Re: [XEN RFC PATCH 25/40] xen/arm: unified entry to parse all NUMA data from device tree

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 11 Aug 2021, Wei Chen wrote:
> In this API, we scan whole device tree to parse CPU node id, memory
> node id and distance-map. Though early_scan_node will invoke has a
> handler to process memory nodes. If we want to parse memory node id
> in this handler, we have to embeded NUMA parse code in this handler.
> But we still need to scan whole device tree to find CPU NUMA id and
> distance-map. In this case, we include memory NUMA id parse in this
> API too. Another benefit is that we have a unique entry for device
> tree NUMA data parse.
> 
> Signed-off-by: Wei Chen <wei.chen@xxxxxxx>
> ---
>  xen/arch/arm/numa_device_tree.c | 31 ++++++++++++++++++++++++++++---
>  xen/include/asm-arm/numa.h      |  1 +
>  2 files changed, 29 insertions(+), 3 deletions(-)
> 
> diff --git a/xen/arch/arm/numa_device_tree.c b/xen/arch/arm/numa_device_tree.c
> index 6e0d1d3d9f..27ffb72f7b 100644
> --- a/xen/arch/arm/numa_device_tree.c
> +++ b/xen/arch/arm/numa_device_tree.c
> @@ -131,7 +131,8 @@ save_memblk:
>  }
>  
>  /* Parse CPU NUMA node info */
> -int __init device_tree_parse_numa_cpu_node(const void *fdt, int node)
> +static int __init
> +device_tree_parse_numa_cpu_node(const void *fdt, int node)
>  {
>      uint32_t nid;
>  
> @@ -147,7 +148,7 @@ int __init device_tree_parse_numa_cpu_node(const void 
> *fdt, int node)
>  }
>  
>  /* Parse memory node NUMA info */
> -int __init
> +static int __init
>  device_tree_parse_numa_memory_node(const void *fdt, int node,
>      const char *name, uint32_t addr_cells, uint32_t size_cells)
>  {
> @@ -202,7 +203,7 @@ device_tree_parse_numa_memory_node(const void *fdt, int 
> node,
>  }
>  
>  /* Parse NUMA distance map v1 */
> -int __init
> +static int __init
>  device_tree_parse_numa_distance_map_v1(const void *fdt, int node)
>  {
>      const struct fdt_property *prop;
> @@ -267,3 +268,27 @@ device_tree_parse_numa_distance_map_v1(const void *fdt, 
> int node)
>  
>      return 0;
>  }
> +
> +static int __init fdt_scan_numa_nodes(const void *fdt,
> +                int node, const char *uname, int depth,
> +                u32 address_cells, u32 size_cells, void *data)
> +{
> +    int ret = 0;
> +
> +    if ( fdt_node_check_type(fdt, node, "cpu") == 0 )
> +        ret = device_tree_parse_numa_cpu_node(fdt, node);
> +    else if ( fdt_node_check_type(fdt, node, "memory") == 0 )
> +        ret = device_tree_parse_numa_memory_node(fdt, node, uname,
> +                                address_cells, size_cells);
> +    else if ( fdt_node_check_compatible(fdt, node,
> +                                "numa-distance-map-v1") == 0 )
> +        ret = device_tree_parse_numa_distance_map_v1(fdt, node);
> +
> +    return ret;
> +}

Julien, do you have an opinion on whether it might be worth reusing the
existing early_scan_node function for this to avoiding another full FDT
scan (to avoid another call to device_tree_for_each_node)?