Re: [Qemu-devel] [PATCH arm-devs v4 3/4] hw/timer: Introduce ARM A9 Global Timer.

[Andreas Färber]

Am 02.12.2013 08:36, schrieb Peter Crosthwaite:
> The ARM A9 MPCore has a timer that is global to all CPUs in the mpcore.
> The timer is shared but each CPU has a private independent comparator
> and interrupt.
> 
> Based on version contributed by Francois LEGAL.
> 
> Signed-off-by: François LEGAL <address@hidden>
> [PC changes:
>  * New commit message
>  * Re-implemented as single timer model
>  * Fixed backwards counting issue in polled mode
>  * completed VMSD fields
>  * macroified magic numbers (and headerified reg definitions)
>  * split of as device-model-only patch

"off"

>  * use bitops for 64 bit register access
>  * Fixed auto increment mode to check condition properly
>  * general cleanup (names/style etc).
> ]
> Signed-off-by: Peter Crosthwaite <address@hidden>
> ---
> Changed sinve v3:
> Add seperate CONFIG_A9_GTIMER (PMM review)
> Changed since v2 (PMM - review):
> Refactored for container embedding
> Made frequency scaler consistent with mptimer
> Fixed missing VMSD ref_counter field
> Fixed missing gtb->inc reset
> Changed Memory region names
> Changed since v1:
> Added /*< private >*/ to struct definition.
> Pulled register definitions out into a header (AF review)
> SOB Francois LEGAL with PC changes indicated.
> 
>  default-configs/arm-softmmu.mak |   1 +
>  hw/timer/Makefile.objs          |   1 +
>  hw/timer/a9gtimer.c             | 369 
> ++++++++++++++++++++++++++++++++++++++++
>  include/hw/timer/a9gtimer.h     |  97 +++++++++++
>  4 files changed, 468 insertions(+)
>  create mode 100644 hw/timer/a9gtimer.c
>  create mode 100644 include/hw/timer/a9gtimer.h
> 
> diff --git a/default-configs/arm-softmmu.mak b/default-configs/arm-softmmu.mak
> index a555eef..e48f102 100644
> --- a/default-configs/arm-softmmu.mak
> +++ b/default-configs/arm-softmmu.mak
> @@ -41,6 +41,7 @@ CONFIG_ARM_GIC=y
>  CONFIG_ARM_GIC_KVM=$(CONFIG_KVM)
>  CONFIG_ARM_TIMER=y
>  CONFIG_ARM_MPTIMER=y
> +CONFIG_A9_GTIMER=y
>  CONFIG_PL011=y
>  CONFIG_PL022=y
>  CONFIG_PL031=y
> diff --git a/hw/timer/Makefile.objs b/hw/timer/Makefile.objs
> index eca5905..3ae091c 100644
> --- a/hw/timer/Makefile.objs
> +++ b/hw/timer/Makefile.objs
> @@ -1,5 +1,6 @@
>  common-obj-$(CONFIG_ARM_TIMER) += arm_timer.o
>  common-obj-$(CONFIG_ARM_MPTIMER) += arm_mptimer.o
> +common-obj-$(CONFIG_A9_GTIMER) += a9gtimer.o
>  common-obj-$(CONFIG_CADENCE) += cadence_ttc.o
>  common-obj-$(CONFIG_DS1338) += ds1338.o
>  common-obj-$(CONFIG_HPET) += hpet.o
> diff --git a/hw/timer/a9gtimer.c b/hw/timer/a9gtimer.c
> new file mode 100644
> index 0000000..0f08c67
> --- /dev/null
> +++ b/hw/timer/a9gtimer.c
> @@ -0,0 +1,369 @@
> +/*
> + * Global peripheral timer block for ARM A9MP
> + *
> + * (C) 2013 Xilinx Inc.
> + *
> + * Written by François LEGAL
> + * Written by Peter Crosthwaite <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.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#include "hw/timer/a9gtimer.h"
> +#include "qemu/timer.h"
> +#include "qemu/bitops.h"
> +#include "qemu/log.h"
> +
> +#ifndef A9_GTIMER_ERR_DEBUG
> +#define A9_GTIMER_ERR_DEBUG 0
> +#endif
> +
> +#define DB_PRINT_L(level, ...) do { \
> +    if (A9_GTIMER_ERR_DEBUG > (level)) { \
> +        fprintf(stderr,  ": %s: ", __func__); \
> +        fprintf(stderr, ## __VA_ARGS__); \
> +    } \
> +} while (0);
> +
> +#define DB_PRINT(...) DB_PRINT_L(0, ## __VA_ARGS__)
> +
> +static inline int a9_gtimer_get_current_cpu(A9GTimerState *s)
> +{
> +    if (current_cpu->cpu_index >= s->num_cpu) {
> +        hw_error("arm_mptimer: num-cpu %d but this cpu is %d!\n",

Copy&paste?

