diff mbox series

[05/16] hw/misc/iotkit-sysctl: Implement IoTKit system control element

Message ID 20180809130115.28951-6-peter.maydell@linaro.org
State New
Headers show
Series arm: Implement MPS2 watchdogs and DMA | expand

Commit Message

Peter Maydell Aug. 9, 2018, 1:01 p.m. UTC
The Arm IoTKit includes a system control element which
provides a block of read-only ID registers and a block
of read-write control registers. Implement a minimal
version of this.

Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
---
 hw/misc/Makefile.objs           |   1 +
 include/hw/misc/iotkit-sysctl.h |  50 +++++
 hw/misc/iotkit-sysctl.c         | 324 ++++++++++++++++++++++++++++++++
 MAINTAINERS                     |   2 +
 default-configs/arm-softmmu.mak |   1 +
 hw/misc/trace-events            |   7 +
 6 files changed, 385 insertions(+)
 create mode 100644 include/hw/misc/iotkit-sysctl.h
 create mode 100644 hw/misc/iotkit-sysctl.c

Comments

Philippe Mathieu-Daudé Aug. 18, 2018, 12:23 a.m. UTC | #1
Hi Peter,

On 08/09/2018 10:01 AM, Peter Maydell wrote:
> The Arm IoTKit includes a system control element which
> provides a block of read-only ID registers and a block
> of read-write control registers. Implement a minimal
> version of this.
> 
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  hw/misc/Makefile.objs           |   1 +
>  include/hw/misc/iotkit-sysctl.h |  50 +++++
>  hw/misc/iotkit-sysctl.c         | 324 ++++++++++++++++++++++++++++++++
>  MAINTAINERS                     |   2 +
>  default-configs/arm-softmmu.mak |   1 +
>  hw/misc/trace-events            |   7 +
>  6 files changed, 385 insertions(+)
>  create mode 100644 include/hw/misc/iotkit-sysctl.h
>  create mode 100644 hw/misc/iotkit-sysctl.c
> 
> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
> index 93509008451..dbadb41d57a 100644
> --- a/hw/misc/Makefile.objs
> +++ b/hw/misc/Makefile.objs
> @@ -65,6 +65,7 @@ obj-$(CONFIG_MPS2_SCC) += mps2-scc.o
>  obj-$(CONFIG_TZ_MPC) += tz-mpc.o
>  obj-$(CONFIG_TZ_PPC) += tz-ppc.o
>  obj-$(CONFIG_IOTKIT_SECCTL) += iotkit-secctl.o
> +obj-$(CONFIG_IOTKIT_SYSCTL) += iotkit-sysctl.o
>  
>  obj-$(CONFIG_PVPANIC) += pvpanic.o
>  obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
> diff --git a/include/hw/misc/iotkit-sysctl.h b/include/hw/misc/iotkit-sysctl.h
> new file mode 100644
> index 00000000000..c3b14ccee4c
> --- /dev/null
> +++ b/include/hw/misc/iotkit-sysctl.h
> @@ -0,0 +1,50 @@
> +/*
> + * ARM IoTKit system control element
> + *
> + * Copyright (c) 2018 Linaro Limited
> + * Written by Peter Maydell
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License version 2 or
> + *  (at your option) any later version.
> + */
> +
> +/*
> + * This is a model of the "system control element" which is part of the
> + * Arm IoTKit and documented in
> + * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ecm0601256/index.html
> + * Specifically, it implements the "system information block" and
> + * "system control register" blocks.
> + *
> + * QEMU interface:
> + *  + sysbus MMIO region 0: the system information register bank
> + *  + sysbus MMIO region 1: the system control register bank
> + */
> +
> +#ifndef HW_MISC_IOTKIT_SYSCTL_H
> +#define HW_MISC_IOTKIT_SYSCTL_H
> +
> +#include "hw/sysbus.h"
> +
> +#define TYPE_IOTKIT_SYSCTL "iotkit-sysctl"
> +#define IOTKIT_SYSCTL(obj) OBJECT_CHECK(IoTKitSysCtl, (obj), \
> +                                        TYPE_IOTKIT_SYSCTL)
> +
> +typedef struct IoTKitSysCtl {
> +    /*< private >*/
> +    SysBusDevice parent_obj;
> +
> +    /*< public >*/
> +    MemoryRegion sysinfo_iomem;
> +    MemoryRegion sysctl_iomem;
> +
> +    uint32_t secure_debug;
> +    uint32_t reset_syndrome;
> +    uint32_t reset_mask;
> +    uint32_t gretreg;
> +    uint32_t initsvrtor0;
> +    uint32_t cpuwait;
> +    uint32_t wicctrl;
> +} IoTKitSysCtl;
> +
> +#endif
> diff --git a/hw/misc/iotkit-sysctl.c b/hw/misc/iotkit-sysctl.c
> new file mode 100644
> index 00000000000..9445500be76
> --- /dev/null
> +++ b/hw/misc/iotkit-sysctl.c
> @@ -0,0 +1,324 @@
> +/*
> + * ARM IoTKit system control element
> + *
> + * Copyright (c) 2018 Linaro Limited
> + * Written by Peter Maydell
> + *
> + *  This program is free software; you can redistribute it and/or modify
> + *  it under the terms of the GNU General Public License version 2 or
> + *  (at your option) any later version.
> + */
> +
> +/*
> + * This is a model of the "system control element" which is part of the
> + * Arm IoTKit and documented in
> + * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ecm0601256/index.html
> + * Specifically, it implements the "system information block" and
> + * "system control register" blocks.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu/log.h"
> +#include "trace.h"
> +#include "qapi/error.h"
> +#include "sysemu/sysemu.h"
> +#include "hw/sysbus.h"
> +#include "hw/registerfields.h"
> +#include "hw/misc/iotkit-sysctl.h"
> +
> +/* sysinfo block registers */
> +REG32(SYS_VERSION, 0x0)
> +REG32(SYS_CONFIG, 0x4)

I find it a bit confuse to have the both SYSINFO/SYSCONTROL in the same
"iotkit-sysctl" device. They share the same state but there is no
particular need for it, then you need connect them as 2 different
devices in iotkit_realize but they have the same name "iotkit-sysctl".

Why not declare 2 different TypeInfo? I am probably missing what state
they need to share.

