[PATCH] clk: fixed_rate: Avoid calling dev_read_*() if CONFIG_OF_PLATDATA=y

[Simon Glass]

Hi Marek,

On Wed, 19 Nov 2025 at 21:14, Marek Vasut
<marek.vasut+renesas at mailbox.org> wrote:
>
> If CONFIG_OF_PLATDATA=y , then the udevice has no valid OF node associated
> with it and ofnode_valid(node) evaluates to 0. The dev_read_u32_default()
> call ultimately reaches ofnode_read_u32_index() which invokes fdt_getprop()
> and passes result of ofnode_to_offset(node) as an offset parameter into it.
>
> The ofnode_to_offset(node) returns -1 for invalid node, which leads to an
> fdt_getprop(..., -1, ...) invocation, which will crash sandbox with SIGSEGV
> because libfdt can not handle negative node offsets without full tree check,
> which U-Boot inhibits to keep size lower.
>
> Add dev_has_ofnode(dev) check and do not assign clock rate in case the
> device has no valid node associated with it, and do not call any of the
> dev_read_*() functions for devices without valid nodes.
>
> Signed-off-by: Marek Vasut <marek.vasut+renesas at mailbox.org>
> ---
> Cc: Patrice Chotard <patrice.chotard at foss.st.com>
> Cc: Patrick Delaunay <patrick.delaunay at foss.st.com>
> Cc: Sean Anderson <seanga2 at gmail.com>
> Cc: Tom Rini <trini at konsulko.com>
> Cc: u-boot at lists.denx.de
> ---
>  drivers/clk/clk_fixed_rate.c | 2 +-
>  1 file changed, 1 insertion(+), 1 deletion(-)
>
> diff --git a/drivers/clk/clk_fixed_rate.c b/drivers/clk/clk_fixed_rate.c
> index 95a77d2e041..5c32ae207fe 100644
> --- a/drivers/clk/clk_fixed_rate.c
> +++ b/drivers/clk/clk_fixed_rate.c
> @@ -35,7 +35,7 @@ void clk_fixed_rate_ofdata_to_plat_(struct udevice *dev,
>                                     struct clk_fixed_rate *plat)
>  {
>         struct clk *clk = &plat->clk;
> -       if (CONFIG_IS_ENABLED(OF_REAL))
> +       if (CONFIG_IS_ENABLED(OF_REAL) && dev_has_ofnode(dev))
>                 plat->fixed_rate = dev_read_u32_default(dev, "clock-frequency",
>                                                         0);

What is happening here? It should already be checking this:

static inline __attribute_const__ bool dev_has_ofnode(const struct udevice *dev)
{
#if CONFIG_IS_ENABLED(OF_REAL)
return ofnode_valid(dev_ofnode(dev));
#else
return false;
#endif
}

Regards,
Simon