On Sat, Oct 19, 2019 at 4:47 PM Philippe Mathieu-Daudé <f4...@amsat.org> wrote:
>
> We will soon implement the SYS_timer. This timer is used by Linux
> in the thermal subsystem, so once available, the subsystem will be
> enabled and poll the temperature sensors. We need to provide the
> minimum required to keep Linux booting.
>
> Add a dummy thermal sensor returning ~25°C based on:
> https://github.com/raspberrypi/linux/blob/rpi-5.3.y/drivers/thermal/broadcom/bcm2835_thermal.c
>
> Signed-off-by: Philippe Mathieu-Daudé <f4...@amsat.org>
Reviewed-by: Alistair Francis <alistair.fran...@wdc.com>
Alistair
> ---
> v2:
> - Explicit g_assert_not_reached() with comment (Alex)
> - Add vmstate and reset handler (Peter)
>
> checkpatch warning:
> WARNING: added, moved or deleted file(s), does MAINTAINERS need updating?
> This is OK because the regex are:
>
> F: hw/*/bcm283*
> F: include/hw/*/bcm283*
> ---
> hw/misc/Makefile.objs | 1 +
> hw/misc/bcm2835_thermal.c | 135 ++++++++++++++++++++++++++++++
> include/hw/misc/bcm2835_thermal.h | 27 ++++++
> 3 files changed, 163 insertions(+)
> create mode 100644 hw/misc/bcm2835_thermal.c
> create mode 100644 include/hw/misc/bcm2835_thermal.h
>
> diff --git a/hw/misc/Makefile.objs b/hw/misc/Makefile.objs
> index a150680966..c89f3816a5 100644
> --- a/hw/misc/Makefile.objs
> +++ b/hw/misc/Makefile.objs
> @@ -53,6 +53,7 @@ common-obj-$(CONFIG_OMAP) += omap_tap.o
> common-obj-$(CONFIG_RASPI) += bcm2835_mbox.o
> common-obj-$(CONFIG_RASPI) += bcm2835_property.o
> common-obj-$(CONFIG_RASPI) += bcm2835_rng.o
> +common-obj-$(CONFIG_RASPI) += bcm2835_thermal.o
> common-obj-$(CONFIG_SLAVIO) += slavio_misc.o
> common-obj-$(CONFIG_ZYNQ) += zynq_slcr.o
> common-obj-$(CONFIG_ZYNQ) += zynq-xadc.o
> diff --git a/hw/misc/bcm2835_thermal.c b/hw/misc/bcm2835_thermal.c
> new file mode 100644
> index 0000000000..c6f3b1ad60
> --- /dev/null
> +++ b/hw/misc/bcm2835_thermal.c
> @@ -0,0 +1,135 @@
> +/*
> + * BCM2835 dummy thermal sensor
> + *
> + * Copyright (C) 2019 Philippe Mathieu-Daudé <f4...@amsat.org>
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#include "qemu/osdep.h"
> +#include "qemu/log.h"
> +#include "qapi/error.h"
> +#include "hw/misc/bcm2835_thermal.h"
> +#include "hw/registerfields.h"
> +#include "migration/vmstate.h"
> +
> +REG32(CTL, 0)
> +FIELD(CTL, POWER_DOWN, 0, 1)
> +FIELD(CTL, RESET, 1, 1)
> +FIELD(CTL, BANDGAP_CTRL, 2, 3)
> +FIELD(CTL, INTERRUPT_ENABLE, 5, 1)
> +FIELD(CTL, DIRECT, 6, 1)
> +FIELD(CTL, INTERRUPT_CLEAR, 7, 1)
> +FIELD(CTL, HOLD, 8, 10)
> +FIELD(CTL, RESET_DELAY, 18, 8)
> +FIELD(CTL, REGULATOR_ENABLE, 26, 1)
> +
> +REG32(STAT, 4)
> +FIELD(STAT, DATA, 0, 10)
> +FIELD(STAT, VALID, 10, 1)
> +FIELD(STAT, INTERRUPT, 11, 1)
> +
> +#define THERMAL_OFFSET_C 412
> +#define THERMAL_COEFF (-0.538f)
> +
> +static uint16_t bcm2835_thermal_temp2adc(int temp_C)
> +{
> + return (temp_C - THERMAL_OFFSET_C) / THERMAL_COEFF;
> +}
> +
> +static uint64_t bcm2835_thermal_read(void *opaque, hwaddr addr, unsigned
> size)
> +{
> + Bcm2835ThermalState *s = BCM2835_THERMAL(opaque);
> + uint32_t val = 0;
> +
> + switch (addr) {
> + case A_CTL:
> + val = s->ctl;
> + break;
> + case A_STAT:
