hw: timer: Add ASPEED RTC device

The RTC is modeled to provide time and date functionality. It is
initialised at zero to match the hardware.

There is no modelling of the alarm functionality, which includes the IRQ
line. As there is no guest code to exercise this function that is
acceptable for now.

Signed-off-by: Joel Stanley <joel@jms.id.au>
Reviewed-by: Peter Maydell <peter.maydell@linaro.org>
Message-id: 20190618165311.27066-4-clg@kaod.org
Signed-off-by: Peter Maydell <peter.maydell@linaro.org>

3 files changed, 185 insertions, 1 deletions

diff --git a/hw/timer/Makefile.objs b/hw/timer/Makefile.objs
index 0e9a4530f8..123d92c969 100644
--- a/hw/timer/Makefile.objs
+++ b/hw/timer/Makefile.objs
@@ -41,7 +41,7 @@ obj-$(CONFIG_MC146818RTC) += mc146818rtc.o
 obj-$(CONFIG_ALLWINNER_A10_PIT) += allwinner-a10-pit.o
 
 common-obj-$(CONFIG_STM32F2XX_TIMER) += stm32f2xx_timer.o
-common-obj-$(CONFIG_ASPEED_SOC) += aspeed_timer.o
+common-obj-$(CONFIG_ASPEED_SOC) += aspeed_timer.o aspeed_rtc.o
 