> +
> +/* sysctl block registers */
> +REG32(SECDBGSTAT, 0x0)
> +REG32(SECDBGSET, 0x4)
> +REG32(SECDBGCLR, 0x8)
> +REG32(RESET_SYNDROME, 0x100)
> +REG32(RESET_MASK, 0x104)
> +REG32(SWRESET, 0x108)
> +    FIELD(SWRESET, SWRESETREQ, 9, 1)
> +REG32(GRETREG, 0x10c)
> +REG32(INITSVRTOR0, 0x110)
> +REG32(CPUWAIT, 0x118)
> +REG32(BUSWAIT, 0x11c)
> +REG32(WICCTRL, 0x120)
> +
> +/* PID registers, same offset in both blocks */
> +REG32(PID4, 0xfd0)
> +REG32(PID5, 0xfd4)
> +REG32(PID6, 0xfd8)
> +REG32(PID7, 0xfdc)
> +REG32(PID0, 0xfe0)
> +REG32(PID1, 0xfe4)
> +REG32(PID2, 0xfe8)
> +REG32(PID3, 0xfec)
> +REG32(CID0, 0xff0)
> +REG32(CID1, 0xff4)
> +REG32(CID2, 0xff8)
> +REG32(CID3, 0xffc)
> +
> +/* PID/CID values */
> +static const int sysinfo_id[] = {
> +    0x04, 0x00, 0x00, 0x00, /* PID4..PID7 */
> +    0x58, 0xb8, 0x0b, 0x00, /* PID0..PID3 */
> +    0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */
> +};
> +
> +static const int sysctl_id[] = {
> +    0x04, 0x00, 0x00, 0x00, /* PID4..PID7 */
> +    0x54, 0xb8, 0x0b, 0x00, /* PID0..PID3 */
> +    0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */
> +};
> +
> +static uint64_t iotkit_sysinfo_read(void *opaque, hwaddr offset,
> +                                    unsigned size)
> +{
> +    uint64_t r;
> +
> +    switch (offset) {
> +    case A_SYS_VERSION:
> +        r = 0x41743;
> +        break;
> +

(superfluous newline)

> +    case A_SYS_CONFIG:
> +        r = 0x31;
> +        break;
> +    case A_PID4 ... A_CID3:
> +        r = sysinfo_id[(offset - A_PID4) / 4];
> +        break;
> +    default:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "IoTKit SysInfo read: bad offset %x\n", (int)offset);
> +        r = 0;
> +        break;
> +    }
> +    trace_iotkit_sysinfo_read(offset, r, size);
> +    return r;
> +}
> +
> +static void iotkit_sysinfo_write(void *opaque, hwaddr offset,
> +                                 uint64_t value, unsigned size)
> +{
> +    trace_iotkit_sysinfo_write(offset, value, size);
> +
> +    qemu_log_mask(LOG_GUEST_ERROR,
> +                  "IoTKit SysInfo: write to RO offset 0x%x\n", (int)offset);
> +}
> +
> +static const MemoryRegionOps iotkit_sysinfo_ops = {
> +    .read = iotkit_sysinfo_read,
> +    .write = iotkit_sysinfo_write,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +    /* byte/halfword accesses are just zero-padded on reads and writes */
> +    .impl.min_access_size = 4,
> +    .impl.max_access_size = 4,
> +    .valid.min_access_size = 1,
> +    .valid.max_access_size = 4,
> +};
> +
> +static uint64_t iotkit_sysctl_read(void *opaque, hwaddr offset,
> +                                    unsigned size)
> +{
> +    IoTKitSysCtl *s = IOTKIT_SYSCTL(opaque);
> +    uint64_t r;
> +
> +    switch (offset) {
> +    case A_SECDBGSTAT:
> +        r = s->secure_debug;
> +        break;
> +    case A_RESET_SYNDROME:
> +        r = s->reset_syndrome;
> +        break;
> +    case A_RESET_MASK:
> +        r = s->reset_mask;
> +        break;
> +    case A_GRETREG:
> +        r = s->gretreg;
> +        break;
> +    case A_INITSVRTOR0:
> +        r = s->initsvrtor0;
> +        break;
> +    case A_CPUWAIT:
> +        r = s->cpuwait;
> +        break;
> +    case A_BUSWAIT:
> +        /* In IoTKit BUSWAIT is reserved, R/O, zero */
> +        r = 0;
> +        break;
> +    case A_WICCTRL:
> +        r = s->wicctrl;
> +        break;
> +    case A_PID4 ... A_CID3:
> +        r = sysctl_id[(offset - A_PID4) / 4];
> +        break;
> +    case A_SECDBGSET:
> +    case A_SECDBGCLR:
> +    case A_SWRESET:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "IoTKit SysCtl read: read of WO offset %x\n",
> +                      (int)offset);
> +        r = 0;
> +        break;
> +    default:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "IoTKit SysCtl read: bad offset %x\n", (int)offset);
> +        r = 0;
> +        break;
> +    }
> +    trace_iotkit_sysctl_read(offset, r, size);
> +    return r;
> +}
> +
> +static void iotkit_sysctl_write(void *opaque, hwaddr offset,
> +                                 uint64_t value, unsigned size)
> +{
> +    IoTKitSysCtl *s = IOTKIT_SYSCTL(opaque);
> +
> +    trace_iotkit_sysctl_write(offset, value, size);
> +
> +    /*
> +     * Most of the state here has to do with control of reset and
> +     * similar kinds of power up -- for instance the guest can ask
> +     * what the reason for the last reset was, or forbid reset for
> +     * some causes (like the non-secure watchdog). Most of this is
> +     * not relevant to QEMU, which doesn't really model anything other
> +     * than a full power-on reset.
> +     * We just model the registers as reads-as-written.
> +     */
> +
> +    switch (offset) {
> +    case A_RESET_SYNDROME:
> +        qemu_log_mask(LOG_UNIMP,
> +                      "IoTKit SysCtl RESET_SYNDROME unimplemented\n");

Maybe warn_report() or warn_once() is more appropriate than UNIMP?

> +        s->reset_syndrome = value;
> +        break;
> +    case A_RESET_MASK:
> +        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl RESET_MASK unimplemented\n");

Ditto.

> +        s->reset_mask = value;
> +        break;
> +    case A_GRETREG:
> +        /*
> +         * General retention register, which is only reset by a power-on
> +         * reset. Technically this implementation is complete, since
> +         * QEMU only supports power-on resets...
> +         */
> +        s->gretreg = value;
> +        break;
> +    case A_INITSVRTOR0:
> +        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl INITSVRTOR0 unimplemented\n");
> +        s->initsvrtor0 = value;
> +        break;
> +    case A_CPUWAIT:
> +        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl CPUWAIT unimplemented\n");
> +        s->cpuwait = value;
> +        break;
> +    case A_WICCTRL:
> +        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl WICCTRL unimplemented\n");
> +        s->wicctrl = value;
> +        break;
> +    case A_SECDBGSET:
> +        /* write-1-to-set */
> +        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl SECDBGSET unimplemented\n");
> +        s->secure_debug |= value;
> +        break;
> +    case A_SECDBGCLR:
> +        /* write-1-to-clear */
> +        s->secure_debug &= ~value;
> +        break;
> +    case A_SWRESET:
> +        /* One w/o bit to request a reset; all other bits reserved */
> +        if (value & R_SWRESET_SWRESETREQ_MASK) {
> +            qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
> +        }

Shouldn't this be:

