Re: [Qemu-devel] [PATCH v2 1/2] hw/misc/arm_sp810: Create SP810 device

[Aggeler Fabian]

On 06 Aug 2014, at 01:03, Peter Crosthwaite <address@hidden> wrote:

> On Tue, Aug 5, 2014 at 7:32 PM, Fabian Aggeler <address@hidden> wrote:
>> This adds a device model for the PrimeXsys System Controller (SP810)
>> which is present in the Versatile Express motherboards. It is
>> so far read-only but allows to set the SCCTRL register.
>> 
>> Signed-off-by: Fabian Aggeler <address@hidden>
>> ---
>> default-configs/arm-softmmu.mak |  1 +
>> hw/misc/Makefile.objs           |  1 +
>> hw/misc/arm_sp810.c             | 98 
>> +++++++++++++++++++++++++++++++++++++++++
>> include/hw/misc/arm_sp810.h     | 85 +++++++++++++++++++++++++++++++++++
>> 4 files changed, 185 insertions(+)
>> create mode 100644 hw/misc/arm_sp810.c
>> create mode 100644 include/hw/misc/arm_sp810.h
>> 
>> diff --git a/default-configs/arm-softmmu.mak 
>> b/default-configs/arm-softmmu.mak
>> index f3513fa..67ba99a 100644
>> --- a/default-configs/arm-softmmu.mak
>> +++ b/default-configs/arm-softmmu.mak
>> @@ -55,6 +55,7 @@ CONFIG_PL181=y
>> CONFIG_PL190=y
>> CONFIG_PL310=y
>> CONFIG_PL330=y
>> +CONFIG_SP810=y
>> CONFIG_CADENCE=y
>> CONFIG_XGMAC=y
>> CONFIG_EXYNOS4=y
>> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
>> index 979e532..49d023b 100644
>> --- a/hw/misc/Makefile.objs
>> +++ b/hw/misc/Makefile.objs
>> @@ -13,6 +13,7 @@ common-obj-$(CONFIG_PL310) += arm_l2x0.o
>> common-obj-$(CONFIG_INTEGRATOR_DEBUG) += arm_integrator_debug.o
>> common-obj-$(CONFIG_A9SCU) += a9scu.o
>> common-obj-$(CONFIG_ARM11SCU) += arm11scu.o
>> +common-obj-$(CONFIG_SP810) += arm_sp810.o
>> 
>> # PKUnity SoC devices
>> common-obj-$(CONFIG_PUV3) += puv3_pm.o
>> diff --git a/hw/misc/arm_sp810.c b/hw/misc/arm_sp810.c
>> new file mode 100644
>> index 0000000..21eb816
>> --- /dev/null
>> +++ b/hw/misc/arm_sp810.c
>> @@ -0,0 +1,98 @@
>> +/*
>> + * ARM PrimeXsys System Controller (SP810)
>> + *
>> + * Copyright (C) 2014 Fabian Aggeler <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/misc/arm_sp810.h"
>> +
>> +static const VMStateDescription vmstate_arm_sysctl = {
>> +    .name = "arm_sp810",
>> +    .version_id = 1,
>> +    .minimum_version_id = 1,
>> +    .fields = (VMStateField[]) {
>> +        VMSTATE_UINT32(sc_ctrl, arm_sp810_state),
>> +        VMSTATE_END_OF_LIST()
>> +    }
>> +};
>> +
>> +static uint64_t arm_sp810_read(void *opaque, hwaddr offset, unsigned size)
>> +{
>> +    arm_sp810_state *s = opaque;
>> +
>> +    switch (offset) {
>> +    case SCCTRL:
>> +        return s->sc_ctrl;
>> +    default:
>> +        qemu_log_mask(LOG_UNIMP,
>> +                "arm_sp810_read: Register not yet implemented: %s\n",
>> +                HWADDR_PRIx);
>> +        return 0;
>> +    }
>> +}
>> +
>> +static void arm_sp810_write(void *opaque, hwaddr offset,
>> +                            uint64_t val, unsigned size)
>> +{
>> +    switch (offset) {
>> +    default:
>> +        qemu_log_mask(LOG_UNIMP,
>> +                "arm_sp810_write: Register not yet implemented: %s\n",
>> +                HWADDR_PRIx);
>> +        return;
>> +    }
>> +}
>> +
>> +static const MemoryRegionOps arm_sp810_ops = {
>> +    .read = arm_sp810_read,
>> +    .write = arm_sp810_write,
>> +    .endianness = DEVICE_NATIVE_ENDIAN,
>> +};
>> +
>> +static void arm_sp810_init(Object *obj)
>> +{
>> +    arm_sp810_state *s = ARM_SP810(obj);
>> +
>> +    memory_region_init_io(&s->iomem, obj, &arm_sp810_ops, s, "arm-sp810",
>> +                          0x1000);
>> +    sysbus_init_mmio(SYS_BUS_DEVICE(obj), &s->iomem);
>> +}
>> +
>> +static Property arm_sp810_properties[] = {
>> +    DEFINE_PROP_UINT32("sc-ctrl", arm_sp810_state, sc_ctrl, 0x000009),
>> +    DEFINE_PROP_END_OF_LIST(),
>> +};
>> +
> 
> So it looks to me like the SCCTRL contains multiple register fields
> for multiple configurable options. Although i'm having trouble getting
> my head around it as I could not easily find public docco for this
> core (have a link handy?).

