Re: [PATCH 10/19] hw/timer/bcm2835: Add the BCM2835 SYS_timer

[Philippe Mathieu-Daudé]

On 10/8/19 4:52 PM, Alex Bennée wrote:
> Philippe Mathieu-Daudé <address@hidden> writes:
>
> > Add the 64-bit free running timer. Do not model the COMPARE register
> > (no IRQ generated).
> > This timer is used by U-Boot and recent Linux kernels:
> > https://github.com/u-boot/u-boot/blob/v2019.07/include/configs/rpi.h#L19
> >
> > Datasheet used:
> > https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
> >
> > Signed-off-by: Philippe Mathieu-Daudé <address@hidden>
> > ---
> > Since which kernels? 4.19 seems to use it.
> >
> > 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/timer/Makefile.objs            |   1 +
> >   hw/timer/bcm2835_systmr.c         | 100 ++++++++++++++++++++++++++++++
> >   hw/timer/trace-events             |   4 ++
> >   include/hw/timer/bcm2835_systmr.h |  30 +++++++++
> >   4 files changed, 135 insertions(+)
> >   create mode 100644 hw/timer/bcm2835_systmr.c
> >   create mode 100644 include/hw/timer/bcm2835_systmr.h
> >
> > diff --git a/hw/timer/Makefile.objs b/hw/timer/Makefile.objs
> > index 123d92c969..696cda5905 100644
> > --- a/hw/timer/Makefile.objs
> > +++ b/hw/timer/Makefile.objs
> > @@ -47,3 +47,4 @@ common-obj-$(CONFIG_SUN4V_RTC) += sun4v-rtc.o
> >   common-obj-$(CONFIG_CMSDK_APB_TIMER) += cmsdk-apb-timer.o
> >   common-obj-$(CONFIG_CMSDK_APB_DUALTIMER) += cmsdk-apb-dualtimer.o
> >   common-obj-$(CONFIG_MSF2) += mss-timer.o
> > +common-obj-$(CONFIG_RASPI) += bcm2835_systmr.o
> > diff --git a/hw/timer/bcm2835_systmr.c b/hw/timer/bcm2835_systmr.c
> > new file mode 100644
> > index 0000000000..c4d2b488bd
> > --- /dev/null
> > +++ b/hw/timer/bcm2835_systmr.c
> > @@ -0,0 +1,100 @@
> > +/*
> > + * BCM2835 SYS timer emulation
> > + *
> > + * Copyright (C) 2019 Philippe Mathieu-Daudé <address@hidden>
> > + *
> > + * 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.
> > + *
> > + * Datasheet: BCM2835 ARM Peripherals (C6357-M-1398)
> > + * https://www.raspberrypi.org/app/uploads/2012/02/BCM2835-ARM-Peripherals.pdf
> > + *
> > + * Only the free running 64-bit counter is implemented.
> > + * The 4 COMPARE registers and the interruption are not implemented.
> > + */
> > +
> > +#include "qemu/osdep.h"
> > +#include "qemu/timer.h"
> > +#include "qemu/log.h"
> > +#include "hw/registerfields.h"
> > +#include "hw/timer/bcm2835_systmr.h"
> > +#include "trace.h"
> > +
> > +REG32(CTRL_STATUS,  0x00)
> > +REG32(COUNTER_LOW,  0x04)
> > +REG32(COUNTER_HIGH, 0x08)
> > +REG32(COMPARE0,     0x0c)
> > +REG32(COMPARE1,     0x10)
> > +REG32(COMPARE2,     0x14)
> > +REG32(COMPARE3,     0x18)
> > +
> > +static uint64_t bcm2835_sys_timer_read(void *opaque, hwaddr offset,
> > +                                       unsigned size)
> > +{
> > +    uint64_t r = 0;
> > +
> > +    switch (offset) {
> > +    case A_CTRL_STATUS:
> > +    case A_COMPARE0 ... A_COMPARE3:
>
> Probably worth a LOG_UNIMP in here if we are not going to do it.