           } else {
               cpu_reset(...);
           }

> +        break;
> +    case A_BUSWAIT:        /* In IoTKit BUSWAIT is reserved, R/O, zero */
> +    case A_SECDBGSTAT:
> +    case A_PID4 ... A_CID3:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "IoTKit SysCtl write: write of RO offset %x\n",
> +                      (int)offset);
> +        break;
> +    default:
> +        qemu_log_mask(LOG_GUEST_ERROR,
> +                      "IoTKit SysCtl write: bad offset %x\n", (int)offset);
> +        break;
> +    }
> +}
> +
> +static const MemoryRegionOps iotkit_sysctl_ops = {
> +    .read = iotkit_sysctl_read,
> +    .write = iotkit_sysctl_write,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +    /* byte/halfword accesses are just zero-padded on reads and writes */
> +    .impl.min_access_size = 4,
> +    .impl.max_access_size = 4,
> +    .valid.min_access_size = 1,
> +    .valid.max_access_size = 4,
> +};
> +
> +static void iotkit_sysctl_reset(DeviceState *dev)
> +{
> +    IoTKitSysCtl *s = IOTKIT_SYSCTL(dev);
> +
> +    trace_iotkit_sysctl_reset();
> +    s->secure_debug = 0;
> +    s->reset_syndrome = 1;
> +    s->reset_mask = 0;
> +    s->gretreg = 0;
> +    s->initsvrtor0 = 0x10000000;

This one could be a property (now now ;) ).

> +    s->cpuwait = 0;
> +    s->wicctrl = 0;
> +}
> +
> +static void iotkit_sysctl_init(Object *obj)
> +{
> +    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
> +    IoTKitSysCtl *s = IOTKIT_SYSCTL(obj);
> +
> +    memory_region_init_io(&s->sysinfo_iomem, obj, &iotkit_sysinfo_ops,
> +                          s, "iotkit-sysinfo", 0x1000);
> +    memory_region_init_io(&s->sysctl_iomem, obj, &iotkit_sysctl_ops,
> +                          s, "iotkit-sysctl", 0x1000);
> +    sysbus_init_mmio(sbd, &s->sysinfo_iomem);
> +    sysbus_init_mmio(sbd, &s->sysctl_iomem);
> +}
> +
> +static const VMStateDescription iotkit_sysctl_vmstate = {
> +    .name = "iotkit-sysctl",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT32(secure_debug, IoTKitSysCtl),
> +        VMSTATE_UINT32(reset_syndrome, IoTKitSysCtl),
> +        VMSTATE_UINT32(reset_mask, IoTKitSysCtl),
> +        VMSTATE_UINT32(gretreg, IoTKitSysCtl),
> +        VMSTATE_UINT32(initsvrtor0, IoTKitSysCtl),
> +        VMSTATE_UINT32(cpuwait, IoTKitSysCtl),
> +        VMSTATE_UINT32(wicctrl, IoTKitSysCtl),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static void iotkit_sysctl_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->vmsd = &iotkit_sysctl_vmstate;
> +    dc->reset = iotkit_sysctl_reset;
> +}
> +
> +static const TypeInfo iotkit_sysctl_info = {
> +    .name = TYPE_IOTKIT_SYSCTL,
> +    .parent = TYPE_SYS_BUS_DEVICE,
> +    .instance_size = sizeof(IoTKitSysCtl),
> +    .instance_init = iotkit_sysctl_init,
> +    .class_init = iotkit_sysctl_class_init,
> +};
> +
> +static void iotkit_sysctl_register_types(void)
> +{
> +    type_register_static(&iotkit_sysctl_info);
> +}
> +
> +type_init(iotkit_sysctl_register_types);
> diff --git a/MAINTAINERS b/MAINTAINERS
> index 7ea39c0176b..96fe011e952 100644
> --- a/MAINTAINERS
> +++ b/MAINTAINERS
> @@ -537,6 +537,8 @@ F: hw/misc/mps2-*.c
>  F: include/hw/misc/mps2-*.h
>  F: hw/arm/iotkit.c
>  F: include/hw/arm/iotkit.h
> +F: hw/misc/iotkit-sysctl.c
> +F: include/hw/misc/iotkit-sysctl.h
>  
>  Musicpal
>  M: Jan Kiszka <jan.kiszka@web.de>
> diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
> index 521c3d459fa..da59b820a4f 100644
> --- a/default-configs/arm-softmmu.mak
> +++ b/default-configs/arm-softmmu.mak
> @@ -114,6 +114,7 @@ CONFIG_TZ_MPC=y
>  CONFIG_TZ_PPC=y
>  CONFIG_IOTKIT=y
>  CONFIG_IOTKIT_SECCTL=y
> +CONFIG_IOTKIT_SYSCTL=y
>  
>  CONFIG_VERSATILE=y
>  CONFIG_VERSATILE_PCI=y
> diff --git a/hw/misc/trace-events b/hw/misc/trace-events
> index c956e1419b7..83ab58c30f5 100644
> --- a/hw/misc/trace-events
> +++ b/hw/misc/trace-events
> @@ -109,3 +109,10 @@ iotkit_secctl_s_write(uint32_t offset, uint64_t data, unsigned size) "IoTKit Sec
>  iotkit_secctl_ns_read(uint32_t offset, uint64_t data, unsigned size) "IoTKit SecCtl NS regs read: offset 0x%x data 0x%" PRIx64 " size %u"
>  iotkit_secctl_ns_write(uint32_t offset, uint64_t data, unsigned size) "IoTKit SecCtl NS regs write: offset 0x%x data 0x%" PRIx64 " size %u"
>  iotkit_secctl_reset(void) "IoTKit SecCtl: reset"
> +
> +# hw/misc/iotkit-sysctl.c
> +iotkit_sysinfo_read(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysInfo read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
> +iotkit_sysinfo_write(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysInfo write: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
> +iotkit_sysctl_read(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysCtl read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
> +iotkit_sysctl_write(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysCtl write: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
> +iotkit_sysctl_reset(void) "IoTKit SysCtl: reset"
>
Peter Maydell Aug. 18, 2018, 10:04 a.m. UTC | #2
On 18 August 2018 at 01:23, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
> Hi Peter,
>
> On 08/09/2018 10:01 AM, Peter Maydell wrote:
>> The Arm IoTKit includes a system control element which
>> provides a block of read-only ID registers and a block
>> of read-write control registers. Implement a minimal
>> version of this.
>>
>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>> ---
>>  hw/misc/Makefile.objs           |   1 +
>>  include/hw/misc/iotkit-sysctl.h |  50 +++++
>>  hw/misc/iotkit-sysctl.c         | 324 ++++++++++++++++++++++++++++++++
>>  MAINTAINERS                     |   2 +
>>  default-configs/arm-softmmu.mak |   1 +
>>  hw/misc/trace-events            |   7 +
>>  6 files changed, 385 insertions(+)
>>  create mode 100644 include/hw/misc/iotkit-sysctl.h
>>  create mode 100644 hw/misc/iotkit-sysctl.c
>>
>> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
>> index 93509008451..dbadb41d57a 100644
>> --- a/hw/misc/Makefile.objs
>> +++ b/hw/misc/Makefile.objs
>> @@ -65,6 +65,7 @@ obj-$(CONFIG_MPS2_SCC) += mps2-scc.o
>>  obj-$(CONFIG_TZ_MPC) += tz-mpc.o
>>  obj-$(CONFIG_TZ_PPC) += tz-ppc.o
>>  obj-$(CONFIG_IOTKIT_SECCTL) += iotkit-secctl.o
>> +obj-$(CONFIG_IOTKIT_SYSCTL) += iotkit-sysctl.o
>>
>>  obj-$(CONFIG_PVPANIC) += pvpanic.o
>>  obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
>> diff --git a/include/hw/misc/iotkit-sysctl.h b/include/hw/misc/iotkit-sysctl.h
>> new file mode 100644
>> index 00000000000..c3b14ccee4c
>> --- /dev/null
>> +++ b/include/hw/misc/iotkit-sysctl.h
>> @@ -0,0 +1,50 @@
>> +/*
>> + * ARM IoTKit system control element
>> + *
>> + * Copyright (c) 2018 Linaro Limited
>> + * Written by Peter Maydell
>> + *
>> + *  This program is free software; you can redistribute it and/or modify
>> + *  it under the terms of the GNU General Public License version 2 or
>> + *  (at your option) any later version.
>> + */
>> +
>> +/*
>> + * This is a model of the "system control element" which is part of the
>> + * Arm IoTKit and documented in
>> + * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ecm0601256/index.html
>> + * Specifically, it implements the "system information block" and
>> + * "system control register" blocks.
>> + *
>> + * QEMU interface:
>> + *  + sysbus MMIO region 0: the system information register bank
>> + *  + sysbus MMIO region 1: the system control register bank
>> + */
>> +
>> +#ifndef HW_MISC_IOTKIT_SYSCTL_H
>> +#define HW_MISC_IOTKIT_SYSCTL_H
>> +
>> +#include "hw/sysbus.h"
>> +
>> +#define TYPE_IOTKIT_SYSCTL "iotkit-sysctl"
>> +#define IOTKIT_SYSCTL(obj) OBJECT_CHECK(IoTKitSysCtl, (obj), \
>> +                                        TYPE_IOTKIT_SYSCTL)
>> +
>> +typedef struct IoTKitSysCtl {
>> +    /*< private >*/
>> +    SysBusDevice parent_obj;
>> +
>> +    /*< public >*/
>> +    MemoryRegion sysinfo_iomem;
>> +    MemoryRegion sysctl_iomem;
>> +
>> +    uint32_t secure_debug;
>> +    uint32_t reset_syndrome;
>> +    uint32_t reset_mask;
>> +    uint32_t gretreg;
>> +    uint32_t initsvrtor0;
>> +    uint32_t cpuwait;
>> +    uint32_t wicctrl;
>> +} IoTKitSysCtl;
>> +
>> +#endif
>> diff --git a/hw/misc/iotkit-sysctl.c b/hw/misc/iotkit-sysctl.c
>> new file mode 100644
>> index 00000000000..9445500be76
>> --- /dev/null
>> +++ b/hw/misc/iotkit-sysctl.c
>> @@ -0,0 +1,324 @@
>> +/*
>> + * ARM IoTKit system control element
>> + *
>> + * Copyright (c) 2018 Linaro Limited
>> + * Written by Peter Maydell
>> + *
>> + *  This program is free software; you can redistribute it and/or modify
>> + *  it under the terms of the GNU General Public License version 2 or
>> + *  (at your option) any later version.
>> + */
>> +
>> +/*
>> + * This is a model of the "system control element" which is part of the
>> + * Arm IoTKit and documented in
>> + * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ecm0601256/index.html
>> + * Specifically, it implements the "system information block" and
>> + * "system control register" blocks.
>> + */
>> +
>> +#include "qemu/osdep.h"
>> +#include "qemu/log.h"
>> +#include "trace.h"
>> +#include "qapi/error.h"
>> +#include "sysemu/sysemu.h"
>> +#include "hw/sysbus.h"
>> +#include "hw/registerfields.h"
>> +#include "hw/misc/iotkit-sysctl.h"
>> +
>> +/* sysinfo block registers */
>> +REG32(SYS_VERSION, 0x0)
>> +REG32(SYS_CONFIG, 0x4)
>
> I find it a bit confuse to have the both SYSINFO/SYSCONTROL in the same
> "iotkit-sysctl" device. They share the same state but there is no
> particular need for it, then you need connect them as 2 different
> devices in iotkit_realize but they have the same name "iotkit-sysctl".
>
> Why not declare 2 different TypeInfo? I am probably missing what state
> they need to share.

