diff options
Diffstat (limited to 'hw/timer/sifive_pwm.c')
| -rw-r--r-- | hw/timer/sifive_pwm.c | 468 |
1 files changed, 468 insertions, 0 deletions
diff --git a/hw/timer/sifive_pwm.c b/hw/timer/sifive_pwm.c new file mode 100644 index 000000000..c664480cc --- /dev/null +++ b/hw/timer/sifive_pwm.c @@ -0,0 +1,468 @@ +/* + * SiFive PWM + * + * Copyright (c) 2020 Western Digital + * + * Author: Alistair Francis <alistair.francis@wdc.com> + * + * Permission is hereby granted, free of charge, to any person obtaining a copy + * of this software and associated documentation files (the "Software"), to deal + * in the Software without restriction, including without limitation the rights + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell + * copies of the Software, and to permit persons to whom the Software is + * furnished to do so, subject to the following conditions: + * + * The above copyright notice and this permission notice shall be included in + * all copies or substantial portions of the Software. + * + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY, + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN + * THE SOFTWARE. + */ + +#include "qemu/osdep.h" +#include "trace.h" +#include "hw/irq.h" +#include "hw/timer/sifive_pwm.h" +#include "hw/qdev-properties.h" +#include "hw/registerfields.h" +#include "migration/vmstate.h" +#include "qemu/log.h" +#include "qemu/module.h" + +#define HAS_PWM_EN_BITS(cfg) ((cfg & R_CONFIG_ENONESHOT_MASK) || \ + (cfg & R_CONFIG_ENALWAYS_MASK)) + +#define PWMCMP_MASK 0xFFFF +#define PWMCOUNT_MASK 0x7FFFFFFF + +REG32(CONFIG, 0x00) + FIELD(CONFIG, SCALE, 0, 4) + FIELD(CONFIG, STICKY, 8, 1) + FIELD(CONFIG, ZEROCMP, 9, 1) + FIELD(CONFIG, DEGLITCH, 10, 1) + FIELD(CONFIG, ENALWAYS, 12, 1) + FIELD(CONFIG, ENONESHOT, 13, 1) + FIELD(CONFIG, CMP0CENTER, 16, 1) + FIELD(CONFIG, CMP1CENTER, 17, 1) + FIELD(CONFIG, CMP2CENTER, 18, 1) + FIELD(CONFIG, CMP3CENTER, 19, 1) + FIELD(CONFIG, CMP0GANG, 24, 1) + FIELD(CONFIG, CMP1GANG, 25, 1) + FIELD(CONFIG, CMP2GANG, 26, 1) + FIELD(CONFIG, CMP3GANG, 27, 1) + FIELD(CONFIG, CMP0IP, 28, 1) + FIELD(CONFIG, CMP1IP, 29, 1) + FIELD(CONFIG, CMP2IP, 30, 1) + FIELD(CONFIG, CMP3IP, 31, 1) +REG32(COUNT, 0x08) +REG32(PWMS, 0x10) +REG32(PWMCMP0, 0x20) +REG32(PWMCMP1, 0x24) +REG32(PWMCMP2, 0x28) +REG32(PWMCMP3, 0x2C) + +static inline uint64_t sifive_pwm_ns_to_ticks(SiFivePwmState *s, + uint64_t time) +{ + return muldiv64(time, s->freq_hz, NANOSECONDS_PER_SECOND); +} + +static inline uint64_t sifive_pwm_ticks_to_ns(SiFivePwmState *s, + uint64_t ticks) +{ + return muldiv64(ticks, NANOSECONDS_PER_SECOND, s->freq_hz); +} + +static inline uint64_t sifive_pwm_compute_scale(SiFivePwmState *s) +{ + return s->pwmcfg & R_CONFIG_SCALE_MASK; +} + +static void sifive_pwm_set_alarms(SiFivePwmState *s) +{ + uint64_t now_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); + + if (HAS_PWM_EN_BITS(s->pwmcfg)) { + /* + * Subtract ticks from number of ticks when the timer was zero + * and mask to the register width. + */ + uint64_t pwmcount = (sifive_pwm_ns_to_ticks(s, now_ns) - + s->tick_offset) & PWMCOUNT_MASK; + uint64_t scale = sifive_pwm_compute_scale(s); + /* PWMs only contains