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-rw-r--r--hw/misc/a9scu.c59
-rw-r--r--hw/misc/meson.build4
-rw-r--r--hw/misc/npcm7xx_clk.c266
-rw-r--r--hw/misc/npcm7xx_gcr.c269
-rw-r--r--hw/misc/trace-events8
5 files changed, 575 insertions, 31 deletions
diff --git a/hw/misc/a9scu.c b/hw/misc/a9scu.c
index 324371a1c0..a375ebc987 100644
--- a/hw/misc/a9scu.c
+++ b/hw/misc/a9scu.c
@@ -12,8 +12,12 @@
 #include "hw/misc/a9scu.h"
 #include "hw/qdev-properties.h"
 #include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qemu/log.h"
 #include "qemu/module.h"
 
+#define A9_SCU_CPU_MAX  4
+
 static uint64_t a9_scu_read(void *opaque, hwaddr offset,
                             unsigned size)
 {
@@ -25,12 +29,6 @@ static uint64_t a9_scu_read(void *opaque, hwaddr offset,
         return (((1 << s->num_cpu) - 1) << 4) | (s->num_cpu - 1);
     case 0x08: /* CPU Power Status */
         return s->status;
-    case 0x09: /* CPU status.  */
-        return s->status >> 8;
-    case 0x0a: /* CPU status.  */
-        return s->status >> 16;
-    case 0x0b: /* CPU status.  */
-        return s->status >> 24;
     case 0x0c: /* Invalidate All Registers In Secure State */
         return 0;
     case 0x40: /* Filtering Start Address Register */
@@ -41,6 +39,8 @@ static uint64_t a9_scu_read(void *opaque, hwaddr offset,
     case 0x54: /* SCU Non-secure Access Control Register */
         /* unimplemented, fall through */
     default:
+        qemu_log_mask(LOG_UNIMP, "%s: Unsupported offset 0x%"HWADDR_PRIx"\n",
+                      __func__, offset);
         return 0;
     }
 }
@@ -49,23 +49,6 @@ static void a9_scu_write(void *opaque, hwaddr offset,
                          uint64_t value, unsigned size)
 {
     A9SCUState *s = (A9SCUState *)opaque;
-    uint32_t mask;
-    uint32_t shift;
-    switch (size) {
-    case 1:
-        mask = 0xff;
-        break;
-    case 2:
-        mask = 0xffff;
-        break;
-    case 4:
-        mask = 0xffffffff;
-        break;
-    default:
-        fprintf(stderr, "Invalid size %u in write to a9 scu register %x\n",
-                size, (unsigned)offset);
-        return;
-    }
 
     switch (offset) {
     case 0x00: /* Control */
@@ -74,9 +57,7 @@ static void a9_scu_write(void *opaque, hwaddr offset,
     case 0x4: /* Configuration: RO */
         break;
     case 0x08: case 0x09: case 0x0A: case 0x0B: /* Power Control */
-        shift = (offset - 0x8) * 8;
-        s->status &= ~(mask << shift);
-        s->status |= ((value & mask) << shift);
+        s->status = value;
         break;
     case 0x0c: /* Invalidate All Registers In Secure State */
         /* no-op as we do not implement caches */
@@ -89,6 +70,9 @@ static void a9_scu_write(void *opaque, hwaddr offset,
