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Re: [Qemu-devel] [fixed-up][PATCH v6 2/5] hw/timer: add sunxi timer devi


From: Li Guang
Subject: Re: [Qemu-devel] [fixed-up][PATCH v6 2/5] hw/timer: add sunxi timer device
Date: Fri, 29 Nov 2013 15:55:48 +0800
User-agent: Mozilla/5.0 (X11; U; Linux i686 (x86_64); en-US; rv:1.9.1.16) Gecko/20120421 Iceape/2.0.11

Peter Crosthwaite wrote:
On Wed, Nov 27, 2013 at 11:35 PM, Peter Crosthwaite
<address@hidden>  wrote:
On Wed, Nov 27, 2013 at 6:29 PM, liguang<address@hidden>  wrote:
Signed-off-by: liguang<address@hidden>
---
  default-configs/arm-softmmu.mak |    2 +
  hw/timer/Makefile.objs          |    1 +
  hw/timer/sunxi-pit.c            |  254 +++++++++++++++++++++++++++++++++++++++
  include/hw/timer/sunxi-pit.h    |   56 +++++++++
  4 files changed, 313 insertions(+), 0 deletions(-)
  create mode 100644 hw/timer/sunxi-pit.c
  create mode 100644 include/hw/timer/sunxi-pit.h

diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
index a555eef..7bf5ad0 100644
--- a/default-configs/arm-softmmu.mak
+++ b/default-configs/arm-softmmu.mak
@@ -81,3 +81,5 @@ CONFIG_VERSATILE_I2C=y

  CONFIG_SDHCI=y
  CONFIG_INTEGRATOR_DEBUG=y
+
+CONFIG_SUNXI_PIT=y
diff --git a/hw/timer/Makefile.objs b/hw/timer/Makefile.objs
index eca5905..f7888e9 100644
--- a/hw/timer/Makefile.objs
+++ b/hw/timer/Makefile.objs
@@ -27,3 +27,4 @@ obj-$(CONFIG_SH4) += sh_timer.o
  obj-$(CONFIG_TUSB6010) += tusb6010.o

  obj-$(CONFIG_MC146818RTC) += mc146818rtc.o
+obj-$(CONFIG_SUNXI_PIT) += sunxi-pit.o
diff --git a/hw/timer/sunxi-pit.c b/hw/timer/sunxi-pit.c
new file mode 100644
index 0000000..19bc16c
--- /dev/null
+++ b/hw/timer/sunxi-pit.c
@@ -0,0 +1,254 @@
+/*
+ * Allwinner sunxi timer device emulation
May need to do global find/replace on sunxi, depending on outcoming of
the naming discussion.

+ *
+ * Copyright (C) 2013 Li Guang
+ * Written by Li Guang<address@hidden>
+ *
+ * This program is free software; you can redistribute it and/or modify it
+ * under the terms of the GNU General Public License as published by the
+ * Free Software Foundation; either version 2 of the License, or
+ * (at your option) any later version.
+ *
+ * This program 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 General Public License
+ * for more details.
+ */
+
+#include "hw/sysbus.h"
+#include "hw/ptimer.h"
+#include "sysemu/sysemu.h"
+#include "hw/timer/sunxi-pit.h"
+
+
+static uint64_t sunxi_pit_read(void *opaque, hwaddr offset, unsigned size)
+{
+    SunxiPITState *s = SUNXI_PIT(opaque);
+    uint8_t index;
+
+    switch (offset) {
+    case SUNXI_TIMER_IRQ_EN:
+        return s->irq_enable;
+    case SUNXI_TIMER_IRQ_ST:
+        return s->irq_status;
+    case SUNXI_TIMER_BASE ...  SUNXI_TIMER_BASE * 6 + SUNXI_TIMER_COUNT:
+        index = offset&  0xf0;
+        index>>= 4;
+        index -= 1;
+        switch (offset&  0x0f) {
+        case SUNXI_TIMER_CONTROL:
+            return s->control[index];
+        case SUNXI_TIMER_INTERVAL:
+            return s->interval[index];
+        case SUNXI_TIMER_COUNT:
+            s->count[index] = ptimer_get_count(s->timer[index]);
+            return s->count[index];
+        default:
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: Bad offset 0x%x\n",  __func__, (int)offset);
+            break;
+        }
+    case SUNXI_WDOG_CONTROL:
+        break;
+    case SUNXI_WDOG_MODE:
+        break;
+    case SUNXI_COUNT_LO:
+        return s->count_lo;
+        break;
break after return.

git diff | grep "return" -A 1 | grep "break"

It's crude, but will find any you missed.

