Re: [Qemu-devel] [PATCH v2 1/5] timer: Initial commit of xlnx-pmu-iomod-pit device

["Philippe Mathieu-Daudé" <f4bug@amsat.org>]

On 02/28/2018 07:31 PM, Alistair Francis wrote:
> Signed-off-by: Alistair Francis <alistair.francis@xilinx.com>
> ---
> V2:
>  - Use UINT32_MAX and uint64_t in xlnx_iomod_pit_ctr_pr()
>  - Name frequency varaible frequency_hz
>  - Shorten R_MAX #define
> 
>  include/hw/timer/xlnx-pmu-iomod-pit.h |  58 ++++++++
>  hw/timer/xlnx-pmu-iomod-pit.c         | 241 ++++++++++++++++++++++++++++++++++
>  hw/timer/Makefile.objs                |   2 +
>  3 files changed, 301 insertions(+)
>  create mode 100644 include/hw/timer/xlnx-pmu-iomod-pit.h
>  create mode 100644 hw/timer/xlnx-pmu-iomod-pit.c
> 
> diff --git a/include/hw/timer/xlnx-pmu-iomod-pit.h b/include/hw/timer/xlnx-pmu-iomod-pit.h
> new file mode 100644
> index 0000000000..75cac6bedd
> --- /dev/null
> +++ b/include/hw/timer/xlnx-pmu-iomod-pit.h
> @@ -0,0 +1,58 @@
> +/*
> + * QEMU model of Xilinx I/O Module PIT
> + *
> + * Copyright (c) 2013 Xilinx Inc
> + * Written by Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/ptimer.h"
> +
> +#define TYPE_XLNX_ZYNQMP_IOMODULE_PIT "xlnx.pmu_iomodule_pit"
> +
> +#define XLNX_ZYNQMP_IOMODULE_PIT(obj) \
> +     OBJECT_CHECK(XlnxPMUPIT, (obj), TYPE_XLNX_ZYNQMP_IOMODULE_PIT)
> +
> +#define XLNX_ZYNQMP_IOMOD_PIT_R_MAX (0x08 + 1)

0x04?

