Qemu-NUC980(二)：时钟clock代码添加

概述

本文描述了在qemu下模拟实现时钟框架的代码，在讲述过程中，为了便于阅读，删减了完成代码，感兴趣的同学可以去文末链接，查看工程链接。

本文主要讲述的模拟980的时钟的框架步骤，不细节上讲述每一个实现的原理。

添加步骤

1、在include/hw/misc/目录下创建nuc980_clk.h，如下所示:

+号部分为新增加内容

diff --git a/include/hw/misc/nuc980_clk.h b/include/hw/misc/nuc980_clk.h
new file mode 100644
index 00000000..2f25399a
--- /dev/null
+++ b/include/hw/misc/nuc980_clk.h
@@ -0,0 +1,72 @@
+/*
+ * NUC980 SOC System emulation.
+ *
+ * Copyright (c) 2023- yanl1229@163.com.
+ * Written by yanl1229
+ *
+ * This code is licensed under the GPL.
+ */
+#ifndef NUC980_CLK__H
+#define NUC980_CLK__H
+
+#include "hw/sysbus.h"
+
+#define CLK_PMCON       0x00
+#define CLK_HCLKEN      0x10
+#define CLK_PCLKEN0     0x18
+#define CLK_PCLKEN1     0x1c
+#define CLK_DIVCTL0     0x20
+#define CLK_DIVCTL1     0x24
+#define CLK_DIVCTL2     0x28
+#define CLK_DIVCTL3     0x2c
+#define CLK_DIVCTL4     0x30
+#define CLK_DIVCTL5     0x34
+#define CLK_DIVCTL6     0x38
+#define CLK_DIVCTL7     0x3c
+#define CLK_DIVCTL8     0x40
+#define CLK_DIVCTL9     0x44
+#define CLK_APLLCON     0x60
+#define CLK_UPLLCON     0x64
+#define CLK_PLLSTBCNTR  0x80
+
+#define TYPE_NUC980_CLK "nuc980-clk"
+#define NUC980_CLK(obj) \
+    OBJECT_CHECK(NUC980ClockState, (obj), TYPE_NUC980_CLK)
+
+#define SYS_UPLL    1
+#define SYS_APLL    2
+#define SYS_SYSTEM    3
+#define SYS_HCLK    4
+#define SYS_PCLK01    5
+#define SYS_PCLK2    6
+#define SYS_CPU    7
+
+typedef struct {
+    /* <private> */
+    SysBusDevice parent_obj;
+
+    /* <public> */
+    MemoryRegion mmio;
+
+    uint32_t clk_pmcon;
+    uint32_t clk_hclken;
+    uint32_t clk_pclken0;
+    uint32_t clk_pclken1;
+    uint32_t clk_divctrl0;
+    uint32_t clk_divctrl1;
+    uint32_t clk_divctrl2;
+    uint32_t clk_divctrl3;
+    uint32_t clk_divctrl4;
+    uint32_t clk_divctrl5;
+    uint32_t clk_divctrl6;
+    uint32_t clk_divctrl7;
+    uint32_t clk_divctrl8;
+    uint32_t clk_divctrl9;
+    uint32_t clk_applcon;
+    uint32_t clk_upllcon;
+    uint32_t clk_pllstbcntr;
+
+} NUC980ClockState;
+
+extern uint64_t nuc980_get_timer_clock(int id);
+#endif

2、修改hw/misc/目录下创建nuc980_clk.c，如下所示:

