diff options
Diffstat (limited to 'hw/openrisc/cputimer.c')
-rw-r--r-- | hw/openrisc/cputimer.c | 101 |
1 files changed, 101 insertions, 0 deletions
diff --git a/hw/openrisc/cputimer.c b/hw/openrisc/cputimer.c new file mode 100644 index 0000000..f6c877f --- /dev/null +++ b/hw/openrisc/cputimer.c @@ -0,0 +1,101 @@ +/* + * 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, next; + uint32_t wait; + + now = qemu_get_clock_ns(vm_clock); + if (!is_counting) { + qemu_del_timer(cpu->env.timer); + last_clk = now; + return; + } + + cpu->env.ttcr += (uint32_t)muldiv64(now - last_clk, TIMER_FREQ, + get_ticks_per_sec()); + last_clk = now; + + 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); + qemu_mod_timer(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) +{ + is_counting = 0; + cpu_openrisc_count_update(cpu); +} + +static void openrisc_timer_cb(void *opaque) +{ + OpenRISCCPU *cpu = opaque; + + if ((cpu->env.ttmr & TTMR_IE) && + qemu_timer_expired(cpu->env.timer, qemu_get_clock_ns(vm_clock))) { + cpu->env.ttmr |= TTMR_IP; + cpu->env.interrupt_request |= CPU_INTERRUPT_TIMER; + } + + switch (cpu->env.ttmr & TTMR_M) { + case TIMER_NONE: + break; + case TIMER_INTR: + cpu->env.ttcr = 0; + cpu_openrisc_count_start(cpu); + break; + case TIMER_SHOT: + cpu_openrisc_count_stop(cpu); + break; + case TIMER_CONT: + cpu_openrisc_count_start(cpu); + break; + } +} + +void cpu_openrisc_clock_init(OpenRISCCPU *cpu) +{ + cpu->env.timer = qemu_new_timer_ns(vm_clock, &openrisc_timer_cb, cpu); + cpu->env.ttmr = 0x00000000; + cpu->env.ttcr = 0x00000000; +} |