From 2a2cf1f536f985330054cf47f47ec7d2455e35fa Mon Sep 17 00:00:00 2001 From: Kevin O'Connor Date: Wed, 21 Aug 2019 12:05:56 -0400 Subject: [PATCH] armcm_boot: Add generic code for early board init on armcm machines Add basic ARM Cortex-M C init code and build linker scripts to src/generic/ code. This can be used to simplify the various ARM board code. Signed-off-by: Kevin O'Connor --- scripts/buildcommands.py | 44 ++++++++++++++++++++++ src/generic/armcm_boot.c | 73 ++++++++++++++++++++++++++++++++++++ src/generic/armcm_boot.h | 20 ++++++++++ src/generic/armcm_boot.lds.S | 63 +++++++++++++++++++++++++++++++ src/generic/armcm_timer.c | 2 + 5 files changed, 202 insertions(+) create mode 100644 src/generic/armcm_boot.c create mode 100644 src/generic/armcm_boot.h create mode 100644 src/generic/armcm_boot.lds.S diff --git a/scripts/buildcommands.py b/scripts/buildcommands.py index e796994e..6ef5c80a 100644 --- a/scripts/buildcommands.py +++ b/scripts/buildcommands.py @@ -209,6 +209,50 @@ const int initial_pins_size PROGMEM = ARRAY_SIZE(initial_pins); Handlers.append(HandleInitialPins()) +###################################################################### +# ARM IRQ vector table generation +###################################################################### + +# Create ARM IRQ vector table from interrupt handler declarations +class Handle_arm_irq: + def __init__(self): + self.irqs = {} + self.ctr_dispatch = { 'DECL_ARMCM_IRQ': self.decl_armcm_irq } + def decl_armcm_irq(self, req): + func, num = req.split()[1:] + num = decode_integer(num) + if num in self.irqs and self.irqs[num] != func: + error("Conflicting IRQ definition %d (old %s new %s)" + % (num, self.irqs[num], func)) + self.irqs[num] = func + def update_data_dictionary(self, data): + pass + def generate_code(self, options): + armcm_offset = 16 + if 1 - armcm_offset not in self.irqs: + # The ResetHandler was not defined - don't build VectorTable + return "" + max_irq = max(self.irqs.keys()) + table = [" DefaultHandler,\n"] * (max_irq + armcm_offset + 1) + defs = [] + for num, func in self.irqs.items(): + if num < 1 - armcm_offset: + error("Invalid IRQ %d (%s)" % (num, func)) + defs.append("extern void %s(void);\n" % (func,)) + table[num + armcm_offset] = " %s,\n" % (func,) + table[0] = " &_stack_end,\n" + fmt = """ +extern void DefaultHandler(void); +extern uint32_t _stack_end; +%s +const void *VectorTable[] __visible __section(".vector_table") = { +%s}; +""" + return fmt % (''.join(defs), ''.join(table)) + +Handlers.append(Handle_arm_irq()) + + ###################################################################### # Wire protocol commands and responses ###################################################################### diff --git a/src/generic/armcm_boot.c b/src/generic/armcm_boot.c new file mode 100644 index 00000000..c559c1c1 --- /dev/null +++ b/src/generic/armcm_boot.c @@ -0,0 +1,73 @@ +// ARM Cortex-M vector table and initial bootup handling +// +// Copyright (C) 2019 Kevin O'Connor +// +// This file may be distributed under the terms of the GNU GPLv3 license. + +#include "armcm_boot.h" // DECL_ARMCM_IRQ +#include "board/internal.h" // SystemInit + +// Symbols created by armcm_boot.lds.S linker script +extern uint32_t _data_start, _data_end, _data_flash; +extern uint32_t _bss_start, _bss_end, _stack_start; + + +/**************************************************************** + * Basic interrupt handlers + ****************************************************************/ + +// Initial code entry point - invoked by the processor after a reset +void +ResetHandler(void) +{ + // Copy global variables from flash to ram + uint32_t count = (&_data_end - &_data_start) * 4; + __builtin_memcpy(&_data_start, &_data_flash, count); + + // Clear