     case 0x54: /* SCU Non-secure Access Control Register */
         /* unimplemented, fall through */
     default:
+        qemu_log_mask(LOG_UNIMP, "%s: Unsupported offset 0x%"HWADDR_PRIx
+                                 " value 0x%"PRIx64"\n",
+                      __func__, offset, value);
         break;
     }
 }
@@ -96,6 +80,14 @@ static void a9_scu_write(void *opaque, hwaddr offset,
 static const MemoryRegionOps a9_scu_ops = {
     .read = a9_scu_read,
     .write = a9_scu_write,
+    .impl = {
+        .min_access_size = 4,
+        .max_access_size = 4,
+    },
+    .valid = {
+        .min_access_size = 1,
+        .max_access_size = 4,
+    },
     .endianness = DEVICE_NATIVE_ENDIAN,
 };
 
@@ -105,12 +97,17 @@ static void a9_scu_reset(DeviceState *dev)
     s->control = 0;
 }
 
-static void a9_scu_init(Object *obj)
+static void a9_scu_realize(DeviceState *dev, Error **errp)
 {
-    A9SCUState *s = A9_SCU(obj);
-    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    A9SCUState *s = A9_SCU(dev);
+    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
+
+    if (!s->num_cpu || s->num_cpu > A9_SCU_CPU_MAX) {
+        error_setg(errp, "Illegal CPU count: %u", s->num_cpu);
+        return;
+    }
 
-    memory_region_init_io(&s->iomem, obj, &a9_scu_ops, s,
+    memory_region_init_io(&s->iomem, OBJECT(s), &a9_scu_ops, s,
                           "a9-scu", 0x100);
     sysbus_init_mmio(sbd, &s->iomem);
 }
@@ -138,13 +135,13 @@ static void a9_scu_class_init(ObjectClass *klass, void *data)
     device_class_set_props(dc, a9_scu_properties);
     dc->vmsd = &vmstate_a9_scu;
     dc->reset = a9_scu_reset;
+    dc->realize = a9_scu_realize;
 }
 
 static const TypeInfo a9_scu_info = {
     .name          = TYPE_A9_SCU,
     .parent        = TYPE_SYS_BUS_DEVICE,
     .instance_size = sizeof(A9SCUState),
-    .instance_init = a9_scu_init,
     .class_init    = a9_scu_class_init,
 };
 
diff --git a/hw/misc/meson.build b/hw/misc/meson.build
index bd24132757..793d45b1dc 100644
--- a/hw/misc/meson.build
+++ b/hw/misc/meson.build
@@ -56,6 +56,10 @@ softmmu_ss.add(when: 'CONFIG_IMX', if_true: files(
 ))
 softmmu_ss.add(when: 'CONFIG_MILKYMIST', if_true: files('milkymist-hpdmc.c', 'milkymist-pfpu.c'))
 softmmu_ss.add(when: 'CONFIG_MAINSTONE', if_true: files('mst_fpga.c'))
+softmmu_ss.add(when: 'CONFIG_NPCM7XX', if_true: files(
+  'npcm7xx_clk.c',
+  'npcm7xx_gcr.c',
+))
 softmmu_ss.add(when: 'CONFIG_OMAP', if_true: files(
   'omap_clk.c',
   'omap_gpmc.c',
diff --git a/hw/misc/npcm7xx_clk.c b/hw/misc/npcm7xx_clk.c
new file mode 100644
index 0000000000..21ab4200d1
--- /dev/null
+++ b/hw/misc/npcm7xx_clk.c
@@ -0,0 +1,266 @@
+/*
+ * Nuvoton NPCM7xx Clock Control Registers.
