nuttx/arch/risc-v/src/nuttsbi/sbi_mexception.c
Ville Juven ae64f28344 RISC-V: Implement simple and native NuttX SBI
This is a minimalistic SBI implementation for NuttX.

Provides a single service for now:
- Access to machine timer

Provides a start trampoline to start NuttX in S-mode:
- Exceptions / faults are delegated to S-mode.
- External interrupts are delegated to S-mode.

Machine mode timer is used as follows:
- The timer compare match register reload happens in M-mode, via
  call gate "riscv_sbi_set_timer"
- The compare match event is dispatched to S-mode ISR, which will
  notify the kernel to advance time
- Clearing the STIP interrupt does not work from S-mode,
  so the call gate does this from M-mode

The only supported (tested) target for now is MPFS.
2023-06-07 01:48:15 +08:00

38 lines
1.5 KiB
C

/****************************************************************************
* arch/risc-v/src/nuttsbi/sbi_mexception.c
*
* Licensed to the Apache Software Foundation (ASF) under one or more
* contributor license agreements. See the NOTICE file distributed with
* this work for additional information regarding copyright ownership. The
* ASF licenses this file to you under the Apache License, Version 2.0 (the
* "License"); you may not use this file except in compliance with the
* License. You may obtain a copy of the License at
*
* http://www.apache.org/licenses/LICENSE-2.0
*
* Unless required by applicable law or agreed to in writing, software
* distributed under the License is distributed on an "AS IS" BASIS, WITHOUT
* WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied. See the
* License for the specific language governing permissions and limitations
* under the License.
*
****************************************************************************/
/****************************************************************************
* Included Files
****************************************************************************/
#include <nuttx/config.h>
#include <stdint.h>
/****************************************************************************
* Public Functions
****************************************************************************/
void sbi_mexception(uintptr_t mcause, uintptr_t *mepc)
{
(void) mcause;
(void) mepc;
}