[PATCH V2 0/4] USB Fixes for Gadget Mode on DWC3

[PATCH V2 0/4] USB Fixes for Gadget Mode on DWC3

[Chris Morgan]

From: Chris Morgan <macromorgan@hotmail.com>

In order to get gadget mode functional (for fastboot and ums) I need to
pull two patches in from mainline Linux. After applying these two
patches to U-Boot I am able to use ums and fastboot on my Anbernic
RG353P device for testing purposes.

Changes since V1:
 - Take the existing dwc3_core_soft_reset() function from the upstream
   Linux core.c file. This necessitates including another patch to add
   support from upstream Linux for the ip and version_type field and
   accompanying macros and functions to initialize it.
 - Specify the timeout changes made in the gadget driver as part of
   a separate patch and note the change is required.
 - Remove change in dwc3_ref_clk_period() as it was not intended to
   be included.

Chris Morgan (4):
  usb: dwc3: core: Add ip and version_type support from Linux
  usb: dwc3: Increase DWC3 controller halt timeout
  usb: dwc3: gadget: Don't send unintended link state change
  usb: dwc3: core: improve reset sequence

 drivers/usb/dwc3/core.c   | 92 +++++++++++++++++++++++++--------------
 drivers/usb/dwc3/core.h   | 60 +++++++++++++++++++++++++
 drivers/usb/dwc3/gadget.c | 20 ++++-----
 drivers/usb/dwc3/gadget.h | 14 ++++++
 4 files changed, 143 insertions(+), 43 deletions(-)

-- 
2.43.0

[PATCH V2 1/4] usb: dwc3: core: Add ip and version_type support from Linux

[Chris Morgan]

From: Chris Morgan <macromorgan@hotmail.com>

Add support for the ip and version_type fields from the Linux
version of the dwc3 driver. Included in this is support for a
few additional macros in the header from Linux as well.

Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/usb/dwc3/core.c | 26 ++++++++++++++----
 drivers/usb/dwc3/core.h | 60 +++++++++++++++++++++++++++++++++++++++++
 2 files changed, 81 insertions(+), 5 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 847fa1f82c3..4827c83e96d 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -580,6 +580,26 @@ static void dwc3_set_incr_burst_type(struct dwc3 *dwc)
 	dwc3_writel(dwc->regs, DWC3_GSBUSCFG0, cfg);
 }
 
+static bool dwc3_core_is_valid(struct dwc3 *dwc)
+{
+	u32 reg;
+
+	reg = dwc3_readl(dwc->regs, DWC3_GSNPSID);
+	dwc->ip = DWC3_GSNPS_ID(reg);
+
+	/* This should read as U3 followed by revision number */
+	if (DWC3_IP_IS(DWC3)) {
+		dwc->revision = reg;
+	} else if (DWC3_IP_IS(DWC31) || DWC3_IP_IS(DWC32)) {
+		dwc->revision = dwc3_readl(dwc->regs, DWC3_VER_NUMBER);
+		dwc->version_type = dwc3_readl(dwc->regs, DWC3_VER_TYPE);
+	} else {
+		return false;
+	}
+
+	return true;
+}
+
 /**
  * dwc3_core_init - Low-level initialization of DWC3 Core
  * @dwc: Pointer to our controller context structure
@@ -592,15 +612,11 @@ static int dwc3_core_init(struct dwc3 *dwc)
 	u32			reg;
 	int			ret;
 
-	reg = dwc3_readl(dwc->regs, DWC3_GSNPSID);
-	/* This should read as U3 followed by revision number */
-	if ((reg & DWC3_GSNPSID_MASK) != 0x55330000 &&
-	    (reg & DWC3_GSNPSID_MASK) != 0x33310000) {
+	if (!dwc3_core_is_valid(dwc)) {
 		dev_err(dwc->dev, "this is not a DesignWare USB3 DRD Core\n");
 		ret = -ENODEV;
 		goto err0;
 	}
-	dwc->revision = reg;
 
 	/* Handle USB2.0-only core configuration */
 	if (DWC3_GHWPARAMS3_SSPHY_IFC(dwc->hwparams.hwparams3) ==
diff --git a/drivers/usb/dwc3/core.h b/drivers/usb/dwc3/core.h
index b572ea340c8..cdbfdce76bb 100644
--- a/drivers/usb/dwc3/core.h
+++ b/drivers/usb/dwc3/core.h
@@ -56,6 +56,7 @@
 #define DWC3_GEVNTCOUNT_MASK	0xfffc
 #define DWC3_GSNPSID_MASK	0xffff0000
 #define DWC3_GSNPSREV_MASK	0xffff
+#define DWC3_GSNPS_ID(p)	(((p) & DWC3_GSNPSID_MASK) >> 16)
 
 /* DWC3 registers memory space boundries */
 #define DWC3_XHCI_REGS_START		0x0
@@ -99,6 +100,9 @@
 #define DWC3_GPRTBIMAP_FS0	0xc188
 #define DWC3_GPRTBIMAP_FS1	0xc18c
 
+#define DWC3_VER_NUMBER		0xc1a0
+#define DWC3_VER_TYPE		0xc1a4
+
 #define DWC3_GUSB2PHYCFG(n)	(0xc200 + (n * 0x04))
 #define DWC3_GUSB2I2CCTL(n)	(0xc240 + (n * 0x04))
 
@@ -686,7 +690,9 @@ struct dwc3_scratchpad_array {
  * @num_event_buffers: calculated number of event buffers
  * @u1u2: only used on revisions <1.83a for workaround
  * @maximum_speed: maximum speed requested (mainly for testing purposes)
+ * @ip: controller's ID
  * @revision: revision register contents
+ * @version_type: VERSIONTYPE register contents, a sub release of a revision
  * @dr_mode: requested mode of operation
  * @hsphy_mode: UTMI phy mode, one of following:
  *		- USBPHY_INTERFACE_MODE_UTMI
@@ -795,6 +801,13 @@ struct dwc3 {
 	u32			num_event_buffers;
 	u32			u1u2;
 	u32			maximum_speed;
+
+	u32			ip;
+
+#define DWC3_IP			0x5533
+#define DWC31_IP		0x3331
+#define DWC32_IP		0x3332
+
 	u32			revision;
 
 #define DWC3_REVISION_173A	0x5533173a
@@ -817,6 +830,32 @@ struct dwc3 {
 #define DWC3_REVISION_270A	0x5533270a
 #define DWC3_REVISION_280A	0x5533280a
 #define DWC3_REVISION_290A	0x5533290a
+#define DWC3_REVISION_300A	0x5533300a
+#define DWC3_REVISION_310A	0x5533310a
+#define DWC3_REVISION_320A	0x5533320a
+#define DWC3_REVISION_330A	0x5533330a
+
+#define DWC31_REVISION_ANY	0x0
+#define DWC31_REVISION_110A	0x3131302a
+#define DWC31_REVISION_120A	0x3132302a
+#define DWC31_REVISION_160A	0x3136302a
+#define DWC31_REVISION_170A	0x3137302a
+#define DWC31_REVISION_180A	0x3138302a
+#define DWC31_REVISION_190A	0x3139302a
+#define DWC31_REVISION_200A	0x3230302a
+
+#define DWC32_REVISION_ANY	0x0
+#define DWC32_REVISION_100A	0x3130302a
+
+	u32			version_type;
+
+#define DWC31_VERSIONTYPE_ANY		0x0
+#define DWC31_VERSIONTYPE_EA01		0x65613031
+#define DWC31_VERSIONTYPE_EA02		0x65613032
+#define DWC31_VERSIONTYPE_EA03		0x65613033
+#define DWC31_VERSIONTYPE_EA04		0x65613034
+#define DWC31_VERSIONTYPE_EA05		0x65613035
+#define DWC31_VERSIONTYPE_EA06		0x65613036
 
 	enum dwc3_ep0_next	ep0_next_event;
 	enum dwc3_ep0_state	ep0state;
@@ -1062,6 +1101,27 @@ void dwc3_of_parse(struct dwc3 *dwc);
 int dwc3_init(struct dwc3 *dwc);
 void dwc3_remove(struct dwc3 *dwc);
 
