hw/loongarch: Add LoongArch ls7a rtc device support

This patch add ls7a rtc device support.

Signed-off-by: Xiaojuan Yang <yangxiaojuan@loongson.cn>
Signed-off-by: Song Gao <gaosong@loongson.cn>
Reviewed-by: Richard Henderson <richard.henderson@linaro.org>
Message-Id: <20220606124333.2060567-39-yangxiaojuan@loongson.cn>
Signed-off-by: Richard Henderson <richard.henderson@linaro.org>

3 files changed, 532 insertions, 0 deletions

diff --git a/hw/rtc/Kconfig b/hw/rtc/Kconfig
index 730c272bc5..d0d8dda084 100644
--- a/hw/rtc/Kconfig
+++ b/hw/rtc/Kconfig
@@ -27,3 +27,6 @@ config SUN4V_RTC
 
 config GOLDFISH_RTC
     bool
+
+config LS7A_RTC
+    bool
diff --git a/hw/rtc/ls7a_rtc.c b/hw/rtc/ls7a_rtc.c
new file mode 100644
index 0000000000..fe6710310f
--- /dev/null
+++ b/hw/rtc/ls7a_rtc.c
@@ -0,0 +1,528 @@
+/* SPDX-License-Identifier: GPL-2.0-or-later */
+/*
+ * Loongarch LS7A Real Time Clock emulation
+ *
+ * Copyright (C) 2021 Loongson Technology Corporation Limited
+ */
+
+#include "qemu/osdep.h"
+#include "hw/sysbus.h"
+#include "hw/irq.h"
+#include "include/hw/register.h"
+#include "qemu/timer.h"
+#include "sysemu/sysemu.h"
+#include "qemu/cutils.h"
+#include "qemu/log.h"
+#include "migration/vmstate.h"
+#include "hw/misc/unimp.h"
+#include "sysemu/rtc.h"
+#include "hw/registerfields.h"
+
+#define SYS_TOYTRIM        0x20
+#define SYS_TOYWRITE0      0x24
+#define SYS_TOYWRITE1      0x28
+#define SYS_TOYREAD0       0x2C
+#define SYS_TOYREAD1       0x30
+#define SYS_TOYMATCH0      0x34
+#define SYS_TOYMATCH1      0x38
+#define SYS_TOYMATCH2      0x3C
+#define SYS_RTCCTRL        0x40
+#define SYS_RTCTRIM        0x60
+#define SYS_RTCWRTIE0      0x64
+#define SYS_RTCREAD0       0x68
+#define SYS_RTCMATCH0      0x6C
+#define SYS_RTCMATCH1      0x70
+#define SYS_RTCMATCH2      0x74
+
+#define LS7A_RTC_FREQ     32768
+#define TIMER_NUMS        3
+/*
+ * Shift bits and filed mask
+ */
+
+FIELD(TOY, MON, 26, 6)
+FIELD(TOY, DAY, 21, 5)
+FIELD(TOY, HOUR, 16, 5)
+FIELD(TOY, MIN, 10, 6)
+FIELD(TOY, SEC, 4, 6)
+FIELD(TOY, MSEC, 0, 4)
+
+FIELD(TOY_MATCH, YEAR, 26, 6)
+FIELD(TOY_MATCH, MON, 22, 4)
+FIELD(TOY_MATCH, DAY, 17, 5)
+FIELD(TOY_MATCH, HOUR, 12, 5)
+FIELD(TOY_MATCH, MIN, 6, 6)
+FIELD(TOY_MATCH, SEC, 0, 6)
+
+FIELD(RTC_CTRL, RTCEN, 13, 1)
+FIELD(RTC_CTRL, TOYEN, 11, 1)
+FIELD(RTC_CTRL, EO, 8, 1)
+
+#define TYPE_LS7A_RTC "ls7a_rtc"
+OBJECT_DECLARE_SIMPLE_TYPE(LS7ARtcState, LS7A_RTC)
+
+struct LS7ARtcState {
+    SysBusDevice parent_obj;
+
+    MemoryRegion iomem;
+    /*
+     * Needed to preserve the tick_count across migration, even if the
+     * absolute value of the rtc_clock is different on the source and
+     * destination.
