[PATCH v2] clk: fixed_rate: Avoid calling dev_read_*() if CONFIG_OF_PLATDATA=y

[Marek Vasut]

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
---
V2: Call only dev_has_ofnode(), which internally checks for OF_REAL
---
 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..681bd3db20e 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 (dev_has_ofnode(dev))
 		plat->fixed_rate = dev_read_u32_default(dev, "clock-frequency",
 							0);
 
-- 
2.51.0