Re: [PATCH QEMU v2 4/5] ARM: PL061: Add gpiodev support

[Philippe Mathieu-Daudé]

On 4/23/20 11:01 AM, Geert Uytterhoeven wrote:
> Make the PL061 GPIO controller user-creatable, and allow the user to tie
> a newly created instance to a gpiochip on the host.
> 
> To create a new GPIO controller, the QEMU command line must be augmented
> with:
> 
>     -device pl061,host=<gpiochip>
> 
> with <gpiochip> the name or label of the gpiochip on the host.
> 
> Signed-off-by: Geert Uytterhoeven <address@hidden>
> ---
> v2:
>   - New.
> ---
>  hw/gpio/pl061.c | 35 +++++++++++++++++++++++++++++++++++
>  qemu-options.hx |  9 +++++++++
>  2 files changed, 44 insertions(+)
> 
> diff --git a/hw/gpio/pl061.c b/hw/gpio/pl061.c
> index 74ba733a8a5e8ca5..98204f9a586ae8c8 100644
> --- a/hw/gpio/pl061.c
> +++ b/hw/gpio/pl061.c
> @@ -12,11 +12,14 @@
>  #include "hw/arm/fdt.h"
>  #include "hw/gpio/pl061.h"
>  #include "hw/irq.h"
> +#include "hw/qdev-properties.h"
>  #include "hw/sysbus.h"
>  #include "migration/vmstate.h"
> +#include "qapi/error.h"
>  #include "qemu/log.h"
>  #include "qemu/module.h"
>  #include "sysemu/device_tree.h"
> +#include "sysemu/gpiodev.h"
>  
>  //#define DEBUG_PL061 1
>  
> @@ -41,6 +44,9 @@ static const uint8_t pl061_id_luminary[12] =
>  typedef struct PL061State {
>      SysBusDevice parent_obj;
>  
> +#ifdef CONFIG_GPIODEV
> +    char *host;
> +#endif
>      MemoryRegion iomem;
>      uint32_t locked;
>      uint32_t data;
> @@ -370,10 +376,39 @@ static void pl061_init(Object *obj)
>      qdev_init_gpio_out(dev, s->out, 8);

Not related to this patch, but we should replace this 8 magic value by a
proper definition...

>  }
>  
> +#ifdef CONFIG_GPIODEV
> +static Property pl061_properties[] = {
> +    DEFINE_PROP_STRING("host", PL061State, host),
> +    DEFINE_PROP_END_OF_LIST(),
> +};
> +
> +static void pl061_realize(DeviceState *dev, Error **errp)
> +{
> +    PL061State *s = PL061(dev);
> +
> +    if (!dev->opts) {
> +        /* Not created by user */
> +        return;
> +    }
> +
> +    if (!s->host) {
> +        error_setg(errp, "'host' property is required");
> +        return;
> +    }
> +
> +    qemu_gpiodev_add(dev, s->host, 8, errp);
> +}
> +#endif /* CONFIG_GPIODEV */
> +
>  static void pl061_class_init(ObjectClass *klass, void *data)
>  {
>      DeviceClass *dc = DEVICE_CLASS(klass);
>  
> +#ifdef CONFIG_GPIODEV
> +    device_class_set_props(dc, pl061_properties);
> +    dc->realize = pl061_realize;
> +    dc->user_creatable = true;
> +#endif
>      dc->vmsd = &vmstate_pl061;
>      dc->reset = &pl061_reset;
>  }
> diff --git a/qemu-options.hx b/qemu-options.hx
> index 292d4e7c0cef6097..182de7fb63923b38 100644
> --- a/qemu-options.hx
> +++ b/qemu-options.hx
> @@ -875,6 +875,15 @@ SRST
>  ``-device isa-ipmi-bt,bmc=id[,ioport=val][,irq=val]``
>      Like the KCS interface, but defines a BT interface. The default port
>      is 0xe4 and the default interrupt is 5.
> +
> +#ifdef CONFIG_GPIODEV
> +``-device pl061,host=gpiochip``
> +    Add a PL061 GPIO controller, and map its virtual GPIO lines to a GPIO
> +    controller on the host.
> +
> +    ``host=gpiochip``
> +        The name or label of the GPIO controller on the host.
> +#endif
>  ERST
>  
>  DEF("name", HAS_ARG, QEMU_OPTION_name,
> 

Instead of restricting this to the pl061, it would be cleaner you add a
GPIO_PLUGGABLE_INTERFACE (or GPIO_BINDABLE_INTERFACE or better name),
and have TYPE_PL061 implement it.