[PATCH] usb: gadget: renesas: add support for RZ/G2L SoC

[PATCH] usb: gadget: renesas: add support for RZ/G2L SoC

[Michele Bisogno]

Support the Renesas RZ/G2L (r9a07g044) USBHS IP by addressing
platform-specific reset, glue logic, and FIFO access requirements.

- regulator: rzg2l: Implement CON_CTRL manual connectivity notification.
  By setting SEL_CONNECT and CONNECT_1, the UTM+ core is notified of
  connection status in peripheral mode.
- gadget: common: Add "renesas,rzg2l-usbhs" compatible and support
  reset deassertion. Fix a re-entrancy bug by calling usb_del_gadget_udc()
  in the remove callback to prevent stale UDC list entries.
- gadget: fifo: Refactor PIO push/pop logic to handle trailing bytes
  using iowrite8/ioread8. This ensures correct data alignment on
  RZ/G2L and simplifies the data transfer loop.

Signed-off-by: Michele Bisogno <micbis.openwrt@gmail.com>
---
 .../power/regulator/rzg2l-usbphy-regulator.c  | 10 ++++++--
 drivers/usb/gadget/rcar/common.c              | 15 ++++++++++++
 drivers/usb/gadget/rcar/fifo.c                | 23 +++++++++++--------
 3 files changed, 36 insertions(+), 12 deletions(-)

diff --git a/drivers/power/regulator/rzg2l-usbphy-regulator.c b/drivers/power/regulator/rzg2l-usbphy-regulator.c
index 0354555d0b5..03f8dec4f08 100644
--- a/drivers/power/regulator/rzg2l-usbphy-regulator.c
+++ b/drivers/power/regulator/rzg2l-usbphy-regulator.c
@@ -9,16 +9,22 @@
 #include <renesas/rzg2l-usbphy.h>
 
 #define VBENCTL			0x03c
+#define CON_CTRL		0x020
 #define VBENCTL_VBUS_SEL	BIT(0)
+#define SEL_CONNECT		BIT(4)
+#define CONNECT_1		BIT(0)
 
 static int rzg2l_usbphy_regulator_set_enable(struct udevice *dev, bool enable)
 {
 	struct rzg2l_usbphy_ctrl_priv *priv = dev_get_priv(dev->parent);
 
-	if (enable)
+	if (enable) {
 		clrbits_le32(priv->regs + VBENCTL, VBENCTL_VBUS_SEL);
-	else
+		setbits_le32(priv->regs + CON_CTRL, SEL_CONNECT | CONNECT_1);
+	} else {
 		setbits_le32(priv->regs + VBENCTL, VBENCTL_VBUS_SEL);
+		clrbits_le32(priv->regs + CON_CTRL, SEL_CONNECT | CONNECT_1);
+	}
 
 	return 0;
 }
diff --git a/drivers/usb/gadget/rcar/common.c b/drivers/usb/gadget/rcar/common.c
index 2ba022a3f2c..1f266ae5ac9 100644
--- a/drivers/usb/gadget/rcar/common.c
+++ b/drivers/usb/gadget/rcar/common.c
@@ -16,6 +16,7 @@
 #include <linux/usb/ch9.h>
 #include <linux/usb/gadget.h>
 #include <usb.h>
+#include <reset.h>
 
 #include "common.h"
 
@@ -397,6 +398,7 @@ static int usbhs_udc_otg_probe(struct udevice *dev)
 	struct usbhs_priv_otg_data *priv = dev_get_priv(dev);
 	struct usb_gadget *gadget;
 	struct clk_bulk clk_bulk;
+	struct reset_ctl_bulk reset_bulk;
 	int ret = -EINVAL;
 
 	priv->base = dev_read_addr_ptr(dev);
@@ -411,6 +413,14 @@ static int usbhs_udc_otg_probe(struct udevice *dev)
 	if (ret)
 		return ret;
 
+	ret = reset_get_bulk(dev, &reset_bulk);
+	if (ret)
+		return ret;
+
+	ret = reset_deassert_bulk(&reset_bulk);
+	if (ret)
+		return ret;
+
 	clrsetbits_le32(priv->base + UGCTRL2, UGCTRL2_USB0SEL_MASK, UGCTRL2_USB0SEL_EHCI);
 	clrsetbits_le16(priv->base + LPSTS, LPSTS_SUSPM, LPSTS_SUSPM);
 
@@ -447,7 +457,11 @@ err_clk:
 static int usbhs_udc_otg_remove(struct udevice *dev)
 {
 	struct usbhs_priv_otg_data *priv = dev_get_priv(dev);
+	struct usb_gadget *gadget;
 
