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

[Marek Vasut]

On 11/21/25 12:40 AM, Simon Glass wrote:
> 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
> }
I do not understand the question -- this patch _adds_ the 
dev_has_ofnode() test into clk_fixed_rate_ofdata_to_plat_() , it wasn't 
present before. Can you please rephrase your question / concern ?