Correct :)

> > +        break;
> > +    case A_COUNTER_LOW:
> > +    case A_COUNTER_HIGH:
> > +        /* Free running counter at 1MHz */
> > +        r = qemu_clock_get_us(QEMU_CLOCK_VIRTUAL);
> > +        r >>= 8 * (offset - A_COUNTER_LOW);
> > +        r &= UINT32_MAX;
> > +        break;
> > +    default:
> > +        qemu_log_mask(LOG_GUEST_ERROR, "%s: bad offset 0x%" HWADDR_PRIx "\n",
> > +                      __func__, offset);
> > +        break;
> > +    }
> > +    trace_bcm2835_sys_timer_read(offset, r);
> > +
> > +    return r;
> > +}
> > +
> > +static void bcm2835_sys_timer_write(void *opaque, hwaddr offset,
> > +                                    uint64_t value, unsigned size)
> > +{
> > +    trace_bcm2835_sys_timer_write(offset, value);
> > +
> > +    qemu_log_mask(LOG_UNIMP, "%s: bad offset 0x%" HWADDR_PRIx "\n",
> > +                  __func__, offset);
> > +}
> > +
> > +static const MemoryRegionOps bcm2835_sys_timer_ops = {
> > +    .read = bcm2835_sys_timer_read,
> > +    .write = bcm2835_sys_timer_write,
> > +    .endianness = DEVICE_LITTLE_ENDIAN,
> > +    .impl = {
> > +        .min_access_size = 4,
> > +        .max_access_size = 4,
> > +    },
> > +};
> > +
> > +static void bcm2835_sys_timer_init(Object *obj)
> > +{
> > +    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
> > +    BCM2835SysTimerState *s = BCM2835_SYSTIMER(obj);
> > +
> > +    memory_region_init_io(&s->iomem, obj, &bcm2835_sys_timer_ops,
> > +                          s, "bcm2835-sys-timer", 0x20);
> > +    sysbus_init_mmio(sbd, &s->iomem);
> > +    sysbus_init_irq(sbd, &s->irq);
> > +}
> > +
> > +static const TypeInfo bcm2835_sys_timer_info = {
> > +    .name = TYPE_BCM2835_SYSTIMER,
> > +    .parent = TYPE_SYS_BUS_DEVICE,
> > +    .instance_size = sizeof(BCM2835SysTimerState),
> > +    .instance_init = bcm2835_sys_timer_init,
> > +};
> > +
> > +static void bcm2835_sys_timer_register_types(void)
> > +{
> > +    type_register_static(&bcm2835_sys_timer_info);
> > +}
> > +
> > +type_init(bcm2835_sys_timer_register_types);
> > diff --git a/hw/timer/trace-events b/hw/timer/trace-events
> > index db02a9142c..81967a1a19 100644
> > --- a/hw/timer/trace-events
> > +++ b/hw/timer/trace-events
> > @@ -87,3 +87,7 @@ pl031_read(uint32_t addr, uint32_t value) "addr 0x%08x value 
> > 0x%08x"
> >   pl031_write(uint32_t addr, uint32_t value) "addr 0x%08x value 0x%08x"
> >   pl031_alarm_raised(void) "alarm raised"
> >   pl031_set_alarm(uint32_t ticks) "alarm set for %u ticks"
> > +
> > +# bcm2835_systmr.c
> > +bcm2835_sys_timer_read(uint64_t offset, uint64_t data) "timer read: offset 0x%" PRIx64 
> > " data 0x%" PRIx64
> > +bcm2835_sys_timer_write(uint64_t offset, uint64_t data) "timer write: offset 0x%" PRIx64 
> > " data 0x%" PRIx64
> > diff --git a/include/hw/timer/bcm2835_systmr.h 
> > b/include/hw/timer/bcm2835_systmr.h
> > new file mode 100644
> > index 0000000000..6ac7f8ec5a
> > --- /dev/null
> > +++ b/include/hw/timer/bcm2835_systmr.h
> > @@ -0,0 +1,30 @@
> > +/*
> > + * BCM2835 SYS timer emulation
> > + *
> > + * Copyright (c) 2019 Philippe Mathieu-Daudé <address@hidden>
> > + *
> > + *  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.
> > + */
> > +
> > +#ifndef BCM2835_SYSTIMER_H
> > +#define BCM2835_SYSTIMER_H
> > +
> > +#include "hw/sysbus.h"
> > +#include "hw/irq.h"
> > +
> > +#define TYPE_BCM2835_SYSTIMER "bcm2835-sys-timer"
> > +#define BCM2835_SYSTIMER(obj) \
> > +    OBJECT_CHECK(BCM2835SysTimerState, (obj), TYPE_BCM2835_SYSTIMER)
> > +
> > +typedef struct {
> > +    /*< private >*/
> > +    SysBusDevice parent_obj;
> > +
> > +    /*< public >*/
> > +    MemoryRegion iomem;
> > +    qemu_irq irq;
> > +} BCM2835SysTimerState;
> > +
> > +#endif
>
>
> --
> Alex Bennée