+#define DWC3_IP_IS(_ip)							\
+	(dwc->ip == _ip##_IP)
+
+#define DWC3_VER_IS(_ip, _ver)						\
+	(DWC3_IP_IS(_ip) && dwc->revision == _ip##_REVISION_##_ver)
+
+#define DWC3_VER_IS_PRIOR(_ip, _ver)					\
+	(DWC3_IP_IS(_ip) && dwc->revision < _ip##_REVISION_##_ver)
+
+#define DWC3_VER_IS_WITHIN(_ip, _from, _to)				\
+	(DWC3_IP_IS(_ip) &&						\
+	 dwc->revision >= _ip##_REVISION_##_from &&			\
+	 (!(_ip##_REVISION_##_to) ||					\
+	  dwc->revision <= _ip##_REVISION_##_to))
+
+#define DWC3_VER_TYPE_IS_WITHIN(_ip, _ver, _from, _to)			\
+	(DWC3_VER_IS(_ip, _ver) &&					\
+	 dwc->version_type >= _ip##_VERSIONTYPE_##_from &&		\
+	 (!(_ip##_VERSIONTYPE_##_to) ||					\
+	  dwc->version_type <= _ip##_VERSIONTYPE_##_to))
+
 static inline int dwc3_host_init(struct dwc3 *dwc)
 { return 0; }
 static inline void dwc3_host_exit(struct dwc3 *dwc)
-- 
2.43.0

Re: [PATCH V2 1/4] usb: dwc3: core: Add ip and version_type support from Linux

[Mattijs Korpershoek]

Hi Chris,

Thank you for the patch.

On Thu, Jan 15, 2026 at 17:01, Chris Morgan <macroalpha82@gmail.com> wrote:

> From: Chris Morgan <macromorgan@hotmail.com>
>
> Add support for the ip and version_type fields from the Linux
> version of the dwc3 driver. Included in this is support for a
> few additional macros in the header from Linux as well.
>
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>

> ---
>  drivers/usb/dwc3/core.c | 26 ++++++++++++++----
>  drivers/usb/dwc3/core.h | 60 +++++++++++++++++++++++++++++++++++++++++
>  2 files changed, 81 insertions(+), 5 deletions(-)
>

[PATCH V2 2/4] usb: dwc3: Increase DWC3 controller halt timeout

[Chris Morgan]

From: Chris Morgan <macromorgan@hotmail.com>

Since EP0 transactions need to be completed before the controller halt
sequence is finished, this may take some time depending on the host and the
enabled functions.  Increase the controller halt timeout, so that we give
the controller sufficient time to handle EP0 transfers.

This patch was originally submitted to Linux in 2022, but is required to
use USB gadget mode on my device in U-Boot.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=461ee467507cb98a348fa91ff8460908bb0ea423

Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/usb/dwc3/gadget.c | 4 ++--
 1 file changed, 2 insertions(+), 2 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index 2b01113d54c..d2ae892d554 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -1396,7 +1396,7 @@ static int dwc3_gadget_set_selfpowered(struct usb_gadget *g,
 static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
 {
 	u32			reg;
-	u32			timeout = 500;
+	u32			timeout = 2000;
 
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 	if (is_on) {
@@ -1425,6 +1425,7 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
 	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
 
 	do {
+		udelay(2000);
 		reg = dwc3_readl(dwc->regs, DWC3_DSTS);
 		if (is_on) {
 			if (!(reg & DWC3_DSTS_DEVCTRLHLT))
@@ -1436,7 +1437,6 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
 		timeout--;
 		if (!timeout)
 			return -ETIMEDOUT;
-		udelay(1);
 	} while (1);
 
 	dev_vdbg(dwc->dev, "gadget %s data soft-%s\n",
-- 
2.43.0

Re: [PATCH V2 2/4] usb: dwc3: Increase DWC3 controller halt timeout

[Mattijs Korpershoek]

Hi Chris,

Thank you for the patch.

On Thu, Jan 15, 2026 at 17:01, Chris Morgan <macroalpha82@gmail.com> wrote:

> From: Chris Morgan <macromorgan@hotmail.com>
>
> Since EP0 transactions need to be completed before the controller halt
> sequence is finished, this may take some time depending on the host and the
> enabled functions.  Increase the controller halt timeout, so that we give
> the controller sufficient time to handle EP0 transfers.
>
> This patch was originally submitted to Linux in 2022, but is required to
> use USB gadget mode on my device in U-Boot.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/commit/?id=461ee467507cb98a348fa91ff8460908bb0ea423
>
> Signed-off-by: Wesley Cheng <quic_wcheng@quicinc.com>
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>

> ---
>  drivers/usb/dwc3/gadget.c | 4 ++--
>  1 file changed, 2 insertions(+), 2 deletions(-)
>

[PATCH V2 3/4] usb: dwc3: gadget: Don't send unintended link state change

[Chris Morgan]

From: Chris Morgan <macromorgan@hotmail.com>

DCTL.ULSTCHNGREQ is a write-only field. When doing a read-modify-write
to DCTL, the driver must make sure that there's no unintended link state
change request from whatever is read from DCTL.ULSTCHNGREQ. Set link
state change to no-action when the driver writes to DCTL.

Note that this patch was submitted upstream in Linux in 2020 [1],
and I've confirmed I need it in U-Boot to enable gadget mode.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/dwc3?id=5b738211fb59e114727381d07c647a77c0010996

Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/usb/dwc3/gadget.c | 16 +++++++---------
 drivers/usb/dwc3/gadget.h | 14 ++++++++++++++
 2 files changed, 21 insertions(+), 9 deletions(-)

diff --git a/drivers/usb/dwc3/gadget.c b/drivers/usb/dwc3/gadget.c
index d2ae892d554..24ae0c232f6 100644
--- a/drivers/usb/dwc3/gadget.c
+++ b/drivers/usb/dwc3/gadget.c
@@ -62,7 +62,7 @@ int dwc3_gadget_set_test_mode(struct dwc3 *dwc, int mode)
 		return -EINVAL;
 	}
 
-	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+	dwc3_gadget_dctl_write_safe(dwc, reg);
 
 	return 0;
 }
@@ -1422,7 +1422,7 @@ static int dwc3_gadget_run_stop(struct dwc3 *dwc, int is_on, int suspend)
 		dwc->pullups_connected = false;
 	}
 
-	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+	dwc3_gadget_dctl_write_safe(dwc, reg);
 
 	do {
 		udelay(2000);
@@ -2137,10 +2137,8 @@ static void dwc3_gadget_disconnect_interrupt(struct dwc3 *dwc)
 
