Re: [Minios-devel] [UNIKRAFT PATCHv4 3/9] plat/common: Introduce fdt_interrupt_cells helper to parse irq

[Sharan Santhanam <sharan.santhanam@xxxxxxxxx>]

Hello Jia He,

This patch seems fine.

Reviewed-by: Sharan Santhanam <sharan.santhanam@xxxxxxxxx>

Thanks & Regards
Sharan

On 3/27/19 3:34 AM, Jia He wrote:
> From: Wei Chen <wei.chen@xxxxxxx>
>
> From: Wei Chen <wei.chen@xxxxxxx>
> This helper retrieves the number of cells by scan "#interrupt-cells"
> property of fdt.
> We will use this helper to parse IRQ number for devices, like
> timers and UARTs.
>
> Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> Signed-off-by: Jia He <justin.he@xxxxxxx>
> ---
>   plat/common/fdt.c         | 42 +++++++++++++++++++++++++++++++++++++++
>   plat/common/include/fdt.h | 20 +++++++++++++++++++
>   2 files changed, 62 insertions(+)
>
> diff --git a/plat/common/fdt.c b/plat/common/fdt.c
> index 47f7c74..916a263 100644
> --- a/plat/common/fdt.c
> +++ b/plat/common/fdt.c
> @@ -57,3 +57,45 @@ int fdt_getprop_u32_by_offset(const void *fdt, int offset,
>   
>   	return -FDT_ERR_NOTFOUND;
>   }
> +
> +static int fdt_find_irq_parent_offset(const void *fdt, int offset)
> +{
> +       uint32_t irq_parent;
> +
> +       do {
> +               /* Find the interrupt-parent phandle */
> +               if (!fdt_getprop_u32_by_offset(fdt, offset,
> +                               "interrupt-parent", &irq_parent))
> +                       break;
> +
> +               /* Try to find in parent node */
> +               offset = fdt_parent_offset(fdt, offset);
> +       } while (offset >= 0);
> +
> +       if (offset < 0)
> +               return offset;
> +
> +       /* Get interrupt parent node by phandle */
> +       return fdt_node_offset_by_phandle(fdt, irq_parent);
> +}
> +
> +int fdt_interrupt_cells(const void *fdt, int offset)
> +{
> +       int intc_offset;
> +       int val;
> +       int ret;
> +
> +       intc_offset = fdt_find_irq_parent_offset(fdt, offset);
> +       if (intc_offset < 0)
> +               return intc_offset;
> +
> +       ret = fdt_getprop_u32_by_offset(fdt, intc_offset, "#interrupt-cells",
> +                                       (uint32_t *)&val);
> +       if (ret < 0)
> +               return ret;
> +
> +       if ((val <= 0) || (val > FDT_MAX_NCELLS))
> +               return -FDT_ERR_BADNCELLS;
> +
> +       return val;
> +}
> diff --git a/plat/common/include/fdt.h b/plat/common/include/fdt.h
> index 8ff88d7..afc4753 100644
> --- a/plat/common/include/fdt.h
> +++ b/plat/common/include/fdt.h
> @@ -56,4 +56,24 @@
>   int fdt_getprop_u32_by_offset(const void *fdt, int nodeoffset,
>                 const char *name, uint32_t *out);
>   
> +/**
> + * fdt_interrupt_cells - retrieve the number of cells needed to encode an
> + *                       interrupt source
> + * @fdt: pointer to the device tree blob
> + * @nodeoffset: offset of the node to find the interrupt for.
> + *
> + * When the node has a valid #interrupt-cells property, returns its value.
> + *
> + * returns:
> + *     0 <= n < FDT_MAX_NCELLS, on success
> + *      -FDT_ERR_BADNCELLS, if the node has a badly formatted or invalid
> + *             #interrupt-cells property
> + *     -FDT_ERR_BADMAGIC,
> + *     -FDT_ERR_BADVERSION,
> + *     -FDT_ERR_BADSTATE,
> + *     -FDT_ERR_BADSTRUCTURE,
> + *     -FDT_ERR_TRUNCATED, standard meanings
> + */
> +int fdt_interrupt_cells(const void *fdt, int nodeoffset);
> +
>   #endif
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