[PATCH v2] lib: utils: Implement "ranges" property parsing

[Anup Patel]

> -----Original Message-----
> From: Atish Patra <atish.patra at wdc.com>
> Sent: 21 October 2020 06:09
> To: opensbi at lists.infradead.org
> Cc: Atish Patra <Atish.Patra at wdc.com>; Anup Patel <Anup.Patel at wdc.com>
> Subject: [PATCH v2] lib: utils: Implement "ranges" property parsing
> 
> The "reg" property in a device node may not be the correct address always.
> If a parent node defines a "ranges" property, the child address need to be
> translated with respect to parents address. If the ranges property is not
> present, it will just use 1:1 translation.
> 
> Signed-off-by: Atish Patra <atish.patra at wdc.com>
> ---
> Changes from v1->v2:
> 1. Improved the range parsing by supporting multiple parent nodes.
> ---
>  lib/utils/fdt/fdt_helper.c | 49
> ++++++++++++++++++++++++++++++++++++--
>  1 file changed, 47 insertions(+), 2 deletions(-)
> 
> diff --git a/lib/utils/fdt/fdt_helper.c b/lib/utils/fdt/fdt_helper.c index
> aec73a0598d7..90d55dcd8e71 100644
> --- a/lib/utils/fdt/fdt_helper.c
> +++ b/lib/utils/fdt/fdt_helper.c
> @@ -71,10 +71,47 @@ int fdt_find_match(void *fdt, int startoff,
>  	return SBI_ENODEV;
>  }
> 
> +int fdt_translate_address(void *fdt, uint64_t reg, int parent, unsigned
> +long *addr) {

If fdt_translate_address() is a public function then it should be declared
in fdt_helper.h otherwise make it static.

> +	int i, rlen;
> +	int cell_addr, cell_size;
> +	const fdt32_t *ranges;
> +	uint64_t offset = 0, caddr = 0, paddr = 0, rsize = 0;
> +
> +	cell_addr = fdt_address_cells(fdt, parent);
> +	if (cell_addr < 1)
> +		return SBI_ENODEV;
> +
> +	cell_size = fdt_size_cells(fdt, parent);
> +	if (cell_size < 0)
> +		return SBI_ENODEV;
> +
> +	ranges = fdt_getprop(fdt, parent, "ranges", &rlen);
> +	if (ranges && rlen > 0) {
> +		for (i = 0; i < cell_addr; i++)
> +			caddr = (caddr << 32) | fdt32_to_cpu(*ranges++);
> +		for (i = 0; i < cell_addr; i++)
> +			paddr = (paddr << 32) | fdt32_to_cpu(*ranges++);
> +		for (i = 0; i < cell_size; i++)
> +			rsize = (rsize << 32) | fdt32_to_cpu(*ranges++);
> +		if (reg < caddr || caddr >= (reg + rsize )) {
> +			sbi_printf("invalid address translation\n");
> +			return SBI_ENODEV;
> +		}
> +		offset = reg - caddr;
> +		*addr = paddr + offset;
> +	} else {
> +		/* No translation required */
> +		*addr = reg;
> +	}
> +
> +	return 0;
> +}
> +
>  int fdt_get_node_addr_size(void *fdt, int node, unsigned long *addr,
>  			   unsigned long *size)
>  {
> -	int parent, len, i;
> +	int parent, len, i, rc;
>  	int cell_addr, cell_size;
>  	const fdt32_t *prop_addr, *prop_size;
>  	uint64_t temp = 0;
> @@ -98,7 +135,15 @@ int fdt_get_node_addr_size(void *fdt, int node,
> unsigned long *addr,
>  	if (addr) {
>  		for (i = 0; i < cell_addr; i++)
>  			temp = (temp << 32) | fdt32_to_cpu(*prop_addr++);
> -		*addr = temp;
> +		do {
> +			if (parent < 0)
> +				break;
> +			rc  = fdt_translate_address(fdt, temp, parent, addr);
> +			if (rc)
> +				break;
> +			parent = fdt_parent_offset(fdt, parent);
> +			temp = *addr;
> +		} while (1);
>  	}
>  	temp = 0;
> 
> --
> 2.25.1

Apart from above looks good to me.

Reviewed-by: Anup Patel <anup.patel at wdc.com>

Regards,
Anup