+ *
+ * Copyright 2020 Google LLC
+ *
+ * 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 "qemu/osdep.h"
+
+#include "hw/misc/npcm7xx_clk.h"
+#include "migration/vmstate.h"
+#include "qemu/error-report.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qemu/timer.h"
+#include "qemu/units.h"
+#include "trace.h"
+
+#define PLLCON_LOKI     BIT(31)
+#define PLLCON_LOKS     BIT(30)
+#define PLLCON_PWDEN    BIT(12)
+
+enum NPCM7xxCLKRegisters {
+    NPCM7XX_CLK_CLKEN1,
+    NPCM7XX_CLK_CLKSEL,
+    NPCM7XX_CLK_CLKDIV1,
+    NPCM7XX_CLK_PLLCON0,
+    NPCM7XX_CLK_PLLCON1,
+    NPCM7XX_CLK_SWRSTR,
+    NPCM7XX_CLK_IPSRST1         = 0x20 / sizeof(uint32_t),
+    NPCM7XX_CLK_IPSRST2,
+    NPCM7XX_CLK_CLKEN2,
+    NPCM7XX_CLK_CLKDIV2,
+    NPCM7XX_CLK_CLKEN3,
+    NPCM7XX_CLK_IPSRST3,
+    NPCM7XX_CLK_WD0RCR,
+    NPCM7XX_CLK_WD1RCR,
+    NPCM7XX_CLK_WD2RCR,
+    NPCM7XX_CLK_SWRSTC1,
+    NPCM7XX_CLK_SWRSTC2,
+    NPCM7XX_CLK_SWRSTC3,
+    NPCM7XX_CLK_SWRSTC4,
+    NPCM7XX_CLK_PLLCON2,
+    NPCM7XX_CLK_CLKDIV3,
+    NPCM7XX_CLK_CORSTC,
+    NPCM7XX_CLK_PLLCONG,
+    NPCM7XX_CLK_AHBCKFI,
+    NPCM7XX_CLK_SECCNT,
+    NPCM7XX_CLK_CNTR25M,
+    NPCM7XX_CLK_REGS_END,
+};
+
+/*
+ * These reset values were taken from version 0.91 of the NPCM750R data sheet.
+ *
+ * All are loaded on power-up reset. CLKENx and SWRSTR should also be loaded on
+ * core domain reset, but this reset type is not yet supported by QEMU.
+ */
+static const uint32_t cold_reset_values[NPCM7XX_CLK_NR_REGS] = {
+    [NPCM7XX_CLK_CLKEN1]        = 0xffffffff,
+    [NPCM7XX_CLK_CLKSEL]        = 0x004aaaaa,
+    [NPCM7XX_CLK_CLKDIV1]       = 0x5413f855,
+    [NPCM7XX_CLK_PLLCON0]       = 0x00222101 | PLLCON_LOKI,
+    [NPCM7XX_CLK_PLLCON1]       = 0x00202101 | PLLCON_LOKI,
+    [NPCM7XX_CLK_IPSRST1]       = 0x00001000,
+    [NPCM7XX_CLK_IPSRST2]       = 0x80000000,
+    [NPCM7XX_CLK_CLKEN2]        = 0xffffffff,
+    [NPCM7XX_CLK_CLKDIV2]       = 0xaa4f8f9f,
+    [NPCM7XX_CLK_CLKEN3]        = 0xffffffff,
+    [NPCM7XX_CLK_IPSRST3]       = 0x03000000,
+    [NPCM7XX_CLK_WD0RCR]        = 0xffffffff,
+    [NPCM7XX_CLK_WD1RCR]        = 0xffffffff,
+    [NPCM7XX_CLK_WD2RCR]        = 0xffffffff,
+    [NPCM7XX_CLK_SWRSTC1]       = 0x00000003,
+    [NPCM7XX_CLK_PLLCON2]       = 0x00c02105 | PLLCON_LOKI,
+    [NPCM7XX_CLK_CORSTC]        = 0x04000003,
+    [NPCM7XX_CLK_PLLCONG]       = 0x01228606 | PLLCON_LOKI,
+    [NPCM7XX_CLK_AHBCKFI]       = 0x000000c8,
+};
+
+static uint64_t npcm7xx_clk_read(void *opaque, hwaddr offset, unsigned size)
+{
+    uint32_t reg = offset / sizeof(uint32_t);
+    NPCM7xxCLKState *s = opaque;
+    int64_t now_ns;
+    uint32_t value = 0;
+
+    if (reg >= NPCM7XX_CLK_NR_REGS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: offset 0x%04" HWADDR_PRIx " out of range\n",
+                      __func__, offset);
+        return 0;
+    }
+
+    switch (reg) {
+    case NPCM7XX_CLK_SWRSTR:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: register @ 0x%04" HWADDR_PRIx " is write-only\n",
+                      __func__, offset);
+        break;
+
+    case NPCM7XX_CLK_SECCNT:
+        now_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+        value = (now_ns - s->ref_ns) / NANOSECONDS_PER_SECOND;
+        break;
+
+    case NPCM7XX_CLK_CNTR25M:
+        now_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+        /*
+         * This register counts 25 MHz cycles, updating every 640 ns. It rolls
+         * over to zero every second.
