRC_DIR)/*.S) +OBJ_FILES = $(C_FILES:$(SRC_DIR)/%.c=$(BUILD_DIR)/%_c.o) +OBJ_FILES += $(ASM_FILES:$(SRC_DIR)/%.S=$(BUILD_DIR)/%_s.o) -image: kernel8.img +ifndef VERBOSE + VERB := @ +endif -kernel: os.elf +$(BUILD_DIR)/%_c.o: $(SRC_DIR)/%.c + $(VERB) echo Compiling $< + $(VERB) mkdir -p $(@D) + $(VERB) $(CC) $(COPS) -MMD -c $< -o $@ -real_hardware: kernel8.img - mkdir -p staging - cp -v raspi_fw/boot/bcm2710-rpi-3-b.dtb staging - cp -v raspi_fw/boot/bcm2710-rpi-3-b-plus.dtb staging - cp -v raspi_fw/boot/bcm2710-rpi-cm3.dtb staging - cp -v raspi_fw/boot/bcm2711-rpi-4-b.dtb staging - cp -v raspi_fw/boot/bcm2711-rpi-400.dtb staging - cp -v raspi_fw/boot/bcm2711-rpi-cm4.dtb staging - cp -v raspi_fw/boot/bcm2711-rpi-cm4s.dtb staging - cp -v raspi_fw/boot/*.dat staging - cp -v raspi_fw/boot/*.elf staging - cp -v raspi_fw/boot/bootcode.bin staging - cp -v kernel8.img staging +$(BUILD_DIR)/%_s.o: $(SRC_DIR)/%.S + $(VERB) echo Compiling $< + $(VERB) mkdir -p $(@D) + $(VERB) $(CC) $(ASMOPS) -MMD -c $< -o $@ +$(BUILD_DIR)/kernel8.elf: $(SRC_DIR)/linker.ld $(OBJ_FILES) + $(VERB) echo Linking kernel8.elf + $(VERB) $(LD) -T $(SRC_DIR)/linker.ld -o $(BUILD_DIR)/kernel8.elf $(OBJ_FILES) + +$(BUILD_DIR)/kernel8.img: $(BUILD_DIR)/kernel8.elf + $(VERB) echo Building kernel8.img + $(VERB) $(OBJCPY) $(BUILD_DIR)/kernel8.elf -O binary $(BUILD_DIR)/kernel8.img + +.PHONY: image kernel real_hardware + +flat: $(BUILD_DIR)/kernel8.img + +kernel: $(BUILD_DIR)/kernel8.elf + +$(BUILD_DIR)/r4.img: $(BUILD_DIR)/kernel8.img src/config.txt third-party/raspi-firmware/boot/* + $(VERB) echo Building the image + + $(VERB) echo -- Making the image file \($(BUILD_DIR)/tmp.img\) + $(VERB) dd if=/dev/zero of=$(BUILD_DIR)/tmp.img count=64 bs=1M + $(VERB) echo -e "unit: sectors\n/dev/hdc1 : Id=0c" | sfdisk $(BUILD_DIR)/tmp.img > /dev/null + $(VERB) mkfs.vfat -F 32 $(BUILD_DIR)/tmp.img > /dev/null + + $(VERB) echo -- Copying files to `$(BUILD_DIR)/staging` + $(VERB) mkdir -p $(BUILD_DIR)/staging + $(VERB) cp third-party/raspi-firmware/boot/bcm2710-rpi-3-b.dtb $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/bcm2710-rpi-3-b-plus.dtb $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/bcm2710-rpi-cm3.dtb $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/bcm2711-rpi-4-b.dtb $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/bcm2711-rpi-400.dtb $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/bcm2711-rpi-cm4.dtb $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/bcm2711-rpi-cm4s.dtb $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/*.dat $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/*.elf $(BUILD_DIR)/staging/ + $(VERB) cp third-party/raspi-firmware/boot/bootcode.bin $(BUILD_DIR)/staging/ + $(VERB) cp src/config.txt $(BUILD_DIR)/staging/ + $(VERB) cp $(BUILD_DIR)/kernel8.img $(BUILD_DIR)/staging/kernel8.img + + $(VERB) echo -- Gzipping