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 	reg &= ~DWC3_DCTL_INITU1ENA;
-	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
-
 	reg &= ~DWC3_DCTL_INITU2ENA;
-	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+	dwc3_gadget_dctl_write_safe(dwc, reg);
 
 	dwc3_disconnect_gadget(dwc);
 	dwc->start_config_issued = false;
@@ -2189,7 +2187,7 @@ static void dwc3_gadget_reset_interrupt(struct dwc3 *dwc)
 
 	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 	reg &= ~DWC3_DCTL_TSTCTRL_MASK;
-	dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+	dwc3_gadget_dctl_write_safe(dwc, reg);
 	dwc->test_mode = false;
 
 	dwc3_stop_active_transfers(dwc);
@@ -2305,11 +2303,11 @@ static void dwc3_gadget_conndone_interrupt(struct dwc3 *dwc)
 		if (dwc->has_lpm_erratum && dwc->revision >= DWC3_REVISION_240A)
 			reg |= DWC3_DCTL_LPM_ERRATA(dwc->lpm_nyet_threshold);
 
-		dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+		dwc3_gadget_dctl_write_safe(dwc, reg);
 	} else {
 		reg = dwc3_readl(dwc->regs, DWC3_DCTL);
 		reg &= ~DWC3_DCTL_HIRD_THRES_MASK;
-		dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+		dwc3_gadget_dctl_write_safe(dwc, reg);
 	}
 
 	dep = dwc->eps[0];
@@ -2417,7 +2415,7 @@ static void dwc3_gadget_linksts_change_interrupt(struct dwc3 *dwc,
 
 				reg &= ~u1u2;
 
-				dwc3_writel(dwc->regs, DWC3_DCTL, reg);
+				dwc3_gadget_dctl_write_safe(dwc, reg);
 				break;
 			default:
 				/* do nothing */
diff --git a/drivers/usb/dwc3/gadget.h b/drivers/usb/dwc3/gadget.h
index f28a9755dcb..e4f5a096956 100644
--- a/drivers/usb/dwc3/gadget.h
+++ b/drivers/usb/dwc3/gadget.h
@@ -104,4 +104,18 @@ static inline u32 dwc3_gadget_ep_get_transfer_index(struct dwc3 *dwc, u8 number)
 	return DWC3_DEPCMD_GET_RSC_IDX(res_id);
 }
 
+/**
+ * dwc3_gadget_dctl_write_safe - write to DCTL safe from link state change
+ * @dwc: pointer to our context structure
+ * @value: value to write to DCTL
+ *
+ * Use this function when doing read-modify-write to DCTL. It will not
+ * send link state change request.
+ */
+static inline void dwc3_gadget_dctl_write_safe(struct dwc3 *dwc, u32 value)
+{
+	value &= ~DWC3_DCTL_ULSTCHNGREQ_MASK;
+	dwc3_writel(dwc->regs, DWC3_DCTL, value);
+}
+
 #endif /* __DRIVERS_USB_DWC3_GADGET_H */
-- 
2.43.0

Re: [PATCH V2 3/4] usb: dwc3: gadget: Don't send unintended link state change

[Mattijs Korpershoek]

Hi Chris,

Thank you for the patch.

On Thu, Jan 15, 2026 at 17:01, Chris Morgan <macroalpha82@gmail.com> wrote:

> From: Chris Morgan <macromorgan@hotmail.com>
>
> DCTL.ULSTCHNGREQ is a write-only field. When doing a read-modify-write
> to DCTL, the driver must make sure that there's no unintended link state
> change request from whatever is read from DCTL.ULSTCHNGREQ. Set link
> state change to no-action when the driver writes to DCTL.
>
> Note that this patch was submitted upstream in Linux in 2020 [1],
> and I've confirmed I need it in U-Boot to enable gadget mode.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/dwc3?id=5b738211fb59e114727381d07c647a77c0010996
>
> Signed-off-by: Thinh Nguyen <thinhn@synopsys.com>
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>

> ---
>  drivers/usb/dwc3/gadget.c | 16 +++++++---------
>  drivers/usb/dwc3/gadget.h | 14 ++++++++++++++
>  2 files changed, 21 insertions(+), 9 deletions(-)
>

[PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Chris Morgan]

From: Chris Morgan <macromorgan@hotmail.com>

According to Synopsys Databook, we shouldn't be
relying on GCTL.CORESOFTRESET bit as that's only for
debugging purposes. Instead, let's use DCTL.CSFTRST
if we're OTG or PERIPHERAL mode.

Host side block will be reset by XHCI driver if
necessary. Note that this reduces amount of time
spent on dwc3_probe() by a long margin.

We're still gonna wait for reset to finish for a
long time (default to 1ms max), but tests show that
the reset polling loop executed at most 19 times
(modprobe dwc3 && modprobe -r dwc3 executed 1000
times in a row).

Note that this patch was submitted to Linux in 2016 [1], however I can
confirm it is needed to support gadget mode in U-Boot on my device.
While I am referencing this patch from Linux I am in fact taking the
full existing dwc3_core_soft_reset() function from Linux as it exists
in v6.19-rc5, so it may differ slightly from the information in the
2016 patch.

[1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813

Suggested-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
Signed-off-by: Chris Morgan <macromorgan@hotmail.com>
---
 drivers/usb/dwc3/core.c | 66 ++++++++++++++++++++++++-----------------
 1 file changed, 39 insertions(+), 27 deletions(-)

diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index 4827c83e96d..6f22b9232ba 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -59,40 +59,52 @@ static void dwc3_set_mode(struct dwc3 *dwc, u32 mode)
 static int dwc3_core_soft_reset(struct dwc3 *dwc)
 {
 	u32		reg;
+	int		retries = 1000;
 
-	/* Before Resetting PHY, put Core in Reset */
-	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
-	reg |= DWC3_GCTL_CORESOFTRESET;
-	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
-
-	/* Assert USB3 PHY reset */
-	reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
-	reg |= DWC3_GUSB3PIPECTL_PHYSOFTRST;
-	dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);
+	/*
+	 * We're resetting only the device side because, if we're in host mode,
+	 * XHCI driver will reset the host block. If dwc3 was configured for
+	 * host-only mode, then we can return early.
+	 */
+	if (dwc->dr_mode == USB_DR_MODE_HOST)
+		return 0;
 
-	/* Assert USB2 PHY reset */
-	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
-	reg |= DWC3_GUSB2PHYCFG_PHYSOFTRST;
-	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+	reg = dwc3_readl(dwc->regs, DWC3_DCTL);
+	reg |= DWC3_DCTL_CSFTRST;
+	reg &= ~DWC3_DCTL_RUN_STOP;
+	dwc3_gadget_dctl_write_safe(dwc, reg);
 
-	mdelay(100);
+	/*
+	 * For DWC_usb31 controller 1.90a and later, the DCTL.CSFRST bit
+	 * is cleared only after all the clocks are synchronized. This can
+	 * take a little more than 50ms. Set the polling rate at 20ms
+	 * for 10 times instead.
+	 */
+	if (DWC3_VER_IS_WITHIN(DWC31, 190A, ANY) || DWC3_IP_IS(DWC32))
+		retries = 10;
 
-	/* Clear USB3 PHY reset */
-	reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
-	reg &= ~DWC3_GUSB3PIPECTL_PHYSOFTRST;
-	dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);
+	do {
+		reg = dwc3_readl(dwc->regs, DWC3_DCTL);
+		if (!(reg & DWC3_DCTL_CSFTRST))
+			goto done;
 
