Files
lk/platform/sifive/plic.c
Elliot Berman acfe991c7f [arch][riscv] Expose RISC-V mp kernel start
Support mp lk start on RISC-V. Several changes throughout were required:
- Add signal in asm start to force secondary harts to wait for bss to be
  cleared.
- Use mhartid in arch_curr_cpu_num, PLIC, and CLINT
- Use tp register as thread pointer instead of global variable.
- Support sending IPIs between harts using CLINT
- Add spinlock implementation
2020-01-16 23:06:28 -08:00

95 lines
2.6 KiB
C

/*
* Copyright (c) 2018 Travis Geiselbrecht
*
* Use of this source code is governed by a MIT-style
* license that can be found in the LICENSE file or at
* https://opensource.org/licenses/MIT
*/
#include "platform_p.h"
#include <assert.h>
#include <lk/err.h>
#include <lk/debug.h>
#include <lk/reg.h>
#include <lk/trace.h>
#include <kernel/debug.h>
#include <kernel/thread.h>
#include <platform/interrupts.h>
#include <platform/sifive.h>
#define LOCAL_TRACE 0
// Driver for PLIC implementation in SiFive E and U boards
#define PLIC_PRIORITY(irq) (PLIC_BASE + 4 * (irq))
#define PLIC_PENDING(irq) (PLIC_BASE + 0x1000 + (4 * ((irq) / 32)))
#define PLIC_ENABLE(irq, hart) (PLIC_BASE + 0x2000 + (0x80 * PLIC_HART_IDX(hart)) + (4 * ((irq) / 32)))
#define PLIC_THRESHOLD(hart) (PLIC_BASE + 0x200000 + (0x1000 * PLIC_HART_IDX(hart)))
#define PLIC_COMPLETE(hart) (PLIC_BASE + 0x200004 + (0x1000 * PLIC_HART_IDX(hart)))
#define PLIC_CLAIM(hart) PLIC_COMPLETE(hart)
static struct int_handlers {
int_handler handler;
void *arg;
} handlers[SIFIVE_NUM_IRQS];
void plic_early_init(void) {
// mask all irqs and set their priority to 1
for (int i = 1; i < SIFIVE_NUM_IRQS; i++) {
*REG32(PLIC_ENABLE(i, riscv_current_hart())) &= ~(1 << (i % 32));
*REG32(PLIC_PRIORITY(i)) = 1;
}
// set global priority threshold to 0
*REG32(PLIC_THRESHOLD(riscv_current_hart())) = 0;
}
void plic_init(void) {
}
status_t mask_interrupt(unsigned int vector) {
*REG32(PLIC_ENABLE(vector, riscv_current_hart())) &= ~(1 << (vector % 32));
return NO_ERROR;
}
status_t unmask_interrupt(unsigned int vector) {
*REG32(PLIC_ENABLE(vector, riscv_current_hart())) |= (1 << (vector % 32));
return NO_ERROR;
}
void register_int_handler(unsigned int vector, int_handler handler, void *arg) {
LTRACEF("vector %u handler %p arg %p\n", vector, handler, arg);
DEBUG_ASSERT(vector < SIFIVE_NUM_IRQS);
handlers[vector].handler = handler;
handlers[vector].arg = arg;
}
enum handler_return riscv_platform_irq(void) {
// see what irq triggered it
uint32_t vector = *REG32(PLIC_CLAIM(riscv_current_hart()));
LTRACEF("vector %u\n", vector);
if (unlikely(vector == 0)) {
// nothing pending
return INT_NO_RESCHEDULE;
}
THREAD_STATS_INC(interrupts);
KEVLOG_IRQ_ENTER(vector);
enum handler_return ret = INT_NO_RESCHEDULE;
if (handlers[vector].handler) {
ret = handlers[vector].handler(handlers[vector].arg);
}
// ack the interrupt
*REG32(PLIC_COMPLETE(riscv_current_hart())) = vector;
KEVLOG_IRQ_EXIT(vector);
return ret;
}