i2c: Avoid calling dev_read_*() if CONFIG_OF_PLATDATA=y

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.

Since i2c_child_post_bind() already calls dev_has_ofnode(dev), reuse the
same call and assign i2c->speed_hz = I2C_SPEED_STANDARD_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@mailbox.org>

diff --git a/drivers/i2c/i2c-uclass.c b/drivers/i2c/i2c-uclass.c
index 97466597d77c59d8324ed8a201395d4e8b6da3d7..bb32ebd9981fe00638aeb757c16708bf375fdaec 100644 (file)
--- a/drivers/i2c/i2c-uclass.c
+++ b/drivers/i2c/i2c-uclass.c
@@ -703,12 +703,14 @@ int i2c_deblock(struct udevice *bus)
 
 static int i2c_pre_probe(struct udevice *dev)
 {
-#if CONFIG_IS_ENABLED(OF_REAL)
        struct dm_i2c_bus *i2c = dev_get_uclass_priv(dev);
        unsigned int max = 0;
        ofnode node;
        int ret;
 
+       if (!dev_has_ofnode(dev))
+               return 0;
+
        i2c->max_transaction_bytes = 0;
        dev_for_each_subnode(node, dev) {
                ret = ofnode_read_u32(node,
@@ -720,22 +722,22 @@ static int i2c_pre_probe(struct udevice *dev)
 
        debug("%s: I2C bus: %s max transaction bytes: %d\n", __func__,
              dev->name, i2c->max_transaction_bytes);
-#endif
+
        return 0;
 }
 
 static int i2c_post_probe(struct udevice *dev)
 {
-#if CONFIG_IS_ENABLED(OF_REAL)
        struct dm_i2c_bus *i2c = dev_get_uclass_priv(dev);
 
-       i2c->speed_hz = dev_read_u32_default(dev, "clock-frequency",
-                                            I2C_SPEED_STANDARD_RATE);
+       if (dev_has_ofnode(dev)) {
+               i2c->speed_hz = dev_read_u32_default(dev, "clock-frequency",
+                                                    I2C_SPEED_STANDARD_RATE);
+       } else {
+               i2c->speed_hz = I2C_SPEED_STANDARD_RATE;
+       }
 
        return dm_i2c_set_bus_speed(dev, i2c->speed_hz);
-#else
-       return 0;
-#endif
 }
 
 static int i2c_child_post_bind(struct udevice *dev)