Re: [Qemu-devel] [PATCH v3 08/33] Add function to control reset with gpio inputs

[David Gibson <david@gibson.dropbear.id.au>]

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On Mon, Jul 29, 2019 at 04:56:29PM +0200, Damien Hedde wrote:
> It adds the possibility to add 2 gpios to control the warm and cold reset.
> With theses ios, the reset can be maintained during some time.
> Each io is associated with a state to detect level changes.
> 
> Vmstate subsections are also added to the existsing device_reset
> subsection.

This doesn't seem like a thing that should be present on every single
DeviceState.

> 
> Signed-off-by: Damien Hedde <damien.hedde@greensocs.com>
> ---
>  hw/core/qdev-vmstate.c | 15 ++++++++++
>  hw/core/qdev.c         | 65 ++++++++++++++++++++++++++++++++++++++++++
>  include/hw/qdev-core.h | 57 ++++++++++++++++++++++++++++++++++++
>  3 files changed, 137 insertions(+)
> 
> diff --git a/hw/core/qdev-vmstate.c b/hw/core/qdev-vmstate.c
> index 24f8465c61..72f84c6cee 100644
> --- a/hw/core/qdev-vmstate.c
> +++ b/hw/core/qdev-vmstate.c
> @@ -24,10 +24,23 @@ static int device_vmstate_reset_post_load(void *opaque, int version_id)
>  {
>      DeviceState *dev = (DeviceState *) opaque;
>      BusState *bus;
> +    uint32_t io_count = 0;
> +
>      QLIST_FOREACH(bus, &dev->child_bus, sibling) {
>          bus->resetting = dev->resetting;
>          bus->reset_is_cold = dev->reset_is_cold;
>      }
> +
> +    if (dev->cold_reset_input.state) {
> +        io_count += 1;
> +    }
> +    if (dev->warm_reset_input.state) {
> +        io_count += 1;
> +    }
> +    /* ensure resetting count is coherent with io states */
> +    if (dev->resetting < io_count) {
> +        return -1;
> +    }
>      return 0;
>  }
>  
> @@ -40,6 +53,8 @@ const struct VMStateDescription device_vmstate_reset = {
>      .fields = (VMStateField[]) {
>          VMSTATE_UINT32(resetting, DeviceState),
>          VMSTATE_BOOL(reset_is_cold, DeviceState),
> +        VMSTATE_BOOL(cold_reset_input.state, DeviceState),
> +        VMSTATE_BOOL(warm_reset_input.state, DeviceState),
>          VMSTATE_END_OF_LIST()
>      },
>  };
> diff --git a/hw/core/qdev.c b/hw/core/qdev.c
> index 88387d3743..11a4de55ea 100644
> --- a/hw/core/qdev.c
> +++ b/hw/core/qdev.c
> @@ -450,6 +450,67 @@ void qdev_init_gpio_in(DeviceState *dev, qemu_irq_handler handler, int n)
>      qdev_init_gpio_in_named(dev, handler, NULL, n);
>  }
>  
> +static DeviceResetInputState *device_get_reset_input_state(DeviceState *dev,
> +                                                            bool cold)
> +{
> +    return cold ? &dev->cold_reset_input : &dev->warm_reset_input;
> +}
> +
> +static void device_reset_handler(DeviceState *dev, bool cold, bool level)
> +{
> +    DeviceResetInputState *dris = device_get_reset_input_state(dev, cold);
> +
> +    if (dris->type == DEVICE_RESET_ACTIVE_LOW) {
> +        level = !level;
> +    }
> +
> +    if (dris->state == level) {
> +        /* io state has not changed */
> +        return;
> +    }
> +
> +    dris->state = level;
> +
> +    if (level) {
> +        resettable_assert_reset(OBJECT(dev), cold);
> +    } else {
> +        resettable_deassert_reset(OBJECT(dev));
> +    }
> +}
> +
> +static void device_cold_reset_handler(void *opaque, int n, int level)
> +{
> +    device_reset_handler((DeviceState *) opaque, true, level);
> +}
> +
> +static void device_warm_reset_handler(void *opaque, int n, int level)
> +{
> +    device_reset_handler((DeviceState *) opaque, false, level);
> +}
> +
> +void qdev_init_reset_gpio_in_named(DeviceState *dev, const char *name,
> +                                   bool cold, DeviceResetActiveType type)
> +{
> +    DeviceResetInputState *dris = device_get_reset_input_state(dev, cold);
> +    qemu_irq_handler handler;
> +
> +    switch (type) {
> +    case DEVICE_RESET_ACTIVE_LOW:
> +    case DEVICE_RESET_ACTIVE_HIGH:
> +        break;
> +    default:
> +        assert(false);
> +        break;
> +    }
> +
> +    assert(!dris->exists);
> +    dris->exists = true;