+	gadget = usbhsg_get_gadget(&priv->usbhs_priv);
+	if (gadget)
+		usb_del_gadget_udc(gadget);
 	usbhs_rcar3_power_ctrl(&priv->usbhs_priv, false);
 	usbhs_mod_remove(&priv->usbhs_priv);
 	usbhs_fifo_remove(&priv->usbhs_priv);
@@ -460,6 +474,7 @@ static int usbhs_udc_otg_remove(struct udevice *dev)
 
 static const struct udevice_id usbhs_udc_otg_ids[] = {
 	{ .compatible = "renesas,rcar-gen3-usbhs" },
+	{ .compatible = "renesas,rzg2l-usbhs"},
 	{},
 };
 
diff --git a/drivers/usb/gadget/rcar/fifo.c b/drivers/usb/gadget/rcar/fifo.c
index 6016b2987d5..b5340b4d860 100644
--- a/drivers/usb/gadget/rcar/fifo.c
+++ b/drivers/usb/gadget/rcar/fifo.c
@@ -535,18 +535,21 @@ static int usbhsf_pio_try_push(struct usbhs_pkt *pkt, int *is_done)
 	 * 32-bit access only
 	 */
 	if (len >= 4 && !((unsigned long)buf & 0x03)) {
-		iowrite32_rep(addr, buf, len / 4);
-		len %= 4;
-		buf += total_len - len;
+		int words = len / 4;
+
+		iowrite32_rep(addr, buf, words);
+		buf += (words * 4);
+		len -= (words * 4);
 	}
 
 	/* the rest operation */
-	if (usbhs_get_dparam(priv, cfifo_byte_addr)) {
-		for (i = 0; i < len; i++)
-			iowrite8(buf[i], addr + (i & 0x03));
-	} else {
-		for (i = 0; i < len; i++)
-			iowrite8(buf[i], addr + (0x03 - (i & 0x03)));
+	if (len > 0) {
+		if (len == 2 && !((unsigned long)buf & 0x01)) {
+			iowrite16(*(u16 *)buf, addr);
+		} else {
+			for (i = 0; i < len; i++)
+				iowrite8(buf[i], addr);
+		}
 	}
 
 	/*
@@ -716,7 +719,7 @@ static int usbhsf_pio_try_pop(struct usbhs_pkt *pkt, int *is_done)
 		if (!(i & 0x03))
 			data = ioread32(addr);
 
-		buf[i] = (data >> ((i & 0x03) * 8)) & 0xff;
+		buf[i] = ioread8(addr);
 	}
 
 usbhs_fifo_read_end:
-- 
2.34.1

Re: [PATCH] usb: gadget: renesas: add support for RZ/G2L SoC

[Marek Vasut]

On 4/15/26 7:21 PM, Michele Bisogno wrote:
> Support the Renesas RZ/G2L (r9a07g044) USBHS IP by addressing
> platform-specific reset, glue logic, and FIFO access requirements.
> 
> - regulator: rzg2l: Implement CON_CTRL manual connectivity notification.
>    By setting SEL_CONNECT and CONNECT_1, the UTM+ core is notified of
>    connection status in peripheral mode.
> - gadget: common: Add "renesas,rzg2l-usbhs" compatible and support
>    reset deassertion. Fix a re-entrancy bug by calling usb_del_gadget_udc()
>    in the remove callback to prevent stale UDC list entries.
> - gadget: fifo: Refactor PIO push/pop logic to handle trailing bytes
>    using iowrite8/ioread8. This ensures correct data alignment on
>    RZ/G2L and simplifies the data transfer loop.
> 
> Signed-off-by: Michele Bisogno <micbis.openwrt@gmail.com>
> ---
>   .../power/regulator/rzg2l-usbphy-regulator.c  | 10 ++++++--

Regulator change should be a separate patch please.

>   drivers/usb/gadget/rcar/common.c              | 15 ++++++++++++
>   drivers/usb/gadget/rcar/fifo.c                | 23 +++++++++++--------
drivers/usb/gadget/rcar is pulled from Linux 1b4861e32e46 ("Linux 
6.9.3") , but none of these changes in this patch are even in Linux 
next. Is there at least a submitted Linux kernel patch which adds these 
matching changes ? I would very much like to keep the USBHS drivers 
synchronized between U-Boot and Linux.

The addition of RZ/G2L into USBHS driver in Linux was much simpler:

https://lore.kernel.org/r/20240319105356.87287-5-biju.das.jz@bp.renesas.com

Re: [PATCH] usb: gadget: renesas: add support for RZ/G2L SoC

[Michele Bisogno]

Hi Marek,

Thank you for the review and the link to the Linux implementation.

> Regulator change should be a separate patch please.