+     */
+    int64_t offset_toy;
+    int64_t offset_rtc;
+    uint64_t save_toy_mon;
+    uint64_t save_toy_year;
+    uint64_t save_rtc;
+    int64_t data;
+    int tidx;
+    uint32_t toymatch[3];
+    uint32_t toytrim;
+    uint32_t cntrctl;
+    uint32_t rtctrim;
+    uint32_t rtccount;
+    uint32_t rtcmatch[3];
+    QEMUTimer *toy_timer[TIMER_NUMS];
+    QEMUTimer *rtc_timer[TIMER_NUMS];
+    qemu_irq irq;
+};
+
+/* switch nanoseconds time to rtc ticks */
+static inline uint64_t ls7a_rtc_ticks(void)
+{
+    return qemu_clock_get_ns(rtc_clock) * LS7A_RTC_FREQ / NANOSECONDS_PER_SECOND;
+}
+
+/* switch rtc ticks to nanoseconds */
+static inline uint64_t ticks_to_ns(uint64_t ticks)
+{
+    return ticks * NANOSECONDS_PER_SECOND / LS7A_RTC_FREQ;
+}
+
+static inline bool toy_enabled(LS7ARtcState *s)
+{
+    return FIELD_EX32(s->cntrctl, RTC_CTRL, TOYEN) &&
+           FIELD_EX32(s->cntrctl, RTC_CTRL, EO);
+}
+
+static inline bool rtc_enabled(LS7ARtcState *s)
+{
+    return FIELD_EX32(s->cntrctl, RTC_CTRL, RTCEN) &&
+           FIELD_EX32(s->cntrctl, RTC_CTRL, EO);
+}
+
+/* parse toy value to struct tm */
+static inline void toy_val_to_time_mon(uint64_t toy_val, struct tm *tm)
+{
+    tm->tm_sec = FIELD_EX32(toy_val, TOY, SEC);
+    tm->tm_min = FIELD_EX32(toy_val, TOY, MIN);
+    tm->tm_hour = FIELD_EX32(toy_val, TOY, HOUR);
+    tm->tm_mday = FIELD_EX32(toy_val, TOY, DAY);
+    tm->tm_mon = FIELD_EX32(toy_val, TOY, MON) - 1;
+}
+
+static inline void toy_val_to_time_year(uint64_t toy_year, struct tm *tm)
+{
+    tm->tm_year = toy_year;
+}
+
+/* parse struct tm to toy value */
+static inline uint64_t toy_time_to_val_mon(struct tm tm)
+{
+    uint64_t val = 0;
+
+    val = FIELD_DP32(val, TOY, MON, tm.tm_mon + 1);
+    val = FIELD_DP32(val, TOY, DAY, tm.tm_mday);
+    val = FIELD_DP32(val, TOY, HOUR, tm.tm_hour);
+    val = FIELD_DP32(val, TOY, MIN, tm.tm_min);
+    val = FIELD_DP32(val, TOY, SEC, tm.tm_sec);
+    return val;
+}
+
+static inline uint64_t toy_time_to_val_year(struct tm tm)
+{
+    uint64_t year;
+
+    year = tm.tm_year;
+    return year;
+}
+
+static inline void toymatch_val_to_time(uint64_t val, struct tm *tm)
+{
+    tm->tm_sec = FIELD_EX32(val, TOY_MATCH, SEC);
+    tm->tm_min = FIELD_EX32(val, TOY_MATCH, MIN);
+    tm->tm_hour = FIELD_EX32(val, TOY_MATCH, HOUR);
+    tm->tm_mday = FIELD_EX32(val, TOY_MATCH, DAY);
+    tm->tm_mon = FIELD_EX32(val, TOY_MATCH, MON) - 1;
+    tm->tm_year += (FIELD_EX32(val, TOY_MATCH, YEAR) - (tm->tm_year & 0x3f));
+}
+
+static void toymatch_write(LS7ARtcState *s, struct tm *tm, uint64_t val, int num)
+{
+    int64_t now, expire_time;
+
+    /* it do not support write when toy disabled */
+    if (toy_enabled(s)) {
+        s->toymatch[num] = val;
+        /* caculate expire time */
+        now = qemu_clock_get_ms(rtc_clock);
+        toymatch_val_to_time(val, tm);
+        expire_time = now + (qemu_timedate_diff(tm) - s->offset_toy) * 1000;
+        timer_mod(s->toy_timer[num], expire_time);
+    }
+}
+
+static void rtcmatch_write(LS7ARtcState *s, uint64_t val, int num)
+{
+    uint64_t expire_ns;
+
+    /* it do not support write when toy disabled */
+    if (rtc_enabled(s)) {
+        s->rtcmatch[num] = val;
+        /* caculate expire time */
+        expire_ns = ticks_to_ns(val) - ticks_to_ns(s->offset_rtc);
+        timer_mod_ns(s->rtc_timer[num], expire_ns);
+    }
+}
+
+static void ls7a_toy_stop(LS7ARtcState *s)
+{
+    int i;
+    struct tm tm;
+    /*
+     * save time when disabled toy,
+     * because toy time not add counters.