+         *
+         * The 4 LSBs are always zero: (1e9 / 640) << 4 = 25000000.
+         */
+        value = (((now_ns - s->ref_ns) / 640) << 4) % NPCM7XX_TIMER_REF_HZ;
+        break;
+
+    default:
+        value = s->regs[reg];
+        break;
+    };
+
+    trace_npcm7xx_clk_read(offset, value);
+
+    return value;
+}
+
+static void npcm7xx_clk_write(void *opaque, hwaddr offset,
+                              uint64_t v, unsigned size)
+{
+    uint32_t reg = offset / sizeof(uint32_t);
+    NPCM7xxCLKState *s = opaque;
+    uint32_t value = v;
+
+    trace_npcm7xx_clk_write(offset, value);
+
+    if (reg >= NPCM7XX_CLK_NR_REGS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: offset 0x%04" HWADDR_PRIx " out of range\n",
+                      __func__, offset);
+        return;
+    }
+
+    switch (reg) {
+    case NPCM7XX_CLK_SWRSTR:
+        qemu_log_mask(LOG_UNIMP, "%s: SW reset not implemented: 0x%02x\n",
+                      __func__, value);
+        value = 0;
+        break;
+
+    case NPCM7XX_CLK_PLLCON0:
+    case NPCM7XX_CLK_PLLCON1:
+    case NPCM7XX_CLK_PLLCON2:
+    case NPCM7XX_CLK_PLLCONG:
+        if (value & PLLCON_PWDEN) {
+            /* Power down -- clear lock and indicate loss of lock */
+            value &= ~PLLCON_LOKI;
+            value |= PLLCON_LOKS;
+        } else {
+            /* Normal mode -- assume always locked */
+            value |= PLLCON_LOKI;
+            /* Keep LOKS unchanged unless cleared by writing 1 */
+            if (value & PLLCON_LOKS) {
+                value &= ~PLLCON_LOKS;
+            } else {
+                value |= (value & PLLCON_LOKS);
+            }
+        }
+        break;
+
+    case NPCM7XX_CLK_CNTR25M:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: register @ 0x%04" HWADDR_PRIx " is read-only\n",
+                      __func__, offset);
+        return;
+    }
+
+    s->regs[reg] = value;
+}
+
+static const struct MemoryRegionOps npcm7xx_clk_ops = {
+    .read       = npcm7xx_clk_read,
+    .write      = npcm7xx_clk_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid      = {
+        .min_access_size        = 4,
+        .max_access_size        = 4,
+        .unaligned              = false,
+    },
+};
+
+static void npcm7xx_clk_enter_reset(Object *obj, ResetType type)
+{
+    NPCM7xxCLKState *s = NPCM7XX_CLK(obj);
+
+    QEMU_BUILD_BUG_ON(sizeof(s->regs) != sizeof(cold_reset_values));
+
+    switch (type) {
+    case RESET_TYPE_COLD:
+        memcpy(s->regs, cold_reset_values, sizeof(cold_reset_values));
+        s->ref_ns = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
+        return;
+    }
+
+    /*
+     * A small number of registers need to be reset on a core domain reset,
+     * but no such reset type exists yet.