-	/* Clear USB2 PHY reset */
-	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
-	reg &= ~DWC3_GUSB2PHYCFG_PHYSOFTRST;
-	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+		if (DWC3_VER_IS_WITHIN(DWC31, 190A, ANY) || DWC3_IP_IS(DWC32))
+			mdelay(20);
+		else
+			udelay(1);
+	} while (--retries);
 
-	mdelay(100);
+	dev_warn(dwc->dev, "DWC3 controller soft reset failed.\n");
+	return -ETIMEDOUT;
 
-	/* After PHYs are stable we can take Core out of reset state */
-	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
-	reg &= ~DWC3_GCTL_CORESOFTRESET;
-	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
+done:
+	/*
+	 * For DWC_usb31 controller 1.80a and prior, once DCTL.CSFRST bit
+	 * is cleared, we must wait at least 50ms before accessing the PHY
+	 * domain (synchronization delay).
+	 */
+	if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A))
+		mdelay(50);
 
 	return 0;
 }
-- 
2.43.0

Re: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Ernest Van Hoecke]

On Thu, Jan 15, 2026 at 05:01:35PM -0600, Chris Morgan wrote:
> From: Chris Morgan <macromorgan@hotmail.com>
> 
> According to Synopsys Databook, we shouldn't be
> relying on GCTL.CORESOFTRESET bit as that's only for
> debugging purposes. Instead, let's use DCTL.CSFTRST
> if we're OTG or PERIPHERAL mode.
> 
> Host side block will be reset by XHCI driver if
> necessary. Note that this reduces amount of time
> spent on dwc3_probe() by a long margin.
> 
> We're still gonna wait for reset to finish for a
> long time (default to 1ms max), but tests show that
> the reset polling loop executed at most 19 times
> (modprobe dwc3 && modprobe -r dwc3 executed 1000
> times in a row).
> 
> Note that this patch was submitted to Linux in 2016 [1], however I can
> confirm it is needed to support gadget mode in U-Boot on my device.
> While I am referencing this patch from Linux I am in fact taking the
> full existing dwc3_core_soft_reset() function from Linux as it exists
> in v6.19-rc5, so it may differ slightly from the information in the
> 2016 patch.
> 
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813
> 

Hi Chris,

Thanks for your work here. We also have issues with gadget mode on the
iMX95 DWC3 IP, noticed on our Aquila iMX95 SoM. This patch series fixes
our issues, but only with a small change:

> -	mdelay(100);
> +	dev_warn(dwc->dev, "DWC3 controller soft reset failed.\n");
> +	return -ETIMEDOUT;
>  
> -	/* After PHYs are stable we can take Core out of reset state */
> -	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> -	reg &= ~DWC3_GCTL_CORESOFTRESET;
> -	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> +done:
> +	/*
> +	 * For DWC_usb31 controller 1.80a and prior, once DCTL.CSFRST bit
> +	 * is cleared, we must wait at least 50ms before accessing the PHY
> +	 * domain (synchronization delay).
> +	 */
> +	if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A))
> +		mdelay(50);

On the iMX95 I also need this delay to get everything functional. If I
remove the conditional version check here, it works well.
'dwc->revision' is 0x5533330B.

Is anyone aware of the DWC3 requirements on the iMX95?

Thanks and kind regards,
Ernest

Re: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Marek Vasut]

On 1/22/26 1:15 PM, Ernest Van Hoecke wrote:
> On Thu, Jan 15, 2026 at 05:01:35PM -0600, Chris Morgan wrote:
>> From: Chris Morgan <macromorgan@hotmail.com>
>>
>> According to Synopsys Databook, we shouldn't be
>> relying on GCTL.CORESOFTRESET bit as that's only for
>> debugging purposes. Instead, let's use DCTL.CSFTRST
>> if we're OTG or PERIPHERAL mode.
>>
>> Host side block will be reset by XHCI driver if
>> necessary. Note that this reduces amount of time
>> spent on dwc3_probe() by a long margin.
>>
>> We're still gonna wait for reset to finish for a
>> long time (default to 1ms max), but tests show that
>> the reset polling loop executed at most 19 times
>> (modprobe dwc3 && modprobe -r dwc3 executed 1000
>> times in a row).
>>
>> Note that this patch was submitted to Linux in 2016 [1], however I can
>> confirm it is needed to support gadget mode in U-Boot on my device.
>> While I am referencing this patch from Linux I am in fact taking the
>> full existing dwc3_core_soft_reset() function from Linux as it exists
>> in v6.19-rc5, so it may differ slightly from the information in the
>> 2016 patch.
>>
>> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813
>>
> 
> Hi Chris,
> 
> Thanks for your work here. We also have issues with gadget mode on the
> iMX95 DWC3 IP, noticed on our Aquila iMX95 SoM. This patch series fixes
> our issues, but only with a small change:
> 
>> -	mdelay(100);
>> +	dev_warn(dwc->dev, "DWC3 controller soft reset failed.\n");
>> +	return -ETIMEDOUT;
>>   
>> -	/* After PHYs are stable we can take Core out of reset state */
>> -	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
>> -	reg &= ~DWC3_GCTL_CORESOFTRESET;
>> -	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
>> +done:
>> +	/*
>> +	 * For DWC_usb31 controller 1.80a and prior, once DCTL.CSFRST bit
>> +	 * is cleared, we must wait at least 50ms before accessing the PHY
>> +	 * domain (synchronization delay).
>> +	 */
>> +	if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A))
>> +		mdelay(50);
> 
> On the iMX95 I also need this delay to get everything functional. If I
> remove the conditional version check here, it works well.
> 'dwc->revision' is 0x5533330B.
> 
> Is anyone aware of the DWC3 requirements on the iMX95?
Likely Alice or Peng.

回复: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Alice Guo (OSS)]