+    case SUNXI_COUNT_HI:
+        return s->count_hi;
+        break;
+    case SUNXI_COUNT_CTL:
+        return s->count_ctl;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Bad offset 0x%x\n",  __func__, (int)offset);
+        break;
+    }
+
+    return 0;
+}
+
+static void sunxi_pit_write(void *opaque, hwaddr offset, uint64_t value,
+                            unsigned size)
+{
+     SunxiPITState *s = SUNXI_PIT(opaque);
+     uint8_t index;
+
+    switch (offset) {
+    case SUNXI_TIMER_IRQ_EN:
+        s->irq_enable = value;
+        break;
+    case SUNXI_TIMER_IRQ_ST:
+        s->irq_status&= ~value;
+        break;
+    case SUNXI_TIMER_BASE ...  SUNXI_TIMER_BASE * 6 + SUNXI_TIMER_COUNT:
+        index = offset&  0xf0;
+        index>>= 4;
+        index -= 1;
+        switch (offset&  0x0f) {
+        case SUNXI_TIMER_CONTROL:
+            s->control[index] = value;
+            if (s->control[index]&  SUNXI_TIMER_RELOAD) {
+                ptimer_set_count(s->timer[index], s->interval[index]);
+            }
+            if (s->control[index]&  SUNXI_TIMER_EN) {
+                ptimer_run(s->timer[index], 1);
+            } else {
+                ptimer_stop(s->timer[index]);
+            }
+            break;
+        case SUNXI_TIMER_INTERVAL:
+            s->interval[index] = value;
+            ptimer_set_count(s->timer[index], s->interval[index]);
+            break;
+        case SUNXI_TIMER_COUNT:
+            s->count[index] = value;
+            break;
+        default:
+            qemu_log_mask(LOG_GUEST_ERROR,
+                          "%s: Bad offset 0x%x\n",  __func__, (int)offset);
+        }
+        break;
+    case SUNXI_WDOG_CONTROL:
+        s->watch_dog_control = value;
+        break;
+    case SUNXI_WDOG_MODE:
+        s->watch_dog_mode = value;
+        break;
+    case SUNXI_COUNT_LO:
+        s->count_lo = value;
+        break;
+    case SUNXI_COUNT_HI:
+        s->count_hi = value;
+        break;
+    case SUNXI_COUNT_CTL:
+        s->count_ctl = value;
+        if (s->count_ctl&  SUNXI_COUNT_RL_EN) {
+            s->count_lo = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+            s->count_hi = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL)>>  32;
+            s->count_ctl&= ~SUNXI_COUNT_RL_EN;
+        }
+        if (s->count_ctl&  SUNXI_COUNT_CLR_EN) {
+            s->count_lo =0;
+            s->count_hi =0;
+            s->count_ctl&= ~SUNXI_COUNT_CLR_EN;
+        }
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: Bad offset 0x%x\n",  __func__, (int)offset);
+        break;
+    }
+}
+
+static const MemoryRegionOps sunxi_pit_ops = {
+    .read = sunxi_pit_read,
+    .write = sunxi_pit_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static const VMStateDescription vmstate_sunxi_pit = {
+    .name = "sunxi.pit",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .minimum_version_id_old = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(irq_enable, SunxiPITState),
+        VMSTATE_UINT32(irq_status, SunxiPITState),
+        VMSTATE_UINT32_ARRAY(control, SunxiPITState, SUNXI_TIMER_NR),
+        VMSTATE_UINT32_ARRAY(interval, SunxiPITState, SUNXI_TIMER_NR),
+        VMSTATE_UINT32_ARRAY(count, SunxiPITState, SUNXI_TIMER_NR),
+        VMSTATE_UINT32(watch_dog_mode, SunxiPITState),
+        VMSTATE_UINT32(watch_dog_control, SunxiPITState),
+        VMSTATE_UINT32(count_lo, SunxiPITState),
+        VMSTATE_UINT32(count_hi, SunxiPITState),
+        VMSTATE_UINT32(count_ctl, SunxiPITState),
+        VMSTATE_PTIMER_ARRAY(timer, SunxiPITState, SUNXI_TIMER_NR),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void sunxi_pit_reset(DeviceState *dev)
+{
+    SunxiPITState *s = SUNXI_PIT(dev);
+    uint8_t i;
+
+    s->irq_enable = 0;
+    s->irq_status = 0;
+    for (i = 0; i<  6; i++) {
+        s->control[i] = SUNXI_DEFAULT_CLOCK;
+        s->interval[i] = 0;
+        s->count[i] = 0;
+        ptimer_stop(s->timer[i]);
+    }
+    s->watch_dog_mode = 0;
+    s->watch_dog_control = 0;
+    s->count_lo = 0;
+    s->count_hi = 0;
+    s->count_ctl = 0;
+}
+
+static void sunxi_pit_timer_cb(void *opaque)
+{
+    SunxiPITState *s = SUNXI_PIT(opaque);
+    uint8_t i;
+
+    for (i = 0; i<  SUNXI_TIMER_NR; i++) {
+        if (s->control[i]&  SUNXI_TIMER_EN&&
+            ptimer_get_count(s->timer[i]) == 0) {
+            s->irq_status |= 1<<  i;
+            if (!(s->control[i]&  SUNXI_TIMER_MODE)) {
+                ptimer_set_count(s->timer[i], s->interval[i]);
+                ptimer_run(s->timer[i], 1);
So looking at this more closely, I see you are chaining one-shot
ptimers. My understanding is that you shouldn't do this, as it leads
to small slips in time, that over many hits integrate to a noticable
slippage. You should refactor the intial ptimer_run to not one-shot
when !SUNXI_TIMER_MODE.


