Re: [PATCH v2 1/1] libfdt: overlay: make overlay_get_target() public

[David Gibson <david-xT8FGy+AXnRB3Ne2BGzF6laj5H9X9Tb+@public.gmane.org>]

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On Wed, Nov 17, 2021 at 06:53:56PM -0800, Vikram Garhwal wrote:
> This is done to get the target path for the overlay nodes which is very useful
> in many cases. For example, Xen hypervisor needs it when applying overlays
> because Xen needs to do further processing of the overlay nodes, e.g. mapping of
> resources(IRQs and IOMMUs) to other VMs, creation of SMMU pagetables, etc.
> 
> Signed-off-by: Vikram Garhwal <fnu.vikram-gjFFaj9aHVfQT0dZR+AlfA@public.gmane.org>

Applied, thanks.

If you can follow up with some testcases for the newly-public
function, that would be most appreciated.

> ---
>  libfdt/fdt_overlay.c | 29 +++++++----------------------
>  libfdt/libfdt.h      | 18 ++++++++++++++++++
>  libfdt/version.lds   |  1 +
>  3 files changed, 26 insertions(+), 22 deletions(-)
> 
> diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c
> index d217e79..5c0c398 100644
> --- a/libfdt/fdt_overlay.c
> +++ b/libfdt/fdt_overlay.c
> @@ -40,37 +40,22 @@ static uint32_t overlay_get_target_phandle(const void *fdto, int fragment)
>  	return fdt32_to_cpu(*val);
>  }
>  
> -/**
> - * overlay_get_target - retrieves the offset of a fragment's target
> - * @fdt: Base device tree blob
> - * @fdto: Device tree overlay blob
> - * @fragment: node offset of the fragment in the overlay
> - * @pathp: pointer which receives the path of the target (or NULL)
> - *
> - * overlay_get_target() retrieves the target offset in the base
> - * device tree of a fragment, no matter how the actual targeting is
> - * done (through a phandle or a path)
> - *
> - * returns:
> - *      the targeted node offset in the base device tree
> - *      Negative error code on error
> - */
> -static int overlay_get_target(const void *fdt, const void *fdto,
> -			      int fragment, char const **pathp)
> +int fdt_overlay_target_offset(const void *fdt, const void *fdto,
> +			      int fragment_offset, char const **pathp)
>  {
>  	uint32_t phandle;
>  	const char *path = NULL;
>  	int path_len = 0, ret;
>  
>  	/* Try first to do a phandle based lookup */
> -	phandle = overlay_get_target_phandle(fdto, fragment);
> +	phandle = overlay_get_target_phandle(fdto, fragment_offset);
>  	if (phandle == (uint32_t)-1)
>  		return -FDT_ERR_BADPHANDLE;
>  
>  	/* no phandle, try path */
>  	if (!phandle) {
>  		/* And then a path based lookup */
> -		path = fdt_getprop(fdto, fragment, "target-path", &path_len);
> +		path = fdt_getprop(fdto, fragment_offset, "target-path", &path_len);
>  		if (path)
>  			ret = fdt_path_offset(fdt, path);
>  		else
> @@ -636,7 +621,7 @@ static int overlay_merge(void *fdt, void *fdto)
>  		if (overlay < 0)
>  			return overlay;
>  
> -		target = overlay_get_target(fdt, fdto, fragment, NULL);
> +		target = fdt_overlay_target_offset(fdt, fdto, fragment, NULL);
>  		if (target < 0)
>  			return target;
>  
> @@ -779,7 +764,7 @@ static int overlay_symbol_update(void *fdt, void *fdto)
>  			return -FDT_ERR_BADOVERLAY;
>  
>  		/* get the target of the fragment */
> -		ret = overlay_get_target(fdt, fdto, fragment, &target_path);
> +		ret = fdt_overlay_target_offset(fdt, fdto, fragment, &target_path);
>  		if (ret < 0)
>  			return ret;
>  		target = ret;
> @@ -801,7 +786,7 @@ static int overlay_symbol_update(void *fdt, void *fdto)
>  
>  		if (!target_path) {
>  			/* again in case setprop_placeholder changed it */
> -			ret = overlay_get_target(fdt, fdto, fragment, &target_path);
> +			ret = fdt_overlay_target_offset(fdt, fdto, fragment, &target_path);
>  			if (ret < 0)
>  				return ret;
>  			target = ret;
> diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
> index 7f117e8..a7f432c 100644
> --- a/libfdt/libfdt.h
> +++ b/libfdt/libfdt.h
> @@ -2116,6 +2116,24 @@ int fdt_del_node(void *fdt, int nodeoffset);
>   */
>  int fdt_overlay_apply(void *fdt, void *fdto);
>  
> +/**
> + * fdt_overlay_target_offset - retrieves the offset of a fragment's target
> + * @fdt: Base device tree blob
> + * @fdto: Device tree overlay blob
> + * @fragment_offset: node offset of the fragment in the overlay
> + * @pathp: pointer which receives the path of the target (or NULL)
> + *
> + * fdt_overlay_target_offset() retrieves the target offset in the base
> + * device tree of a fragment, no matter how the actual targeting is
> + * done (through a phandle or a path)
> + *
> + * returns:
> + *      the targeted node offset in the base device tree
> + *      Negative error code on error
> + */
> +int fdt_overlay_target_offset(const void *fdt, const void *fdto,
> +			      int fragment_offset, char const **pathp);
> +
>  /**********************************************************************/
>  /* Debugging / informational functions                                */
>  /**********************************************************************/
> diff --git a/libfdt/version.lds b/libfdt/version.lds
> index 7ab85f1..cbce5d4 100644
> --- a/libfdt/version.lds
> +++ b/libfdt/version.lds
> @@ -77,6 +77,7 @@ LIBFDT_1.2 {
>  		fdt_appendprop_addrrange;
>  		fdt_setprop_inplace_namelen_partial;
>  		fdt_create_with_flags;
> +		fdt_overlay_target_offset;
>  	local:
>  		*;
>  };

-- 
David Gibson			| I'll have my music baroque, and my code
david AT gibson.dropbear.id.au	| minimalist, thank you.  NOT _the_ _other_
				| _way_ _around_!
http://www.ozlabs.org/~dgibson

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