mirror of
https://github.com/RIOT-OS/RIOT.git
synced 2024-12-29 04:50:03 +01:00
ff7f8ae2f0
RIOT supports two distinct families of the MSP430: The [MSP430 x1xx]
MCU family and the [MSP430 F2xx/G2xx] MCU family. For both incompatible
MCU families the code was located in the msp430fxyz folder, resulting
in case of the UART driver in particularly bizarre code looking roughly
like this:
#ifndef UART_USE_USCI
/* implementation of x1xx peripheral ... */
#else
/* implementation of F2xx/G2xx peripheral ... */
#endif
/* zero shared code between both variants */
This splits the peripheral drivers for USCI and USART serial IP blocks
into separate files and relocates everything in cpu/msp430, similar to
how cpu/stm32 is organized.
[MSP430 x1xx]: https://www.ti.com/lit/ug/slau049f/slau049f.pdf
[MSP430 F2xx/G2xx]: https://www.ti.com/lit/ug/slau144k/slau144k.pdf
137 lines
3.9 KiB
C
137 lines
3.9 KiB
C
/*
|
|
* Copyright (C) 2016 Kaspar Schleiser <kaspar@schleiser.de>
|
|
* 2014, Freie Universitaet Berlin (FUB) & INRIA.
|
|
* All rights reserved.
|
|
*
|
|
* This file is subject to the terms and conditions of the GNU Lesser
|
|
* General Public License v2.1. See the file LICENSE in the top level
|
|
* directory for more details.
|
|
*/
|
|
|
|
#include "cpu.h"
|
|
#include "kernel_init.h"
|
|
#include "irq.h"
|
|
#include "sched.h"
|
|
#include "thread.h"
|
|
|
|
/*
|
|
* This function can both be called from ISR and from thread context.
|
|
*
|
|
* In both cases, the caller will use "CALL", which pushes the return
|
|
* address on the stack before executing the function's first instruction.
|
|
*
|
|
* If called within ISR, just set sched_context_switch_request and
|
|
* directly return to the call site. A regular function return does this.
|
|
*
|
|
* If called from stack context, it needs to prepare the stack so it looks exactly
|
|
* as if the thread had been interrupted by an ISR, which requires the SR to be on
|
|
* stack right after the return address. So we do this manually.
|
|
* __save_context() will then save the remaining registers, then store the stack
|
|
* pointer in the thread's thread_t.
|
|
*
|
|
* At this point, the thread context is properly saved. sched_run (possibly) changes
|
|
* the currently active thread, which __restore_context() then restores, resuming
|
|
* execution at the call site using reti.
|
|
*
|
|
*/
|
|
void thread_yield_higher(void)
|
|
{
|
|
if (irq_is_in()) {
|
|
sched_context_switch_request = 1;
|
|
}
|
|
else {
|
|
__asm__ volatile (
|
|
"push r2" "\n\t" /* save SR */
|
|
"dint" "\n\t" /* reti will restore SR, and thus, IRQ state */
|
|
"nop" "\n\t" /* dint takes an additional CPU cycle to take into effect */
|
|
: /* no outputs */
|
|
: /* no inputs */
|
|
: /* no clobbers */
|
|
);
|
|
|
|
__save_context();
|
|
|
|
/* have thread_get_active() point to the next thread */
|
|
sched_run();
|
|
|
|
__restore_context();
|
|
|
|
UNREACHABLE();
|
|
}
|
|
}
|
|
|
|
/* This function calculates the ISR_usage */
|
|
int thread_isr_stack_usage(void)
|
|
{
|
|
/* TODO */
|
|
return -1;
|
|
}
|
|
|
|
void *thread_isr_stack_pointer(void)
|
|
{
|
|
/* TODO */
|
|
return (void *)-1;
|
|
}
|
|
|
|
void *thread_isr_stack_start(void)
|
|
{
|
|
/* TODO */
|
|
return (void *)-1;
|
|
}
|
|
|
|
NORETURN void cpu_switch_context_exit(void)
|
|
{
|
|
sched_run();
|
|
|
|
__restore_context();
|
|
|
|
UNREACHABLE();
|
|
}
|
|
|
|
/**
|
|
* mspgcc handles main specially - it does not return but falls
|
|
* through to section .fini9.
|
|
* To "fix" this, we put a return in section .fini9 to make main
|
|
* behave like a regular function. This enables a common
|
|
* thread_stack_init behavior. */
|
|
__attribute__((section (".fini9"))) void __main_epilogue(void) { __asm__("ret"); }
|
|
|
|
/* ------------------------------------------------------------------------- */
|
|
/* Processor specific routine - here for MSP */
|
|
/* ------------------------------------------------------------------------- */
|
|
char *thread_stack_init(thread_task_func_t task_func, void *arg, void *stack_start, int stack_size)
|
|
{
|
|
unsigned short stk = (unsigned short)((uintptr_t) stack_start + stack_size);
|
|
|
|
/* ensure correct stack alignment (on 16-bit boundary) */
|
|
stk &= 0xfffe;
|
|
unsigned short *stackptr = (unsigned short *)stk;
|
|
|
|
/* now make SP point on the first AVAILABLE slot in stack */
|
|
--stackptr;
|
|
|
|
*stackptr = (unsigned short) sched_task_exit;
|
|
--stackptr;
|
|
|
|
*stackptr = (unsigned short) task_func;
|
|
--stackptr;
|
|
|
|
/* initial value for SR */
|
|
*stackptr = GIE;
|
|
--stackptr;
|
|
|
|
/* Space for registers. */
|
|
for (unsigned int i = 15; i > 4; i--) {
|
|
*stackptr = i;
|
|
--stackptr;
|
|
}
|
|
|
|
/* set arg to R12
|
|
this was R15 in mspgcc, see https://www.ti.com/lit/an/slaa664/slaa664.pdf
|
|
stackptr points to R3, so write arg 9 words after that.
|
|
*/
|
|
stackptr[8] = (intptr_t)arg;
|
|
|
|
return (char *) stackptr;
|
|
}
|