> +
> +typedef struct XlnxPMUPIT {
> +    SysBusDevice parent_obj;
> +    MemoryRegion iomem;
> +
> +    QEMUBH *bh;
> +    ptimer_state *ptimer;
> +
> +    qemu_irq irq;
> +    /* IRQ to pulse out when present timer hits zero */
> +    qemu_irq hit_out;
> +
> +    /* Counter in Pre-Scalar(ps) Mode */
> +    uint32_t ps_counter;
> +    /* ps_mode irq-in to enable/disable pre-scalar */
> +    bool ps_enable;
> +    /* State var to remember hit_in level */
> +    bool ps_level;
> +
> +    uint32_t frequency_hz;
> +
> +    uint32_t regs[XLNX_ZYNQMP_IOMOD_PIT_R_MAX];
> +    RegisterInfo regs_info[XLNX_ZYNQMP_IOMOD_PIT_R_MAX];
> +} XlnxPMUPIT;
> diff --git a/hw/timer/xlnx-pmu-iomod-pit.c b/hw/timer/xlnx-pmu-iomod-pit.c
> new file mode 100644
> index 0000000000..a6bdc5211d
> --- /dev/null
> +++ b/hw/timer/xlnx-pmu-iomod-pit.c
> @@ -0,0 +1,241 @@
> +/*
> + * QEMU model of Xilinx I/O Module PIT
> + *
> + * Copyright (c) 2013 Xilinx Inc
> + * Written by Edgar E. Iglesias <edgar.iglesias@xilinx.com>
> + *
> + * Permission is hereby granted, free of charge, to any person obtaining a copy
> + * of this software and associated documentation files (the "Software"), to deal
> + * in the Software without restriction, including without limitation the rights
> + * to use, copy, modify, merge, publish, distribute, sublicense, and/or sell
> + * copies of the Software, and to permit persons to whom the Software is
> + * furnished to do so, subject to the following conditions:
> + *
> + * The above copyright notice and this permission notice shall be included in
> + * all copies or substantial portions of the Software.
> + *
> + * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND, EXPRESS OR
> + * IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF MERCHANTABILITY,
> + * FITNESS FOR A PARTICULAR PURPOSE AND NONINFRINGEMENT. IN NO EVENT SHALL
> + * THE AUTHORS OR COPYRIGHT HOLDERS BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER
> + * LIABILITY, WHETHER IN AN ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM,
> + * OUT OF OR IN CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN
> + * THE SOFTWARE.
> + */
> +
> +#include "qemu/osdep.h"
> +#include "hw/sysbus.h"
> +#include "hw/ptimer.h"
> +#include "hw/register.h"
> +#include "qemu/main-loop.h"
> +#include "qemu/log.h"
> +#include "qapi/error.h"
> +#include "hw/timer/xlnx-pmu-iomod-pit.h"
> +
> +#ifndef XLNX_ZYNQMP_IOMODULE_PIT_ERR_DEBUG
> +#define XLNX_ZYNQMP_IOMODULE_PIT_ERR_DEBUG 0
> +#endif
> +
> +REG32(PIT_PRELOAD, 0x00)
> +REG32(PIT_COUNTER, 0x04)
> +REG32(PIT_CONTROL, 0x08)
> +    FIELD(PIT_CONTROL, PRELOAD, 1, 1)
> +    FIELD(PIT_CONTROL, EN, 0, 1)
> +
> +static uint64_t xlnx_iomod_pit_ctr_pr(RegisterInfo *reg, uint64_t val)
> +{
> +    XlnxPMUPIT *s = XLNX_ZYNQMP_IOMODULE_PIT(reg->opaque);
> +    uint64_t ret;
> +
> +    if (s->ps_enable) {
> +        ret = s->ps_counter;
> +    } else {
> +        ret = ptimer_get_count(s->ptimer);
> +    }
> +
> +    return ret & UINT32_MAX;
> +}
> +
> +static void xlnx_iomod_pit_control_pw(RegisterInfo *reg, uint64_t val)
> +{
> +    XlnxPMUPIT *s = XLNX_ZYNQMP_IOMODULE_PIT(reg->opaque);
> +
> +    ptimer_stop(s->ptimer);
> +
> +    if (val & R_PIT_CONTROL_EN_MASK) {
> +        if (s->ps_enable) {
> +            /* pre-scalar mode do-Nothing here */
> +            s->ps_counter = s->regs[R_PIT_PRELOAD];
> +        } else {
> +            ptimer_set_limit(s->ptimer, s->regs[R_PIT_PRELOAD], 1);
> +            ptimer_run(s->ptimer, !(val & R_PIT_CONTROL_PRELOAD_MASK));
> +

blank line

> +        }
> +    }
> +}
> +
> +static const RegisterAccessInfo xlnx_iomod_pit_regs_info[] = {
> +    { .name = "PIT_PRELOAD",  .addr = A_PIT_PRELOAD,
> +        .ro = 0xffffffff,

Or UINT32_MAX

> +    },{ .name = "PIT_COUNTER",  .addr = A_PIT_COUNTER,
> +        .ro = 0xffffffff,
> +        .post_read = xlnx_iomod_pit_ctr_pr,
> +    },{ .name = "PIT_CONTROL",  .addr = A_PIT_CONTROL,
> +        .rsvd = 0xfffffffc,

Or        = ~(R_PIT_CONTROL_PRELOAD_MASK | R_PIT_CONTROL_EN_MASK),

and I always forgot this is mostly generated.