> +                 s->num_cpu, current_cpu->cpu_index);
> +    }
> +    return current_cpu->cpu_index;
> +}
> +
> +static inline uint64_t a9_gtimer_get_conv(A9GTimerState *s)
> +{
> +    uint64_t prescale = extract32(s->control, R_CONTROL_PRESCALER_SHIFT,
> +                                  R_CONTROL_PRESCALER_LEN);
> +
> +    return (prescale + 1) * 10;
> +}
> +
> +static A9GTimerUpdate a9_gtimer_get_update(A9GTimerState *s)
> +{
> +    A9GTimerUpdate ret;
> +
> +    ret.now = qemu_clock_get_ns(QEMU_CLOCK_VIRTUAL);
> +    ret.new = s->ref_counter +
> +              (ret.now - s->cpu_ref_time) / a9_gtimer_get_conv(s);
> +    return ret;
> +}
> +
> +static void a9_gtimer_update(A9GTimerState *s, bool sync)
> +{
> +
> +    A9GTimerUpdate update = a9_gtimer_get_update(s);
> +    int i;
> +    int64_t next_cdiff = 0;
> +
> +    for (i = 0; i < s->num_cpu; ++i) {
> +        A9GTimerPerCPU *gtb = &s->per_cpu[i];
> +        int64_t cdiff = 0;
> +
> +        if ((s->control & R_CONTROL_TIMER_ENABLE) &&
> +                (gtb->control & R_CONTROL_COMP_ENABLE)) {
> +            /* R2p0+, where the compare function is >= */
> +            while (gtb->compare < update.new) {
> +                DB_PRINT("Compare event happened for CPU %d\n", i);
> +                gtb->status = 1;
> +                if (gtb->control & R_CONTROL_AUTO_INCREMENT) {
> +                    DB_PRINT("Auto incrementing timer compare by %" PRId32 
> "\n",
> +                             gtb->inc);
> +                    gtb->compare += gtb->inc;
> +                } else {
> +                    break;
> +                }
> +            }
> +            cdiff = (int64_t)gtb->compare - (int64_t)update.new + 1;
> +            if (cdiff > 0 && (cdiff < next_cdiff || !next_cdiff)) {
> +                next_cdiff = cdiff;
> +            }
> +        }
> +
> +        qemu_set_irq(gtb->irq,
> +                     gtb->status && (gtb->control & R_CONTROL_IRQ_ENABLE));
> +    }
> +
> +    timer_del(s->timer);
> +    if (next_cdiff) {
> +        DB_PRINT("scheduling qemu_timer to fire again in %"
> +                 PRIx64 " cycles\n", next_cdiff);
> +        timer_mod(s->timer, update.now + next_cdiff * a9_gtimer_get_conv(s));
> +    }
> +
> +    if (s->control & R_CONTROL_TIMER_ENABLE) {
> +        s->counter = update.new;
> +    }
> +
> +    if (sync) {
> +        s->cpu_ref_time = update.now;
> +        s->ref_counter = s->counter;
> +    }
> +}
> +
> +static void a9_gtimer_update_no_sync(void *opaque)
> +{
> +    A9GTimerState *s = A9_GTIMER(opaque);
> +
> +    return a9_gtimer_update(s, false);
> +}
> +
> +static uint64_t a9_gtimer_read(void *opaque, hwaddr addr, unsigned size)
> +{
> +    A9GTimerPerCPU *gtb = (A9GTimerPerCPU *)opaque;
> +    A9GTimerState *s = gtb->parent;
> +    A9GTimerUpdate update;
> +    uint64_t ret = 0;
> +    int shift = 0;
> +
> +    switch (addr) {
> +    case R_COUNTER_HI:
> +        shift = 32;
> +        /* fallthrough */
> +    case R_COUNTER_LO:
> +        update = a9_gtimer_get_update(s);
> +        ret = extract64(update.new, shift, 32);
> +        break;
> +    case R_CONTROL:
> +        ret = s->control | gtb->control;