the kernel + $(VERB) gzip $(BUILD_DIR)/staging/kernel8.img + $(VERB) mv $(BUILD_DIR)/staging/kernel8.img.gz $(BUILD_DIR)/staging/kernel8.img + + $(VERB) echo -- Copying files into the image + $(VERB) mcopy -i $(BUILD_DIR)/tmp.img $(BUILD_DIR)/staging/* ::/ + + $(VERB) mv $(BUILD_DIR)/tmp.img $(BUILD_DIR)/r4.img + $(VERB) echo Done! + +real_hardware: $(BUILD_DIR)/r4.img + clean: - rm boot.o kernel.o os.elf kernel8.img - rm -rf staging + rm -rf $(BUILD_DIR) *.img diff --git a/include/mini_uart.h b/include/mini_uart.h new file mode 100644 index 0000000..d3bd2dc --- /dev/null +++ b/include/mini_uart.h @@ -0,0 +1,9 @@ +#ifndef _MINI_UART_H +#define _MINI_UART_H + +void uart_init ( void ); +char uart_recv ( void ); +void uart_send ( char c ); +void uart_send_string(char* str); + +#endif /*_MINI_UART_H */ diff --git a/include/mm.h b/include/mm.h new file mode 100644 index 0000000..784ac4b --- /dev/null +++ b/include/mm.h @@ -0,0 +1,19 @@ +#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) + +#define LOW_MEMORY (2 * SECTION_SIZE) + +#ifndef __ASSEMBLER__ + +void memzero(unsigned long src, unsigned long n); + +#endif + +#endif /*_MM_H */ diff --git a/src/mmio.h b/include/mmio.h similarity index 100% rename from src/mmio.h rename to include/mmio.h diff --git a/include/peripherals/base.h b/include/peripherals/base.h new file mode 100644 index 0000000..a055708 --- /dev/null +++ b/include/peripherals/base.h @@ -0,0 +1,6 @@ +#ifndef _P_BASE_H +#define _P_BASE_H + +#define PBASE 0xFE000000 + +#endif /*_P_BASE_H */ diff --git a/include/peripherals/gpio.h b/include/peripherals/gpio.h new file mode 100644 index 0000000..5e9af26 --- /dev/null +++ b/include/peripherals/gpio.h @@ -0,0 +1,12 @@ +#ifndef _P_GPIO_H +#define _P_GPIO_H + +#include "peripherals/base.h" + +#define GPFSEL1 (PBASE+0x00200004) +#define GPSET0 (PBASE+0x0020001C) +#define GPCLR0 (PBASE+0x00200028) +#define GPPUD (PBASE+0x00200094) +#define GPPUDCLK0 (PBASE+0x00200098) + +#endif /*_P_GPIO_H */ diff --git a/include/peripherals/mini_uart.h b/include/peripherals/mini_uart.h new file mode 100644 index 0000000..af95a3b --- /dev/null +++ b/include/peripherals/mini_uart.h @@ -0,0 +1,19 @@ +#ifndef _P_MINI_UART_H +#define _P_MINI_UART_H + +#include "peripherals/base.h" + +#define AUX_ENABLES (PBASE+0x00215004) +#define AUX_MU_IO_REG (PBASE+0x00215040) +#define AUX_MU_IER_REG (PBASE+0x00215044) +#define AUX_MU_IIR_REG (PBASE+0x00215048) +#define AUX_MU_LCR_REG (PBASE+0x0021504C) +#define AUX_MU_MCR_REG (PBASE+0x00215050) +#define AUX_MU_LSR_REG (PBASE+0x00215054) +#define AUX_MU_MSR_REG (PBASE+0x00215058) +#define AUX_MU_SCRATCH (PBASE+0x0021505C) +#define AUX_MU_CNTL_REG (PBASE+0x00215060) +#define AUX_MU_STAT_REG (PBASE+0x00215064) +#define AUX_MU_BAUD_REG (PBASE+0x00215068) + +#endif /*_P_MINI_UART_H */ diff --git a/src/uart.h b/include/uart.h similarity index 100% rename