> -----邮件原件-----
> 发件人: U-Boot <u-boot-bounces@lists.denx.de> 代表 Marek Vasut
> 发送时间: 2026年1月22日 20:34
> 收件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>; Chris Morgan
> <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>; Alice
> Guo <alice.guo@nxp.com>
> 抄送: u-boot@lists.denx.de; thinhn@synopsys.com;
> neil.armstrong@linaro.org; quic_varada@quicinc.com;
> felipe.balbi@linux.intel.com; mkorpershoek@kernel.org; lukma@denx.de;
> trini@konsulko.com; macromorgan@hotmail.com; Thinh Nguyen
> <Thinh.Nguyen@synopsys.com>; Mian Yousaf Kaukab
> <yousaf.kaukab@intel.com>
> 主题: Re: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence
> 
> On 1/22/26 1:15 PM, Ernest Van Hoecke wrote:
> > On Thu, Jan 15, 2026 at 05:01:35PM -0600, Chris Morgan wrote:
> >> From: Chris Morgan <macromorgan@hotmail.com>
> >>
> >> According to Synopsys Databook, we shouldn't be relying on
> >> GCTL.CORESOFTRESET bit as that's only for debugging purposes.
> >> Instead, let's use DCTL.CSFTRST if we're OTG or PERIPHERAL mode.
> >>
> >> Host side block will be reset by XHCI driver if necessary. Note that
> >> this reduces amount of time spent on dwc3_probe() by a long margin.
> >>
> >> We're still gonna wait for reset to finish for a long time (default
> >> to 1ms max), but tests show that the reset polling loop executed at
> >> most 19 times (modprobe dwc3 && modprobe -r dwc3 executed 1000
> times
> >> in a row).
> >>
> >> Note that this patch was submitted to Linux in 2016 [1], however I
> >> can confirm it is needed to support gadget mode in U-Boot on my device.
> >> While I am referencing this patch from Linux I am in fact taking the
> >> full existing dwc3_core_soft_reset() function from Linux as it exists
> >> in v6.19-rc5, so it may differ slightly from the information in the
> >> 2016 patch.
> >>
> >> [1]
> >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/pa
> >> tch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813
> >>
> >
> > Hi Chris,
> >
> > Thanks for your work here. We also have issues with gadget mode on the
> > iMX95 DWC3 IP, noticed on our Aquila iMX95 SoM. This patch series
> > fixes our issues, but only with a small change:
> >
> >> -	mdelay(100);
> >> +	dev_warn(dwc->dev, "DWC3 controller soft reset failed.\n");
> >> +	return -ETIMEDOUT;
> >>
> >> -	/* After PHYs are stable we can take Core out of reset state */
> >> -	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> >> -	reg &= ~DWC3_GCTL_CORESOFTRESET;
> >> -	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> >> +done:
> >> +	/*
> >> +	 * For DWC_usb31 controller 1.80a and prior, once DCTL.CSFRST bit
> >> +	 * is cleared, we must wait at least 50ms before accessing the PHY
> >> +	 * domain (synchronization delay).
> >> +	 */
> >> +	if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A))
> >> +		mdelay(50);
> >
> > On the iMX95 I also need this delay to get everything functional. If I
> > remove the conditional version check here, it works well.
> > 'dwc->revision' is 0x5533330B.
> >
> > Is anyone aware of the DWC3 requirements on the iMX95?
> Likely Alice or Peng.

Hi Ernest,

Thank you for your feedback on i.MX95.

I tested this patch series on the i.MX95 19x19 EVK board with USB SDP boot over the USB3 interface, and it works correctly without the additional delay.

The Universal Serial Bus 3.0 Controller on i.MX95 does not need this delay in my testing. Could you please verify that the Universal Serial Bus 3.0 PHY is configured correctly in your setup?

Best regards,
Alice Guo

Re: 回复: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Ernest Van Hoecke]

On Fri, Jan 23, 2026 at 07:24:04AM +0000, Alice Guo (OSS) wrote:
> > -----邮件原件-----
> > 发件人: U-Boot <u-boot-bounces@lists.denx.de> 代表 Marek Vasut
> > 发送时间: 2026年1月22日 20:34
> > 收件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>; Chris Morgan
> > <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>; Alice
> > Guo <alice.guo@nxp.com>
> > 抄送: u-boot@lists.denx.de; thinhn@synopsys.com;
> > neil.armstrong@linaro.org; quic_varada@quicinc.com;
> > felipe.balbi@linux.intel.com; mkorpershoek@kernel.org; lukma@denx.de;
> > trini@konsulko.com; macromorgan@hotmail.com; Thinh Nguyen
> > <Thinh.Nguyen@synopsys.com>; Mian Yousaf Kaukab
> > <yousaf.kaukab@intel.com>
> > 主题: Re: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence
> > 
> > On 1/22/26 1:15 PM, Ernest Van Hoecke wrote:
> > > On Thu, Jan 15, 2026 at 05:01:35PM -0600, Chris Morgan wrote:
> > >> From: Chris Morgan <macromorgan@hotmail.com>
> > >>
> > >> According to Synopsys Databook, we shouldn't be relying on
> > >> GCTL.CORESOFTRESET bit as that's only for debugging purposes.
> > >> Instead, let's use DCTL.CSFTRST if we're OTG or PERIPHERAL mode.
> > >>
> > >> Host side block will be reset by XHCI driver if necessary. Note that
> > >> this reduces amount of time spent on dwc3_probe() by a long margin.
> > >>
> > >> We're still gonna wait for reset to finish for a long time (default
> > >> to 1ms max), but tests show that the reset polling loop executed at
> > >> most 19 times (modprobe dwc3 && modprobe -r dwc3 executed 1000
> > times
> > >> in a row).
> > >>
> > >> Note that this patch was submitted to Linux in 2016 [1], however I
> > >> can confirm it is needed to support gadget mode in U-Boot on my device.
> > >> While I am referencing this patch from Linux I am in fact taking the
> > >> full existing dwc3_core_soft_reset() function from Linux as it exists
> > >> in v6.19-rc5, so it may differ slightly from the information in the
> > >> 2016 patch.
> > >>
> > >> [1]
> > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/pa
> > >> tch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813
> > >>
> > >
> > > Hi Chris,
> > >
> > > Thanks for your work here. We also have issues with gadget mode on the
> > > iMX95 DWC3 IP, noticed on our Aquila iMX95 SoM. This patch series
> > > fixes our issues, but only with a small change:
> > >
> > >> -	mdelay(100);
> > >> +	dev_warn(dwc->dev, "DWC3 controller soft reset failed.\n");
> > >> +	return -ETIMEDOUT;
> > >>
> > >> -	/* After PHYs are stable we can take Core out of reset state */
> > >> -	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> > >> -	reg &= ~DWC3_GCTL_CORESOFTRESET;
> > >> -	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> > >> +done:
> > >> +	/*
> > >> +	 * For DWC_usb31 controller 1.80a and prior, once DCTL.CSFRST bit
> > >> +	 * is cleared, we must wait at least 50ms before accessing the PHY
> > >> +	 * domain (synchronization delay).
> > >> +	 */
> > >> +	if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A))
> > >> +		mdelay(50);
> > >
> > > On the iMX95 I also need this delay to get everything functional. If I
> > > remove the conditional version check here, it works well.
> > > 'dwc->revision' is 0x5533330B.
> > >
> > > Is anyone aware of the DWC3 requirements on the iMX95?
> > Likely Alice or Peng.
> 
> Hi Ernest,
> 
> Thank you for your feedback on i.MX95.
> 
> I tested this patch series on the i.MX95 19x19 EVK board with USB SDP boot over the USB3 interface, and it works correctly without the additional delay.
> 
> The Universal Serial Bus 3.0 Controller on i.MX95 does not need this delay in my testing. Could you please verify that the Universal Serial Bus 3.0 PHY is configured correctly in your setup?
> 
> Best regards,
> Alice Guo

Hi Alice,

I spent some time testing again and comparing the differences between
19x19 EVK and our Aquila iMX95 device trees to make sure the DWC3 and
DWC3 PHY configs were the same, and I cannot get the USB gadget to
function without this delay in U-Boot proper. It works in the U-Boot
SPL, does it also work in U-Boot proper for the EVK, or just the SPL?

If there really is some difference here I can dig up an EVK and continue
my testing. Thank you for your help.