+     */
+    qemu_log_mask(LOG_UNIMP, "%s: reset type %d not implemented.",
+                  __func__, type);
+}
+
+static void npcm7xx_clk_init(Object *obj)
+{
+    NPCM7xxCLKState *s = NPCM7XX_CLK(obj);
+
+    memory_region_init_io(&s->iomem, obj, &npcm7xx_clk_ops, s,
+                          TYPE_NPCM7XX_CLK, 4 * KiB);
+    sysbus_init_mmio(&s->parent, &s->iomem);
+}
+
+static const VMStateDescription vmstate_npcm7xx_clk = {
+    .name = "npcm7xx-clk",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(regs, NPCM7xxCLKState, NPCM7XX_CLK_NR_REGS),
+        VMSTATE_INT64(ref_ns, NPCM7xxCLKState),
+        VMSTATE_END_OF_LIST(),
+    },
+};
+
+static void npcm7xx_clk_class_init(ObjectClass *klass, void *data)
+{
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    QEMU_BUILD_BUG_ON(NPCM7XX_CLK_REGS_END > NPCM7XX_CLK_NR_REGS);
+
+    dc->desc = "NPCM7xx Clock Control Registers";
+    dc->vmsd = &vmstate_npcm7xx_clk;
+    rc->phases.enter = npcm7xx_clk_enter_reset;
+}
+
+static const TypeInfo npcm7xx_clk_info = {
+    .name               = TYPE_NPCM7XX_CLK,
+    .parent             = TYPE_SYS_BUS_DEVICE,
+    .instance_size      = sizeof(NPCM7xxCLKState),
+    .instance_init      = npcm7xx_clk_init,
+    .class_init         = npcm7xx_clk_class_init,
+};
+
+static void npcm7xx_clk_register_type(void)
+{
+    type_register_static(&npcm7xx_clk_info);
+}
+type_init(npcm7xx_clk_register_type);
diff --git a/hw/misc/npcm7xx_gcr.c b/hw/misc/npcm7xx_gcr.c
new file mode 100644
index 0000000000..745f690809
--- /dev/null
+++ b/hw/misc/npcm7xx_gcr.c
@@ -0,0 +1,269 @@
+/*
+ * Nuvoton NPCM7xx System Global Control Registers.
+ *
+ * Copyright 2020 Google LLC
+ *
+ * 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 "qemu/osdep.h"
+
+#include "hw/misc/npcm7xx_gcr.h"
+#include "hw/qdev-properties.h"
+#include "migration/vmstate.h"
+#include "qapi/error.h"
+#include "qemu/cutils.h"
+#include "qemu/log.h"
+#include "qemu/module.h"
+#include "qemu/units.h"
+
+#include "trace.h"
+
+#define NPCM7XX_GCR_MIN_DRAM_SIZE   (128 * MiB)
+#define NPCM7XX_GCR_MAX_DRAM_SIZE   (2 * GiB)
+
+enum NPCM7xxGCRRegisters {
+    NPCM7XX_GCR_PDID,
+    NPCM7XX_GCR_PWRON,
+    NPCM7XX_GCR_MFSEL1          = 0x0c / sizeof(uint32_t),
+    NPCM7XX_GCR_MFSEL2,
+    NPCM7XX_GCR_MISCPE,
+    NPCM7XX_GCR_SPSWC           = 0x038 / sizeof(uint32_t),
+    NPCM7XX_GCR_INTCR,
+    NPCM7XX_GCR_INTSR,
+    NPCM7XX_GCR_HIFCR           = 0x050 / sizeof(uint32_t),
+    NPCM7XX_GCR_INTCR2          = 0x060 / sizeof(uint32_t),
+    NPCM7XX_GCR_MFSEL3,
+    NPCM7XX_GCR_SRCNT,
+    NPCM7XX_GCR_RESSR,
+    NPCM7XX_GCR_RLOCKR1,
+    NPCM7XX_GCR_FLOCKR1,
+    NPCM7XX_GCR_DSCNT,
+    NPCM7XX_GCR_MDLR,
