On Mon, Nov 15, 2021 at 03:30:43PM -0800, Vikram Garhwal wrote:
> Add fdt_ prefix to overlay_get_target() and remove static type.
The short description is burying the lede a bit, the key point is that
you're making this function public.
> 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@xxxxxxxxxx>
The concept looks fine to me. A few details to polish noted below:
> ---
> libfdt/fdt_overlay.c | 23 ++++-------------------
> libfdt/libfdt.h | 19 +++++++++++++++++++
> libfdt/version.lds | 1 +
> 3 files changed, 24 insertions(+), 19 deletions(-)
>
> diff --git a/libfdt/fdt_overlay.c b/libfdt/fdt_overlay.c
> index d217e79..e141053 100644
> --- a/libfdt/fdt_overlay.c
> +++ b/libfdt/fdt_overlay.c
> @@ -40,22 +40,7 @@ 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 fdt_overlay_get_target(const void *fdt, const void *fdto,
> int fragment, char const **pathp)
"overlay_get_target" was fine as an internal name. When published, I
think "fdt_overlay_target_offset" would better fit the naming
conventions for the rest of the interface.
Similarly, I'd like the @fragment parameter renamed @fragment_offset.
[The insistent use of explicit "offset" throughout the interface is
deliberate - it's an attempt to constantly remind users that these
quantities are explicit offsets in the blob, which can be invalidated
by other changes, rather than some sort of safe, stable handle on a
node]
> {
> uint32_t phandle;
> @@ -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_get_target(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_get_target(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_get_target(fdt, fdto, fragment, &target_path);
> if (ret < 0)
> return ret;
> target = ret;
> diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
> index 7f117e8..5d42533 100644
> --- a/libfdt/libfdt.h
> +++ b/libfdt/libfdt.h
> @@ -2116,6 +2116,25 @@ int fdt_del_node(void *fdt, int nodeoffset);
> */
> int fdt_overlay_apply(void *fdt, void *fdto);
>
> +/**
> + * fdt_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)
> + *
> + * fdt_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
> + */
> +
> +int fdt_overlay_get_target(const void *fdt, const void *fdto, int fragment,
> + char const **pathp);
> +
> /**********************************************************************/
> /* Debugging / informational functions */
> /**********************************************************************/
> diff --git a/libfdt/version.lds b/libfdt/version.lds
> index 7ab85f1..9e0daa1 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_get_target;
> 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
Attachment:
signature.asc
Description: PGP signature
