Re: [PATCH v6 1/7] xen/arm: introduce new helper device_tree_get_meminfo

[Stefano Stabellini <sstabellini@xxxxxxxxxx>]

On Wed, 8 Sep 2021, Penny Zheng wrote:
> This commit creates a new helper device_tree_get_meminfo to iterate over a
> device tree property to get memory info, like "reg".
> 
> Signed-off-by: Penny Zheng <penny.zheng@xxxxxxx>

Reviewed-by: Stefano Stabellini <sstabellini@xxxxxxxxxx>


> ---
>  xen/arch/arm/bootfdt.c | 83 ++++++++++++++++++++++++------------------
>  1 file changed, 47 insertions(+), 36 deletions(-)
> 
> diff --git a/xen/arch/arm/bootfdt.c b/xen/arch/arm/bootfdt.c
> index 476e32e0f5..b01badda3e 100644
> --- a/xen/arch/arm/bootfdt.c
> +++ b/xen/arch/arm/bootfdt.c
> @@ -63,6 +63,52 @@ void __init device_tree_get_reg(const __be32 **cell, u32 
> address_cells,
>      *size = dt_next_cell(size_cells, cell);
>  }
>  
> +static int __init device_tree_get_meminfo(const void *fdt, int node,
> +                                          const char *prop_name,
> +                                          u32 address_cells, u32 size_cells,
> +                                          void *data)
> +{
> +    const struct fdt_property *prop;
> +    unsigned int i, banks;
> +    const __be32 *cell;
> +    u32 reg_cells = address_cells + size_cells;
> +    paddr_t start, size;
> +    struct meminfo *mem = data;
> +
> +    if ( address_cells < 1 || size_cells < 1 )
> +    {
> +        printk("fdt: property `%s': invalid #address-cells or #size-cells",
> +               prop_name);
> +        return -EINVAL;
> +    }
> +
> +    prop = fdt_get_property(fdt, node, prop_name, NULL);
> +    if ( !prop )
> +        return -ENOENT;
> +
> +    cell = (const __be32 *)prop->data;
> +    banks = fdt32_to_cpu(prop->len) / (reg_cells * sizeof (u32));
> +
> +    for ( i = 0; i < banks && mem->nr_banks < NR_MEM_BANKS; i++ )
> +    {
> +        device_tree_get_reg(&cell, address_cells, size_cells, &start, &size);
> +        /* Some DT may describe empty bank, ignore them */
> +        if ( !size )
> +            continue;
> +        mem->bank[mem->nr_banks].start = start;
> +        mem->bank[mem->nr_banks].size = size;
> +        mem->nr_banks++;
> +    }
> +
> +    if ( i < banks )
> +    {
> +        printk("Warning: Max number of supported memory regions reached.\n");
> +        return -ENOSPC;
> +    }
> +
> +    return 0;
> +}
> +
>  u32 __init device_tree_get_u32(const void *fdt, int node,
>                                 const char *prop_name, u32 dflt)
>  {
> @@ -139,42 +185,7 @@ static int __init process_memory_node(const void *fdt, 
> int node,
>                                        u32 address_cells, u32 size_cells,
>                                        void *data)
>  {
> -    const struct fdt_property *prop;
> -    int i;
> -    int banks;
> -    const __be32 *cell;
> -    paddr_t start, size;
> -    u32 reg_cells = address_cells + size_cells;
> -    struct meminfo *mem = data;
> -
> -    if ( address_cells < 1 || size_cells < 1 )
> -    {
> -        printk("fdt: node `%s': invalid #address-cells or #size-cells",
> -               name);
> -        return -EINVAL;
> -    }
> -
> -    prop = fdt_get_property(fdt, node, "reg", NULL);
> -    if ( !prop )
> -        return -ENOENT;
> -
> -    cell = (const __be32 *)prop->data;
> -    banks = fdt32_to_cpu(prop->len) / (reg_cells * sizeof (u32));
> -
> -    for ( i = 0; i < banks && mem->nr_banks < NR_MEM_BANKS; i++ )
> -    {
> -        device_tree_get_reg(&cell, address_cells, size_cells, &start, &size);
> -        /* Some DT may describe empty bank, ignore them */
> -        if ( !size )
> -            continue;
> -        mem->bank[mem->nr_banks].start = start;
> -        mem->bank[mem->nr_banks].size = size;
> -        mem->nr_banks++;
> -    }
> -
> -    if ( i < banks )
> -        return -ENOSPC;
> -    return 0;
> +    return device_tree_get_meminfo(fdt, node, "reg", address_cells, 
> size_cells, data);
>  }
>  
>  static int __init process_reserved_memory_node(const void *fdt, int node,
> -- 
> 2.25.1
>