+     */
+    qemu_get_timedate(&tm, s->offset_toy);
+    s->save_toy_mon = toy_time_to_val_mon(tm);
+    s->save_toy_year = toy_time_to_val_year(tm);
+
+    /* delete timers, and when re-enabled, recaculate expire time */
+    for (i = 0; i < TIMER_NUMS; i++) {
+        timer_del(s->toy_timer[i]);
+    }
+}
+
+static void ls7a_rtc_stop(LS7ARtcState *s)
+{
+    int i;
+    uint64_t time;
+
+    /* save rtc time */
+    time = ls7a_rtc_ticks() + s->offset_rtc;
+    s->save_rtc = time;
+
+    /* delete timers, and when re-enabled, recaculate expire time */
+    for (i = 0; i < TIMER_NUMS; i++) {
+        timer_del(s->rtc_timer[i]);
+    }
+}
+
+static void ls7a_toy_start(LS7ARtcState *s)
+{
+    int i;
+    uint64_t expire_time, now;
+    struct tm tm;
+    /*
+     * need to recaculate toy offset
+     * and expire time when enable it.
+     */
+    toy_val_to_time_mon(s->save_toy_mon, &tm);
+    toy_val_to_time_year(s->save_toy_year, &tm);
+
+    s->offset_toy = qemu_timedate_diff(&tm);
+    now = qemu_clock_get_ms(rtc_clock);
+
+    /* recaculate expire time and enable timer */
+    for (i = 0; i < TIMER_NUMS; i++) {
+        toymatch_val_to_time(s->toymatch[i], &tm);
+        expire_time = now + (qemu_timedate_diff(&tm) - s->offset_toy) * 1000;
+        timer_mod(s->toy_timer[i], expire_time);
+    }
+}
+
+static void ls7a_rtc_start(LS7ARtcState *s)
+{
+    int i;
+    uint64_t expire_time, now;
+
+    /*
+     * need to recaculate rtc offset
+     * and expire time when enable it.
+     */
+    now = ls7a_rtc_ticks();
+    s->offset_rtc = s->save_rtc - now;
+
+    /* recaculate expire time and enable timer */
+    for (i = 0; i < TIMER_NUMS; i++) {
+        expire_time = ticks_to_ns(s->rtcmatch[i]) - ticks_to_ns(s->offset_rtc);
+        timer_mod_ns(s->rtc_timer[i], expire_time);
+    }
+}
+
+static uint64_t ls7a_rtc_read(void *opaque, hwaddr addr, unsigned size)
+{
+    LS7ARtcState *s = LS7A_RTC(opaque);
+    struct tm tm;
+    int val = 0;
+
+    switch (addr) {
+    case SYS_TOYREAD0:
+        /* if toy disabled, read save toy time */
+        if (toy_enabled(s)) {
+            qemu_get_timedate(&tm, s->offset_toy);
+            val = toy_time_to_val_mon(tm);
+        } else {
+            /* read save mon val */
+            val = s->save_toy_mon;
+        }
+        break;
+    case SYS_TOYREAD1:
+        /* if toy disabled, read save toy time */
+        if (toy_enabled(s)) {
+            qemu_get_timedate(&tm, s->offset_toy);
+            val = tm.tm_year;
+        } else {
+            /* read save year val */
+            val = s->save_toy_year;
+        }
+        break;
+    case SYS_TOYMATCH0:
+        val = s->toymatch[0];
+        break;
+    case SYS_TOYMATCH1:
+        val = s->toymatch[1];
+        break;
+    case SYS_TOYMATCH2:
+        val = s->toymatch[2];
+        break;
+    case SYS_RTCCTRL:
+        val = s->cntrctl;
+        break;
+    case SYS_RTCREAD0:
+        /* if rtc disabled, read save rtc time */
+        if (rtc_enabled(s)) {
+            val = ls7a_rtc_ticks() + s->offset_rtc;
+        } else {
+            val = s->save_rtc;
+        }
+        break;
