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authorAlistair Francis <alistair.francis@wdc.com>2021-09-09 13:55:02 +1000
committerAlistair Francis <alistair.francis@wdc.com>2021-09-21 07:56:49 +1000
commit5bf6f1acdda980a4ad0e8f01fe515c6d6e130fce (patch)
treeedfc73224760fee76047e27d9d2bb52a257e974c /hw/timer
parent57a3a6226529e60ef4eb5e11b577f2e532a72acc (diff)
hw/timer: Add SiFive PWM support
This is the initial commit of the SiFive PWM timer. This is used by guest software as a timer and is included in the SiFive FU540 SoC. Signed-off-by: Justin Restivo <jrestivo@draper.com> Signed-off-by: Alexandra Clifford <aclifford@draper.com> Signed-off-by: Amanda Strnad <astrnad@draper.com> Signed-off-by: Alistair Francis <alistair.francis@wdc.com> Reviewed-by: Bin Meng <bmeng.cn@gmail.com> Message-id: 9f70a210acbfaf0e1ea6ad311ab892ac69134d8b.1631159656.git.alistair.francis@wdc.com
Diffstat (limited to 'hw/timer')
-rw-r--r--hw/timer/Kconfig3
-rw-r--r--hw/timer/meson.build1
-rw-r--r--hw/timer/sifive_pwm.c468
-rw-r--r--hw/timer/trace-events6
4 files changed, 478 insertions, 0 deletions
diff --git a/hw/timer/Kconfig b/hw/timer/Kconfig
index 1e73da7e12..010be7ed1f 100644
--- a/hw/timer/Kconfig
+++ b/hw/timer/Kconfig
@@ -25,6 +25,9 @@ config ALLWINNER_A10_PIT
bool
select PTIMER
+config SIFIVE_PWM
+ bool
+
config STM32F2XX_TIMER
bool
diff --git a/hw/timer/meson.build b/hw/timer/meson.build
index e67478a8f1..03092e2ceb 100644
--- a/hw/timer/meson.build
+++ b/hw/timer/meson.build
@@ -35,5 +35,6 @@ softmmu_ss.add(when: 'CONFIG_STELLARIS_GPTM', if_true: files('stellaris-gptm.c')
softmmu_ss.add(when: 'CONFIG_STM32F2XX_TIMER', if_true: files('stm32f2xx_timer.c'))
softmmu_ss.add(when: 'CONFIG_XILINX', if_true: files('xilinx_timer.c'))
specific_ss.add(when: 'CONFIG_IBEX', if_true: files('ibex_timer.c'))
+softmmu_ss.add(when: 'CONFIG_SIFIVE_PWM', if_true: files('sifive_pwm.c'))
specific_ss.add(when: 'CONFIG_AVR_TIMER16', if_true: files('avr_timer16.c'))
diff --git a/hw/timer/sifive_pwm.c b/hw/timer/sifive_pwm.c
new file mode 100644
index 0000000000..c664480ccf
--- /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)
diff --git a/hw/timer/trace-events b/hw/timer/trace-events
index 5234c0ea9e..d0edcd2a80 100644
--- a/hw/timer/trace-events
+++ b/hw/timer/trace-events
@@ -88,3 +88,9 @@ sse_counter_reset(void) "SSE system counter: reset"
sse_timer_read(uint64_t offset, uint64_t data, unsigned size) "SSE system timer read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
sse_timer_write(uint64_t offset, uint64_t data, unsigned size) "SSE system timer write: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
sse_timer_reset(void) "SSE system timer: reset"
+
+# sifive_pwm.c
+sifive_pwm_set_alarm(uint64_t alarm, uint64_t now) "Setting alarm to: 0x%" PRIx64 ", now: 0x%" PRIx64
+sifive_pwm_interrupt(int num) "Interrupt %d"
+sifive_pwm_read(uint64_t offset) "Read at address: 0x%" PRIx64
+sifive_pwm_write(uint64_t data, uint64_t offset) "Write 0x%" PRIx64 " at address: 0x%" PRIx64