Unfortunately not as it seems ARM marked it as obsolete. We found 
the document offline. I could not find it on the web either. 
See also 
http://lists.infradead.org/pipermail/linux-arm-kernel/2011-January/038722.html

Indeed SCCTRL has many configuration bits, not just these 4 configuration 
options. 

> 
> Anyways, the thinking is you should define multiple configurable
> options as invididual QOM properties, rather than have board level
> code init registers. This would mean that you
> 
> DEFINE_PROP_UINT8("timeren0-sel", ...)
> DEFINE_PROP_UINT8("timeren1-sel", ...)
> 
> Have a look at hw/dma/pl330.c for an example of invidividual configs
> getting packed into a single sw visible register.

Okay, I will have a look at pl330 then.

> 
> However these look like software configurable options. Does the
> hardware IP provide the option to configure these with a default or
> must software (probably early stage firmware) configure these to match
> clocking?

These fields are indeed software configurable options. Apparently older versions
of the V2M firmware configured these bits by default to REFCLK, which makes the
SP804 run at 1MHz. On newer boards software has to set it itself to increase 
the timer
to 1MHz, which is what Linux does (see link in my summary).

I didn’t add functionality to switch the speed of the SP804 timer but if you 
could point
me into the right direction I could look into it. Since the speed of the SP804 
for vexpress
boards in QEMU is fixed to 1MHz at the moment I set the bits of SCCTRL 
accordingly
at initialisation. 

What do you suggest? 