 common-obj-$(CONFIG_SUN4V_RTC) += sun4v-rtc.o
 common-obj-$(CONFIG_CMSDK_APB_TIMER) += cmsdk-apb-timer.o
diff --git a/hw/timer/aspeed_rtc.c b/hw/timer/aspeed_rtc.c
new file mode 100644
index 0000000000..19f061c846
--- /dev/null
+++ b/hw/timer/aspeed_rtc.c
@@ -0,0 +1,180 @@
+/*
+ * ASPEED Real Time Clock
+ * Joel Stanley <joel@jms.id.au>
+ *
+ * Copyright 2019 IBM Corp
+ * SPDX-License-Identifier: GPL-2.0-or-later
+ */
+
+#include "qemu/osdep.h"
+#include "qemu-common.h"
+#include "hw/timer/aspeed_rtc.h"
+#include "qemu/log.h"
+#include "qemu/timer.h"
+
+#include "trace.h"
+
+#define COUNTER1        (0x00 / 4)
+#define COUNTER2        (0x04 / 4)
+#define ALARM           (0x08 / 4)
+#define CONTROL         (0x10 / 4)
+#define ALARM_STATUS    (0x14 / 4)
+
+#define RTC_UNLOCKED    BIT(1)
+#define RTC_ENABLED     BIT(0)
+
+static void aspeed_rtc_calc_offset(AspeedRtcState *rtc)
+{
+    struct tm tm;
+    uint32_t year, cent;
+    uint32_t reg1 = rtc->reg[COUNTER1];
+    uint32_t reg2 = rtc->reg[COUNTER2];
+
+    tm.tm_mday = (reg1 >> 24) & 0x1f;
+    tm.tm_hour = (reg1 >> 16) & 0x1f;
+    tm.tm_min = (reg1 >> 8) & 0x3f;
+    tm.tm_sec = (reg1 >> 0) & 0x3f;
+
+    cent = (reg2 >> 16) & 0x1f;
+    year = (reg2 >> 8) & 0x7f;
+    tm.tm_mon = ((reg2 >>  0) & 0x0f) - 1;
+    tm.tm_year = year + (cent * 100) - 1900;
+
+    rtc->offset = qemu_timedate_diff(&tm);
+}
+
+static uint32_t aspeed_rtc_get_counter(AspeedRtcState *rtc, int r)
+{
+    uint32_t year, cent;
+    struct tm now;
+
+    qemu_get_timedate(&now, rtc->offset);
+
+    switch (r) {
+    case COUNTER1:
+        return (now.tm_mday << 24) | (now.tm_hour << 16) |
+            (now.tm_min << 8) | now.tm_sec;
+    case COUNTER2:
+        cent = (now.tm_year + 1900) / 100;
+        year = now.tm_year % 100;
+        return ((cent & 0x1f) << 16) | ((year & 0x7f) << 8) |
+            ((now.tm_mon + 1) & 0xf);
+    default:
+        g_assert_not_reached();
+    }
+}
+
+static uint64_t aspeed_rtc_read(void *opaque, hwaddr addr,
+                                unsigned size)
+{
+    AspeedRtcState *rtc = opaque;
+    uint64_t val;
+    uint32_t r = addr >> 2;
+
+    switch (r) {
+    case COUNTER1:
+    case COUNTER2:
+        if (rtc->reg[CONTROL] & RTC_ENABLED) {
+            rtc->reg[r] = aspeed_rtc_get_counter(rtc, r);
+        }
+        /* fall through */
+    case CONTROL:
+        val = rtc->reg[r];
+        break;
+    case ALARM:
+    case ALARM_STATUS:
+    default:
+        qemu_log_mask(LOG_UNIMP, "%s: 0x%" HWADDR_PRIx "\n", __func__, addr);
+        return 0;
+    }
+
+    trace_aspeed_rtc_read(addr, val);
+
+    return val;
+}
+
+static void aspeed_rtc_write(void *opaque, hwaddr addr,
+                             uint64_t val, unsigned size)
+{
+    AspeedRtcState *rtc = opaque;
+    uint32_t r = addr >> 2;
+
+    switch (r) {
+    case COUNTER1:
+    case COUNTER2:
+        if (!(rtc->reg[CONTROL] & RTC_UNLOCKED)) {
+            break;
+        }
+        /* fall through */
+    case CONTROL:
+        rtc->reg[r] = val;
+        aspeed_rtc_calc_offset(rtc);
+        break;
+    case ALARM:
+    case ALARM_STATUS:
+    default:
+        qemu_log_mask(LOG_UNIMP, "%s: 0x%" HWADDR_PRIx "\n", __func__, addr);
+        break;
+    }
+    trace_aspeed_rtc_write(addr, val);
+}
+
+static void aspeed_rtc_reset(DeviceState *d)
+{
+    AspeedRtcState *rtc = ASPEED_RTC(d);
+
+    rtc->offset = 0;
+    memset(rtc->reg, 0, sizeof(rtc->reg));
+}
+
+static const MemoryRegionOps aspeed_rtc_ops = {
+    .read = aspeed_rtc_read,
+    .write = aspeed_rtc_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static const VMStateDescription vmstate_aspeed_rtc = {
+    .name = TYPE_ASPEED_RTC,
+    .version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(reg, AspeedRtcState, 0x18),
+        VMSTATE_INT32(offset, AspeedRtcState),
+        VMSTATE_INT32(offset, AspeedRtcState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void aspeed_rtc_realize(DeviceState *dev, Error **errp)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    AspeedRtcState *s = ASPEED_RTC(dev);
+
+    sysbus_init_irq(sbd, &s->irq);
+
+    memory_region_init_io(&s->iomem, OBJECT(s), &aspeed_rtc_ops, s,
+                          "aspeed-rtc", 0x18ULL);
+    sysbus_init_mmio(sbd, &s->iomem);
+}
+
+static void aspeed_rtc_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->realize = aspeed_rtc_realize;
+    dc->vmsd = &vmstate_aspeed_rtc;
+    dc->reset = aspeed_rtc_reset;
+}
+
+static const TypeInfo aspeed_rtc_info = {
+    .name          = TYPE_ASPEED_RTC,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(AspeedRtcState),
+    .class_init    = aspeed_rtc_class_init,
+};
+
+static void aspeed_rtc_register_types(void)
+{
+    type_register_static(&aspeed_rtc_info);
+}
+
+type_init(aspeed_rtc_register_types)
diff --git a/hw/timer/trace-events b/hw/timer/trace-events
index dcaf3d6da6..db02a9142c 100644
--- a/hw/timer/trace-events
+++ b/hw/timer/trace-events
@@ -66,6 +66,10 @@ cmsdk_apb_dualtimer_read(uint64_t offset, uint64_t data, unsigned size) "CMSDK A
 cmsdk_apb_dualtimer_write(uint64_t offset, uint64_t data, unsigned size) "CMSDK APB dualtimer write: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
 cmsdk_apb_dualtimer_reset(void) "CMSDK APB dualtimer: reset"
 
+# hw/timer/aspeed-rtc.c
+aspeed_rtc_read(uint64_t addr, uint64_t value) "addr 0x%02" PRIx64 " value 0x%08" PRIx64
+aspeed_rtc_write(uint64_t addr, uint64_t value) "addr 0x%02" PRIx64 " value 0x%08" PRIx64
+
 # sun4v-rtc.c
 sun4v_rtc_read(uint64_t addr, uint64_t value) "read: addr 0x%" PRIx64 " value 0x%" PRIx64
 sun4v_rtc_write(uint64_t addr, uint64_t value) "write: addr 0x%" PRIx64 " value 0x%" PRIx64