+    NPCM7XX_GCR_SCRPAD3,
+    NPCM7XX_GCR_SCRPAD2,
+    NPCM7XX_GCR_DAVCLVLR        = 0x098 / sizeof(uint32_t),
+    NPCM7XX_GCR_INTCR3,
+    NPCM7XX_GCR_VSINTR          = 0x0ac / sizeof(uint32_t),
+    NPCM7XX_GCR_MFSEL4,
+    NPCM7XX_GCR_CPBPNTR         = 0x0c4 / sizeof(uint32_t),
+    NPCM7XX_GCR_CPCTL           = 0x0d0 / sizeof(uint32_t),
+    NPCM7XX_GCR_CP2BST,
+    NPCM7XX_GCR_B2CPNT,
+    NPCM7XX_GCR_CPPCTL,
+    NPCM7XX_GCR_I2CSEGSEL,
+    NPCM7XX_GCR_I2CSEGCTL,
+    NPCM7XX_GCR_VSRCR,
+    NPCM7XX_GCR_MLOCKR,
+    NPCM7XX_GCR_SCRPAD          = 0x013c / sizeof(uint32_t),
+    NPCM7XX_GCR_USB1PHYCTL,
+    NPCM7XX_GCR_USB2PHYCTL,
+    NPCM7XX_GCR_REGS_END,
+};
+
+static const uint32_t cold_reset_values[NPCM7XX_GCR_NR_REGS] = {
+    [NPCM7XX_GCR_PDID]          = 0x04a92750,   /* Poleg A1 */
+    [NPCM7XX_GCR_MISCPE]        = 0x0000ffff,
+    [NPCM7XX_GCR_SPSWC]         = 0x00000003,
+    [NPCM7XX_GCR_INTCR]         = 0x0000035e,
+    [NPCM7XX_GCR_HIFCR]         = 0x0000004e,
+    [NPCM7XX_GCR_INTCR2]        = (1U << 19),   /* DDR initialized */
+    [NPCM7XX_GCR_RESSR]         = 0x80000000,
+    [NPCM7XX_GCR_DSCNT]         = 0x000000c0,
+    [NPCM7XX_GCR_DAVCLVLR]      = 0x5a00f3cf,
+    [NPCM7XX_GCR_SCRPAD]        = 0x00000008,
+    [NPCM7XX_GCR_USB1PHYCTL]    = 0x034730e4,
+    [NPCM7XX_GCR_USB2PHYCTL]    = 0x034730e4,
+};
+
+static uint64_t npcm7xx_gcr_read(void *opaque, hwaddr offset, unsigned size)
+{
+    uint32_t reg = offset / sizeof(uint32_t);
+    NPCM7xxGCRState *s = opaque;
+
+    if (reg >= NPCM7XX_GCR_NR_REGS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: offset 0x%04" HWADDR_PRIx " out of range\n",
+                      __func__, offset);
+        return 0;
+    }
+
+    trace_npcm7xx_gcr_read(offset, s->regs[reg]);
+
+    return s->regs[reg];
+}
+
+static void npcm7xx_gcr_write(void *opaque, hwaddr offset,
+                              uint64_t v, unsigned size)
+{
+    uint32_t reg = offset / sizeof(uint32_t);
+    NPCM7xxGCRState *s = opaque;
+    uint32_t value = v;
+
+    trace_npcm7xx_gcr_write(offset, value);
+
+    if (reg >= NPCM7XX_GCR_NR_REGS) {
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: offset 0x%04" HWADDR_PRIx " out of range\n",
+                      __func__, offset);
+        return;
+    }
+
+    switch (reg) {
+    case NPCM7XX_GCR_PDID:
+    case NPCM7XX_GCR_PWRON:
+    case NPCM7XX_GCR_INTSR:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "%s: register @ 0x%04" HWADDR_PRIx " is read-only\n",
+                      __func__, offset);
+        return;
+
+    case NPCM7XX_GCR_RESSR:
+    case NPCM7XX_GCR_CP2BST:
+        /* Write 1 to clear */
+        value = s->regs[reg] & ~value;
+        break;