You're right, they don't share anything internally. It just
seemed a bit unnecessary to have a device that implements
2 read-only registers and nothing else. It probably is better
to split them up, though.

>> +    /*
>> +     * Most of the state here has to do with control of reset and
>> +     * similar kinds of power up -- for instance the guest can ask
>> +     * what the reason for the last reset was, or forbid reset for
>> +     * some causes (like the non-secure watchdog). Most of this is
>> +     * not relevant to QEMU, which doesn't really model anything other
>> +     * than a full power-on reset.
>> +     * We just model the registers as reads-as-written.
>> +     */
>> +
>> +    switch (offset) {
>> +    case A_RESET_SYNDROME:
>> +        qemu_log_mask(LOG_UNIMP,
>> +                      "IoTKit SysCtl RESET_SYNDROME unimplemented\n");
>
> Maybe warn_report() or warn_once() is more appropriate than UNIMP?

LOG_UNIMP is what we generally use for warning about accesses
to unimplemented registers.


>> +    case A_SWRESET:
>> +        /* One w/o bit to request a reset; all other bits reserved */
>> +        if (value & R_SWRESET_SWRESETREQ_MASK) {
>> +            qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
>> +        }
>
> Shouldn't this be:
>
>            } else {
>                cpu_reset(...);
>            }

Why? The register function is "write 1 to request a system reset".
Writing a zero does nothing.


>> +        break;
>> +    case A_BUSWAIT:        /* In IoTKit BUSWAIT is reserved, R/O, zero */
>> +    case A_SECDBGSTAT:
>> +    case A_PID4 ... A_CID3:
>> +        qemu_log_mask(LOG_GUEST_ERROR,
>> +                      "IoTKit SysCtl write: write of RO offset %x\n",
>> +                      (int)offset);
>> +        break;
>> +    default:
>> +        qemu_log_mask(LOG_GUEST_ERROR,
>> +                      "IoTKit SysCtl write: bad offset %x\n", (int)offset);
>> +        break;
>> +    }
>> +}
>> +
>> +static const MemoryRegionOps iotkit_sysctl_ops = {
>> +    .read = iotkit_sysctl_read,
>> +    .write = iotkit_sysctl_write,
>> +    .endianness = DEVICE_LITTLE_ENDIAN,
>> +    /* byte/halfword accesses are just zero-padded on reads and writes */
>> +    .impl.min_access_size = 4,
>> +    .impl.max_access_size = 4,
>> +    .valid.min_access_size = 1,
>> +    .valid.max_access_size = 4,
>> +};
>> +
>> +static void iotkit_sysctl_reset(DeviceState *dev)
>> +{
>> +    IoTKitSysCtl *s = IOTKIT_SYSCTL(dev);
>> +
>> +    trace_iotkit_sysctl_reset();
>> +    s->secure_debug = 0;
>> +    s->reset_syndrome = 1;
>> +    s->reset_mask = 0;
>> +    s->gretreg = 0;
>> +    s->initsvrtor0 = 0x10000000;
>
> This one could be a property (now now ;) ).