Kind regards,
Ernest

回复: 回复: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Alice Guo (OSS)]

> -----邮件原件-----
> 发件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>
> 发送时间: 2026年1月23日 22:13
> 收件人: Alice Guo (OSS) <alice.guo@oss.nxp.com>
> 抄送: Marek Vasut <marek.vasut@mailbox.org>; Chris Morgan
> <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>; Alice
> Guo <alice.guo@nxp.com>; u-boot@lists.denx.de; thinhn@synopsys.com;
> neil.armstrong@linaro.org; quic_varada@quicinc.com;
> felipe.balbi@linux.intel.com; mkorpershoek@kernel.org; lukma@denx.de;
> trini@konsulko.com; macromorgan@hotmail.com; Thinh Nguyen
> <Thinh.Nguyen@synopsys.com>; Mian Yousaf Kaukab
> <yousaf.kaukab@intel.com>
> 主题: Re: 回复: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence
> 
> On Fri, Jan 23, 2026 at 07:24:04AM +0000, Alice Guo (OSS) wrote:
> > > -----邮件原件-----
> > > 发件人: U-Boot <u-boot-bounces@lists.denx.de> 代表 Marek Vasut
> > > 发送时间: 2026年1月22日 20:34
> > > 收件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>; Chris Morgan
> > > <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>;
> > > Alice Guo <alice.guo@nxp.com>
> > > 抄送: u-boot@lists.denx.de; thinhn@synopsys.com;
> > > neil.armstrong@linaro.org; quic_varada@quicinc.com;
> > > felipe.balbi@linux.intel.com; mkorpershoek@kernel.org;
> > > lukma@denx.de; trini@konsulko.com; macromorgan@hotmail.com; Thinh
> > > Nguyen <Thinh.Nguyen@synopsys.com>; Mian Yousaf Kaukab
> > > <yousaf.kaukab@intel.com>
> > > 主题: Re: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence
> > >
> > > On 1/22/26 1:15 PM, Ernest Van Hoecke wrote:
> > > > On Thu, Jan 15, 2026 at 05:01:35PM -0600, Chris Morgan wrote:
> > > >> From: Chris Morgan <macromorgan@hotmail.com>
> > > >>
> > > >> According to Synopsys Databook, we shouldn't be relying on
> > > >> GCTL.CORESOFTRESET bit as that's only for debugging purposes.
> > > >> Instead, let's use DCTL.CSFTRST if we're OTG or PERIPHERAL mode.
> > > >>
> > > >> Host side block will be reset by XHCI driver if necessary. Note
> > > >> that this reduces amount of time spent on dwc3_probe() by a long
> margin.
> > > >>
> > > >> We're still gonna wait for reset to finish for a long time
> > > >> (default to 1ms max), but tests show that the reset polling loop
> > > >> executed at most 19 times (modprobe dwc3 && modprobe -r dwc3
> > > >> executed 1000
> > > times
> > > >> in a row).
> > > >>
> > > >> Note that this patch was submitted to Linux in 2016 [1], however
> > > >> I can confirm it is needed to support gadget mode in U-Boot on my
> device.
> > > >> While I am referencing this patch from Linux I am in fact taking
> > > >> the full existing dwc3_core_soft_reset() function from Linux as
> > > >> it exists in v6.19-rc5, so it may differ slightly from the
> > > >> information in the
> > > >> 2016 patch.
> > > >>
> > > >> [1]
> > > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gi
> > > >> t/pa
> > > >>
> tch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813
> > > >>
> > > >
> > > > Hi Chris,
> > > >
> > > > Thanks for your work here. We also have issues with gadget mode on
> > > > the
> > > > iMX95 DWC3 IP, noticed on our Aquila iMX95 SoM. This patch series
> > > > fixes our issues, but only with a small change:
> > > >
> > > >> -	mdelay(100);
> > > >> +	dev_warn(dwc->dev, "DWC3 controller soft reset failed.\n");
> > > >> +	return -ETIMEDOUT;
> > > >>
> > > >> -	/* After PHYs are stable we can take Core out of reset state */
> > > >> -	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> > > >> -	reg &= ~DWC3_GCTL_CORESOFTRESET;
> > > >> -	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> > > >> +done:
> > > >> +	/*
> > > >> +	 * For DWC_usb31 controller 1.80a and prior, once DCTL.CSFRST bit
> > > >> +	 * is cleared, we must wait at least 50ms before accessing the PHY
> > > >> +	 * domain (synchronization delay).
> > > >> +	 */
> > > >> +	if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A))
> > > >> +		mdelay(50);
> > > >
> > > > On the iMX95 I also need this delay to get everything functional.
> > > > If I remove the conditional version check here, it works well.
> > > > 'dwc->revision' is 0x5533330B.
> > > >
> > > > Is anyone aware of the DWC3 requirements on the iMX95?
> > > Likely Alice or Peng.
> >
> > Hi Ernest,
> >
> > Thank you for your feedback on i.MX95.
> >
> > I tested this patch series on the i.MX95 19x19 EVK board with USB SDP boot
> over the USB3 interface, and it works correctly without the additional delay.
> >
> > The Universal Serial Bus 3.0 Controller on i.MX95 does not need this delay in
> my testing. Could you please verify that the Universal Serial Bus 3.0 PHY is
> configured correctly in your setup?
> >
> > Best regards,
> > Alice Guo
> 
> Hi Alice,
> 
> I spent some time testing again and comparing the differences between
> 19x19 EVK and our Aquila iMX95 device trees to make sure the DWC3 and
> DWC3 PHY configs were the same, and I cannot get the USB gadget to function
> without this delay in U-Boot proper. It works in the U-Boot SPL, does it also work
> in U-Boot proper for the EVK, or just the SPL?
> 
> If there really is some difference here I can dig up an EVK and continue my
> testing. Thank you for your help.
> 
> Kind regards,
> Ernest

Hi Ernest,

I tested the UMS feature in U-Boot proper, and it works correctly without this delay.

Best regards,
Alice Guo

Re: 回复: 回复: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Ernest Van Hoecke]