PWMCMP_MASK bits starting at scale */ + uint64_t pwms = (pwmcount & (PWMCMP_MASK << scale)) >> scale; + + for (int i = 0; i < SIFIVE_PWM_CHANS; i++) { + uint64_t pwmcmp = s->pwmcmp[i] & PWMCMP_MASK; + uint64_t pwmcmp_ticks = pwmcmp << scale; + + /* + * Per circuit diagram and spec, both cases raises corresponding + * IP bit one clock cycle after time expires. + */ + if (pwmcmp > pwms) { + uint64_t offset = pwmcmp_ticks - pwmcount + 1; + uint64_t when_to_fire = now_ns + + sifive_pwm_ticks_to_ns(s, offset); + + trace_sifive_pwm_set_alarm(when_to_fire, now_ns); + timer_mod(&s->timer[i], when_to_fire); + } else { + /* Schedule interrupt for next cycle */ + trace_sifive_pwm_set_alarm(now_ns + 1, now_ns); + timer_mod(&s->timer[i], now_ns + 1); + } + + } + } else { + /* + * If timer incrementing disabled, just do pwms > pwmcmp check since + * a write may have happened to PWMs. + */ + uint64_t pwmcount = (s->tick_offset) & PWMCOUNT_MASK; + uint64_t scale = sifive_pwm_compute_scale(s); + uint64_t pwms = (pwmcount & (PWMCMP_MASK << scale)) >> scale; + + for (int i = 0; i < SIFIVE_PWM_CHANS; i++) { + uint64_t pwmcmp = s->pwmcmp[i] & PWMCMP_MASK; + + if (pwms >= pwmcmp) { + trace_sifive_pwm_set_alarm(now_ns + 1, now_ns); + timer_mod(&s->timer[i], now_ns + 1); + } else { + /* Effectively disable timer by scheduling far in future. */ + trace_sifive_pwm_set_alarm(0xFFFFFFFFFFFFFF, now_ns); + timer_mod(&s->timer[i], 0xFFFFFFFFFFFFFF); + } + } + } +} + +static void sifive_pwm_interrupt(SiFivePwmState *s, int num) +{ + uint64_t now = sifive_pwm_ns_to_ticks(s, + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); + bool was_incrementing = HAS_PWM_EN_BITS(s->pwmcfg); + + trace_sifive_pwm_interrupt(num); + + s->pwmcfg |= R_CONFIG_CMP0IP_MASK << num; + qemu_irq_raise(s->irqs[num]); + + /* + * If the zerocmp is set and pwmcmp0 raised the interrupt + * reset the zero ticks. + */ + if ((s->pwmcfg & R_CONFIG_ZEROCMP_MASK) && (num == 0)) { + /* If reset signal conditions, disable ENONESHOT. */ + s->pwmcfg &= ~R_CONFIG_ENONESHOT_MASK; + + if (was_incrementing) { + /* If incrementing, time in ticks is when pwmcount is zero */ + s->tick_offset = now; + } else { + /* If not incrementing, pwmcount = 0 */ + s->tick_offset = 0; + } + } + + /* + * If carryout bit set, which we discern via looking for overflow, + * also reset ENONESHOT. + */ + if (was_incrementing && + ((now & PWMCOUNT_MASK) < (s->tick_offset & PWMCOUNT_MASK))) { + s->pwmcfg &= ~R_CONFIG_ENONESHOT_MASK; + } + + /* Schedule or disable interrupts */ + sifive_pwm_set_alarms(s); + + /* If was enabled, and now not enabled, switch tick rep */ + if (was_incrementing && !HAS_PWM_EN_BITS(s->pwmcfg)) { + s->tick_offset = (now - s->tick_offset) & PWMCOUNT_MASK; + } +} + +static void sifive_pwm_interrupt_0(void *opaque) +{ + SiFivePwmState *s = opaque; + + sifive_pwm_interrupt(s, 0); +} + +static void sifive_pwm_interrupt_1(void *opaque) +{ + SiFivePwmState *s = opaque; + + sifive_pwm_interrupt(s, 1); +} + +static void sifive_pwm_interrupt_2(void *opaque) +{ + SiFivePwmState *s = opaque; + + sifive_pwm_interrupt(s, 2); +} + +static void sifive_pwm_interrupt_3(void *opaque) +{ + SiFivePwmState *s = opaque; + + sifive_pwm_interrupt(s, 3); +} + +static uint64_t sifive_pwm_read(void *opaque, hwaddr addr, + unsigned int size) +{ + SiFivePwmState *s = opaque; + uint64_t cur_time, scale; + uint64_t now = sifive_pwm_ns_to_ticks(s, + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); + + trace_sifive_pwm_read(addr); + + switch (addr) { + case A_CONFIG: + return s->pwmcfg; + case A_COUNT: + cur_time = s->tick_offset; + + if (HAS_PWM_EN_BITS(s->pwmcfg)) { + cur_time = now - cur_time; + } + + /* + * Return the value in the counter with bit 31 always 0 + * This is allowed to wrap around so we don't need to check that. + */ + return cur_time & PWMCOUNT_MASK; + case A_PWMS: + cur_time = s->tick_offset; + scale = sifive_pwm_compute_scale(s); + + if (HAS_PWM_EN_BITS(s->pwmcfg)) { + cur_time = now - cur_time; + } + + return ((cur_time & PWMCOUNT_MASK) >> scale) & PWMCMP_MASK; + case A_PWMCMP0: + return s->pwmcmp[0] & PWMCMP_MASK; + case A_PWMCMP1: + return s->pwmcmp[1] & PWMCMP_MASK; + case A_PWMCMP2: + return s->pwmcmp[2] & PWMCMP_MASK; + case A_PWMCMP3: + return s->pwmcmp[3] & PWMCMP_MASK; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr); + return 0; + } + + return 0; +} + +static void sifive_pwm_write(void *opaque, hwaddr addr, + uint64_t val64, unsigned int size) +{ + SiFivePwmState *s = opaque; + uint32_t value = val64; + uint64_t new_offset, scale; + uint64_t now = sifive_pwm_ns_to_ticks(s, + qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)); + + trace_sifive_pwm_write(value, addr); + + switch (addr) { + case A_CONFIG: + if (value & (R_CONFIG_CMP0CENTER_MASK | R_CONFIG_CMP1CENTER_MASK | + R_CONFIG_CMP2CENTER_MASK | R_CONFIG_CMP3CENTER_MASK)) { + qemu_log_mask(LOG_UNIMP, "%s: CMPxCENTER is not supported\n", + __func__); + } + + if (value & (R_CONFIG_CMP0GANG_MASK | R_CONFIG_CMP1GANG_MASK | + R_CONFIG_CMP2GANG_MASK | R_CONFIG_CMP3GANG_MASK)) { + qemu_log_mask(LOG_UNIMP, "%s: CMPxGANG is not supported\n", + __func__); + } + + if (value & (R_CONFIG_CMP0IP_MASK | R_CONFIG_CMP1IP_MASK | + R_CONFIG_CMP2IP_MASK | R_CONFIG_CMP3IP_MASK)) { + qemu_log_mask(LOG_UNIMP, "%s: CMPxIP is not supported\n", + __func__); + } + + if (!(value & R_CONFIG_CMP0IP_MASK)) { + qemu_irq_lower(s->irqs[0]); + } + + if (!(value & R_CONFIG_CMP1IP_MASK)) { + qemu_irq_lower(s->irqs[1]); + } + + if (!(value & R_CONFIG_CMP2IP_MASK)) { + qemu_irq_lower(s->irqs[2]); + } + + if (!(value & R_CONFIG_CMP3IP_MASK)) { + qemu_irq_lower(s->irqs[3]); + } + + /* + * If this write enables the timer increment + * set the time when pwmcount was zero to be cur_time - pwmcount. + * If this write disables the timer increment + * convert back from pwmcount to the time in ticks + * when pwmcount was zero. + */ + if ((!HAS_PWM_EN_BITS(s->pwmcfg) && HAS_PWM_EN_BITS(value)) || + (HAS_PWM_EN_BITS(s->pwmcfg) && !HAS_PWM_EN_BITS(value))) { + s->tick_offset = (now - s->tick_offset) & PWMCOUNT_MASK; + } + + s->pwmcfg = value; + break; + case A_COUNT: + /* The guest changed the counter, updated the offset value. */ + new_offset = value; + + if (HAS_PWM_EN_BITS(s->pwmcfg)) { + new_offset = now - new_offset; + } + + s->tick_offset = new_offset; + break; + case A_PWMS: + scale = sifive_pwm_compute_scale(s); + new_offset = (((value & PWMCMP_MASK) << scale) & PWMCOUNT_MASK); + + if (HAS_PWM_EN_BITS(s->pwmcfg)) { + new_offset = now - new_offset; + } + + s->tick_offset = new_offset; + break; + case A_PWMCMP0: + s->pwmcmp[0] = value & PWMCMP_MASK; + break; + case A_PWMCMP1: + s->pwmcmp[1] = value & PWMCMP_MASK; + break; + case A_PWMCMP2: + s->pwmcmp[2] = value & PWMCMP_MASK; + break; + case A_PWMCMP3: + s->pwmcmp[3] = value & PWMCMP_MASK; + break; + default: + qemu_log_mask(LOG_GUEST_ERROR, + "%s: Bad offset 0x%"HWADDR_PRIx"\n", __func__, addr); + } + + /* Update the alarms to reflect possible updated values */ + sifive_pwm_set_alarms(s); +} + +static void sifive_pwm_reset(DeviceState *dev) +{ + SiFivePwmState *s = SIFIVE_PWM(dev); + uint64_t now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL); + + s->pwmcfg = 0x00000000; + s->pwmcmp[0] = 0x00000000; + s->pwmcmp[1] = 0x00000000; + s->pwmcmp[2] = 0x00000000; + s->pwmcmp[3] = 0x00000000; + + s->tick_offset = sifive_pwm_ns_to_ticks(s, now); +} + +static const MemoryRegionOps sifive_pwm_ops = { + .read = sifive_pwm_read, + .write = sifive_pwm_write, + .endianness = DEVICE_NATIVE_ENDIAN, +}; + +static const VMStateDescription vmstate_sifive_pwm = { + .name = TYPE_SIFIVE_PWM, + .version_id = 1, + .minimum_version_id = 1, + .fields = (VMStateField[]) { + VMSTATE_TIMER_ARRAY(timer, SiFivePwmState, 4), + VMSTATE_UINT64(tick_offset, SiFivePwmState), + VMSTATE_UINT32(pwmcfg, SiFivePwmState), + VMSTATE_UINT32_ARRAY(pwmcmp, SiFivePwmState, 4), + VMSTATE_END_OF_LIST() + } +}; + +static Property sifive_pwm_properties[] = { + /* 0.5Ghz per spec after FSBL */ + DEFINE_PROP_UINT64("clock-frequency", struct SiFivePwmState, + freq_hz, 500000000ULL), + DEFINE_PROP_END_OF_LIST(), +}; + +static void sifive_pwm_init(Object *obj) +{ + SiFivePwmState *s = SIFIVE_PWM(obj); + int i; + + for (i = 0; i < SIFIVE_PWM_IRQS; i++) { + sysbus_init_irq(SYS_BUS_DEVICE(obj), &s->irqs[i]); + } + + memory_region_init_io(&s->mmio, obj, &sifive_pwm_ops, s, + TYPE_SIFIVE_PWM, 0x100); + sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio); +} + +static void sifive_pwm_realize(DeviceState *dev, Error **errp) +{ + SiFivePwmState *s = SIFIVE_PWM(dev); + + timer_init_ns(&s->timer[0], QEMU_CLOCK_VIRTUAL, + sifive_pwm_interrupt_0, s); + + timer_init_ns(&s->timer[1], QEMU_CLOCK_VIRTUAL, + sifive_pwm_interrupt_1, s); + + timer_init_ns(&s->timer[2], QEMU_CLOCK_VIRTUAL, + sifive_pwm_interrupt_2, s); + + timer_init_ns(&s->timer[3], QEMU_CLOCK_VIRTUAL, + sifive_pwm_interrupt_3, s); +} + +static void sifive_pwm_class_init(ObjectClass *klass, void *data) +{ + DeviceClass *dc = DEVICE_CLASS(klass); + + dc->reset = sifive_pwm_reset; + device_class_set_props(dc, sifive_pwm_properties); + dc->vmsd = &vmstate_sifive_pwm; + dc->realize = sifive_pwm_realize; +} + +static const TypeInfo sifive_pwm_info = { + .name = TYPE_SIFIVE_PWM, + .parent = TYPE_SYS_BUS_DEVICE, + .instance_size = sizeof(SiFivePwmState), + .instance_init = sifive_pwm_init, + .class_init = sifive_pwm_class_init, +}; + +static void sifive_pwm_register_types(void) +{ + type_register_static(&sifive_pwm_info); +} + +type_init(sifive_pwm_register_types) |