It could be, but given that we don't actually support letting
the guest change the SVRTOR reset value on the CPU for the
next reset I think that would be overkill.

>> +    s->cpuwait = 0;
>> +    s->wicctrl = 0;
>> +}

thanks
-- PMM
Philippe Mathieu-Daudé Aug. 18, 2018, 7:54 p.m. UTC | #3
On 08/18/2018 07:04 AM, Peter Maydell wrote:
> On 18 August 2018 at 01:23, Philippe Mathieu-Daudé <f4bug@amsat.org> wrote:
>> Hi Peter,
>>
>> On 08/09/2018 10:01 AM, Peter Maydell wrote:
>>> The Arm IoTKit includes a system control element which
>>> provides a block of read-only ID registers and a block
>>> of read-write control registers. Implement a minimal
>>> version of this.
>>>
>>> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
>>> ---
>>>  hw/misc/Makefile.objs           |   1 +
>>>  include/hw/misc/iotkit-sysctl.h |  50 +++++
>>>  hw/misc/iotkit-sysctl.c         | 324 ++++++++++++++++++++++++++++++++
>>>  MAINTAINERS                     |   2 +
>>>  default-configs/arm-softmmu.mak |   1 +
>>>  hw/misc/trace-events            |   7 +
>>>  6 files changed, 385 insertions(+)
>>>  create mode 100644 include/hw/misc/iotkit-sysctl.h
>>>  create mode 100644 hw/misc/iotkit-sysctl.c
>>>
>>> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
>>> index 93509008451..dbadb41d57a 100644
>>> --- a/hw/misc/Makefile.objs
>>> +++ b/hw/misc/Makefile.objs
>>> @@ -65,6 +65,7 @@ obj-$(CONFIG_MPS2_SCC) += mps2-scc.o
>>>  obj-$(CONFIG_TZ_MPC) += tz-mpc.o
>>>  obj-$(CONFIG_TZ_PPC) += tz-ppc.o
>>>  obj-$(CONFIG_IOTKIT_SECCTL) += iotkit-secctl.o
>>> +obj-$(CONFIG_IOTKIT_SYSCTL) += iotkit-sysctl.o
>>>
>>>  obj-$(CONFIG_PVPANIC) += pvpanic.o
>>>  obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
>>> diff --git a/include/hw/misc/iotkit-sysctl.h b/include/hw/misc/iotkit-sysctl.h
>>> new file mode 100644
>>> index 00000000000..c3b14ccee4c
>>> --- /dev/null
>>> +++ b/include/hw/misc/iotkit-sysctl.h
>>> @@ -0,0 +1,50 @@
>>> +/*
>>> + * ARM IoTKit system control element
>>> + *
>>> + * Copyright (c) 2018 Linaro Limited
>>> + * Written by Peter Maydell
>>> + *
>>> + *  This program is free software; you can redistribute it and/or modify
>>> + *  it under the terms of the GNU General Public License version 2 or
>>> + *  (at your option) any later version.
>>> + */
>>> +
>>> +/*
>>> + * This is a model of the "system control element" which is part of the
>>> + * Arm IoTKit and documented in
>>> + * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ecm0601256/index.html
>>> + * Specifically, it implements the "system information block" and
>>> + * "system control register" blocks.
>>> + *
>>> + * QEMU interface:
>>> + *  + sysbus MMIO region 0: the system information register bank
>>> + *  + sysbus MMIO region 1: the system control register bank
>>> + */
>>> +
>>> +#ifndef HW_MISC_IOTKIT_SYSCTL_H
>>> +#define HW_MISC_IOTKIT_SYSCTL_H
>>> +
>>> +#include "hw/sysbus.h"
>>> +
>>> +#define TYPE_IOTKIT_SYSCTL "iotkit-sysctl"
>>> +#define IOTKIT_SYSCTL(obj) OBJECT_CHECK(IoTKitSysCtl, (obj), \
>>> +                                        TYPE_IOTKIT_SYSCTL)
>>> +
>>> +typedef struct IoTKitSysCtl {
>>> +    /*< private >*/
>>> +    SysBusDevice parent_obj;
>>> +
>>> +    /*< public >*/
>>> +    MemoryRegion sysinfo_iomem;
>>> +    MemoryRegion sysctl_iomem;
>>> +
>>> +    uint32_t secure_debug;
>>> +    uint32_t reset_syndrome;
>>> +    uint32_t reset_mask;
>>> +    uint32_t gretreg;
>>> +    uint32_t initsvrtor0;
>>> +    uint32_t cpuwait;
>>> +    uint32_t wicctrl;
>>> +} IoTKitSysCtl;
>>> +
>>> +#endif
>>> diff --git a/hw/misc/iotkit-sysctl.c b/hw/misc/iotkit-sysctl.c
>>> new file mode 100644
>>> index 00000000000..9445500be76
>>> --- /dev/null
>>> +++ b/hw/misc/iotkit-sysctl.c
>>> @@ -0,0 +1,324 @@
>>> +/*
>>> + * ARM IoTKit system control element
>>> + *
>>> + * Copyright (c) 2018 Linaro Limited
>>> + * Written by Peter Maydell
>>> + *
>>> + *  This program is free software; you can redistribute it and/or modify
>>> + *  it under the terms of the GNU General Public License version 2 or
>>> + *  (at your option) any later version.
>>> + */
>>> +
>>> +/*
>>> + * This is a model of the "system control element" which is part of the
>>> + * Arm IoTKit and documented in
>>> + * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ecm0601256/index.html
>>> + * Specifically, it implements the "system information block" and
>>> + * "system control register" blocks.
>>> + */
>>> +
>>> +#include "qemu/osdep.h"
>>> +#include "qemu/log.h"
>>> +#include "trace.h"
>>> +#include "qapi/error.h"
>>> +#include "sysemu/sysemu.h"
>>> +#include "hw/sysbus.h"
>>> +#include "hw/registerfields.h"
>>> +#include "hw/misc/iotkit-sysctl.h"
>>> +
>>> +/* sysinfo block registers */
>>> +REG32(SYS_VERSION, 0x0)
>>> +REG32(SYS_CONFIG, 0x4)
>>
>> I find it a bit confuse to have the both SYSINFO/SYSCONTROL in the same
>> "iotkit-sysctl" device. They share the same state but there is no
>> particular need for it, then you need connect them as 2 different
>> devices in iotkit_realize but they have the same name "iotkit-sysctl".
>>
>> Why not declare 2 different TypeInfo? I am probably missing what state
>> they need to share.
> 
> You're right, they don't share anything internally. It just
> seemed a bit unnecessary to have a device that implements
> 2 read-only registers and nothing else. It probably is better
> to split them up, though.

