Re: [PATCH] Connecting the SB600's i8259 controller rather in pasemi's pci.c than in pasemi's setup.c.

["Christophe Leroy (CS GROUP)" <chleroy@kernel.org>]

Le 28/07/2026 à 14:50, Christian Zigotzky a écrit :
> On 27/07/26 15:43, Christophe Leroy (CS GROUP) wrote:
>  >
>  > Should be better in arch/powerpc/platforms/pasemi/pasemi.h
>  >
> 
> Hello Christophe,
> 
> Thank you for your answer. I modified the patch today. The Nemo board 
> boots without any problems if I compile the RC5 of kernel 7.2 with this 
> patch.
> 
> Could you please check the following modified patch?

b4 doesn't see it as a patch. Can you resend as a regular patch ?

$ b4 shazam --single-message 
f5ed5a79-4235-31b6-5bd9-c68d1a6b50cf@xenosoft.de
Single-message mode, ignoring any follow-ups
Grabbing thread from 
lore.kernel.org/all/f5ed5a79-4235-31b6-5bd9-c68d1a6b50cf@xenosoft.de/t.mbox.gz
Analyzing 1 messages in the thread
No patches found.

Thanks
Christophe

> 
> Thanks,
> Christian
> 
> ---
> 
> powerpc/pasemi: Move Nemo i8259 initialization to pci.c
> 
> The Nemo board requires the PCIe ports to be initialized before the
> SB600 ISA bridge can be accessed.
> 
> Since pas_pci_init() is now called later during boot, the i8259
> initialization in pas_init_IRQ() happens too early and accesses
> registers that are not yet mapped, preventing the board from booting.
> 
> Move the Nemo-specific i8259 initialization to pas_add_bridge(),
> after the ISA bridge has been discovered.
> 
> Suggested-by: Darren Stevens <darren@stevens-zone.net>
> Tested-by: Christian Zigotzky <chzigotzky@xenosoft.de>
> Signed-off-by: Christian Zigotzky <chzigotzky@xenosoft.de>
> 
> ---
> v2:
> - Move Nemo i8259 initialization out of pas_init_IRQ() and into
>    pas_add_bridge() after the ISA bridge has been discovered.
> - Change nemo_init_IRQ() to no longer depend on the MPIC instance passed
>    from the IRQ setup path.
> - Move the nemo_init_IRQ() declaration to pasemi.h and add a no-op stub
>    for non-Nemo builds.
> - Fix missing prototype warning reported by Christophe Leroy.
> - Fix indentation and clean up the commit message.
> 
> diff -rupN a/arch/powerpc/platforms/pasemi/pasemi.h b/arch/powerpc/ 
> platforms/pasemi/pasemi.h
> --- a/arch/powerpc/platforms/pasemi/pasemi.h    2026-07-26 
> 23:45:48.000000000 +0200
> +++ b/arch/powerpc/platforms/pasemi/pasemi.h    2026-07-28 
> 07:44:31.924168227 +0200
> @@ -7,6 +7,12 @@ extern void pas_pci_init(void);
>   struct pci_dev;
>   extern void pas_pci_dma_dev_setup(struct pci_dev *dev);
> 
> +#ifdef CONFIG_PPC_PASEMI_NEMO
> +extern void __init nemo_init_IRQ(void);
> +#else
> +static inline void __init nemo_init_IRQ(void) { }
> +#endif
> +
>   void __iomem *__init pasemi_pci_getcfgaddr(struct pci_dev *dev, int 
> offset);
> 
>   extern void __init pasemi_map_registers(void);
> diff -rupN a/arch/powerpc/platforms/pasemi/pci.c b/arch/powerpc/ 
> platforms/pasemi/pci.c
> --- a/arch/powerpc/platforms/pasemi/pci.c    2026-07-26 
> 23:45:48.000000000 +0200
> +++ b/arch/powerpc/platforms/pasemi/pci.c    2026-07-28 
> 07:34:37.036634023 +0200
> @@ -265,6 +265,11 @@ static int __init pas_add_bridge(struct
>        */
>       isa_bridge_find_early(hose);
> 
> +    /*
> +     * ISA bridge is now active, add the i8259 cascade (if needed)
> +     */
> +    nemo_init_IRQ();
> +
>       return 0;
>   }
> 
> diff -rupN a/arch/powerpc/platforms/pasemi/setup.c b/arch/powerpc/ 
> platforms/pasemi/setup.c
> --- a/arch/powerpc/platforms/pasemi/setup.c    2026-07-26 
> 23:45:48.000000000 +0200
> +++ b/arch/powerpc/platforms/pasemi/setup.c    2026-07-28 
> 07:54:54.147863161 +0200
> @@ -214,10 +214,12 @@ static void sb600_8259_cascade(struct ir
>       chip->irq_eoi(&desc->irq_data);
>   }
> 
> -static void __init nemo_init_IRQ(struct mpic *mpic)
> +void __init nemo_init_IRQ(void)
>   {
>       struct device_node *np;
>       int gpio_virq;
> +    struct mpic *mpic;
> +
>       /* Connect the SB600's legacy i8259 controller */
>       np = of_find_node_by_path("/pxp@0,e0000000");
>       i8259_init(np, 0);
> @@ -228,14 +230,10 @@ static void __init nemo_init_IRQ(struct
>       irq_set_chained_handler(gpio_virq, sb600_8259_cascade);
>       mpic_unmask_irq(irq_get_irq_data(gpio_virq));
> 
> +    mpic = irq_get_chip_data(gpio_virq);
>       irq_set_default_domain(mpic->irqhost);
>   }
> 
> -#else
> -
> -static inline void nemo_init_IRQ(struct mpic *mpic)
> -{
> -}
>   #endif
> 
>   static __init void pas_init_IRQ(void)
> @@ -297,9 +295,7 @@ static __init void pas_init_IRQ(void)
>           irq_set_irq_type(nmi_virq, IRQ_TYPE_EDGE_RISING);
>           mpic_unmask_irq(irq_get_irq_data(nmi_virq));
>       }
> -
> -    nemo_init_IRQ(mpic);
> -
> +
>       of_node_put(mpic_node);
>       of_node_put(root);
>   }
> 
> 
>