[PATCH 4.14 135/146] phy: tegra: fix device-tree node lookups

Greg Kroah-Hartman
2018-01-01T14:47:08Z

From: Johan Hovold <johan@kernel.org>

commit 046046737bd35bed047460f080ea47e186be731e upstream.

Fix child-node lookups during probe, which ended up searching the whole
device tree depth-first starting at the parents rather than just
matching on their children.

To make things worse, some parent nodes could end up being being
prematurely freed (by tegra_xusb_pad_register()) as
of_find_node_by_name() drops a reference to its first argument.

Fixes: 53d2a715c240 ("phy: Add Tegra XUSB pad controller support")
Cc: Thierry Reding <treding@nvidia.com>
Signed-off-by: Johan Hovold <johan@kernel.org>
Signed-off-by: Kishon Vijay Abraham I <kishon@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

---
drivers/phy/tegra/xusb.c | 60 +++++++++++++++++++++++------------------------
1 file changed, 30 insertions(+), 30 deletions(-)

--- a/drivers/phy/tegra/xusb.c
+++ b/drivers/phy/tegra/xusb.c
@@ -75,14 +75,14 @@ MODULE_DEVICE_TABLE(of, tegra_xusb_padct
static struct device_node *
tegra_xusb_find_pad_node(struct tegra_xusb_padctl *padctl, const char *name)
{
- /*
- * of_find_node_by_name() drops a reference, so make sure to grab one.
- */
- struct device_node *np = of_node_get(padctl->dev->of_node);
+ struct device_node *pads, *np;

- np = of_find_node_by_name(np, "pads");
- if (np)
- np = of_find_node_by_name(np, name);
+ pads = of_get_child_by_name(padctl->dev->of_node, "pads");
+ if (!pads)
+ return NULL;
+
+ np = of_get_child_by_name(pads, name);
+ of_node_put(pads);

return np;
}
@@ -90,16 +90,16 @@ tegra_xusb_find_pad_node(struct tegra_xu
static struct device_node *
tegra_xusb_pad_find_phy_node(struct tegra_xusb_pad *pad, unsigned int index)
{
- /*
- * of_find_node_by_name() drops a reference, so make sure to grab one.
- */
- struct device_node *np = of_node_get(pad->dev.of_node);
+ struct device_node *np, *lanes;

- np = of_find_node_by_name(np, "lanes");
- if (!np)
+ lanes = of_get_child_by_name(pad->dev.of_node, "lanes");
+ if (!lanes)
return NULL;

- return of_find_node_by_name(np, pad->soc->lanes[index].name);
+ np = of_get_child_by_name(lanes, pad->soc->lanes[index].name);
+ of_node_put(lanes);
+
+ return np;
}

static int
@@ -195,7 +195,7 @@ int tegra_xusb_pad_register(struct tegra
unsigned int i;
int err;

- children = of_find_node_by_name(pad->dev.of_node, "lanes");
+ children = of_get_child_by_name(pad->dev.of_node, "lanes");
if (!children)
return -ENODEV;

@@ -444,21 +444,21 @@ static struct device_node *
tegra_xusb_find_port_node(struct tegra_xusb_padctl *padctl, const char *type,
unsigned int index)
{
- /*
- * of_find_node_by_name() drops a reference, so make sure to grab one.
- */
- struct device_node *np = of_node_get(padctl->dev->of_node);
+ struct device_node *ports, *np;
+ char *name;
+
+ ports = of_get_child_by_name(padctl->dev->of_node, "ports");
+ if (!ports)
+ return NULL;

- np = of_find_node_by_name(np, "ports");
- if (np) {
- char *name;
-
- name = kasprintf(GFP_KERNEL, "%s-%u", type, index);
- if (!name)
- return ERR_PTR(-ENOMEM);
- np = of_find_node_by_name(np, name);
- kfree(name);
+ name = kasprintf(GFP_KERNEL, "%s-%u", type, index);
+ if (!name) {
+ of_node_put(ports);
+ return ERR_PTR(-ENOMEM);
}
+ np = of_get_child_by_name(ports, name);
+ kfree(name);
+ of_node_put(ports);

return np;
}
@@ -847,7 +847,7 @@ static void tegra_xusb_remove_ports(stru

static int tegra_xusb_padctl_probe(struct platform_device *pdev)
{
- struct device_node *np = of_node_get(pdev->dev.of_node);
+ struct device_node *np = pdev->dev.of_node;
const struct tegra_xusb_padctl_soc *soc;
struct tegra_xusb_padctl *padctl;
const struct of_device_id *match;
@@ -855,7 +855,7 @@ static int tegra_xusb_padctl_probe(struc
int err;

/* for backwards compatibility with old device trees */
- np = of_find_node_by_name(np, "pads");
+ np = of_get_child_by_name(np, "pads");
if (!np) {
dev_warn(&pdev->dev, "deprecated DT, using legacy driver\n");
return tegra_xusb_padctl_legacy_probe(pdev);