On Fri, May 27, 2016 at 10:28:48AM +0200, Maxime Ripard wrote:
> Add a function to retrieve the highest phandle in a given device tree.
>
> Signed-off-by: Maxime Ripard <maxime.ripard@xxxxxxxxxxxxxxxxxx>
Needs a testcase, plus a couple of smallish problems:
> ---
> libfdt/fdt_ro.c | 15 +++++++++++++++
> libfdt/libfdt.h | 13 +++++++++++++
> 2 files changed, 28 insertions(+)
>
> diff --git a/libfdt/fdt_ro.c b/libfdt/fdt_ro.c
> index 50cce864283c..d5a14178190f 100644
> --- a/libfdt/fdt_ro.c
> +++ b/libfdt/fdt_ro.c
> @@ -88,6 +88,21 @@ static int _fdt_string_eq(const void *fdt, int stroffset,
> return (strlen(p) == len) && (memcmp(p, s, len) == 0);
> }
>
> +uint32_t fdt_get_max_phandle(const void *fdt)
> +{
> + uint32_t max_phandle = 0, phandle;
> + int offset;
> +
> + for (offset = fdt_next_node(fdt, -1, NULL); offset >= 0;
> + offset = fdt_next_node(fdt, offset, NULL)) {
> + phandle = fdt_get_phandle(fdt, offset);
I think you need to check for the case of an invalid -1 valued phandle
- otherwise if there are any of those, it will come up as the max
(unsigned comparison).
> + if (phandle > max_phandle)
> + max_phandle = phandle;
> + }
You need to check for offset != -FDT_ERR_NOTFOUND, which would
indicate some other error from fdt_next_node.
> +
> + return max_phandle;
> +}
> +
> int fdt_get_mem_rsv(const void *fdt, int n, uint64_t *address, uint64_t *size)
> {
> FDT_CHECK_HEADER(fdt);
> diff --git a/libfdt/libfdt.h b/libfdt/libfdt.h
> index 6589e08db7ab..7156b264b1e9 100644
> --- a/libfdt/libfdt.h
> +++ b/libfdt/libfdt.h
> @@ -284,6 +284,19 @@ int fdt_move(const void *fdt, void *buf, int bufsize);
> const char *fdt_string(const void *fdt, int stroffset);
>
> /**
> + * fdt_get_max_phandle - retrieves the highest phandle in a tree
> + * @fdt: pointer to the device tree blob
> + *
> + * fdt_get_max_phandle retrieves the highest phandlle in the given
> + * device tree
> + *
> + * returns:
> + * the highest phandle on success
> + * 0, if an error occured
> + */
> +uint32_t fdt_get_max_phandle(const void *fdt);
> +
> +/**
> * fdt_num_mem_rsv - retrieve the number of memory reserve map entries
> * @fdt: pointer to the device tree blob
> *
--
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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