+
+    case NPCM7XX_GCR_RLOCKR1:
+    case NPCM7XX_GCR_MDLR:
+        /* Write 1 to set */
+        value |= s->regs[reg];
+        break;
+    };
+
+    s->regs[reg] = value;
+}
+
+static const struct MemoryRegionOps npcm7xx_gcr_ops = {
+    .read       = npcm7xx_gcr_read,
+    .write      = npcm7xx_gcr_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    .valid      = {
+        .min_access_size        = 4,
+        .max_access_size        = 4,
+        .unaligned              = false,
+    },
+};
+
+static void npcm7xx_gcr_enter_reset(Object *obj, ResetType type)
+{
+    NPCM7xxGCRState *s = NPCM7XX_GCR(obj);
+
+    QEMU_BUILD_BUG_ON(sizeof(s->regs) != sizeof(cold_reset_values));
+
+    switch (type) {
+    case RESET_TYPE_COLD:
+        memcpy(s->regs, cold_reset_values, sizeof(s->regs));
+        s->regs[NPCM7XX_GCR_PWRON] = s->reset_pwron;
+        s->regs[NPCM7XX_GCR_MDLR] = s->reset_mdlr;
+        s->regs[NPCM7XX_GCR_INTCR3] = s->reset_intcr3;
+        break;
+    }
+}
+
+static void npcm7xx_gcr_realize(DeviceState *dev, Error **errp)
+{
+    ERRP_GUARD();
+    NPCM7xxGCRState *s = NPCM7XX_GCR(dev);
+    uint64_t dram_size;
+    Object *obj;
+
+    obj = object_property_get_link(OBJECT(dev), "dram-mr", errp);
+    if (!obj) {
+        error_prepend(errp, "%s: required dram-mr link not found: ", __func__);
+        return;
+    }
+    dram_size = memory_region_size(MEMORY_REGION(obj));
+    if (!is_power_of_2(dram_size) ||
+        dram_size < NPCM7XX_GCR_MIN_DRAM_SIZE ||
+        dram_size > NPCM7XX_GCR_MAX_DRAM_SIZE) {
+        g_autofree char *sz = size_to_str(dram_size);
+        g_autofree char *min_sz = size_to_str(NPCM7XX_GCR_MIN_DRAM_SIZE);
+        g_autofree char *max_sz = size_to_str(NPCM7XX_GCR_MAX_DRAM_SIZE);
+        error_setg(errp, "%s: unsupported DRAM size %s", __func__, sz);
+        error_append_hint(errp,
+                          "DRAM size must be a power of two between %s and %s,"
+                          " inclusive.\n", min_sz, max_sz);
+        return;
+    }
+
+    /* Power-on reset value */
+    s->reset_intcr3 = 0x00001002;
+
+    /*
+     * The GMMAP (Graphics Memory Map) field is used by u-boot to detect the
+     * DRAM size, and is normally initialized by the boot block as part of DRAM
+     * training. However, since we don't have a complete emulation of the
+     * memory controller and try to make it look like it has already been
+     * initialized, the boot block will skip this initialization, and we need
+     * to make sure this field is set correctly up front.
+     *
+     * WARNING: some versions of u-boot only looks at bits 8 and 9, so 2 GiB of
+     * DRAM will be interpreted as 128 MiB.