On Tue, Jan 27, 2026 at 01:58:28AM +0000, Alice Guo (OSS) wrote:
> > -----邮件原件-----
> > 发件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>
> > 发送时间: 2026年1月23日 22:13
> > 收件人: Alice Guo (OSS) <alice.guo@oss.nxp.com>
> > 抄送: Marek Vasut <marek.vasut@mailbox.org>; Chris Morgan
> > <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>; Alice
> > Guo <alice.guo@nxp.com>; u-boot@lists.denx.de; thinhn@synopsys.com;
> > neil.armstrong@linaro.org; quic_varada@quicinc.com;
> > felipe.balbi@linux.intel.com; mkorpershoek@kernel.org; lukma@denx.de;
> > trini@konsulko.com; macromorgan@hotmail.com; Thinh Nguyen
> > <Thinh.Nguyen@synopsys.com>; Mian Yousaf Kaukab
> > <yousaf.kaukab@intel.com>
> > 主题: Re: 回复: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence
> > 
> > On Fri, Jan 23, 2026 at 07:24:04AM +0000, Alice Guo (OSS) wrote:
> > > > -----邮件原件-----
> > > > 发件人: U-Boot <u-boot-bounces@lists.denx.de> 代表 Marek Vasut
> > > > 发送时间: 2026年1月22日 20:34
> > > > 收件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>; Chris Morgan
> > > > <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>;
> > > > Alice Guo <alice.guo@nxp.com>
> > > > 抄送: u-boot@lists.denx.de; thinhn@synopsys.com;
> > > > neil.armstrong@linaro.org; quic_varada@quicinc.com;
> > > > felipe.balbi@linux.intel.com; mkorpershoek@kernel.org;
> > > > lukma@denx.de; trini@konsulko.com; macromorgan@hotmail.com; Thinh
> > > > Nguyen <Thinh.Nguyen@synopsys.com>; Mian Yousaf Kaukab
> > > > <yousaf.kaukab@intel.com>
> > > > 主题: Re: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence
> > > >
> > > > On 1/22/26 1:15 PM, Ernest Van Hoecke wrote:
> > > > > On Thu, Jan 15, 2026 at 05:01:35PM -0600, Chris Morgan wrote:
> > > > >> From: Chris Morgan <macromorgan@hotmail.com>
> > > > >>
> > > > >> According to Synopsys Databook, we shouldn't be relying on
> > > > >> GCTL.CORESOFTRESET bit as that's only for debugging purposes.
> > > > >> Instead, let's use DCTL.CSFTRST if we're OTG or PERIPHERAL mode.
> > > > >>
> > > > >> Host side block will be reset by XHCI driver if necessary. Note
> > > > >> that this reduces amount of time spent on dwc3_probe() by a long
> > margin.
> > > > >>
> > > > >> We're still gonna wait for reset to finish for a long time
> > > > >> (default to 1ms max), but tests show that the reset polling loop
> > > > >> executed at most 19 times (modprobe dwc3 && modprobe -r dwc3
> > > > >> executed 1000
> > > > times
> > > > >> in a row).
> > > > >>
> > > > >> Note that this patch was submitted to Linux in 2016 [1], however
> > > > >> I can confirm it is needed to support gadget mode in U-Boot on my
> > device.
> > > > >> While I am referencing this patch from Linux I am in fact taking
> > > > >> the full existing dwc3_core_soft_reset() function from Linux as
> > > > >> it exists in v6.19-rc5, so it may differ slightly from the
> > > > >> information in the
> > > > >> 2016 patch.
> > > > >>
> > > > >> [1]
> > > > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.gi
> > > > >> t/pa
> > > > >>
> > tch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813
> > > > >>
> > > > >
> > > > > Hi Chris,
> > > > >
> > > > > Thanks for your work here. We also have issues with gadget mode on
> > > > > the
> > > > > iMX95 DWC3 IP, noticed on our Aquila iMX95 SoM. This patch series
> > > > > fixes our issues, but only with a small change:
> > > > >
> > > > >> -	mdelay(100);
> > > > >> +	dev_warn(dwc->dev, "DWC3 controller soft reset failed.\n");
> > > > >> +	return -ETIMEDOUT;
> > > > >>
> > > > >> -	/* After PHYs are stable we can take Core out of reset state */
> > > > >> -	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> > > > >> -	reg &= ~DWC3_GCTL_CORESOFTRESET;
> > > > >> -	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> > > > >> +done:
> > > > >> +	/*
> > > > >> +	 * For DWC_usb31 controller 1.80a and prior, once DCTL.CSFRST bit
> > > > >> +	 * is cleared, we must wait at least 50ms before accessing the PHY
> > > > >> +	 * domain (synchronization delay).
> > > > >> +	 */
> > > > >> +	if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A))
> > > > >> +		mdelay(50);
> > > > >
> > > > > On the iMX95 I also need this delay to get everything functional.
> > > > > If I remove the conditional version check here, it works well.
> > > > > 'dwc->revision' is 0x5533330B.
> > > > >
> > > > > Is anyone aware of the DWC3 requirements on the iMX95?
> > > > Likely Alice or Peng.
> > >
> > > Hi Ernest,
> > >
> > > Thank you for your feedback on i.MX95.
> > >
> > > I tested this patch series on the i.MX95 19x19 EVK board with USB SDP boot
> > over the USB3 interface, and it works correctly without the additional delay.
> > >
> > > The Universal Serial Bus 3.0 Controller on i.MX95 does not need this delay in
> > my testing. Could you please verify that the Universal Serial Bus 3.0 PHY is
> > configured correctly in your setup?
> > >
> > > Best regards,
> > > Alice Guo
> > 
> > Hi Alice,
> > 
> > I spent some time testing again and comparing the differences between
> > 19x19 EVK and our Aquila iMX95 device trees to make sure the DWC3 and
> > DWC3 PHY configs were the same, and I cannot get the USB gadget to function
> > without this delay in U-Boot proper. It works in the U-Boot SPL, does it also work
> > in U-Boot proper for the EVK, or just the SPL?
> > 
> > If there really is some difference here I can dig up an EVK and continue my
> > testing. Thank you for your help.
> > 
> > Kind regards,
> > Ernest
> 
> Hi Ernest,
> 
> I tested the UMS feature in U-Boot proper, and it works correctly without this delay.
> 
> Best regards,
> Alice Guo

Hi Alice,

Thanks for testing. I can confirm that UMS works. I also tested DFU, and
that also works fine.

The issue turned out to be that we are using fastboot. Fastboot only
works with this additional delay. And even then, it does not work every
time when using the fastboot command after U-Boot proper has started.

I figured out that this is because all functions of the fastboot gadget
config are SuperSpeed capable, while DFU or UMS fall back to a maximum
of high speed in 'drivers/usb/gadget/composite.c:usb_add_config()'.

The following hack, for example, fixes fastboot consistently:

diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
index 04b85419931e..314143321546 100644
--- a/drivers/usb/gadget/composite.c
+++ b/drivers/usb/gadget/composite.c
@@ -539,7 +539,7 @@ int usb_add_config(struct usb_composite_dev *cdev,
 	 */
 	if (gadget_is_superspeed(cdev->gadget)) {
 		list_for_each_entry(f, &config->functions, list) {
-			if (!f->ss_descriptors)
+			if (true)
 				cdev->gadget->max_speed =
 					USB_SPEED_HIGH;
 		}

Note that I have 'phy-imx8mq-usb.c' enabled in my config and device
tree. I tried various quirks as well, to me the PHY seems fine, but
something is still strange with DWC3 on iMX95 when using SuperSpeed.

Thanks and kind regards,
Ernest

回复: 回复: 回复: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Alice Guo (OSS)]