> + /* Temperature is constantly 25°C. */
> + val = FIELD_DP32(bcm2835_thermal_temp2adc(25), STAT, VALID, true);
> + break;
> + default:
> + /* MemoryRegionOps are aligned, so this can not happen. */
> + g_assert_not_reached();
> + }
> + return val;
> +}
> +
> +static void bcm2835_thermal_write(void *opaque, hwaddr addr,
> + uint64_t value, unsigned size)
> +{
> + Bcm2835ThermalState *s = BCM2835_THERMAL(opaque);
> +
> + switch (addr) {
> + case A_CTL:
> + s->ctl = value;
> + break;
> + case A_STAT:
> + qemu_log_mask(LOG_GUEST_ERROR, "%s: write 0x%" PRIx64
> + " to 0x%" HWADDR_PRIx "\n",
> + __func__, value, addr);
> + break;
> + default:
> + /* MemoryRegionOps are aligned, so this can not happen. */
> + g_assert_not_reached();
> + }
> +}
> +
> +static const MemoryRegionOps bcm2835_thermal_ops = {
> + .read = bcm2835_thermal_read,
> + .write = bcm2835_thermal_write,
> + .impl.max_access_size = 4,
> + .valid.min_access_size = 4,
> + .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +static void bcm2835_thermal_reset(DeviceState *dev)
> +{
> + Bcm2835ThermalState *s = BCM2835_THERMAL(dev);
> +
> + s->ctl = 0;
> +}
> +
> +static void bcm2835_thermal_realize(DeviceState *dev, Error **errp)
> +{
> + Bcm2835ThermalState *s = BCM2835_THERMAL(dev);
> +
> + memory_region_init_io(&s->iomem, OBJECT(s), &bcm2835_thermal_ops,
> + s, TYPE_BCM2835_THERMAL, 8);
> + sysbus_init_mmio(SYS_BUS_DEVICE(s), &s->iomem);
> +}
> +
> +static const VMStateDescription bcm2835_thermal_vmstate = {
> + .name = "bcm2835_thermal",
> + .version_id = 1,
> + .minimum_version_id = 1,
> + .fields = (VMStateField[]) {
> + VMSTATE_UINT32(ctl, Bcm2835ThermalState),
> + VMSTATE_END_OF_LIST()
> + }
> +};
> +
> +static void bcm2835_thermal_class_init(ObjectClass *klass, void *data)
> +{
> + DeviceClass *dc = DEVICE_CLASS(klass);
> +
> + dc->realize = bcm2835_thermal_realize;
> + dc->reset = bcm2835_thermal_reset;
> + dc->vmsd = &bcm2835_thermal_vmstate;
> +}
> +
> +static const TypeInfo bcm2835_thermal_info = {
> + .name = TYPE_BCM2835_THERMAL,
> + .parent = TYPE_SYS_BUS_DEVICE,
> + .instance_size = sizeof(Bcm2835ThermalState),
> + .class_init = bcm2835_thermal_class_init,
> +};
> +
> +static void bcm2835_thermal_register_types(void)
> +{
> + type_register_static(&bcm2835_thermal_info);
> +}
> +
> +type_init(bcm2835_thermal_register_types)
> diff --git a/include/hw/misc/bcm2835_thermal.h
> b/include/hw/misc/bcm2835_thermal.h
> new file mode 100644
> index 0000000000..c3651b27ec
> --- /dev/null
> +++ b/include/hw/misc/bcm2835_thermal.h
> @@ -0,0 +1,27 @@
> +/*
> + * BCM2835 dummy thermal sensor
> + *
> + * Copyright (C) 2019 Philippe Mathieu-Daudé <f4...@amsat.org>
> + *
> + * SPDX-License-Identifier: GPL-2.0-or-later
> + */
> +
> +#ifndef HW_MISC_BCM2835_THERMAL_H
> +#define HW_MISC_BCM2835_THERMAL_H
> +
> +#include "hw/sysbus.h"
> +
> +#define TYPE_BCM2835_THERMAL "bcm2835-thermal"
> +
> +#define BCM2835_THERMAL(obj) \
> + OBJECT_CHECK(Bcm2835ThermalState, (obj), TYPE_BCM2835_THERMAL)
> +
> +typedef struct {
> + /*< private >*/
> + SysBusDevice parent_obj;
> + /*< public >*/
> + MemoryRegion iomem;
> + uint32_t ctl;
> +} Bcm2835ThermalState;
> +
> +#endif
> --
> 2.21.0
>
>