OK

+            }
+            qemu_irq_raise(s->irq[i]);
I see that it's an edge triggered interrupt - makes a lot more sense
now. I think there is qemu_irq_pulse for this very purpose. But I also
think you are susceptible to spurious edges here however. If timer A
hits (and doesn't reload), and then timer B hits, I don't see what
stops this logic being reached for timer A again?

This issue is orthogonal and still at large even with one-shot fix.



sorry, currently can't get it?
can you give more details?

Thanks!
Li Guang

Regards,
Peter

+        }
+        qemu_irq_lower(s->irq[i]);
+    }
+}
+
+static void sunxi_pit_realize(DeviceState *dev, Error **errp)
+{
+    SunxiPITState *s = SUNXI_PIT(dev);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+    QEMUBH *bh[SUNXI_TIMER_NR];
+    uint8_t i;
+
+    for (i = 0; i<  SUNXI_TIMER_NR; i++) {
+        sysbus_init_irq(sbd,&s->irq[i]);
+    }
+    memory_region_init_io(&s->iomem, OBJECT(s),&sunxi_pit_ops, s,
+                          TYPE_SUNXI_PIT, 0x400);
+    sysbus_init_mmio(sbd,&s->iomem);
+
+     for (i = 0; i<  SUNXI_TIMER_NR; i++) {
+         bh[i] = qemu_bh_new(sunxi_pit_timer_cb, s);
+         s->timer[i] = ptimer_init(bh[i]);
+         ptimer_set_freq(s->timer[i], 240000);
+     }
+}
+
+static void sunxi_pit_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc  = DEVICE_CLASS(klass);
+
+    dc->realize = sunxi_pit_realize;
+    dc->reset = sunxi_pit_reset;
+    dc->desc = "sunxi timer";
+    dc->vmsd =&vmstate_sunxi_pit;
+}
+
+static const TypeInfo sunxi_pit_info = {
+    .name = TYPE_SUNXI_PIT,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(SunxiPITState),
+    .class_init = sunxi_pit_class_init,
+};
+
+static void sunxi_register_types(void)
+{
+    type_register_static(&sunxi_pit_info);
+}
+
+type_init(sunxi_register_types);
diff --git a/include/hw/timer/sunxi-pit.h b/include/hw/timer/sunxi-pit.h
new file mode 100644
index 0000000..7c84946
--- /dev/null
+++ b/include/hw/timer/sunxi-pit.h
@@ -0,0 +1,56 @@
+#ifndef SUNXI_PIT_H
+#define SUNXI_PIT_H
+
+
+#define TYPE_SUNXI_PIT "sunxi-timer"
+#define SUNXI_PIT(obj) OBJECT_CHECK(SunxiPITState, (obj), TYPE_SUNXI_PIT)
+
+#define SUNXI_TIMER_NR         6
+#define SUNXI_TIMER_IRQ        0x1
+#define SUNXI_WDOG_IRQ         0x100
+
+#define SUNXI_TIMER_IRQ_EN     0
+#define SUNXI_TIMER_IRQ_ST     0x4
+
+#define SUNXI_TIMER_CONTROL    0x0
+#define SUNXI_TIMER_EN         0x1
+#define SUNXI_TIMER_RELOAD     0x2
+#define SUNXI_TIMER_MODE       0x80
+
+#define SUNXI_TIMER_INTERVAL           0x4
+#define SUNXI_TIMER_COUNT              0x8
+#define SUNXI_WDOG_CONTROL             0x90
+#define SUNXI_WDOG_MODE                0x94
+
+#define SUNXI_COUNT_CTL                0xa0
+#define SUNXI_COUNT_RL_EN              0x2
+#define SUNXI_COUNT_CLR_EN             0x1
+#define SUNXI_COUNT_LO                 0xa4
+#define SUNXI_COUNT_HI                 0xa8
+
+#define SUNXI_TIMER_BASE               0x10
+
+#define SUNXI_DEFAULT_CLOCK            0x4
+
+typedef struct SunxiPITState {
+    /*<  private>*/
+    SysBusDevice parent_obj;
+    /*<  public>*/
+    qemu_irq irq[SUNXI_TIMER_NR];
+    ptimer_state *timer[SUNXI_TIMER_NR];
+    MemoryRegion iomem;
+
+    uint32_t  irq_enable;
+    uint32_t irq_status;
+    uint32_t control[SUNXI_TIMER_NR];
+    uint32_t interval[SUNXI_TIMER_NR];
+    uint32_t count[SUNXI_TIMER_NR];
+    uint32_t watch_dog_mode;
+    uint32_t watch_dog_control;
+    uint32_t count_lo;
+    uint32_t count_hi;
+    uint32_t count_ctl;
+} SunxiPITState;
+
+#endif
+
--
1.7.2.5







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