> +        .post_write = xlnx_iomod_pit_control_pw,
> +    }
> +};
> +
> +static void xlnx_iomod_pit_timer_hit(void *opaque)
> +{
> +    XlnxPMUPIT *s = XLNX_ZYNQMP_IOMODULE_PIT(opaque);
> +
> +    qemu_irq_pulse(s->irq);
> +
> +    /* hit_out to make another pit move it's counter in pre-scalar mode. */
> +    qemu_irq_pulse(s->hit_out);
> +}
> +
> +static void xlnx_iomod_pit_ps_config(void *opaque, int n, int level)
> +{
> +    XlnxPMUPIT *s = XLNX_ZYNQMP_IOMODULE_PIT(opaque);
> +
> +    s->ps_enable = level;
> +}
> +
> +static void xlnx_iomod_pit_ps_hit_in(void *opaque, int n, int level)
> +{
> +    XlnxPMUPIT *s = XLNX_ZYNQMP_IOMODULE_PIT(opaque);
> +
> +    if (!ARRAY_FIELD_EX32(s->regs, PIT_CONTROL, EN)) {
> +        /* PIT disabled */
> +        return;
> +    }
> +
> +    /* Count only on positive edge */
> +    if (!s->ps_level && level) {
> +        if (s->ps_counter) {
> +            s->ps_counter--;
> +        }
> +        s->ps_level = level;
> +    } else {
> +        /* Not on positive edge */
> +        s->ps_level = level;
> +        return;
> +    }

Inverting this

if (C) {A} else {B return}

as

if (!C) {B return}
A

is a bit easier to read.

> +
> +    /* If timer expires, try to preload or stop */
> +    if (s->ps_counter == 0) {
> +        xlnx_iomod_pit_timer_hit(opaque);
> +
> +        /* Check for pit preload/one-shot mode */
> +        if (ARRAY_FIELD_EX32(s->regs, PIT_CONTROL, PRELOAD)) {
> +            /* Preload Mode, Reload the ps_counter */
> +            s->ps_counter = s->regs[R_PIT_PRELOAD];
> +        } else {
> +            /* One-Shot mode, turn off the timer */
> +            s->regs[R_PIT_CONTROL] &= ~R_PIT_CONTROL_PRELOAD_MASK;
> +        }
> +    }

Ditto, if (!s->ps_counter) return;