from src/uart.h rename to include/uart.h diff --git a/include/utils.h b/include/utils.h new file mode 100644 index 0000000..a23ae37 --- /dev/null +++ b/include/utils.h @@ -0,0 +1,8 @@ +#ifndef _BOOT_H +#define _BOOT_H + +extern void delay ( unsigned long); +extern void put32 ( unsigned long, unsigned int ); +extern unsigned int get32 ( unsigned long ); + +#endif /*_BOOT_H */ diff --git a/src/boot.S b/src/boot.S index b0a7729..4c61785 100644 --- a/src/boot.S +++ b/src/boot.S @@ -1,33 +1,24 @@ -// AArch64 mode -// To keep this in the first portion of the binary. +#include "mm.h" + .section ".text.boot" -// Make _start global. -.globl _start - -// Entry point for the kernel. Registers: -// x0 -> 32 bit pointer to DTB in memory (primary core only) / 0 (secondary cores) -// x1 -> 0 -// x2 -> 0 -// x3 -> 0 -// x4 -> 32 bit kernel entry point, _start location +.global _start _start: - // set stack before our code - ldr x5, =_start - mov sp, x5 + mrs x0, mpidr_el1 + and x0, x0,#0xFF // Check processor id + cbz x0, master // Hang for all non-primary CPU + b proc_hang - // clear bss - ldr x5, =__bss_start - ldr w6, =__bss_size -1: cbz w6, 2f - str xzr, [x5], #8 - sub w6, w6, #1 - cbnz w6, 1b +proc_hang: + b proc_hang - // jump to C code, should not return -2: bl kernel_main - // for failsafe, halt this core -halt: - wfe - b halt +master: + adr x0, bss_begin + adr x1, bss_end + sub x1, x1, x0 + bl memzero + + mov sp, #LOW_MEMORY + bl kernel_main + b proc_hang // should never come here diff --git a/src/config.txt b/src/config.txt new file mode 100644 index 0000000..df34f9b --- /dev/null +++ b/src/config.txt @@ -0,0 +1,3 @@ +disable_commandline_tags=1 +core_freq_min=500 + diff --git a/src/kernel.c b/src/kernel.c index a570b75..259f5d4 100644 --- a/src/kernel.c +++ b/src/kernel.c @@ -1,45 +1,11 @@ -#include -#include -#include "mmio.h" -#include "uart.h" +#include "mini_uart.h" -volatile uint64_t** core_1 = (void*)0xE0; -volatile uint64_t** core_2 = (void*)0xE8; -volatile uint64_t** core_3 = (void*)0xF0; - - -void _start_core_1(void* addr) { - *core_1 = (uint64_t*)addr; -} - - -void _start_core_2(void* addr) { - *core_2 = (uint64_t*)addr; -} - - -void _start_core_3(void* addr) { - *core_3 = (uint64_t*)addr; -} - -void kernel_main(uint64_t dtb_ptr32, uint64_t x1, uint64_t x2, uint64_t x3) { - uint32_t reg; - char *board; - - asm volatile ("mrs %x0, midr_el1" : "=r" (reg)); - - switch ((reg >> 4) & 0xFFF) { - case 0xD03: - board = "Raspberry Pi 3\0"; - MMIO_BASE = 0x3F000000; - break; - case 0xD08: - board = "Raspberry Pi 4\0"; - MMIO_BASE = 0xFE000000; - break; - } +void kernel_main(void) +{ uart_init(); - uart_puts(board); + uart_send_string("Hello, world!