net: stmmac: add support for RZ/N1 GMAC

Add support for the Renesas RZ/N1 GMAC. This support can make use of a
custom RZ/N1 PCS which is fetched by parsing the pcs-handle device tree
property.

Signed-off-by: Clément Léger <clement.leger@bootlin.com>
Co-developed-by: Romain Gantois <romain.gantois@bootlin.com>
Signed-off-by: Romain Gantois <romain.gantois@bootlin.com>
Reviewed-by: Russell King (Oracle) <rmk+kernel@armlinux.org.uk>
Reviewed-by: Hariprasad Kelam <hkelam@marvell.com>
Link: https://lore.kernel.org/r/20240513-rzn1-gmac1-v7-6-6acf58b5440d@bootlin.com
Signed-off-by: Jakub Kicinski <kuba@kernel.org>

MAINTAINERS

@@ -18874,6 +18874,12 @@ F:	include/dt-bindings/net/pcs-rzn1-miic.h
 F:	include/linux/pcs-rzn1-miic.h
 F:	net/dsa/tag_rzn1_a5psw.c
 
+RENESAS RZ/N1 DWMAC GLUE LAYER
+M:	Romain Gantois <romain.gantois@bootlin.com>
+S:	Maintained
+F:	Documentation/devicetree/bindings/net/renesas,rzn1-gmac.yaml
+F:	drivers/net/ethernet/stmicro/stmmac/dwmac-rzn1.c
+
 RENESAS RZ/N1 RTC CONTROLLER DRIVER
 M:	Miquel Raynal <miquel.raynal@bootlin.com>
 L:	linux-rtc@vger.kernel.org

drivers/net/ethernet/stmicro/stmmac/Kconfig

@@ -142,6 +142,18 @@ config DWMAC_ROCKCHIP
 	  This selects the Rockchip RK3288 SoC glue layer support for
 	  the stmmac device driver.
 
+config DWMAC_RZN1
+	tristate "Renesas RZ/N1 dwmac support"
+	default ARCH_RZN1
+	depends on OF && (ARCH_RZN1 || COMPILE_TEST)
+	select PCS_RZN1_MIIC
+	help
+	  Support for Ethernet controller on Renesas RZ/N1 SoC family.
+
+	  This selects the Renesas RZ/N1 SoC glue layer support for
+	  the stmmac device driver. This support can make use of a custom MII
+	  converter PCS device.
+
 config DWMAC_SOCFPGA
 	tristate "SOCFPGA dwmac support"
 	default ARCH_INTEL_SOCFPGA

drivers/net/ethernet/stmicro/stmmac/Makefile

@@ -21,6 +21,7 @@ obj-$(CONFIG_DWMAC_MEDIATEK)	+= dwmac-mediatek.o
 obj-$(CONFIG_DWMAC_MESON)	+= dwmac-meson.o dwmac-meson8b.o
 obj-$(CONFIG_DWMAC_QCOM_ETHQOS)	+= dwmac-qcom-ethqos.o
 obj-$(CONFIG_DWMAC_ROCKCHIP)	+= dwmac-rk.o
+obj-$(CONFIG_DWMAC_RZN1)	+= dwmac-rzn1.o
 obj-$(CONFIG_DWMAC_SOCFPGA)	+= dwmac-altr-socfpga.o
 obj-$(CONFIG_DWMAC_STARFIVE)	+= dwmac-starfive.o
 obj-$(CONFIG_DWMAC_STI)		+= dwmac-sti.o

drivers/net/ethernet/stmicro/stmmac/dwmac-rzn1.c

@@ -0,0 +1,86 @@
+// SPDX-License-Identifier: GPL-2.0-or-later
+/*
+ * Copyright (C) 2024 Schneider-Electric
+ *
+ * Clément Léger <clement.leger@bootlin.com>
+ */
+
+#include <linux/of.h>
+#include <linux/pcs-rzn1-miic.h>
+#include <linux/phylink.h>
+#include <linux/platform_device.h>
+
+#include "stmmac_platform.h"
+#include "stmmac.h"
+
+static int rzn1_dwmac_pcs_init(struct stmmac_priv *priv)
+{
+	struct device_node *np = priv->device->of_node;
+	struct device_node *pcs_node;
+	struct phylink_pcs *pcs;
+
+	pcs_node = of_parse_phandle(np, "pcs-handle", 0);
+
+	if (pcs_node) {
+		pcs = miic_create(priv->device, pcs_node);
+		of_node_put(pcs_node);
+		if (IS_ERR(pcs))
+			return PTR_ERR(pcs);
+
+		priv->hw->phylink_pcs = pcs;
+	}
+
+	return 0;
+}
+
+static void rzn1_dwmac_pcs_exit(struct stmmac_priv *priv)
+{
+	if (priv->hw->phylink_pcs)
+		miic_destroy(priv->hw->phylink_pcs);
+}
+
+static int rzn1_dwmac_probe(struct platform_device *pdev)
+{
+	struct plat_stmmacenet_data *plat_dat;
+	struct stmmac_resources stmmac_res;
+	struct device *dev = &pdev->dev;
+	int ret;
+
+	ret = stmmac_get_platform_resources(pdev, &stmmac_res);
+	if (ret)
+		return ret;
+
+	plat_dat = devm_stmmac_probe_config_dt(pdev, stmmac_res.mac);
+	if (IS_ERR(plat_dat))
+		return PTR_ERR(plat_dat);
+
+	plat_dat->bsp_priv = plat_dat;
+	plat_dat->pcs_init = rzn1_dwmac_pcs_init;
+	plat_dat->pcs_exit = rzn1_dwmac_pcs_exit;
+
+	ret = stmmac_dvr_probe(dev, plat_dat, &stmmac_res);
+	if (ret)
+		return ret;
+
+	return 0;
+}
+
+static const struct of_device_id rzn1_dwmac_match[] = {
+	{ .compatible = "renesas,rzn1-gmac" },
+	{ }
+};
+MODULE_DEVICE_TABLE(of, rzn1_dwmac_match);
+
+static struct platform_driver rzn1_dwmac_driver = {
+	.probe  = rzn1_dwmac_probe,
+	.remove_new = stmmac_pltfr_remove,
+	.driver = {
+		.name           = "rzn1-dwmac",
+		.of_match_table = rzn1_dwmac_match,
+	},
+};
+module_platform_driver(rzn1_dwmac_driver);
+
+MODULE_AUTHOR("Clément Léger <clement.leger@bootlin.com>");
+MODULE_DESCRIPTION("Renesas RZN1 DWMAC specific glue layer");
+MODULE_LICENSE("GPL");