> +        break;
> +    case R_INTERRUPT_STATUS:
> +        ret = gtb->status;
> +        break;
> +    case R_COMPARATOR_HI:
> +        shift = 32;
> +        /* fallthrough */
> +    case R_COMPARATOR_LO:
> +        ret = extract64(gtb->compare, shift, 32);
> +        break;
> +    case R_AUTO_INCREMENT:
> +        ret =  gtb->inc;
> +        break;
> +    default:
> +        qemu_log_mask(LOG_GUEST_ERROR, "bad a9gtimer register: %x\n",
> +                      (unsigned)addr);
> +        return 0;
> +    }
> +
> +    DB_PRINT("addr:%#x data:%#08" PRIx64 "\n", (unsigned)addr, ret);
> +    return ret;
> +}
> +
> +static void a9_gtimer_write(void *opaque, hwaddr addr, uint64_t value,
> +                            unsigned size)
> +{
> +    A9GTimerPerCPU *gtb = (A9GTimerPerCPU *)opaque;
> +    A9GTimerState *s = gtb->parent;
> +    int shift = 0;
> +
> +    DB_PRINT("addr:%#x data:%#08" PRIx64 "\n", (unsigned)addr, value);
> +
> +    switch (addr) {
> +    case R_COUNTER_HI:
> +        shift = 32;
> +        /* fallthrough */
> +    case R_COUNTER_LO:
> +        /*
> +         * Keep it simple - ARM docco explicitly says to disable timer before
> +         * modding it, so dont bother trying to do all the difficult on the 
> fly
> +         * timer modifications - (if they even work in real hardware??).
> +         */
> +        if (s->control & R_CONTROL_TIMER_ENABLE) {
> +            qemu_log_mask(LOG_GUEST_ERROR, "Cannot mod running ARM 
> gtimer\n");
> +            return;
> +        }
> +        s->counter = deposit64(s->counter, shift, 32, value);
> +        return;
> +    case R_CONTROL:
> +        a9_gtimer_update(s, (value ^ s->control) & R_CONTROL_NEEDS_SYNC);
> +        gtb->control = value & R_CONTROL_BANKED;
> +        s->control = value & ~R_CONTROL_BANKED;
> +        break;
> +    case R_INTERRUPT_STATUS:
> +        a9_gtimer_update(s, false);
> +        gtb->status &= ~value;
> +        break;
> +    case R_COMPARATOR_HI:
> +        shift = 32;
> +        /* fallthrough */
> +    case R_COMPARATOR_LO:
> +        a9_gtimer_update(s, false);
> +        gtb->compare = deposit64(gtb->compare, shift, 32, value);
> +        break;
> +    case R_AUTO_INCREMENT:
> +        gtb->inc = value;
> +        return;
> +    default:
> +        return;
> +    }
> +
> +    a9_gtimer_update(s, false);
> +}
> +
> +/* Wrapper functions to implement the "read global timer for
> + * the current CPU" memory regions.
> + */
> +static uint64_t a9_gtimer_this_read(void *opaque, hwaddr addr,
> +                                    unsigned size)
> +{
> +    A9GTimerState *s = A9_GTIMER(opaque);
> +    int id = a9_gtimer_get_current_cpu(s);
> +
> +    /* no \n so concatenates with message from read fn */
> +    DB_PRINT("CPU:%d:", id);
> +
> +    return a9_gtimer_read(&s->per_cpu[id], addr, size);
> +}
> +
> +static void a9_gtimer_this_write(void *opaque, hwaddr addr,
> +                                 uint64_t value, unsigned size)
> +{
> +    A9GTimerState *s = A9_GTIMER(opaque);
> +    int id = a9_gtimer_get_current_cpu(s);
> +
> +    /* no \n so concatentates with message from write fn */

