Re: [Minios-devel] [UNIKRAFT PATCHv2 6/8] lib/fdt: Add fdt_get_interrupt helper

[Julien Grall <julien.grall@xxxxxxx>]

Hi,

On 11/03/2019 09:14, Jia He wrote:
> From: Wei Chen <wei.chen@xxxxxxx>
> This helper will be used very frequently for devices to
> get their interrupts.
>
> Jira: ENTOS-860
What is it for?

> Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> Signed-off-by: Jia He <justin.he@xxxxxxx>
> ---
>   lib/fdt/exportsyms.uk    |  1 +
>   lib/fdt/fdt_interrupts.c | 23 +++++++++++++++++++++++
>   lib/fdt/include/libfdt.h | 12 ++++++++++++
>   3 files changed, 36 insertions(+)
>
> diff --git a/lib/fdt/exportsyms.uk b/lib/fdt/exportsyms.uk
> index c893caf..bdef33c 100644
> --- a/lib/fdt/exportsyms.uk
> +++ b/lib/fdt/exportsyms.uk
> @@ -63,3 +63,4 @@ fdt_overlay_apply
>   fdt_getprop_u32_by_offset
>   fdt_interrupt_cells
>   fdt_get_address
> +fdt_get_interrupt
> diff --git a/lib/fdt/fdt_interrupts.c b/lib/fdt/fdt_interrupts.c
> index 45ae963..ed8b716 100644
> --- a/lib/fdt/fdt_interrupts.c
> +++ b/lib/fdt/fdt_interrupts.c
> @@ -87,3 +87,26 @@ int fdt_interrupt_cells(const void *fdt, int offset)
>   
>   	return fdt_get_cells(fdt, "#interrupt-cells", intc_offset);
>   }
> +
> +const void *fdt_get_interrupt(const void *fdt, int nodeoffset,
> +                       int index, int *size)
> +{
> +       int nintr, len, term_size;
> +       const void *regs;
> +
> +       nintr = fdt_interrupt_cells(fdt, nodeoffset);
> +       if (nintr < 0 || nintr >= FDT_MAX_NCELLS)
> +               return NULL;
> +
> +       /*
> +        * Interrupt content must cover the index specific irq information.
> +        */
> +       regs = fdt_getprop(fdt, nodeoffset, "interrupts", &len);
How about #interrupts-extended?

> +       term_size = (int)sizeof(fdt32_t) * nintr;
> +       if (regs == NULL || len < term_size * (index + 1))
> +               return NULL;
> +
> +       *size = nintr;
> +
> +       return regs + term_size * index;
> +}
> diff --git a/lib/fdt/include/libfdt.h b/lib/fdt/include/libfdt.h
> index d43e710..d546b81 100644
> --- a/lib/fdt/include/libfdt.h
> +++ b/lib/fdt/include/libfdt.h
> @@ -1178,6 +1178,18 @@ int fdt_interrupt_cells(const void *fdt, int nodeoffset);
>    */
>   int fdt_get_address(const void *fdt, int nodeoffset, int index,
>                         uint64_t *addr, uint64_t *size);
> +/**
> + * fdt_get_interrupt - retrieve device interrupt of a given index
> + * @fdt: pointer to the device tree blob
> + * @nodeoffset: offset of the node to find the address for
> + * @index: the index of interrupt we want to retrieve
> + * @size: interrupt cell size in fdt32_t
> + *
> + * returns:
> + *      NULL on failed, non-NULL on success
> + */
> +const void *fdt_get_interrupt(const void *fdt, int nodeoffset,
> +                       int index, int *size);
>   
>   /**********************************************************************/
>   /* Write-in-place functions                                           */
Cheers,

--
Julien Grall

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