Whichever you prefer is fine by me.

>>> +    /*
>>> +     * Most of the state here has to do with control of reset and
>>> +     * similar kinds of power up -- for instance the guest can ask
>>> +     * what the reason for the last reset was, or forbid reset for
>>> +     * some causes (like the non-secure watchdog). Most of this is
>>> +     * not relevant to QEMU, which doesn't really model anything other
>>> +     * than a full power-on reset.
>>> +     * We just model the registers as reads-as-written.
>>> +     */
>>> +
>>> +    switch (offset) {
>>> +    case A_RESET_SYNDROME:
>>> +        qemu_log_mask(LOG_UNIMP,
>>> +                      "IoTKit SysCtl RESET_SYNDROME unimplemented\n");
>>
>> Maybe warn_report() or warn_once() is more appropriate than UNIMP?
> 
> LOG_UNIMP is what we generally use for warning about accesses
> to unimplemented registers.

Hmm yes, but I understand the warn* API as intended for generic user who
could report to the list if this code is hit, and the LOG_UNIMP for QEMU
developer. Often UNIMP logged registers can be ignored in normal flow,
but for this particular case I wonder if it is safe to silently continue
for generic user not using "-d unimp".

>>> +    case A_SWRESET:
>>> +        /* One w/o bit to request a reset; all other bits reserved */
>>> +        if (value & R_SWRESET_SWRESETREQ_MASK) {
>>> +            qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
>>> +        }
>>
>> Shouldn't this be:
>>
>>            } else {
>>                cpu_reset(...);
>>            }
> 
> Why? The register function is "write 1 to request a system reset".
> Writing a zero does nothing.

Hmm OK, I misinterpreted the datasheet:

"Software Reset Request. Set to HIGH to request a system reset."
I understood as implicit "Set to LOW to request a software reset."

>>> +        break;
>>> +    case A_BUSWAIT:        /* In IoTKit BUSWAIT is reserved, R/O, zero */
>>> +    case A_SECDBGSTAT:
>>> +    case A_PID4 ... A_CID3:
>>> +        qemu_log_mask(LOG_GUEST_ERROR,
>>> +                      "IoTKit SysCtl write: write of RO offset %x\n",
>>> +                      (int)offset);
>>> +        break;
>>> +    default:
>>> +        qemu_log_mask(LOG_GUEST_ERROR,
>>> +                      "IoTKit SysCtl write: bad offset %x\n", (int)offset);
>>> +        break;
>>> +    }
>>> +}
>>> +
>>> +static const MemoryRegionOps iotkit_sysctl_ops = {
>>> +    .read = iotkit_sysctl_read,
>>> +    .write = iotkit_sysctl_write,
>>> +    .endianness = DEVICE_LITTLE_ENDIAN,
>>> +    /* byte/halfword accesses are just zero-padded on reads and writes */
>>> +    .impl.min_access_size = 4,
>>> +    .impl.max_access_size = 4,
>>> +    .valid.min_access_size = 1,
>>> +    .valid.max_access_size = 4,
>>> +};
>>> +
>>> +static void iotkit_sysctl_reset(DeviceState *dev)
>>> +{
>>> +    IoTKitSysCtl *s = IOTKIT_SYSCTL(dev);
>>> +
>>> +    trace_iotkit_sysctl_reset();
>>> +    s->secure_debug = 0;
>>> +    s->reset_syndrome = 1;
>>> +    s->reset_mask = 0;
>>> +    s->gretreg = 0;
>>> +    s->initsvrtor0 = 0x10000000;
>>
>> This one could be a property (now now ;) ).
> 
> It could be, but given that we don't actually support letting
> the guest change the SVRTOR reset value on the CPU for the
> next reset I think that would be overkill.

Sure, not now.

>>> +    s->cpuwait = 0;
>>> +    s->wicctrl = 0;
>>> +}

Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>
diff mbox series

Patch

diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
index 93509008451..dbadb41d57a 100644
--- a/hw/misc/Makefile.objs
+++ b/hw/misc/Makefile.objs
@@ -65,6 +65,7 @@  obj-$(CONFIG_MPS2_SCC) += mps2-scc.o
 obj-$(CONFIG_TZ_MPC) += tz-mpc.o
 obj-$(CONFIG_TZ_PPC) += tz-ppc.o
 obj-$(CONFIG_IOTKIT_SECCTL) += iotkit-secctl.o
+obj-$(CONFIG_IOTKIT_SYSCTL) += iotkit-sysctl.o
 
