net: Add Amlogic GXL MDIO Mux driver
Port the mdio-mux-meson-gxl.c Linux driver introduced in [1],
and adapt it to U-Boot.
This driver is needed to boot U-Boot with Linux DT since v6.4,
since it switched the MDIO mux from the mmio to a proper GXL driver.
[1] 9a24e1ff4326 ("net: mdio: add amlogic gxl mdio mux support")
Link: https://lore.kernel.org/r/20231213-u-boot-gxl-mdio-mux-v2-1-c56bb02a75ea@linaro.org
Signed-off-by: Neil Armstrong <neil.armstrong@linaro.org>
diff --git a/drivers/net/mdio_mux_meson_gxl.c b/drivers/net/mdio_mux_meson_gxl.c
new file mode 100644
index 0000000..8ef3ae5
--- /dev/null
+++ b/drivers/net/mdio_mux_meson_gxl.c
@@ -0,0 +1,138 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Copyright (c) 2022 Baylibre, SAS.
+ * Author: Jerome Brunet <jbrunet@baylibre.com>
+ * Copyright (c) 2023 Neil Armstrong <neil.armstrong@linaro.org>
+ */
+
+#include <dm.h>
+#include <errno.h>
+#include <log.h>
+#include <miiphy.h>
+#include <asm/io.h>
+#include <linux/bitfield.h>
+#include <linux/delay.h>
+
+#define ETH_REG2 0x0
+#define REG2_PHYID GENMASK(21, 0)
+#define EPHY_GXL_ID 0x110181
+#define REG2_LEDACT GENMASK(23, 22)
+#define REG2_LEDLINK GENMASK(25, 24)
+#define REG2_DIV4SEL BIT(27)
+#define REG2_ADCBYPASS BIT(30)
+#define REG2_CLKINSEL BIT(31)
+#define ETH_REG3 0x4
+#define REG3_ENH BIT(3)
+#define REG3_CFGMODE GENMASK(6, 4)
+#define REG3_AUTOMDIX BIT(7)
+#define REG3_PHYADDR GENMASK(12, 8)
+#define REG3_PWRUPRST BIT(21)
+#define REG3_PWRDOWN BIT(22)
+#define REG3_LEDPOL BIT(23)
+#define REG3_PHYMDI BIT(26)
+#define REG3_CLKINEN BIT(29)
+#define REG3_PHYIP BIT(30)
+#define REG3_PHYEN BIT(31)
+#define ETH_REG4 0x8
+#define REG4_PWRUPRSTSIG BIT(0)
+
+#define MESON_GXL_MDIO_EXTERNAL_ID 0
+#define MESON_GXL_MDIO_INTERNAL_ID 1
+
+struct mdio_mux_meson_gxl_priv {
+ phys_addr_t regs;
+};
+
+static int meson_gxl_enable_internal_mdio(struct mdio_mux_meson_gxl_priv *priv)
+{
+ u32 val;
+
+ /* Setup the internal phy */
+ val = (REG3_ENH |
+ FIELD_PREP(REG3_CFGMODE, 0x7) |
+ REG3_AUTOMDIX |
+ FIELD_PREP(REG3_PHYADDR, 8) |
+ REG3_LEDPOL |
+ REG3_PHYMDI |
+ REG3_CLKINEN |
+ REG3_PHYIP);
+
+ writel(REG4_PWRUPRSTSIG, priv->regs + ETH_REG4);
+ writel(val, priv->regs + ETH_REG3);
+ mdelay(10);
+
+ /* NOTE: The HW kept the phy id configurable at runtime.
+ * The id below is arbitrary. It is the one used in the vendor code.
+ * The only constraint is that it must match the one in
+ * drivers/net/phy/meson-gxl.c to properly match the PHY.
+ */
+ writel(FIELD_PREP(REG2_PHYID, EPHY_GXL_ID),
+ priv->regs + ETH_REG2);
+
+ /* Enable the internal phy */
+ val |= REG3_PHYEN;
+ writel(val, priv->regs + ETH_REG3);
+ writel(0, priv->regs + ETH_REG4);
+
+ /* The phy needs a bit of time to power up */
+ mdelay(10);
+
+ return 0;
+}
+
+static int meson_gxl_enable_external_mdio(struct mdio_mux_meson_gxl_priv *priv)
+{
+ /* Reset the mdio bus mux to the external phy */
+ writel(0, priv->regs + ETH_REG3);
+
+ return 0;
+}
+
+static int mdio_mux_meson_gxl_select(struct udevice *mux, int cur, int sel)
+{
+ struct mdio_mux_meson_gxl_priv *priv = dev_get_priv(mux);
+
+ debug("%s: %x -> %x\n", __func__, (u32)cur, (u32)sel);
+
+ /* if last selection didn't change we're good to go */
+ if (cur == sel)
+ return 0;
+
+ switch (sel) {
+ case MESON_GXL_MDIO_EXTERNAL_ID:
+ return meson_gxl_enable_external_mdio(priv);
+ case MESON_GXL_MDIO_INTERNAL_ID:
+ return meson_gxl_enable_internal_mdio(priv);
+ default:
+ return -EINVAL;
+ }
+
+ return 0;
+}
+
+static const struct mdio_mux_ops mdio_mux_meson_gxl_ops = {
+ .select = mdio_mux_meson_gxl_select,
+};
+
+static int mdio_mux_meson_gxl_probe(struct udevice *dev)
+{
+ struct mdio_mux_meson_gxl_priv *priv = dev_get_priv(dev);
+
+ priv->regs = dev_read_addr(dev);
+
+ return 0;
+}
+
+static const struct udevice_id mdio_mux_meson_gxl_ids[] = {
+ { .compatible = "amlogic,gxl-mdio-mux" },
+ { }
+};
+
+U_BOOT_DRIVER(mdio_mux_meson_gxl) = {
+ .name = "mdio_mux_meson_gxl",
+ .id = UCLASS_MDIO_MUX,
+ .of_match = mdio_mux_meson_gxl_ids,
+ .probe = mdio_mux_meson_gxl_probe,
+ .ops = &mdio_mux_meson_gxl_ops,
+ .priv_auto = sizeof(struct mdio_mux_meson_gxl_priv),
+};