+号部分为新增加内容

diff --git a/hw/misc/nuc980_clk.c b/hw/misc/nuc980_clk.c
new file mode 100644
index 00000000..2a4ad4f6
--- /dev/null
+++ b/hw/misc/nuc980_clk.c
@@ -0,0 +1,396 @@
+/*
+ * NUC980 SOC System emulation.
+ *
+ * Copyright (c) 2023- yanl1229@163.com.
+ * Written by yanl1229
+ *
+ * This code is licensed under the GPL.
+ */
+#include "qemu/osdep.h"
+#include "qapi/error.h"
+#include "qemu/log.h"
+#include "hw/misc/nuc980_clk.h"
+#include "hw/irq.h"
+#include "hw/qdev-properties.h"
+#include "migration/vmstate.h"
+#include "qemu/module.h"
+
+#ifndef SYS_ERR_DEBUG
+#define SYS_ERR_DEBUG 0
+#endif
+
+#define DB_PRINT_L(lvl, fmt, args...) do { \
+    if (SYS_ERR_DEBUG >= lvl) { \
+        qemu_log("%s: " fmt, __func__, ## args); \
+    } \
+} while (0);
+
+#define DB_PRINT(fmt, args...) DB_PRINT_L(1, fmt, ## args)
+
+static NUC980ClockState *g_clk_dev = NULL;
+
+static void nuc980_clk_reset(DeviceState *dev)
+{
+    NUC980ClockState *s = NUC980_CLK(dev);
+
   ......
+}
+
+static uint64_t nuc980_clk_read(void *opaque, hwaddr addr,
+                                     unsigned int size)
+{
+    NUC980ClockState *s = opaque;
+    uint64_t retvalue = 0;
+
+    DB_PRINT("Address: 0x%" HWADDR_PRIx "\n", addr);
+    switch(addr) {
+    case CLK_PMCON:
+        retvalue = s->clk_pmcon;
     ......
+    return retvalue;
+}
+
+static void nuc980_clk_write(void *opaque, hwaddr addr,
+                                uint64_t val64, unsigned int size)
+{
+    NUC980ClockState *s = opaque;
+    uint32_t value = val64;
+    ......
+}
+
+static uint32_t sysGetPLL(uint32_t reg)
+{
+    uint32_t N,M,P;
+
+    N =((reg & 0x007F)>>0)+1;
+    M =((reg & 0x1F80)>>7)+1;
+    P =((reg & 0xE000)>>13)+1;
+
+    return (12*N/(M*P));
+}
 ......
+static const MemoryRegionOps nuc980_clk_ops = {
+    .read = nuc980_clk_read,
+    .write = nuc980_clk_write,
+    .endianness = DEVICE_NATIVE_ENDIAN,
+};
+
+static const VMStateDescription vmstate_nuc980_clk = {
+    .name = TYPE_NUC980_CLK,
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(clk_pmcon, NUC980ClockState),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void nuc980_clk_init(Object *obj)
+{
+    NUC980ClockState *s = NUC980_CLK(obj);
+
+    memory_region_init_io(&s->mmio, obj, &nuc980_clk_ops, s,
+                          TYPE_NUC980_CLK, 0x100);
+    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->mmio);
+}
+
+static void nuc980_clk_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->reset = nuc980_clk_reset;
+    dc->vmsd = &vmstate_nuc980_clk;
+}
+
+static const TypeInfo nuc980_clk_info = {
+    .name          = TYPE_NUC980_CLK,
+    .parent        = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(NUC980ClockState),
+    .instance_init = nuc980_clk_init,
+    .class_init    = nuc980_clk_class_init,
+};
+
+static void nuc980_clk_register_types(void)
+{
+    type_register_static(&nuc980_clk_info);
+}
+
+type_init(nuc980_clk_register_types)

3、修改hw/misc/Kconfig，如下所示:

+号部分为新增加内容

diff --git a/hw/misc/Kconfig b/hw/misc/Kconfig
index 21646465..cd32904b 100644
--- a/hw/misc/Kconfig
+++ b/hw/misc/Kconfig
@@ -125,4 +125,7 @@ config MAC_VIA
     select MOS6522
     select ADB
 
+config NUC980_CLK
+    bool
+

4、修改hw/misc/Makefile.objs，如下所示:，如下所示:

+号部分为新增加内容

diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index ba898a57..792be5db 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -82,3 +82,6 @@ common-obj-$(CONFIG_NRF51_SOC) += nrf51_rng.o
 obj-$(CONFIG_MAC_VIA) += mac_via.o
 
 common-obj-$(CONFIG_GRLIB) += grlib_ahb_apb_pnp.o
+
+obj-$(CONFIG_NUC980_CLK) += nuc980_clk.o
+

5、修改hw/arm/目录下的nuc980_soc.c，如下所示:

+号部分为新增加内容

diff --git a/hw/arm/nuc980_soc.c b/hw/arm/nuc980_soc.c
index 3de9d712..cec0c97d 100644
--- a/hw/arm/nuc980_soc.c
+++ b/hw/arm/nuc980_soc.c
@@ -20,10 +20,37 @@
 
 static void nuc980_init(Object *obj)
 {
+
+    NUC980State *s = NUC980(obj);
+
+    object_initialize_child(obj, "cpu", &s->cpu, sizeof(s->cpu),
+                            ARM_CPU_TYPE_NAME("arm926"),
+                            &error_abort, NULL);
+
+    /* clk */
+    sysbus_init_child_obj(obj, "clk", &s->clk, sizeof(s->clk), TYPE_NUC980_CLK);
 }
 
 static void nuc980_realize(DeviceState *dev, Error **errp)
 {
+    NUC980State *s = NUC980(dev);
+    Error *err = NULL;
+    /* By default A9,A15 and ARM1176 CPUs have EL3 enabled.  This board
+     * does not currently support EL3 so the CPU EL3 property is disabled
+     * before realization.
+     */
+    if (object_property_find(OBJECT(&s->cpu), "has_el3", NULL)) {
+        object_property_set_bool(OBJECT(&s->cpu), false, "has_el3", &error_fatal);
+    }
+
+    object_property_set_bool(OBJECT(&s->cpu), true, "realized", &err);
+    if (err) {
+        error_propagate(errp, err);
+        return;
+    }
+    /* clock control */
+    sysbus_mmio_map(SYS_BUS_DEVICE(&s->clk), 0, CLK_CTL_BASE);
+
 }

6、修改hw/arm/目录下的Kconfig，如下所示:

+号部分为新增加内容

diff --git a/hw/arm/Kconfig b/hw/arm/Kconfig
index 2a604c83..b1f4410a 100644
--- a/hw/arm/Kconfig
+++ b/hw/arm/Kconfig
@@ -115,6 +115,7 @@ config NSERIES
 
 config NUC980
     bool
+    select NUC980_CLK
 

总结

本文描述了980时钟的模拟实现，在qemu模拟中，只能模拟寄存器的功能，不能模拟时序特性。

工程链接

https://gitee.com/yanl1229/qemu.git