"concatenates"

> +    DB_PRINT("CPU:%d:", id);
> +
> +    a9_gtimer_write(&s->per_cpu[id], addr, value, size);
> +}
> +
> +static const MemoryRegionOps a9_gtimer_this_ops = {
> +    .read = a9_gtimer_this_read,
> +    .write = a9_gtimer_this_write,
> +    .valid = {
> +        .min_access_size = 4,
> +        .max_access_size = 4,
> +    },
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +static const MemoryRegionOps a9_gtimer_ops = {
> +    .read = a9_gtimer_read,
> +    .write = a9_gtimer_write,
> +    .valid = {
> +        .min_access_size = 4,
> +        .max_access_size = 4,
> +    },
> +    .endianness = DEVICE_NATIVE_ENDIAN,
> +};
> +
> +static void a9_gtimer_reset(DeviceState *dev)
> +{
> +    A9GTimerState *s = A9_GTIMER(dev);
> +    int i;
> +
> +    s->counter = 0;
> +    s->control = 0;
> +
> +    for (i = 0; i < s->num_cpu; i++) {
> +        A9GTimerPerCPU *gtb = &s->per_cpu[i];
> +
> +        gtb->control = 0;
> +        gtb->status = 0;
> +        gtb->compare = 0;
> +        gtb->inc = 0;
> +    }
> +    a9_gtimer_update(s, false);
> +}
> +
> +static void a9_gtimer_realize(DeviceState *dev, Error **errp)
> +{
> +    A9GTimerState *s = A9_GTIMER(dev);
> +    SysBusDevice *sbd = SYS_BUS_DEVICE(dev);
> +    int i;
> +
> +    if (s->num_cpu < 1 || s->num_cpu > A9_GTIMER_MAX_CPUS) {
> +        error_setg(errp, "%s: num-cpu must be between 1 and %d\n",
> +                   __func__, A9_GTIMER_MAX_CPUS);

return; missing.

> +    }
> +
> +    memory_region_init_io(&s->iomem, OBJECT(dev), &a9_gtimer_this_ops, s,
> +                          "a9gtimer shared", 0x20);
> +    sysbus_init_mmio(sbd, &s->iomem);
> +    s->timer = timer_new_ns(QEMU_CLOCK_VIRTUAL, a9_gtimer_update_no_sync, s);
> +
> +    for (i = 0; i < s->num_cpu; i++) {
> +        A9GTimerPerCPU *gtb = &s->per_cpu[i];
> +
> +        gtb->parent = s;
> +        sysbus_init_irq(sbd, &gtb->irq);
> +        memory_region_init_io(&gtb->iomem, OBJECT(dev), &a9_gtimer_ops, gtb,
> +                              "a9gtimer per cpu", 0x20);
> +        sysbus_init_mmio(sbd, &gtb->iomem);
> +    }
> +}
> +
> +static const VMStateDescription vmstate_a9_gtimer_per_cpu = {
> +    .name = "arm.cortex-a9-global-timer.percpu",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_UINT32(control, A9GTimerPerCPU),
> +        VMSTATE_UINT64(compare, A9GTimerPerCPU),
> +        VMSTATE_UINT32(status, A9GTimerPerCPU),
> +        VMSTATE_UINT32(inc, A9GTimerPerCPU),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static const VMStateDescription vmstate_a9_gtimer = {
> +    .name = "arm.cortex-a9-global-timer",
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_TIMER(timer, A9GTimerState),
> +        VMSTATE_UINT64(counter, A9GTimerState),
> +        VMSTATE_UINT64(ref_counter, A9GTimerState),
> +        VMSTATE_UINT64(cpu_ref_time, A9GTimerState),
> +        VMSTATE_STRUCT_VARRAY_UINT32(per_cpu, A9GTimerState, num_cpu,
> +                                     1, vmstate_a9_gtimer_per_cpu,
> +                                     A9GTimerPerCPU),
> +        VMSTATE_END_OF_LIST()
> +    }
> +};
> +
> +static Property a9_gtimer_properties[] = {
> +    DEFINE_PROP_UINT32("num-cpu", A9GTimerState, num_cpu, 0),
> +    DEFINE_PROP_END_OF_LIST()
> +};
> +
> +static void a9_gtimer_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->realize = a9_gtimer_realize;
> +    dc->vmsd = &vmstate_a9_gtimer;
> +    dc->reset = a9_gtimer_reset;
> +    dc->no_user = 1;

There is a series from Markus waiting on my review that renames and
investigates all uses of this field. Please explain why you are using it
(in form of a comment) or drop it. There's only a numeric property
above, so likely the latter.

On a general note, please be aware that use of HWADDR_PRIx is preferred
over the (unsigned) casts I'm seeing in this patch.

