realtek: mdio: harden rtmdio_setup_smi_topology()

Topology setup is used during probing. Improve error checking
to be 100% sure that hardware setup works as expected. While
we are here:

- use GENMASK()
- Be type consistent and add u32 cast for value calculation
- use __ffs(mask) for code deduplication and better readability

Signed-off-by: Markus Stockhausen <markus.stockhausen@gmx.de>
Link: https://github.com/openwrt/openwrt/pull/23204
Signed-off-by: Robert Marko <robimarko@gmail.com>

diff --git a/target/linux/realtek/files-6.18/drivers/net/mdio/mdio-realtek-otto.c b/target/linux/realtek/files-6.18/drivers/net/mdio/mdio-realtek-otto.c
index 5a313e9f3a0c3274bdda79139a672f54303a795f..c200fe6ff91c7c4a53c3524befe71f4efff032e9 100644 (file)
--- a/target/linux/realtek/files-6.18/drivers/net/mdio/mdio-realtek-otto.c
+++ b/target/linux/realtek/files-6.18/drivers/net/mdio/mdio-realtek-otto.c
@@ -595,25 +595,32 @@ static int rtmdio_write_c22(struct mii_bus *bus, int phy, int regnum, u16 val)
        return 0;
 }
 
-static void rtmdio_setup_smi_topology(struct rtmdio_ctrl *ctrl)
+static int rtmdio_setup_smi_topology(struct rtmdio_ctrl *ctrl)
 {
        u32 reg, mask, val, pn;
+       int ret;
 
        for_each_port(ctrl, pn) {
                if (ctrl->cfg->bus_map_base) {
-                       reg = (pn / 16) * 4;
-                       mask = 0x3 << ((pn % 16) * 2);
-                       val = ctrl->port[pn].smi_bus << ((pn % 16) * 2);
-                       regmap_update_bits(ctrl->map, ctrl->cfg->bus_map_base + reg, mask, val);
+                       reg = ctrl->cfg->bus_map_base + (pn / 16) * 4;
+                       mask = GENMASK(1, 0) << ((pn % 16) * 2);
+                       val = (u32)ctrl->port[pn].smi_bus << __ffs(mask);
+                       ret = regmap_update_bits(ctrl->map, reg, mask, val);
+                       if (ret)
+                               return ret;
                }
 
                if (ctrl->cfg->port_map_base) {
-                       reg = (pn / 6) * 4;
-                       mask = 0x1f << ((pn % 6) * 5);
-                       val = ctrl->port[pn].smi_addr << ((pn % 6) * 5);
-                       regmap_update_bits(ctrl->map, ctrl->cfg->port_map_base + reg, mask, val);
+                       reg = ctrl->cfg->port_map_base + (pn / 6) * 4;
+                       mask = GENMASK(4, 0) << ((pn % 6) * 5);
+                       val = (u32)ctrl->port[pn].smi_addr << __ffs(mask);
+                       ret = regmap_update_bits(ctrl->map, reg, mask, val);
+                       if (ret)
+                               return ret;
                }
        }
+
+       return 0;
 }
 
 static u32 rtmdio_get_phy_id(struct phy_device *phydev)
@@ -958,7 +965,10 @@ static int rtmdio_probe(struct platform_device *pdev)
        if (ret)
                return ret;
 
-       rtmdio_setup_smi_topology(ctrl);
+       ret = rtmdio_setup_smi_topology(ctrl);
+       if (ret)
+               return ret;
+
        ctrl->cfg->setup_ctrl(ctrl);
 
        device_for_each_child_node_scoped(dev, child) {