I agree. I will split the regulator changes into a separate patch
for the v2 series to keep the subsystem changes distinct.

> drivers/usb/gadget/rcar is pulled from Linux 1b4861e32e46...
> but none of these changes in this patch are even in Linux next.

The RZ/G2L support in Linux relies heavily on DMA for data transfers.
In U-Boot, we are primarily using the PIO path. The refactoring
in fifo.c (switching to ioread8/iowrite8) was found to be necessary
to handle trailing bytes and alignment specifically for the RZ/G2L
bus when DMA is not active.

Additionally, the usb_del_gadget_udc() change in common.c addresses
a re-entrancy bug unique to U-Boot's gadget lifecycle. Without
this, the UDC list becomes stale, causing the board to crash if
a command like 'ums' is executed more than once.

> The addition of RZ/G2L into USBHS driver in Linux was much simpler

I agree that moving the RZ/G2L specifics in common.c to a platform
dependent file (similar to Linux) would be the cleaner long-term
architecture. However, doing so would require a much more invasive
refactoring of the existing driver structure. I opted for these
minimal changes to maintain stability for existing R-Car Gen3
users while enabling RZ/G2L support.

I will prepare a v2 series with the patches split as requested.

Kind regards,
Michele

Re: [PATCH] usb: gadget: renesas: add support for RZ/G2L SoC

[Marek Vasut]

On 4/16/26 4:14 PM, Michele Bisogno wrote:

Hello Michele,

> Thank you for the review and the link to the Linux implementation.
> 
>> Regulator change should be a separate patch please.
> 
> I agree. I will split the regulator changes into a separate patch
> for the v2 series to keep the subsystem changes distinct.
> 
>> drivers/usb/gadget/rcar is pulled from Linux 1b4861e32e46...
>> but none of these changes in this patch are even in Linux next.
> 
> The RZ/G2L support in Linux relies heavily on DMA for data transfers.
> In U-Boot, we are primarily using the PIO path. The refactoring
> in fifo.c (switching to ioread8/iowrite8) was found to be necessary
> to handle trailing bytes and alignment specifically for the RZ/G2L
> bus when DMA is not active.

If Linux also contains the PIO code, it would also benefit from matching 
improvement, right ?

> Additionally, the usb_del_gadget_udc() change in common.c addresses
> a re-entrancy bug unique to U-Boot's gadget lifecycle. Without
> this, the UDC list becomes stale, causing the board to crash if
> a command like 'ums' is executed more than once.

This should be a separate bugfix patch.

>> The addition of RZ/G2L into USBHS driver in Linux was much simpler
> 
> I agree that moving the RZ/G2L specifics in common.c to a platform
> dependent file (similar to Linux) would be the cleaner long-term
> architecture. However, doing so would require a much more invasive
> refactoring of the existing driver structure. I opted for these
> minimal changes to maintain stability for existing R-Car Gen3
> users while enabling RZ/G2L support.
> 
> I will prepare a v2 series with the patches split as requested.

Ideally, let's try to keep the Linux and U-Boot driver code base 
synchronized as much as possible.

Thank you !

Re: [PATCH] usb: gadget: renesas: add support for RZ/G2L SoC

[Michele Bisogno]

Hi Marek,

thank you for your comments and suggestions.

> If Linux also contains the PIO code, it would also benefit from matching
> improvement, right ?

Yes, though I have found the fix is not strictly required. We can maintain
synchronization between both repositories by utilizing the cfifo_byte_addr
parameter for the RZ/G2L and similar devices, allowing us to leave the
existing PIO code untouched.

> This should be a separate bugfix patch.

Agreed.

> Ideally, let's try to keep the Linux and U-Boot driver code base
> synchronized as much as possible.

Understood. I am currently preparing a revised patch set that aligns with
this approach to ensure consistency between the codebases.

Kind regards,
Michele

Re: [PATCH] usb: gadget: renesas: add support for RZ/G2L SoC

[Marek Vasut]

On 4/21/26 9:32 AM, Michele Bisogno wrote:

Hello Michele,

> thank you for your comments and suggestions.
> 
>> If Linux also contains the PIO code, it would also benefit from matching
>> improvement, right ?
> 
> Yes, though I have found the fix is not strictly required. We can maintain
> synchronization between both repositories by utilizing the cfifo_byte_addr
> parameter for the RZ/G2L and similar devices, allowing us to leave the
> existing PIO code untouched.
> 
>> This should be a separate bugfix patch.
> 
> Agreed.
> 
>> Ideally, let's try to keep the Linux and U-Boot driver code base
>> synchronized as much as possible.
> 
> Understood. I am currently preparing a revised patch set that aligns with
> this approach to ensure consistency between the codebases.
Thank you !