\r\n"); - return; + while (1) { + uart_send(uart_recv() + 1); + } } diff --git a/src/linker.ld b/src/linker.ld index 3776a92..b66baac 100644 --- a/src/linker.ld +++ b/src/linker.ld @@ -1,44 +1,12 @@ -ENTRY(_start) - SECTIONS { - /* Starts at LOADER_ADDR. */ . = 0x80000; - /* For AArch64, use . = 0x80000; */ - __start = .; - __text_start = .; - .text : - { - KEEP(*(.text.boot)) - *(.text) - } - . = ALIGN(4096); /* align to page size */ - __text_end = .; - - __rodata_start = .; - .rodata : - { - *(.rodata) - } - . = ALIGN(4096); /* align to page size */ - __rodata_end = .; - - __data_start = .; - .data : - { - *(.data) - } - . = ALIGN(4096); /* align to page size */ - __data_end = .; - - __bss_start = .; - .bss : - { - bss = .; - *(.bss) - } - . = ALIGN(4096); /* align to page size */ - __bss_end = .; - __bss_size = __bss_end - __bss_start; - __end = .; + .text.boot : { *(.text.boot) } + .text : { *(.text) } + .rodata : { *(.rodata*) } + .data : { *(.data) } + . = ALIGN(0x8); + bss_begin = .; + .bss : { *(.bss*) } + bss_end = .; } diff --git a/src/mini_uart.c b/src/mini_uart.c new file mode 100644 index 0000000..ae4c32a --- /dev/null +++ b/src/mini_uart.c @@ -0,0 +1,56 @@ +#include "utils.h" +#include "peripherals/mini_uart.h" +#include "peripherals/gpio.h" + +void uart_send ( char c ) +{ + while(1) { + if(get32(AUX_MU_LSR_REG)&0x20) + break; + } + put32(AUX_MU_IO_REG,c); +} + +char uart_recv ( void ) +{ + while(1) { + if(get32(AUX_MU_LSR_REG)&0x01) + break; + } + return(get32(AUX_MU_IO_REG)&0xFF); +} + +void uart_send_string(char* str) +{ + for (int i = 0; str[i] != '\0'; i ++) { + uart_send((char)str[i]); + } +} + +void uart_init ( void ) +{ + unsigned int selector; + + 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 gpio15 + put32(GPFSEL1,selector); + + put32(GPPUD,0); + delay(150); + put32(GPPUDCLK0,(1<<14)|(1<<15)); + delay(150); + put32(GPPUDCLK0,0); + + put32(AUX_ENABLES,1); //Enable mini uart (this also enables access to its registers) + put32(AUX_MU_CNTL_REG,0); //Disable auto flow control and disable receiver and transmitter (for now) + put32(AUX_MU_IER_REG,0); //Disable receive and transmit interrupts + put32(AUX_MU_LCR_REG,3); //Enable 8 bit mode + put32(AUX_MU_MCR_REG,0); //Set RTS line to be always high + put32(AUX_MU_BAUD_REG,((500000000/(115200*8))-1)); //Set baud rate to 115200 + put32(AUX_MU_IIR_REG,0); + + put32(AUX_MU_CNTL_REG,3); //Finally, enable transmitter and receiver +} diff --git a/src/mm.S b/src/mm.S new file mode 100644 index 0000000..1bd32ff --- /dev/null +++ b/src/mm.S @@ -0,0 +1,6 @@ +.globl memzero +memzero: + str xzr, [x0], #8 + subs x1, x1, #8 + b.gt memzero + ret diff --git a/src/utils.S b/src/utils.S new file mode 100644 index 0000000..c35527a --- /dev/null +++ b/src/utils.S @@ -0,0 +1,15 @@ +.globl put32 +put32: + str w1,[x0] + ret + +.globl get32 +get32: + ldr w0,[x0] + ret + +.globl delay +delay: + subs x0, x0, #1 + bne delay + ret diff --git a/raspi_fw b/third-party/raspi-firmware similarity index 100% rename from raspi_fw rename to third-party/raspi-firmware