the bss segment + __builtin_memset(&_bss_start, 0, (&_bss_end - &_bss_start) * 4); + + barrier(); + + // Initializing the C library isn't needed... + //__libc_init_array(); + + // Initialize the machine + SystemInit(); + + // Run the main code + extern int main(void); + main(); + + // The main() call should not return + for (;;) + ; +} +DECL_ARMCM_IRQ(ResetHandler, -15); + +// Code called for any undefined interrupts +void +DefaultHandler(void) +{ + for (;;) + ; +} + + +/**************************************************************** + * Dynamic memory range + ****************************************************************/ + +// Return the start of memory available for dynamic allocations +void * +dynmem_start(void) +{ + return &_bss_end; +} + +// Return the end of memory available for dynamic allocations +void * +dynmem_end(void) +{ + return &_stack_start; +} diff --git a/src/generic/armcm_boot.h b/src/generic/armcm_boot.h new file mode 100644 index 00000000..10b17e18 --- /dev/null +++ b/src/generic/armcm_boot.h @@ -0,0 +1,20 @@ +#ifndef __GENERIC_ARMCM_BOOT_H +#define __GENERIC_ARMCM_BOOT_H + +#include "ctr.h" // DECL_CTR_INT + +// Declare an IRQ handler +#define DECL_ARMCM_IRQ(FUNC, NUM) \ + DECL_CTR_INT("DECL_ARMCM_IRQ " __stringify(FUNC), (NUM)) + +// Statically declare an IRQ handler and run-time enable it +#define armcm_enable_irq(FUNC, NUM, PRIORITY) do { \ + DECL_ARMCM_IRQ(FUNC, (NUM)); \ + NVIC_SetPriority((NUM), (PRIORITY)); \ + NVIC_EnableIRQ((NUM)); \ + } while (0) + +// Vectors created by scripts/buildcommands.py from DECL_ARMCM_IRQ commands +extern const void * const VectorTable[]; + +#endif // armcm_boot.h diff --git a/src/generic/armcm_boot.lds.S b/src/generic/armcm_boot.lds.S new file mode 100644 index 00000000..8014a490 --- /dev/null +++ b/src/generic/armcm_boot.lds.S @@ -0,0 +1,63 @@ +// Generic ARM Cortex-M linker script +// +// Copyright (C) 2019 Kevin O'Connor +// +// This file may be distributed under the terms of the GNU GPLv3 license. + +#include "autoconf.h" // CONFIG_FLASH_START + +OUTPUT_FORMAT("elf32-littlearm", "elf32-littlearm", "elf32-littlearm") +OUTPUT_ARCH(arm) + +MEMORY +{ + rom (rx) : ORIGIN = CONFIG_FLASH_START , LENGTH = CONFIG_FLASH_SIZE + ram (rwx) : ORIGIN = CONFIG_RAM_START , LENGTH = CONFIG_RAM_SIZE +} + +SECTIONS +{ + .text : { + . = ALIGN(4); + KEEP(*(.vector_table)) + *(.text .text.*) + *(.rodata .rodata*) + } > rom + + . = ALIGN(4); + _data_flash = .; + + .data : AT (_data_flash) + { + . = ALIGN(4); + _data_start = .; + *(.ramfunc .ramfunc.*); + *(.data .data.*); + . = ALIGN(4); + _data_end = .; + } > ram + + .bss (NOLOAD) : + { + . = ALIGN(4); + _bss_start = .; + *(.bss .bss.*) + *(COMMON) + . = ALIGN(4); + _bss_end = .; + } > ram + + _stack_start = CONFIG_RAM_START + CONFIG_RAM_SIZE - CONFIG_STACK_SIZE ; + .stack _stack_start (NOLOAD) : + { + . = . + CONFIG_STACK_SIZE; + _stack_end = .; + } > ram + + /DISCARD/ : { + // The .init/.fini sections are used by __libc_init_array(), but + // that isn't needed so no need to include them in the binary. + *(.init) + *(.fini) + } +} diff --git a/src/generic/armcm_timer.c b/src/generic/armcm_timer.c index f4ce2b8b..ef38680a 100644 --- a/src/generic/armcm_timer.c +++ b/src/generic/armcm_timer.c @@ -5,6 +5,7 @@ // This file may be distributed under the terms of the GNU GPLv3 license. #include "autoconf.h" // CONFIG_CLOCK_FREQ +#include "armcm_boot.h" // DECL_ARMCM_IRQ #include "board/internal.h" // SysTick #include "board/irq.h" // irq_disable #include "board/misc.h" // timer_from_us @@ -160,6 +161,7 @@ SysTick_Handler(void) timer_set_diff(diff); irq_enable(); } +DECL_ARMCM_IRQ(SysTick_Handler, SysTick_IRQn); // Make sure timer_repeat_until doesn't wrap 32bit comparisons void