 obj-$(CONFIG_PVPANIC) += pvpanic.o
 obj-$(CONFIG_HYPERV_TESTDEV) += hyperv_testdev.o
diff --git a/include/hw/misc/iotkit-sysctl.h b/include/hw/misc/iotkit-sysctl.h
new file mode 100644
index 00000000000..c3b14ccee4c
--- /dev/null
+++ b/include/hw/misc/iotkit-sysctl.h
@@ -0,0 +1,50 @@ 
+/*
+ * ARM IoTKit system control element
+ *
+ * Copyright (c) 2018 Linaro Limited
+ * Written by Peter Maydell
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 or
+ *  (at your option) any later version.
+ */
+
+/*
+ * This is a model of the "system control element" which is part of the
+ * Arm IoTKit and documented in
+ * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ecm0601256/index.html
+ * Specifically, it implements the "system information block" and
+ * "system control register" blocks.
+ *
+ * QEMU interface:
+ *  + sysbus MMIO region 0: the system information register bank
+ *  + sysbus MMIO region 1: the system control register bank
+ */
+
+#ifndef HW_MISC_IOTKIT_SYSCTL_H
+#define HW_MISC_IOTKIT_SYSCTL_H
+
+#include "hw/sysbus.h"
+
+#define TYPE_IOTKIT_SYSCTL "iotkit-sysctl"
+#define IOTKIT_SYSCTL(obj) OBJECT_CHECK(IoTKitSysCtl, (obj), \
+                                        TYPE_IOTKIT_SYSCTL)
+
+typedef struct IoTKitSysCtl {
+    /*< private >*/
+    SysBusDevice parent_obj;
+
+    /*< public >*/
+    MemoryRegion sysinfo_iomem;
+    MemoryRegion sysctl_iomem;
+
+    uint32_t secure_debug;
+    uint32_t reset_syndrome;
+    uint32_t reset_mask;
+    uint32_t gretreg;
+    uint32_t initsvrtor0;
+    uint32_t cpuwait;
+    uint32_t wicctrl;
+} IoTKitSysCtl;
+
+#endif
diff --git a/hw/misc/iotkit-sysctl.c b/hw/misc/iotkit-sysctl.c
new file mode 100644
index 00000000000..9445500be76
--- /dev/null
+++ b/hw/misc/iotkit-sysctl.c
@@ -0,0 +1,324 @@ 
+/*
+ * ARM IoTKit system control element
+ *
+ * Copyright (c) 2018 Linaro Limited
+ * Written by Peter Maydell
+ *
+ *  This program is free software; you can redistribute it and/or modify
+ *  it under the terms of the GNU General Public License version 2 or
+ *  (at your option) any later version.
+ */
+
+/*
+ * This is a model of the "system control element" which is part of the
+ * Arm IoTKit and documented in
+ * http://infocenter.arm.com/help/index.jsp?topic=/com.arm.doc.ecm0601256/index.html
+ * Specifically, it implements the "system information block" and
+ * "system control register" blocks.
+ */
+
+#include "qemu/osdep.h"
+#include "qemu/log.h"
+#include "trace.h"
+#include "qapi/error.h"
+#include "sysemu/sysemu.h"
+#include "hw/sysbus.h"
+#include "hw/registerfields.h"
+#include "hw/misc/iotkit-sysctl.h"
+
+/* sysinfo block registers */
+REG32(SYS_VERSION, 0x0)
+REG32(SYS_CONFIG, 0x4)
+
+/* sysctl block registers */
+REG32(SECDBGSTAT, 0x0)
+REG32(SECDBGSET, 0x4)
+REG32(SECDBGCLR, 0x8)
+REG32(RESET_SYNDROME, 0x100)
+REG32(RESET_MASK, 0x104)
+REG32(SWRESET, 0x108)
+    FIELD(SWRESET, SWRESETREQ, 9, 1)
+REG32(GRETREG, 0x10c)
+REG32(INITSVRTOR0, 0x110)
+REG32(CPUWAIT, 0x118)
+REG32(BUSWAIT, 0x11c)
+REG32(WICCTRL, 0x120)
+
+/* PID registers, same offset in both blocks */
+REG32(PID4, 0xfd0)
+REG32(PID5, 0xfd4)
+REG32(PID6, 0xfd8)
+REG32(PID7, 0xfdc)
+REG32(PID0, 0xfe0)
+REG32(PID1, 0xfe4)
+REG32(PID2, 0xfe8)
+REG32(PID3, 0xfec)
+REG32(CID0, 0xff0)
+REG32(CID1, 0xff4)
+REG32(CID2, 0xff8)
+REG32(CID3, 0xffc)
+
+/* PID/CID values */
+static const int sysinfo_id[] = {
+    0x04, 0x00, 0x00, 0x00, /* PID4..PID7 */
+    0x58, 0xb8, 0x0b, 0x00, /* PID0..PID3 */
+    0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */
+};
+
+static const int sysctl_id[] = {
+    0x04, 0x00, 0x00, 0x00, /* PID4..PID7 */
+    0x54, 0xb8, 0x0b, 0x00, /* PID0..PID3 */
+    0x0d, 0xf0, 0x05, 0xb1, /* CID0..CID3 */
+};
+
+static uint64_t iotkit_sysinfo_read(void *opaque, hwaddr offset,
+                                    unsigned size)
+{
+    uint64_t r;
+
+    switch (offset) {
+    case A_SYS_VERSION:
+        r = 0x41743;
+        break;
+
+    case A_SYS_CONFIG:
+        r = 0x31;
+        break;
+    case A_PID4 ... A_CID3:
+        r = sysinfo_id[(offset - A_PID4) / 4];
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "IoTKit SysInfo read: bad offset %x\n", (int)offset);
+        r = 0;
+        break;
+    }
+    trace_iotkit_sysinfo_read(offset, r, size);
+    return r;
+}
+
+static void iotkit_sysinfo_write(void *opaque, hwaddr offset,
+                                 uint64_t value, unsigned size)
+{
+    trace_iotkit_sysinfo_write(offset, value, size);
+
+    qemu_log_mask(LOG_GUEST_ERROR,
+                  "IoTKit SysInfo: write to RO offset 0x%x\n", (int)offset);
+}
+
+static const MemoryRegionOps iotkit_sysinfo_ops = {
+    .read = iotkit_sysinfo_read,
+    .write = iotkit_sysinfo_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    /* byte/halfword accesses are just zero-padded on reads and writes */
+    .impl.min_access_size = 4,
+    .impl.max_access_size = 4,
+    .valid.min_access_size = 1,
+    .valid.max_access_size = 4,
+};
+
+static uint64_t iotkit_sysctl_read(void *opaque, hwaddr offset,
+                                    unsigned size)
+{
+    IoTKitSysCtl *s = IOTKIT_SYSCTL(opaque);
+    uint64_t r;
+
+    switch (offset) {
+    case A_SECDBGSTAT:
+        r = s->secure_debug;
+        break;
+    case A_RESET_SYNDROME:
+        r = s->reset_syndrome;
+        break;
+    case A_RESET_MASK:
+        r = s->reset_mask;
+        break;
+    case A_GRETREG:
+        r = s->gretreg;
+        break;
+    case A_INITSVRTOR0:
+        r = s->initsvrtor0;
+        break;
+    case A_CPUWAIT:
+        r = s->cpuwait;
+        break;
+    case A_BUSWAIT:
+        /* In IoTKit BUSWAIT is reserved, R/O, zero */
+        r = 0;
+        break;
+    case A_WICCTRL:
+        r = s->wicctrl;
+        break;
+    case A_PID4 ... A_CID3:
+        r = sysctl_id[(offset - A_PID4) / 4];
+        break;
+    case A_SECDBGSET:
+    case A_SECDBGCLR:
+    case A_SWRESET:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "IoTKit SysCtl read: read of WO offset %x\n",
+                      (int)offset);
+        r = 0;
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "IoTKit SysCtl read: bad offset %x\n", (int)offset);
+        r = 0;
+        break;
+    }
+    trace_iotkit_sysctl_read(offset, r, size);
+    return r;
+}
+
+static void iotkit_sysctl_write(void *opaque, hwaddr offset,
+                                 uint64_t value, unsigned size)
+{
+    IoTKitSysCtl *s = IOTKIT_SYSCTL(opaque);
+
+    trace_iotkit_sysctl_write(offset, value, size);
+
+    /*
+     * Most of the state here has to do with control of reset and
+     * similar kinds of power up -- for instance the guest can ask
+     * what the reason for the last reset was, or forbid reset for
+     * some causes (like the non-secure watchdog). Most of this is
+     * not relevant to QEMU, which doesn't really model anything other
+     * than a full power-on reset.
+     * We just model the registers as reads-as-written.
+     */
+
+    switch (offset) {
+    case A_RESET_SYNDROME:
+        qemu_log_mask(LOG_UNIMP,
+                      "IoTKit SysCtl RESET_SYNDROME unimplemented\n");
+        s->reset_syndrome = value;
+        break;
+    case A_RESET_MASK:
+        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl RESET_MASK unimplemented\n");
+        s->reset_mask = value;
+        break;
+    case A_GRETREG:
+        /*
+         * General retention register, which is only reset by a power-on
+         * reset. Technically this implementation is complete, since
+         * QEMU only supports power-on resets...
+         */
+        s->gretreg = value;
+        break;
+    case A_INITSVRTOR0:
+        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl INITSVRTOR0 unimplemented\n");
+        s->initsvrtor0 = value;
+        break;
+    case A_CPUWAIT:
+        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl CPUWAIT unimplemented\n");
+        s->cpuwait = value;
+        break;
+    case A_WICCTRL:
+        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl WICCTRL unimplemented\n");
+        s->wicctrl = value;
+        break;
+    case A_SECDBGSET:
+        /* write-1-to-set */
+        qemu_log_mask(LOG_UNIMP, "IoTKit SysCtl SECDBGSET unimplemented\n");
+        s->secure_debug |= value;
+        break;
+    case A_SECDBGCLR:
+        /* write-1-to-clear */
+        s->secure_debug &= ~value;
+        break;
+    case A_SWRESET:
+        /* One w/o bit to request a reset; all other bits reserved */
+        if (value & R_SWRESET_SWRESETREQ_MASK) {
+            qemu_system_reset_request(SHUTDOWN_CAUSE_GUEST_RESET);
+        }
+        break;
+    case A_BUSWAIT:        /* In IoTKit BUSWAIT is reserved, R/O, zero */
+    case A_SECDBGSTAT:
+    case A_PID4 ... A_CID3:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "IoTKit SysCtl write: write of RO offset %x\n",
+                      (int)offset);
+        break;
+    default:
+        qemu_log_mask(LOG_GUEST_ERROR,
+                      "IoTKit SysCtl write: bad offset %x\n", (int)offset);
+        break;
+    }
+}
+
+static const MemoryRegionOps iotkit_sysctl_ops = {
+    .read = iotkit_sysctl_read,
+    .write = iotkit_sysctl_write,
+    .endianness = DEVICE_LITTLE_ENDIAN,
+    /* byte/halfword accesses are just zero-padded on reads and writes */
+    .impl.min_access_size = 4,
+    .impl.max_access_size = 4,
+    .valid.min_access_size = 1,
+    .valid.max_access_size = 4,
+};
+
+static void iotkit_sysctl_reset(DeviceState *dev)
+{
+    IoTKitSysCtl *s = IOTKIT_SYSCTL(dev);
+
+    trace_iotkit_sysctl_reset();
+    s->secure_debug = 0;
+    s->reset_syndrome = 1;
+    s->reset_mask = 0;
+    s->gretreg = 0;
+    s->initsvrtor0 = 0x10000000;
+    s->cpuwait = 0;
+    s->wicctrl = 0;
+}
+
+static void iotkit_sysctl_init(Object *obj)
+{
+    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
+    IoTKitSysCtl *s = IOTKIT_SYSCTL(obj);
+
+    memory_region_init_io(&s->sysinfo_iomem, obj, &iotkit_sysinfo_ops,
+                          s, "iotkit-sysinfo", 0x1000);
+    memory_region_init_io(&s->sysctl_iomem, obj, &iotkit_sysctl_ops,
+                          s, "iotkit-sysctl", 0x1000);
+    sysbus_init_mmio(sbd, &s->sysinfo_iomem);
+    sysbus_init_mmio(sbd, &s->sysctl_iomem);
+}
+
+static const VMStateDescription iotkit_sysctl_vmstate = {
+    .name = "iotkit-sysctl",
+    .version_id = 1,
+    .minimum_version_id = 1,
+    .fields = (VMStateField[]) {
+        VMSTATE_UINT32(secure_debug, IoTKitSysCtl),
+        VMSTATE_UINT32(reset_syndrome, IoTKitSysCtl),
+        VMSTATE_UINT32(reset_mask, IoTKitSysCtl),
+        VMSTATE_UINT32(gretreg, IoTKitSysCtl),
+        VMSTATE_UINT32(initsvrtor0, IoTKitSysCtl),
+        VMSTATE_UINT32(cpuwait, IoTKitSysCtl),
+        VMSTATE_UINT32(wicctrl, IoTKitSysCtl),
+        VMSTATE_END_OF_LIST()
+    }
+};
+
+static void iotkit_sysctl_class_init(ObjectClass *klass, void *data)
+{
+    DeviceClass *dc = DEVICE_CLASS(klass);
+
+    dc->vmsd = &iotkit_sysctl_vmstate;
+    dc->reset = iotkit_sysctl_reset;
+}
+
+static const TypeInfo iotkit_sysctl_info = {
+    .name = TYPE_IOTKIT_SYSCTL,
+    .parent = TYPE_SYS_BUS_DEVICE,
+    .instance_size = sizeof(IoTKitSysCtl),
+    .instance_init = iotkit_sysctl_init,
+    .class_init = iotkit_sysctl_class_init,
+};
+
+static void iotkit_sysctl_register_types(void)
+{
+    type_register_static(&iotkit_sysctl_info);
+}
+
+type_init(iotkit_sysctl_register_types);
diff --git a/MAINTAINERS b/MAINTAINERS
index 7ea39c0176b..96fe011e952 100644
--- a/MAINTAINERS
+++ b/MAINTAINERS
@@ -537,6 +537,8 @@  F: hw/misc/mps2-*.c
 F: include/hw/misc/mps2-*.h
 F: hw/arm/iotkit.c
 F: include/hw/arm/iotkit.h
+F: hw/misc/iotkit-sysctl.c
+F: include/hw/misc/iotkit-sysctl.h
 
