RE: [PATCH v2 1/3] target/nios2: Move IIC code into CPU object proper

[Wu, Wentong]

On Monday, November 30, 2020 1:40 AM, Peter Maydell wrote:
> The Nios2 architecture supports two different interrupt controller
> options:
> 
>  * The IIC (Internal Interrupt Controller) is part of the CPU itself;
>    it has 32 IRQ input lines and no NMI support.  Interrupt status is
>    queried and controlled via the CPU's ipending and istatus
>    registers.
> 
>  * The EIC (External Interrupt Controller) interface allows the CPU
>    to connect to an external interrupt controller.  The interface
>    allows the interrupt controller to present a packet of information
>    containing:
>     - handler address
>     - interrupt level
>     - register set
>     - NMI mode
> 
> QEMU does not model an EIC currently.  We do model the IIC, but its
> implementation is split across code in hw/nios2/cpu_pic.c and
> hw/intc/nios2_iic.c.  The code in those two files has no state of its own -- 
> the IIC
> state is in the Nios2CPU state struct.
> 
> Because CPU objects now inherit (indirectly) from TYPE_DEVICE, they can have
> GPIO input lines themselves, so we can implement the IIC directly in the CPU
> object the same way that real hardware does.
> 
> Create named "IRQ" GPIO inputs to the Nios2 CPU object, and make the only
> user of the IIC wire up directly to those instead.
> 
> Note that the old code had an "NMI" concept which was entirely unused and
> also as far as I can see not architecturally correct, since only the EIC has a
> concept of an NMI.
> 
> This fixes a Coverity-reported trivial memory leak of the IRQ array allocated 
> in
> nios2_cpu_pic_init().
> 
> Fixes: Coverity CID 1421916
> Signed-off-by: Peter Maydell <peter.maydell@linaro.org>
> ---
>  target/nios2/cpu.h        |  1 -
>  hw/intc/nios2_iic.c       | 95 ---------------------------------------
>  hw/nios2/10m50_devboard.c | 13 +-----
>  hw/nios2/cpu_pic.c        | 31 -------------
>  target/nios2/cpu.c        | 30 +++++++++++++
>  MAINTAINERS               |  1 -
>  hw/intc/meson.build       |  1 -
>  7 files changed, 32 insertions(+), 140 deletions(-)  delete mode 100644
> hw/intc/nios2_iic.c

Reviewed and tested.