+    case SYS_RTCMATCH0:
+        val = s->rtcmatch[0];
+        break;
+    case SYS_RTCMATCH1:
+        val = s->rtcmatch[1];
+        break;
+    case SYS_RTCMATCH2:
+        val = s->rtcmatch[2];
+        break;
+    default:
+        val = 0;
+        break;
+    }
+    return val;
+}
+
+static void ls7a_rtc_write(void *opaque, hwaddr addr,
+                           uint64_t val, unsigned size)
+{
+    int old_toyen, old_rtcen, new_toyen, new_rtcen;
+    LS7ARtcState *s = LS7A_RTC(opaque);
+    struct tm tm;
+
+    switch (addr) {
+    case SYS_TOYWRITE0:
+        /* it do not support write when toy disabled */
+        if (toy_enabled(s)) {
+            qemu_get_timedate(&tm, s->offset_toy);
+            tm.tm_sec = FIELD_EX32(val, TOY, SEC);
+            tm.tm_min = FIELD_EX32(val, TOY, MIN);
+            tm.tm_hour = FIELD_EX32(val, TOY, HOUR);
+            tm.tm_mday = FIELD_EX32(val, TOY, DAY);
+            tm.tm_mon = FIELD_EX32(val, TOY, MON) - 1;
+            s->offset_toy = qemu_timedate_diff(&tm);
+        }
+    break;
+    case SYS_TOYWRITE1:
+        if (toy_enabled(s)) {
+            qemu_get_timedate(&tm, s->offset_toy);
+            tm.tm_year = val;
+            s->offset_toy = qemu_timedate_diff(&tm);
+        }
+        break;
+    case SYS_TOYMATCH0:
+        toymatch_write(s, &tm, val, 0);
+        break;
+    case SYS_TOYMATCH1:
+        toymatch_write(s, &tm, val, 1);
+        break;
+    case SYS_TOYMATCH2:
+        toymatch_write(s, &tm, val, 2);
+        break;
+    case SYS_RTCCTRL:
+        /* get old ctrl */
+        old_toyen = toy_enabled(s);
+        old_rtcen = rtc_enabled(s);
+
+        s->cntrctl = val;
+        /* get new ctrl */
+        new_toyen = toy_enabled(s);
+        new_rtcen = rtc_enabled(s);
+
+        /*
+         * we do not consider if EO changed, as it always set at most time.
+         * toy or rtc enabled should start timer. otherwise, stop timer
+         */
+        if (old_toyen != new_toyen) {
+            if (new_toyen) {
+                ls7a_toy_start(s);
+            } else {
+                ls7a_toy_stop(s);
+            }
+        }
+        if (old_rtcen != new_rtcen) {
+            if (new_rtcen) {
+                ls7a_rtc_start(s);
+            } else {
+                ls7a_rtc_stop(s);
+            }
+        }
+        break;
+    case SYS_RTCWRTIE0:
+        if (rtc_enabled(s)) {
+            s->offset_rtc = val - ls7a_rtc_ticks();
+        }
+        break;
+    case SYS_RTCMATCH0:
+        rtcmatch_write(s, val, 0);
+        break;
+    case SYS_RTCMATCH1:
+        rtcmatch_write(s, val, 1);
+        break;
+    case SYS_RTCMATCH2:
+        rtcmatch_write(s, val, 2);
+        break;
+    default:
+        break;
+    }
+}
+
+static const MemoryRegionOps ls7a_rtc_ops = {
+    .read = ls7a_rtc_read,
+    .write = ls7a_rtc_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
+};
+
+static void toy_timer_cb(void *opaque)
+{
+    LS7ARtcState *s = opaque;
+
+    if (toy_enabled(s)) {
+        qemu_irq_pulse(s->irq);
+    }
+}
+
+static void rtc_timer_cb(void *opaque)
+{
+    LS7ARtcState *s = opaque;
+
+    if (rtc_enabled(s)) {
