usb: host: xhci-rcar: Add Renesas RZ/G3E USB3 Host driver support

The USB3.2 Gen2 Host controller (a.k.a USB3HOST), IP found on the RZ/G3E
SoC is similar to R-Car XHCI, but it doesn't require any firmware.

Signed-off-by: Biju Das <biju.das.jz@bp.renesas.com>
Link: https://lore.kernel.org/r/20250916150255.4231-7-biju.das.jz@bp.renesas.com
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Author: bijudas

drivers/usb/host/Kconfig

@@ -93,7 +93,7 @@ config USB_XHCI_RCAR
 	default ARCH_RENESAS
 	help
 	  Say 'Y' to enable the support for the xHCI host controller
-	  found in Renesas R-Car ARM SoCs.
+	  found in Renesas R-Car and RZ/G3E alike ARM SoCs.
 
 config USB_XHCI_RZV2M
 	bool "xHCI support for Renesas RZ/V2M SoC"

drivers/usb/host/xhci-rcar.c

@@ -11,10 +11,12 @@
 #include <linux/platform_device.h>
 #include <linux/of.h>
 #include <linux/usb/phy.h>
+#include <linux/reset.h>
 
 #include "xhci.h"
 #include "xhci-plat.h"
 #include "xhci-rcar-regs.h"
+#include "xhci-rzg3e-regs.h"
 #include "xhci-rzv2m.h"
 
 #define XHCI_RCAR_FIRMWARE_NAME_V1	"r8a779x_usb3_v1.dlmem"
@@ -67,6 +69,48 @@ static void xhci_rcar_start(struct usb_hcd *hcd)
 	}
 }
 
+static void xhci_rzg3e_start(struct usb_hcd *hcd)
+{
+	u32 int_en;
+
+	if (hcd->regs) {
+		/* Update the controller initial setting */
+		writel(0x03130200, hcd->regs + RZG3E_USB3_HOST_U3P0PIPESC(0));
+		writel(0x00160200, hcd->regs + RZG3E_USB3_HOST_U3P0PIPESC(1));
+		writel(0x03150000, hcd->regs + RZG3E_USB3_HOST_U3P0PIPESC(2));
+		writel(0x03130200, hcd->regs + RZG3E_USB3_HOST_U3P0PIPESC(3));
+		writel(0x00180000, hcd->regs + RZG3E_USB3_HOST_U3P0PIPESC(4));
+
+		/* Interrupt Enable */
+		int_en = readl(hcd->regs + RZG3E_USB3_HOST_INTEN);
+		int_en |= RZG3E_USB3_HOST_INTEN_ENA;
+		writel(int_en, hcd->regs + RZG3E_USB3_HOST_INTEN);
+	}
+}
+
+static int xhci_rzg3e_resume(struct usb_hcd *hcd)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+
+	return reset_control_deassert(xhci->reset);
+}
+
+static int xhci_rzg3e_post_resume(struct usb_hcd *hcd)
+{
+	xhci_rzg3e_start(hcd);
+
+	return 0;
+}
+
+static int xhci_rzg3e_suspend(struct usb_hcd *hcd)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+
+	reset_control_assert(xhci->reset);
+
+	return 0;
+}
+
 static int xhci_rcar_download_firmware(struct usb_hcd *hcd)
 {
 	struct device *dev = hcd->self.controller;
@@ -190,6 +234,14 @@ static const struct xhci_plat_priv xhci_plat_renesas_rzv2m = {
 	.plat_start = xhci_rzv2m_start,
 };
 
+static const struct xhci_plat_priv xhci_plat_renesas_rzg3e = {
+	.quirks = XHCI_NO_64BIT_SUPPORT | XHCI_RESET_ON_RESUME | XHCI_SUSPEND_RESUME_CLKS,
+	.plat_start = xhci_rzg3e_start,
+	.suspend_quirk = xhci_rzg3e_suspend,
+	.resume_quirk = xhci_rzg3e_resume,
+	.post_resume_quirk = xhci_rzg3e_post_resume,
+};
+
 static const struct of_device_id usb_xhci_of_match[] = {
 	{
 		.compatible = "renesas,xhci-r8a7790",
@@ -206,6 +258,9 @@ static const struct of_device_id usb_xhci_of_match[] = {
 	}, {
 		.compatible = "renesas,xhci-r8a7796",
 		.data = &xhci_plat_renesas_rcar_gen3,
+	}, {
+		.compatible = "renesas,r9a09g047-xhci",
+		.data = &xhci_plat_renesas_rzg3e,
 	}, {
 		.compatible = "renesas,rcar-gen2-xhci",
 		.data = &xhci_plat_renesas_rcar_gen2,

drivers/usb/host/xhci-rzg3e-regs.h

@@ -0,0 +1,12 @@
+/* SPDX-License-Identifier: GPL-2.0 */
+#ifndef __XHCI_RZG3E_H
+#define __XHCI_RZG3E_H
+
+#define RZG3E_USB3_HOST_INTEN		0x1044	/* Interrupt Enable */
+#define RZG3E_USB3_HOST_U3P0PIPESC(x)	(0x10c0 + (x) * 4) /* PIPE Status and Control Register */
+
+#define RZG3E_USB3_HOST_INTEN_XHC	BIT(0)
+#define RZG3E_USB3_HOST_INTEN_HSE	BIT(2)
+#define RZG3E_USB3_HOST_INTEN_ENA	(RZG3E_USB3_HOST_INTEN_XHC | RZG3E_USB3_HOST_INTEN_HSE)
+
+#endif /* __XHCI_RZG3E_H */