 Musicpal
 M: Jan Kiszka <jan.kiszka@web.de>
diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
index 521c3d459fa..da59b820a4f 100644
--- a/default-configs/arm-softmmu.mak
+++ b/default-configs/arm-softmmu.mak
@@ -114,6 +114,7 @@  CONFIG_TZ_MPC=y
 CONFIG_TZ_PPC=y
 CONFIG_IOTKIT=y
 CONFIG_IOTKIT_SECCTL=y
+CONFIG_IOTKIT_SYSCTL=y
 
 CONFIG_VERSATILE=y
 CONFIG_VERSATILE_PCI=y
diff --git a/hw/misc/trace-events b/hw/misc/trace-events
index c956e1419b7..83ab58c30f5 100644
--- a/hw/misc/trace-events
+++ b/hw/misc/trace-events
@@ -109,3 +109,10 @@  iotkit_secctl_s_write(uint32_t offset, uint64_t data, unsigned size) "IoTKit Sec
 iotkit_secctl_ns_read(uint32_t offset, uint64_t data, unsigned size) "IoTKit SecCtl NS regs read: offset 0x%x data 0x%" PRIx64 " size %u"
 iotkit_secctl_ns_write(uint32_t offset, uint64_t data, unsigned size) "IoTKit SecCtl NS regs write: offset 0x%x data 0x%" PRIx64 " size %u"
 iotkit_secctl_reset(void) "IoTKit SecCtl: reset"
+
+# hw/misc/iotkit-sysctl.c
+iotkit_sysinfo_read(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysInfo read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
+iotkit_sysinfo_write(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysInfo write: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
+iotkit_sysctl_read(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysCtl read: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
+iotkit_sysctl_write(uint64_t offset, uint64_t data, unsigned size) "IoTKit SysCtl write: offset 0x%" PRIx64 " data 0x%" PRIx64 " size %u"
+iotkit_sysctl_reset(void) "IoTKit SysCtl: reset"