+        qemu_irq_pulse(s->irq);
+    }
+}
+
+static void ls7a_rtc_realize(DeviceState *dev, Error **errp)
+{
+    int i;
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    LS7ARtcState *d = LS7A_RTC(sbd);
+    memory_region_init_io(&d->iomem, NULL, &ls7a_rtc_ops,
+                         (void *)d, "ls7a_rtc", 0x100);
+
+    sysbus_init_irq(sbd, &d->irq);
+
+    sysbus_init_mmio(sbd, &d->iomem);
+    for (i = 0; i < TIMER_NUMS; i++) {
+        d->toymatch[i] = 0;
+        d->rtcmatch[i] = 0;
+        d->toy_timer[i] = timer_new_ms(rtc_clock, toy_timer_cb, d);
+        d->rtc_timer[i] = timer_new_ms(rtc_clock, rtc_timer_cb, d);
+    }
+    d->offset_toy = 0;
+    d->offset_rtc = 0;
+    d->save_toy_mon = 0;
+    d->save_toy_year = 0;
+    d->save_rtc = 0;
+
+    create_unimplemented_device("mmio fallback 1", 0x10013ffc, 0x4);
+}
+
+static int ls7a_rtc_pre_save(void *opaque)
+{
+    LS7ARtcState *s = LS7A_RTC(opaque);
+
+    ls7a_toy_stop(s);
+    ls7a_rtc_stop(s);
+
+    return 0;
+}
+
+static int ls7a_rtc_post_load(void *opaque, int version_id)
+{
+    LS7ARtcState *s = LS7A_RTC(opaque);
+    if (toy_enabled(s)) {
+        ls7a_toy_start(s);
+    }
+
+    if (rtc_enabled(s)) {
+        ls7a_rtc_start(s);
+    }
+
+    return 0;
+}
+
+static const VMStateDescription vmstate_ls7a_rtc = {
+    .name = "ls7a_rtc",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .pre_save = ls7a_rtc_pre_save,
+    .post_load = ls7a_rtc_post_load,
+    .fields = (VMStateField[]) {
+        VMSTATE_INT64(offset_toy, LS7ARtcState),
+        VMSTATE_INT64(offset_rtc, LS7ARtcState),
+        VMSTATE_UINT64(save_toy_mon, LS7ARtcState),
+        VMSTATE_UINT64(save_toy_year, LS7ARtcState),
+        VMSTATE_UINT64(save_rtc, LS7ARtcState),
+        VMSTATE_UINT32_ARRAY(toymatch, LS7ARtcState, TIMER_NUMS),
+        VMSTATE_UINT32_ARRAY(rtcmatch, LS7ARtcState, TIMER_NUMS),
+        VMSTATE_UINT32(cntrctl, LS7ARtcState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void ls7a_rtc_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+    dc->vmsd = &vmstate_ls7a_rtc;
+    dc->realize = ls7a_rtc_realize;
+    dc->desc = "ls7a rtc";
+}
+
+static const TypeInfo ls7a_rtc_info = {
+    .name          = TYPE_LS7A_RTC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(LS7ARtcState),
+    .class_init    = ls7a_rtc_class_init,
+};
+
+static void ls7a_rtc_register_types(void)
+{
+    type_register_static(&ls7a_rtc_info);
+}
+
+type_init(ls7a_rtc_register_types)
diff --git a/hw/rtc/meson.build b/hw/rtc/meson.build
index 7cecdee5dd..dc33973384 100644
--- a/hw/rtc/meson.build
+++ b/hw/rtc/meson.build
@@ -11,6 +11,7 @@ softmmu_ss.add(when: 'CONFIG_EXYNOS4', if_true: files('exynos4210_rtc.c'))
 softmmu_ss.add(when: 'CONFIG_SUN4V_RTC', if_true: files('sun4v-rtc.c'))
 softmmu_ss.add(when: 'CONFIG_ASPEED_SOC', if_true: files('aspeed_rtc.c'))
 softmmu_ss.add(when: 'CONFIG_GOLDFISH_RTC', if_true: files('goldfish_rtc.c'))
+softmmu_ss.add(when: 'CONFIG_LS7A_RTC', if_true: files('ls7a_rtc.c'))
 softmmu_ss.add(when: 'CONFIG_ALLWINNER_H3', if_true: files('allwinner-rtc.c'))
 
 specific_ss.add(when: 'CONFIG_MC146818RTC', if_true: files('mc146818rtc.c'))