Andreas

> +    dc->props = a9_gtimer_properties;
> +}
> +
> +static const TypeInfo a9_gtimer_info = {
> +    .name          = TYPE_A9_GTIMER,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .instance_size = sizeof(A9GTimerState),
> +    .class_init    = a9_gtimer_class_init,
> +};
> +
> +static void a9_gtimer_register_types(void)
> +{
> +    type_register_static(&a9_gtimer_info);
> +}
> +
> +type_init(a9_gtimer_register_types)
> diff --git a/include/hw/timer/a9gtimer.h b/include/hw/timer/a9gtimer.h
> new file mode 100644
> index 0000000..b88c02a
> --- /dev/null
> +++ b/include/hw/timer/a9gtimer.h
> @@ -0,0 +1,97 @@
> +/*
> + * Global peripheral timer block for ARM A9MP
> + *
> + * (C) 2013 Xilinx Inc.
> + *
> + * Written by François LEGAL
> + * Written by Peter Crosthwaite <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.
> + *
> + * You should have received a copy of the GNU General Public License along
> + * with this program; if not, see <http://www.gnu.org/licenses/>.
> + */
> +
> +#ifndef HW_TIMER_A9_GTIMER_H_H
> +#define HW_TIMER_A9_GTIMER_H_H
> +
> +#include "hw/sysbus.h"
> +
> +#define A9_GTIMER_MAX_CPUS 4
> +
> +#define TYPE_A9_GTIMER "arm.cortex-a9-global-timer"
> +#define A9_GTIMER(obj) OBJECT_CHECK(A9GTimerState, (obj), TYPE_A9_GTIMER)
> +
> +#define R_COUNTER_LO                0x00
> +#define R_COUNTER_HI                0x04
> +
> +#define R_CONTROL                   0x08
> +#define R_CONTROL_TIMER_ENABLE      (1 << 0)
> +#define R_CONTROL_COMP_ENABLE       (1 << 1)
> +#define R_CONTROL_IRQ_ENABLE        (1 << 2)
> +#define R_CONTROL_AUTO_INCREMENT    (1 << 2)
> +#define R_CONTROL_PRESCALER_SHIFT   8
> +#define R_CONTROL_PRESCALER_LEN     8
> +#define R_CONTROL_PRESCALER_MASK    (((1 << R_CONTROL_PRESCALER_LEN) - 1) << 
> \
> +                                     R_CONTROL_PRESCALER_SHIFT)
> +
> +#define R_CONTROL_BANKED            (R_CONTROL_COMP_ENABLE | \
> +                                     R_CONTROL_IRQ_ENABLE | \
> +                                     R_CONTROL_AUTO_INCREMENT)
> +#define R_CONTROL_NEEDS_SYNC        (R_CONTROL_TIMER_ENABLE | \
> +                                     R_CONTROL_PRESCALER_MASK)
> +
> +#define R_INTERRUPT_STATUS          0x0C
> +#define R_COMPARATOR_LO             0x10
> +#define R_COMPARATOR_HI             0x14
> +#define R_AUTO_INCREMENT            0x18
> +
> +typedef struct A9GTimerPerCPU A9GTimerPerCPU;
> +typedef struct A9GTimerState A9GTimerState;
> +
> +struct A9GTimerPerCPU {
> +    A9GTimerState *parent;
> +
> +    uint32_t control; /* only per cpu banked bits valid */
> +    uint64_t compare;
> +    uint32_t status;
> +    uint32_t inc;
> +
> +    MemoryRegion iomem;
> +    qemu_irq irq; /* PPI interrupts */
> +};
> +
> +struct A9GTimerState {
> +    /*< private >*/
> +    SysBusDevice parent_obj;
> +    /*< public >*/
> +
> +    MemoryRegion iomem;
> +    /* static props */
> +    uint32_t num_cpu;
> +
> +    QEMUTimer *timer;
> +
> +    uint64_t counter; /* current timer value */
> +
> +    uint64_t ref_counter;
> +    uint64_t cpu_ref_time; /* the cpu time as of last update of ref_counter 
> */
> +    uint32_t control; /* only non per cpu banked bits valid */
> +
> +    A9GTimerPerCPU per_cpu[A9_GTIMER_MAX_CPUS];
> +};
> +
> +typedef struct A9GTimerUpdate {
> +    uint64_t now;
> +    uint64_t new;
> +} A9GTimerUpdate;
> +
> +#endif /* #ifdef HW_TIMER_A9_GTIMER_H_H */
> 


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