+     *
+     * https://github.com/Nuvoton-Israel/u-boot/blob/2aef993bd2aafeb5408dbaad0f3ce099ee40c4aa/board/nuvoton/poleg/poleg.c#L244
+     */
+    s->reset_intcr3 |= ctz64(dram_size / NPCM7XX_GCR_MIN_DRAM_SIZE) << 8;
+}
+
+static void npcm7xx_gcr_init(Object *obj)
+{
+    NPCM7xxGCRState *s = NPCM7XX_GCR(obj);
+
+    memory_region_init_io(&s->iomem, obj, &npcm7xx_gcr_ops, s,
+                          TYPE_NPCM7XX_GCR, 4 * KiB);
+    sysbus_init_mmio(&s->parent, &s->iomem);
+}
+
+static const VMStateDescription vmstate_npcm7xx_gcr = {
+    .name = "npcm7xx-gcr",
+    .version_id = 0,
+    .minimum_version_id = 0,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32_ARRAY(regs, NPCM7xxGCRState, NPCM7XX_GCR_NR_REGS),
+        VMSTATE_END_OF_LIST(),
+    },
+};
+
+static Property npcm7xx_gcr_properties[] = {
+    DEFINE_PROP_UINT32("disabled-modules", NPCM7xxGCRState, reset_mdlr, 0),
+    DEFINE_PROP_UINT32("power-on-straps", NPCM7xxGCRState, reset_pwron, 0),
+    DEFINE_PROP_END_OF_LIST(),
+};
+
+static void npcm7xx_gcr_class_init(ObjectClass *klass, void *data)
+{
+    ResettableClass *rc = RESETTABLE_CLASS(klass);
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    QEMU_BUILD_BUG_ON(NPCM7XX_GCR_REGS_END > NPCM7XX_GCR_NR_REGS);
+
+    dc->desc = "NPCM7xx System Global Control Registers";
+    dc->realize = npcm7xx_gcr_realize;
+    dc->vmsd = &vmstate_npcm7xx_gcr;
+    rc->phases.enter = npcm7xx_gcr_enter_reset;
+
+    device_class_set_props(dc, npcm7xx_gcr_properties);
+}
+
+static const TypeInfo npcm7xx_gcr_info = {
+    .name               = TYPE_NPCM7XX_GCR,
+    .parent             = TYPE_SYS_BUS_DEVICE,
+    .instance_size      = sizeof(NPCM7xxGCRState),
+    .instance_init      = npcm7xx_gcr_init,
+    .class_init         = npcm7xx_gcr_class_init,
+};
+
+static void npcm7xx_gcr_register_type(void)
+{
+    type_register_static(&npcm7xx_gcr_info);
+}
+type_init(npcm7xx_gcr_register_type);
diff --git a/hw/misc/trace-events b/hw/misc/trace-events
index 56a622d1e9..6054f9adf3 100644
--- a/hw/misc/trace-events
+++ b/hw/misc/trace-events
@@ -110,6 +110,14 @@ mos6522_set_sr_int(void) "set sr_int"
 mos6522_write(uint64_t addr, uint64_t val) "reg=0x%"PRIx64 " val=0x%"PRIx64
 mos6522_read(uint64_t addr, unsigned val) "reg=0x%"PRIx64 " val=0x%x"
 
+# npcm7xx_clk.c
+npcm7xx_clk_read(uint64_t offset, uint32_t value) " offset: 0x%04" PRIx64 " value: 0x%08" PRIx32
+npcm7xx_clk_write(uint64_t offset, uint32_t value) "offset: 0x%04" PRIx64 " value: 0x%08" PRIx32
+
+# npcm7xx_gcr.c
+npcm7xx_gcr_read(uint64_t offset, uint32_t value) " offset: 0x%04" PRIx64 " value: 0x%08" PRIx32
+npcm7xx_gcr_write(uint64_t offset, uint32_t value) "offset: 0x%04" PRIx64 " value: 0x%08" PRIx32
+
 # stm32f4xx_syscfg.c
 stm32f4xx_syscfg_set_irq(int gpio, int line, int level) "Interupt: GPIO: %d, Line: %d; Level: %d"
 stm32f4xx_pulse_exti(int irq) "Pulse EXTI: %d"