diff options
Diffstat (limited to 'hw/lm32_timer.c')
| -rw-r--r-- | hw/lm32_timer.c | 222 |
1 files changed, 222 insertions, 0 deletions
diff --git a/hw/lm32_timer.c b/hw/lm32_timer.c new file mode 100644 index 0000000000..ed289847ac --- /dev/null +++ b/hw/lm32_timer.c @@ -0,0 +1,222 @@ +/* + * QEMU model of the LatticeMico32 timer block. + * + * Copyright (c) 2010 Michael Walle <michael@walle.cc> + * + * 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/>. + * + * + * Specification available at: + * http://www.latticesemi.com/documents/mico32timer.pdf + */ + +#include "hw.h" +#include "sysbus.h" +#include "trace.h" +#include "qemu-timer.h" +#include "qemu-error.h" + +#define DEFAULT_FREQUENCY (50*1000000) + +enum { + R_SR = 0, + R_CR, + R_PERIOD, + R_SNAPSHOT, + R_MAX +}; + +enum { + SR_TO = (1 << 0), + SR_RUN = (1 << 1), +}; + +enum { + CR_ITO = (1 << 0), + CR_CONT = (1 << 1), + CR_START = (1 << 2), + CR_STOP = (1 << 3), +}; + +struct LM32TimerState { + SysBusDevice busdev; + + QEMUBH *bh; + ptimer_state *ptimer; + + qemu_irq irq; + uint32_t freq_hz; + + uint32_t regs[R_MAX]; +}; +typedef struct LM32TimerState LM32TimerState; + +static void timer_update_irq(LM32TimerState *s) +{ + int state = (s->regs[R_SR] & SR_TO) && (s->regs[R_CR] & CR_ITO); + + trace_lm32_timer_irq_state(state); + qemu_set_irq(s->irq, state); +} + +static uint32_t timer_read(void *opaque, target_phys_addr_t addr) +{ + LM32TimerState *s = opaque; + uint32_t r = 0; + + addr >>= 2; + switch (addr) { + case R_SR: + case R_CR: + case R_PERIOD: + r = s->regs[addr]; + break; + case R_SNAPSHOT: + r = (uint32_t)ptimer_get_count(s->ptimer); + break; + default: + error_report("lm32_timer: read access to unkown register 0x" + TARGET_FMT_plx, addr << 2); + break; + } + + trace_lm32_timer_memory_read(addr << 2, r); + return r; +} + +static void timer_write(void *opaque, target_phys_addr_t addr, uint32_t value) +{ + LM32TimerState *s = opaque; + + trace_lm32_timer_memory_write(addr, value); + + addr >>= 2; + switch (addr) { + case R_SR: + s->regs[R_SR] &= ~SR_TO; + break; + case R_CR: + s->regs[R_CR] = value; + if (s->regs[R_CR] & CR_START) { + ptimer_run(s->ptimer, 1); + } + if (s->regs[R_CR] & CR_STOP) { + ptimer_stop(s->ptimer); + } + break; + case R_PERIOD: + s->regs[R_PERIOD] = value; + ptimer_set_count(s->ptimer, value); + break; + case R_SNAPSHOT: + error_report("lm32_timer: write access to read only register 0x" + TARGET_FMT_plx, addr << 2); + break; + default: + error_report("lm32_timer: write access to unkown register 0x" + TARGET_FMT_plx, addr << 2); + break; + } + timer_update_irq(s); +} + +static CPUReadMemoryFunc * const timer_read_fn[] = { + NULL, + NULL, + &timer_read, +}; + +static CPUWriteMemoryFunc * const timer_write_fn[] = { + NULL, + NULL, + &timer_write, +}; + +static void timer_hit(void *opaque) +{ + LM32TimerState *s = opaque; + + trace_lm32_timer_hit(); + + s->regs[R_SR] |= SR_TO; + + if (s->regs[R_CR] & CR_CONT) { + ptimer_set_count(s->ptimer, s->regs[R_PERIOD]); + ptimer_run(s->ptimer, 1); + } + timer_update_irq(s); +} + +static void timer_reset(DeviceState *d) +{ + LM32TimerState *s = container_of(d, LM32TimerState, busdev.qdev); + int i; + + for (i = 0; i < R_MAX; i++) { + s->regs[i] = 0; + } + ptimer_stop(s->ptimer); +} + +static int lm32_timer_init(SysBusDevice *dev) +{ + LM32TimerState *s = FROM_SYSBUS(typeof(*s), dev); + int timer_regs; + + sysbus_init_irq(dev, &s->irq); + + s->bh = qemu_bh_new(timer_hit, s); + s->ptimer = ptimer_init(s->bh); + ptimer_set_freq(s->ptimer, s->freq_hz); + + timer_regs = cpu_register_io_memory(timer_read_fn, timer_write_fn, s, + DEVICE_NATIVE_ENDIAN); + sysbus_init_mmio(dev, R_MAX * 4, timer_regs); + + return 0; +} + +static const VMStateDescription vmstate_lm32_timer = { + .name = "lm32-timer", + .version_id = 1, + .minimum_version_id = 1, + .minimum_version_id_old = 1, + .fields = (VMStateField[]) { + VMSTATE_PTIMER(ptimer, LM32TimerState), + VMSTATE_UINT32(freq_hz, LM32TimerState), + VMSTATE_UINT32_ARRAY(regs, LM32TimerState, R_MAX), + VMSTATE_END_OF_LIST() + } +}; + +static SysBusDeviceInfo lm32_timer_info = { + .init = lm32_timer_init, + .qdev.name = "lm32-timer", + .qdev.size = sizeof(LM32TimerState), + .qdev.vmsd = &vmstate_lm32_timer, + .qdev.reset = timer_reset, + .qdev.props = (Property[]) { + DEFINE_PROP_UINT32( + "frequency", LM32TimerState, freq_hz, DEFAULT_FREQUENCY + ), + DEFINE_PROP_END_OF_LIST(), + } +}; + +static void lm32_timer_register(void) +{ + sysbus_register_withprop(&lm32_timer_info); +} + +device_init(lm32_timer_register) |