Re: [PATCH 06/14] leon3: replace PROP_PTR with PROP_LINK

[Peter Maydell]

On Fri, 18 Oct 2019 at 16:43, Marc-André Lureau
<address@hidden> wrote:
>
> "set_pil_in" and "set_pil_in" are used to set a callback, but have a
> single user and cannot be modified by the user.
>
> Simplify the code by calling directly into leon3_set_pil_in(), and use
> a "cpu" link property.
>
> Signed-off-by: Marc-André Lureau <address@hidden>
> ---
>  hw/intc/grlib_irqmp.c | 20 ++++++--------------
>  hw/sparc/leon3.c      |  7 +++----
>  target/sparc/cpu.h    |  1 +
>  3 files changed, 10 insertions(+), 18 deletions(-)
>
> diff --git a/hw/intc/grlib_irqmp.c b/hw/intc/grlib_irqmp.c
> index bc78e1a14f..34b7e1b4e1 100644
> --- a/hw/intc/grlib_irqmp.c
> +++ b/hw/intc/grlib_irqmp.c
> @@ -58,10 +58,8 @@ typedef struct IRQMP {
>
>      MemoryRegion iomem;
>
> -    void *set_pil_in;
> -    void *set_pil_in_opaque;
> -
>      IRQMPState *state;
> +    SPARCCPU *cpu;
>  } IRQMP;
>
>  struct IRQMPState {
> @@ -82,7 +80,6 @@ static void grlib_irqmp_check_irqs(IRQMPState *state)
>      uint32_t      pend   = 0;
>      uint32_t      level0 = 0;
>      uint32_t      level1 = 0;
> -    set_pil_in_fn set_pil_in;
>
>      assert(state != NULL);
>      assert(state->parent != NULL);
> @@ -97,13 +94,11 @@ static void grlib_irqmp_check_irqs(IRQMPState *state)
>      trace_grlib_irqmp_check_irqs(state->pending, state->force[0],
>                                   state->mask[0], level1, level0);
>
> -    set_pil_in = (set_pil_in_fn)state->parent->set_pil_in;
> -
>      /* Trigger level1 interrupt first and level0 if there is no level1 */
>      if (level1 != 0) {
> -        set_pil_in(state->parent->set_pil_in_opaque, level1);
> +        leon3_set_pil_in(state->parent->cpu, level1);
>      } else {
> -        set_pil_in(state->parent->set_pil_in_opaque, level0);
> +        leon3_set_pil_in(state->parent->cpu, level0);
>      }
>  }
>
> @@ -348,14 +343,13 @@ static void grlib_irqmp_realize(DeviceState *dev, Error 
> **errp)
>      IRQMP *irqmp = GRLIB_IRQMP(dev);
>
>          /* Check parameters */
> -    if (irqmp->set_pil_in == NULL) {
> -        error_setg(errp, "set_pil_in cannot be NULL.");
> +    if (irqmp->cpu == NULL) {
> +        error_setg(errp, "cpu cannot be NULL.");
>      }
>  }

>  static Property grlib_irqmp_properties[] = {
> -    DEFINE_PROP_PTR("set_pil_in", IRQMP, set_pil_in),
> -    DEFINE_PROP_PTR("set_pil_in_opaque", IRQMP, set_pil_in_opaque),
> +    DEFINE_PROP_LINK("cpu", IRQMP, cpu, TYPE_SPARC_CPU, SPARCCPU *),
>      DEFINE_PROP_END_OF_LIST(),
>  };

This is using ptr properties to define a callback
mechanism where the device says "call the callback
function, passing it an opaque cookie and a
32-bit value". We already have a generic mechanism
for doing that, which is the qemu_irq. So we should
just use that instead of adding a link property between
the interrupt controller and the CPU.

(Bonus further cleanup: the code currently in
leon3_set_pil_in() should probably be part of the
SPARC CPU object itself, as a handler for an inbound
gpio line, as then you could just wire the qemu_irq
from the interrupt controller to the CPU. But you
can leave it as ad-hoc code in leon3.c for now.)

thanks
-- PMM