Anyway this is fine,
Reviewed-by: Philippe Mathieu-Daudé <f4bug@amsat.org>

> +}
> +
> +static void xlnx_iomod_pit_reset(DeviceState *dev)
> +{
> +    XlnxPMUPIT *s = XLNX_ZYNQMP_IOMODULE_PIT(dev);
> +    unsigned int i;
> +
> +    for (i = 0; i < ARRAY_SIZE(s->regs_info); ++i) {
> +        register_reset(&s->regs_info[i]);
> +    }
> +
> +    s->ps_level = false;
> +}
> +
> +static const MemoryRegionOps xlnx_iomod_pit_ops = {
> +    .read = register_read_memory,
> +    .write = register_write_memory,
> +    .endianness = DEVICE_LITTLE_ENDIAN,
> +    .valid = {
> +        .min_access_size = 4,
> +        .max_access_size = 4,
> +    },
> +};
> +
> +static void xlnx_iomod_pit_realize(DeviceState *dev, Error **errp)
> +{
> +    XlnxPMUPIT *s = XLNX_ZYNQMP_IOMODULE_PIT(dev);
> +
> +    s->bh = qemu_bh_new(xlnx_iomod_pit_timer_hit, s);
> +    s->ptimer = ptimer_init(s->bh, PTIMER_POLICY_DEFAULT);
> +    ptimer_set_freq(s->ptimer, s->frequency_hz);
> +
> +    /* IRQ out to pulse when present timer expires/reloads */
> +    qdev_init_gpio_out_named(dev, &s->hit_out, "ps_hit_out", 1);
> +
> +    /* IRQ in to enable pre-scalar mode. Routed from gpo1 */
> +    qdev_init_gpio_in_named(dev, xlnx_iomod_pit_ps_config, "ps_config", 1);
> +
> +    /* hit_out of neighbouring PIT is received as hit_in */
> +    qdev_init_gpio_in_named(dev, xlnx_iomod_pit_ps_hit_in, "ps_hit_in", 1);
> +}
> +
> +static void xlnx_iomod_pit_init(Object *obj)
> +{
> +    XlnxPMUPIT *s = XLNX_ZYNQMP_IOMODULE_PIT(obj);
> +    SysBusDevice *sbd = SYS_BUS_DEVICE(obj);
> +    RegisterInfoArray *reg_array;
> +
> +    memory_region_init(&s->iomem, obj, TYPE_XLNX_ZYNQMP_IOMODULE_PIT,
> +                       XLNX_ZYNQMP_IOMOD_PIT_R_MAX * 4);
> +    reg_array =
> +        register_init_block32(DEVICE(obj), xlnx_iomod_pit_regs_info,
> +                              ARRAY_SIZE(xlnx_iomod_pit_regs_info),
> +                              s->regs_info, s->regs,
> +                              &xlnx_iomod_pit_ops,
> +                              XLNX_ZYNQMP_IOMODULE_PIT_ERR_DEBUG,
> +                              XLNX_ZYNQMP_IOMOD_PIT_R_MAX * 4);
> +    memory_region_add_subregion(&s->iomem,
> +                                0x0,
> +                                &reg_array->mem);
> +    sysbus_init_mmio(sbd, &s->iomem);
> +    sysbus_init_irq(sbd, &s->irq);
> +}
> +
> +static const VMStateDescription vmstate_xlnx_iomod_pit = {
> +    .name = TYPE_XLNX_ZYNQMP_IOMODULE_PIT,
> +    .version_id = 1,
> +    .minimum_version_id = 1,
> +    .fields = (VMStateField[]) {
> +        VMSTATE_END_OF_LIST(),
> +    }
> +};
> +
> +static Property xlnx_iomod_pit_properties[] = {
> +    DEFINE_PROP_UINT32("frequency", XlnxPMUPIT, frequency_hz, 66000000),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void xlnx_iomod_pit_class_init(ObjectClass *klass, void *data)
> +{
> +    DeviceClass *dc = DEVICE_CLASS(klass);
> +
> +    dc->reset = xlnx_iomod_pit_reset;
> +    dc->realize = xlnx_iomod_pit_realize;
> +    dc->props = xlnx_iomod_pit_properties;
> +    dc->vmsd = &vmstate_xlnx_iomod_pit;
> +}
> +
> +static const TypeInfo xlnx_iomod_pit_info = {
> +    .name          = TYPE_XLNX_ZYNQMP_IOMODULE_PIT,
> +    .parent        = TYPE_SYS_BUS_DEVICE,
> +    .instance_size = sizeof(XlnxPMUPIT),
> +    .class_init    = xlnx_iomod_pit_class_init,
> +    .instance_init = xlnx_iomod_pit_init,
> +};
> +
> +static void xlnx_iomod_pit_register_types(void)
> +{
> +    type_register_static(&xlnx_iomod_pit_info);
> +}
> +
> +type_init(xlnx_iomod_pit_register_types)
> diff --git a/hw/timer/Makefile.objs b/hw/timer/Makefile.objs
> index 8c19eac3b6..805c480cad 100644
> --- a/hw/timer/Makefile.objs
> +++ b/hw/timer/Makefile.objs
> @@ -43,3 +43,5 @@ common-obj-$(CONFIG_ASPEED_SOC) += aspeed_timer.o
>  common-obj-$(CONFIG_SUN4V_RTC) += sun4v-rtc.o
>  common-obj-$(CONFIG_CMSDK_APB_TIMER) += cmsdk-apb-timer.o
>  common-obj-$(CONFIG_MSF2) += mss-timer.o
> +
> +common-obj-$(CONFIG_XLNX_ZYNQMP) += xlnx-pmu-iomod-pit.o
>