> +    dris->type = type;
> +
> +    handler = cold ? device_cold_reset_handler : device_warm_reset_handler;
> +    qdev_init_gpio_in_named(dev, handler, name, 1);
> +}
> +
>  void qdev_init_gpio_out_named(DeviceState *dev, qemu_irq *pins,
>                                const char *name, int n)
>  {
> @@ -1007,6 +1068,10 @@ static void device_initfn(Object *obj)
>      dev->instance_id_alias = -1;
>      dev->realized = false;
>      dev->resetting = 0;
> +    dev->cold_reset_input.exists = false;
> +    dev->cold_reset_input.state = false;
> +    dev->warm_reset_input.exists = false;
> +    dev->warm_reset_input.state = false;
>  
>      object_property_add_bool(obj, "realized",
>                               device_get_realized, device_set_realized, NULL);
> diff --git a/include/hw/qdev-core.h b/include/hw/qdev-core.h
> index 926d4bbcb1..f724ddc8f4 100644
> --- a/include/hw/qdev-core.h
> +++ b/include/hw/qdev-core.h
> @@ -136,6 +136,23 @@ struct NamedGPIOList {
>      QLIST_ENTRY(NamedGPIOList) node;
>  };
>  
> +typedef enum DeviceResetActiveType {
> +    DEVICE_RESET_ACTIVE_LOW,
> +    DEVICE_RESET_ACTIVE_HIGH,
> +} DeviceResetActiveType;
> +
> +/**
> + * DeviceResetInputState:
> + * @exists: tell if io exists
> + * @type: tell whether the io active low or high
> + * @state: true if reset is currently active
> + */
> +typedef struct DeviceResetInputState {
> +    bool exists;
> +    DeviceResetActiveType type;
> +    bool state;
> +} DeviceResetInputState;
> +
>  /**
>   * DeviceState:
>   * @realized: Indicates whether the device has been fully constructed.
> @@ -143,6 +160,8 @@ struct NamedGPIOList {
>   * used to count how many times reset has been initiated on the device.
>   * @reset_is_cold: If the device is under reset, indicates whether it is cold
>   * or warm.
> + * @cold_reset_input: state data for cold reset io
> + * @warm_reset_input: state data for warm reset io
>   *
>   * This structure should not be accessed directly.  We declare it here
>   * so that it can be embedded in individual device state structures.
> @@ -167,6 +186,8 @@ struct DeviceState {
>      uint32_t resetting;
>      bool reset_is_cold;
>      bool reset_hold_needed;
> +    DeviceResetInputState cold_reset_input;
> +    DeviceResetInputState warm_reset_input;
>  };
>  
>  struct DeviceListener {
> @@ -372,6 +393,42 @@ static inline void qdev_init_gpio_in_named(DeviceState *dev,
>  void qdev_pass_gpios(DeviceState *dev, DeviceState *container,
>                       const char *name);
>  
> +/**
> + * qdev_init_reset_gpio_in_named:
> + * Create a gpio controlling the warm or cold reset of the device.
> + *
> + * @cold: specify whether it triggers cold or warm reset
> + * @type: what kind of reset io it is
> + *
> + * Note: the io is considered created in its inactive state. No reset
> + * is started by this function.
> + */
> +void qdev_init_reset_gpio_in_named(DeviceState *dev, const char *name,
> +                                   bool cold, DeviceResetActiveType type);
> +
> +/**
> + * qdev_init_warm_reset_gpio:
> + * Create the input to control the device warm reset.
> + */
> +static inline void qdev_init_warm_reset_gpio(DeviceState *dev,
> +                                             const char *name,
> +                                             DeviceResetActiveType type)
> +{
> +    qdev_init_reset_gpio_in_named(dev, name, false, type);
> +}
> +
> +/**
> + * qdev_init_cold_reset_gpio:
> + * Create the input to control the device cold reset.
> + * It can also be used as a power gate control.
> + */
> +static inline void qdev_init_cold_reset_gpio(DeviceState *dev,
> +                                             const char *name,
> +                                             DeviceResetActiveType type)
> +{
> +    qdev_init_reset_gpio_in_named(dev, name, true, type);
> +}
> +
>  BusState *qdev_get_parent_bus(DeviceState *dev);
>  
>  /*** BUS API. ***/

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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