Re: [PATCH 18/20] nubus: add support for slot IRQs

[Philippe Mathieu-Daudé]

On 9/12/21 9:49 AM, Mark Cave-Ayland wrote:
> Each Nubus slot has an IRQ line that can be used to request service from the
> CPU. Connect the IRQs to the Nubus bridge so that they can be wired up using 
> qdev
> gpios accordingly, and introduce a new nubus_set_irq() function that can be 
> used
> by Nubus devices to control the slot IRQ.
> 
> Signed-off-by: Mark Cave-Ayland <mark.cave-ayland@ilande.co.uk>
> ---
>  hw/nubus/nubus-bridge.c  | 2 ++
>  hw/nubus/nubus-device.c  | 8 ++++++++
>  include/hw/nubus/nubus.h | 6 ++++++
>  3 files changed, 16 insertions(+)
> 
> diff --git a/hw/nubus/nubus-bridge.c b/hw/nubus/nubus-bridge.c
> index 2c7c4ee121..0366d925a9 100644
> --- a/hw/nubus/nubus-bridge.c
> +++ b/hw/nubus/nubus-bridge.c
> @@ -19,6 +19,8 @@ static void nubus_bridge_init(Object *obj)
>      NubusBus *bus = &s->bus;
>  
>      qbus_create_inplace(bus, sizeof(s->bus), TYPE_NUBUS_BUS, DEVICE(s), 
> NULL);
> +
> +    qdev_init_gpio_out(DEVICE(s), bus->irqs, NUBUS_IRQS);
>  }

I'm confused, the IRQs belong to the bus, but you create them
on the bridge device (I know, the bus is not a qdev)...

>  static Property nubus_bridge_properties[] = {
> diff --git a/hw/nubus/nubus-device.c b/hw/nubus/nubus-device.c
> index f316eb7789..67ab281943 100644
> --- a/hw/nubus/nubus-device.c
> +++ b/hw/nubus/nubus-device.c
> @@ -10,12 +10,20 @@
>  
>  #include "qemu/osdep.h"
>  #include "qemu/datadir.h"
> +#include "hw/irq.h"
>  #include "hw/loader.h"
>  #include "hw/nubus/nubus.h"
>  #include "qapi/error.h"
>  #include "qemu/error-report.h"
>  
>  
> +void nubus_set_irq(NubusDevice *nd, int level)
> +{
> +    NubusBus *nubus = NUBUS_BUS(qdev_get_parent_bus(DEVICE(nd)));
> +
> +    qemu_set_irq(nubus->irqs[nd->slot], level);
> +}
> +
>  static void nubus_device_realize(DeviceState *dev, Error **errp)
>  {
>      NubusBus *nubus = NUBUS_BUS(qdev_get_parent_bus(dev));
> diff --git a/include/hw/nubus/nubus.h b/include/hw/nubus/nubus.h
> index 503ebf0c1c..2b9c4c77ac 100644
> --- a/include/hw/nubus/nubus.h
> +++ b/include/hw/nubus/nubus.h
> @@ -24,6 +24,8 @@
>  #define NUBUS_FIRST_SLOT      0x0
>  #define NUBUS_LAST_SLOT       0xf
>  
> +#define NUBUS_IRQS            16
> +
>  #define TYPE_NUBUS_DEVICE "nubus-device"
>  OBJECT_DECLARE_SIMPLE_TYPE(NubusDevice, NUBUS_DEVICE)
>  
> @@ -43,6 +45,8 @@ struct NubusBus {
>      MemoryRegion slot_io;
>  
>      uint32_t slot_available_mask;
> +
> +    qemu_irq irqs[NUBUS_IRQS];
>  };
>  
>  #define NUBUS_DECL_ROM_MAX_SIZE    0xffff
> @@ -58,6 +62,8 @@ struct NubusDevice {
>      MemoryRegion decl_rom;
>  };
>  
> +void nubus_set_irq(NubusDevice *nd, int level);

... then the API only involves a device and a bus, the
bridge is hidden.