> 
>> +static void arm_sp810_class_init(ObjectClass *klass, void *data)
>> +{
>> +    DeviceClass *dc = DEVICE_CLASS(klass);
>> +
>> +    dc->vmsd = &vmstate_arm_sysctl;
>> +    dc->props = arm_sp810_properties;
>> +}
>> +
>> +static const TypeInfo arm_sp810_info = {
>> +    .name          = TYPE_ARM_SP810,
>> +    .parent        = TYPE_SYS_BUS_DEVICE,
>> +    .instance_size = sizeof(arm_sp810_state),
>> +    .instance_init = arm_sp810_init,
>> +    .class_init    = arm_sp810_class_init,
>> +};
>> +
>> +static void arm_sp810_register_types(void)
>> +{
>> +    type_register_static(&arm_sp810_info);
>> +}
>> +
>> +type_init(arm_sp810_register_types)
>> diff --git a/include/hw/misc/arm_sp810.h b/include/hw/misc/arm_sp810.h
>> new file mode 100644
>> index 0000000..33021d5
>> --- /dev/null
>> +++ b/include/hw/misc/arm_sp810.h
>> @@ -0,0 +1,85 @@
>> +/*
>> + * ARM PrimeXsys System Controller (SP810)
>> + *
>> + * Copyright (C) 2014 Fabian Aggeler <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.
>> + *
>> + */
>> +
>> +#ifndef HW_MISC_ARM_SP810H
>> +#define HW_MISC_ARM_SP810H
>> +
>> +#include "hw/hw.h"
>> +#include "hw/sysbus.h"
>> +
>> +#define TYPE_ARM_SP810 "arm_sp810"
>> +#define ARM_SP810(obj) OBJECT_CHECK(arm_sp810_state, (obj), TYPE_ARM_SP810)
>> +
>> +/* Register Offsets */
>> +#define SCCTRL      0x000
>> +#define SCSYSSTAT   0x004
>> +#define SCIMCTRL    0x008
>> +#define SCIMSTAT    0x00C
>> +#define SCXTALCTRL  0x010
>> +#define SCPLLCTRL   0x014
>> +#define SCPLLFCTRL  0x018
>> +#define SCPERCTRL0  0x01C
>> +#define SCPERCTRL1  0x020
>> +#define SCPEREN     0x024
>> +#define SCPERDIS    0x028
>> +#define SCPERCLKEN  0x02C
>> +#define SCPERSTAT   0x030
>> +#define SCSYSID0    0xEE0
>> +#define SCSYSID1    0xEE4
>> +#define SCSYSID2    0xEE8
>> +#define SCSYSID3    0xEEC
>> +#define SCITCR      0xF00
>> +#define SCITIR0     0xF04
>> +#define SCITIR1     0xF08
>> +#define SCITOR      0xF0C
>> +#define SCCNTCTRL   0xF10
>> +#define SCCNTDATA   0xF14
>> +#define SCCNTSTEP   0xF18
>> +#define SCPERIPHID0 0xFE0
>> +#define SCPERIPHID1 0xFE4
>> +#define SCPERIPHID2 0xFE8
>> +#define SCPERIPHID3 0xFEC
>> +#define SCPCELLID0  0xFF0
>> +#define SCPCELLID1  0xFF4
>> +#define SCPCELLID2  0xFF8
>> +#define SCPCELLID3  0xFFC
>> +
>> +/* System Control Register bits */
>> +#define SCCTRL_TIMEREN0SEL (1 << 15)
>> +#define SCCTRL_TIMEREN1SEL (1 << 17)
>> +#define SCCTRL_TIMEREN2SEL (1 << 19)
>> +#define SCCTRL_TIMEREN3SEL (1 << 21)
>> +
>> +static inline DeviceState *sp810_init(hwaddr base, uint32_t scctrl)
>> +{
>> +    DeviceState *sp810;
>> +
>> +    sp810 = qdev_create(NULL, "arm_sp810");
>> +    qdev_prop_set_uint32(sp810, "sc-ctrl", scctrl);
>> +    qdev_init_nofail(sp810);
>> +    sysbus_mmio_map(SYS_BUS_DEVICE(sp810), 0, base);
>> +    return sp810;
>> +}
>> +
> 
> _init helpers are progressively phasing out. Just inline this straight
> into vexpress - its expected for boards code to do its own qdev_foo
> sysbus_foo etc.

I see, I put it there because of your previous comment. It seems I misunderstood
you. Did you mean to only put qdev_create(NULL, "arm_sp810”); into the header? 

Which device is a good example as a reference for new devices in general?

> 
>> +typedef struct {
>> +    SysBusDevice parent_obj;
>> +    MemoryRegion iomem;
>> +
>> +    uint32_t sc_ctrl; /* SCCTRL */
> 
> Redundant comment.

Will remove in the next version.

Thanks,
Fabian

> 
> Regards,
> Peter
> 
>> +} arm_sp810_state;
>> +
>> +#endif
>> --
>> 1.8.3.2