| /* |
| * QEMU OpenRISC timer support |
| * |
| * Copyright (c) 2011-2012 Jia Liu <proljc@gmail.com> |
| * Zhizhou Zhang <etouzh@gmail.com> |
| * |
| * This library is free software; you can redistribute it and/or |
| * modify it under the terms of the GNU Lesser General Public |
| * License as published by the Free Software Foundation; either |
| * version 2 of the License, or (at your option) any later version. |
| * |
| * This library is distributed in the hope that it will be useful, |
| * but WITHOUT ANY WARRANTY; without even the implied warranty of |
| * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the GNU |
| * Lesser General Public License for more details. |
| * |
| * You should have received a copy of the GNU Lesser General Public |
| * License along with this library; if not, see <http://www.gnu.org/licenses/>. |
| */ |
| |
| #include "cpu.h" |
| #include "hw/hw.h" |
| #include "qemu/timer.h" |
| |
| #define TIMER_FREQ (20 * 1000 * 1000) /* 20MHz */ |
| |
| /* The time when TTCR changes */ |
| static uint64_t last_clk; |
| static int is_counting; |
| |
| void cpu_openrisc_count_update(OpenRISCCPU *cpu) |
| { |
| uint64_t now; |
| |
| if (!is_counting) { |
| return; |
| } |
| now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); |
| cpu->env.ttcr += (uint32_t)muldiv64(now - last_clk, TIMER_FREQ, |
| get_ticks_per_sec()); |
| last_clk = now; |
| } |
| |
| void cpu_openrisc_timer_update(OpenRISCCPU *cpu) |
| { |
| uint32_t wait; |
| uint64_t now, next; |
| |
| if (!is_counting) { |
| return; |
| } |
| |
| cpu_openrisc_count_update(cpu); |
| now = last_clk; |
| |
| if ((cpu->env.ttmr & TTMR_TP) <= (cpu->env.ttcr & TTMR_TP)) { |
| wait = TTMR_TP - (cpu->env.ttcr & TTMR_TP) + 1; |
| wait += cpu->env.ttmr & TTMR_TP; |
| } else { |
| wait = (cpu->env.ttmr & TTMR_TP) - (cpu->env.ttcr & TTMR_TP); |
| } |
| next = now + muldiv64(wait, get_ticks_per_sec(), TIMER_FREQ); |
| timer_mod(cpu->env.timer, next); |
| } |
| |
| void cpu_openrisc_count_start(OpenRISCCPU *cpu) |
| { |
| is_counting = 1; |
| cpu_openrisc_count_update(cpu); |
| } |
| |
| void cpu_openrisc_count_stop(OpenRISCCPU *cpu) |
| { |
| timer_del(cpu->env.timer); |
| cpu_openrisc_count_update(cpu); |
| is_counting = 0; |
| } |
| |
| static void openrisc_timer_cb(void *opaque) |
| { |
| OpenRISCCPU *cpu = opaque; |
| |
| if ((cpu->env.ttmr & TTMR_IE) && |
| timer_expired(cpu->env.timer, qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL))) { |
| CPUState *cs = CPU(cpu); |
| |
| cpu->env.ttmr |= TTMR_IP; |
| cs->interrupt_request |= CPU_INTERRUPT_TIMER; |
| } |
| |
| switch (cpu->env.ttmr & TTMR_M) { |
| case TIMER_NONE: |
| break; |
| case TIMER_INTR: |
| cpu->env.ttcr = 0; |
| break; |
| case TIMER_SHOT: |
| cpu_openrisc_count_stop(cpu); |
| break; |
| case TIMER_CONT: |
| break; |
| } |
| |
| cpu_openrisc_timer_update(cpu); |
| } |
| |
| void cpu_openrisc_clock_init(OpenRISCCPU *cpu) |
| { |
| cpu->env.timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, &openrisc_timer_cb, cpu); |
| cpu->env.ttmr = 0x00000000; |
| cpu->env.ttcr = 0x00000000; |
| } |