> -----邮件原件-----
> 发件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>
> 发送时间: 2026年2月6日 1:33
> 收件人: Alice Guo (OSS) <alice.guo@oss.nxp.com>
> 抄送: Marek Vasut <marek.vasut@mailbox.org>; Chris Morgan
> <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>; Alice
> Guo <alice.guo@nxp.com>; u-boot@lists.denx.de; thinhn@synopsys.com;
> neil.armstrong@linaro.org; quic_varada@quicinc.com;
> felipe.balbi@linux.intel.com; mkorpershoek@kernel.org; lukma@denx.de;
> trini@konsulko.com; macromorgan@hotmail.com; Thinh Nguyen
> <Thinh.Nguyen@synopsys.com>; Mian Yousaf Kaukab
> <yousaf.kaukab@intel.com>
> 主题: Re: 回复: 回复: [PATCH V2 4/4] usb: dwc3: core: improve reset
> sequence
> 
> On Tue, Jan 27, 2026 at 01:58:28AM +0000, Alice Guo (OSS) wrote:
> > > -----邮件原件-----
> > > 发件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>
> > > 发送时间: 2026年1月23日 22:13
> > > 收件人: Alice Guo (OSS) <alice.guo@oss.nxp.com>
> > > 抄送: Marek Vasut <marek.vasut@mailbox.org>; Chris Morgan
> > > <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>;
> > > Alice Guo <alice.guo@nxp.com>; u-boot@lists.denx.de;
> > > thinhn@synopsys.com; neil.armstrong@linaro.org;
> > > quic_varada@quicinc.com; felipe.balbi@linux.intel.com;
> > > mkorpershoek@kernel.org; lukma@denx.de; trini@konsulko.com;
> > > macromorgan@hotmail.com; Thinh Nguyen
> <Thinh.Nguyen@synopsys.com>;
> > > Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
> > > 主题: Re: 回复: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence
> > >
> > > On Fri, Jan 23, 2026 at 07:24:04AM +0000, Alice Guo (OSS) wrote:
> > > > > -----邮件原件-----
> > > > > 发件人: U-Boot <u-boot-bounces@lists.denx.de> 代表 Marek Vasut
> > > > > 发送时间: 2026年1月22日 20:34
> > > > > 收件人: Ernest Van Hoecke <ernestvanhoecke@gmail.com>; Chris
> Morgan
> > > > > <macroalpha82@gmail.com>; Peng Fan (OSS) <peng.fan@oss.nxp.com>;
> > > > > Alice Guo <alice.guo@nxp.com>
> > > > > 抄送: u-boot@lists.denx.de; thinhn@synopsys.com;
> > > > > neil.armstrong@linaro.org; quic_varada@quicinc.com;
> > > > > felipe.balbi@linux.intel.com; mkorpershoek@kernel.org;
> > > > > lukma@denx.de; trini@konsulko.com; macromorgan@hotmail.com;
> > > > > Thinh Nguyen <Thinh.Nguyen@synopsys.com>; Mian Yousaf Kaukab
> > > > > <yousaf.kaukab@intel.com>
> > > > > 主题: Re: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence
> > > > >
> > > > > On 1/22/26 1:15 PM, Ernest Van Hoecke wrote:
> > > > > > On Thu, Jan 15, 2026 at 05:01:35PM -0600, Chris Morgan wrote:
> > > > > >> From: Chris Morgan <macromorgan@hotmail.com>
> > > > > >>
> > > > > >> According to Synopsys Databook, we shouldn't be relying on
> > > > > >> GCTL.CORESOFTRESET bit as that's only for debugging purposes.
> > > > > >> Instead, let's use DCTL.CSFTRST if we're OTG or PERIPHERAL mode.
> > > > > >>
> > > > > >> Host side block will be reset by XHCI driver if necessary.
> > > > > >> Note that this reduces amount of time spent on dwc3_probe()
> > > > > >> by a long
> > > margin.
> > > > > >>
> > > > > >> We're still gonna wait for reset to finish for a long time
> > > > > >> (default to 1ms max), but tests show that the reset polling
> > > > > >> loop executed at most 19 times (modprobe dwc3 && modprobe -r
> > > > > >> dwc3 executed 1000
> > > > > times
> > > > > >> in a row).
> > > > > >>
> > > > > >> Note that this patch was submitted to Linux in 2016 [1],
> > > > > >> however I can confirm it is needed to support gadget mode in
> > > > > >> U-Boot on my
> > > device.
> > > > > >> While I am referencing this patch from Linux I am in fact
> > > > > >> taking the full existing dwc3_core_soft_reset() function from
> > > > > >> Linux as it exists in v6.19-rc5, so it may differ slightly
> > > > > >> from the information in the
> > > > > >> 2016 patch.
> > > > > >>
> > > > > >> [1]
> > > > > >> https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linu
> > > > > >> x.gi
> > > > > >> t/pa
> > > > > >>
> > > tch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813
> > > > > >>
> > > > > >
> > > > > > Hi Chris,
> > > > > >
> > > > > > Thanks for your work here. We also have issues with gadget
> > > > > > mode on the
> > > > > > iMX95 DWC3 IP, noticed on our Aquila iMX95 SoM. This patch
> > > > > > series fixes our issues, but only with a small change:
> > > > > >
> > > > > >> -	mdelay(100);
> > > > > >> +	dev_warn(dwc->dev, "DWC3 controller soft reset failed.\n");
> > > > > >> +	return -ETIMEDOUT;
> > > > > >>
> > > > > >> -	/* After PHYs are stable we can take Core out of reset state */
> > > > > >> -	reg = dwc3_readl(dwc->regs, DWC3_GCTL);
> > > > > >> -	reg &= ~DWC3_GCTL_CORESOFTRESET;
> > > > > >> -	dwc3_writel(dwc->regs, DWC3_GCTL, reg);
> > > > > >> +done:
> > > > > >> +	/*
> > > > > >> +	 * For DWC_usb31 controller 1.80a and prior, once DCTL.CSFRST
> bit
> > > > > >> +	 * is cleared, we must wait at least 50ms before accessing the
> PHY
> > > > > >> +	 * domain (synchronization delay).
> > > > > >> +	 */
> > > > > >> +	if (DWC3_VER_IS_WITHIN(DWC31, ANY, 180A))
> > > > > >> +		mdelay(50);
> > > > > >
> > > > > > On the iMX95 I also need this delay to get everything functional.
> > > > > > If I remove the conditional version check here, it works well.
> > > > > > 'dwc->revision' is 0x5533330B.
> > > > > >
> > > > > > Is anyone aware of the DWC3 requirements on the iMX95?
> > > > > Likely Alice or Peng.
> > > >
> > > > Hi Ernest,
> > > >
> > > > Thank you for your feedback on i.MX95.
> > > >
> > > > I tested this patch series on the i.MX95 19x19 EVK board with USB
> > > > SDP boot
> > > over the USB3 interface, and it works correctly without the additional delay.
> > > >
> > > > The Universal Serial Bus 3.0 Controller on i.MX95 does not need
> > > > this delay in
> > > my testing. Could you please verify that the Universal Serial Bus
> > > 3.0 PHY is configured correctly in your setup?
> > > >
> > > > Best regards,
> > > > Alice Guo
> > >
> > > Hi Alice,
> > >
> > > I spent some time testing again and comparing the differences
> > > between
> > > 19x19 EVK and our Aquila iMX95 device trees to make sure the DWC3
> > > and
> > > DWC3 PHY configs were the same, and I cannot get the USB gadget to
> > > function without this delay in U-Boot proper. It works in the U-Boot
> > > SPL, does it also work in U-Boot proper for the EVK, or just the SPL?
> > >
> > > If there really is some difference here I can dig up an EVK and
> > > continue my testing. Thank you for your help.
> > >
> > > Kind regards,
> > > Ernest
> >
> > Hi Ernest,
> >
> > I tested the UMS feature in U-Boot proper, and it works correctly without this
> delay.
> >
> > Best regards,
> > Alice Guo
> 
> Hi Alice,
> 
> Thanks for testing. I can confirm that UMS works. I also tested DFU, and that
> also works fine.
> 
> The issue turned out to be that we are using fastboot. Fastboot only works with
> this additional delay. And even then, it does not work every time when using the
> fastboot command after U-Boot proper has started.
> 
> I figured out that this is because all functions of the fastboot gadget config are
> SuperSpeed capable, while DFU or UMS fall back to a maximum of high speed in
> 'drivers/usb/gadget/composite.c:usb_add_config()'.
> 
> The following hack, for example, fixes fastboot consistently:
> 
> diff --git a/drivers/usb/gadget/composite.c b/drivers/usb/gadget/composite.c
> index 04b85419931e..314143321546 100644
> --- a/drivers/usb/gadget/composite.c
> +++ b/drivers/usb/gadget/composite.c
> @@ -539,7 +539,7 @@ int usb_add_config(struct usb_composite_dev *cdev,
>  	 */
>  	if (gadget_is_superspeed(cdev->gadget)) {
>  		list_for_each_entry(f, &config->functions, list) {
> -			if (!f->ss_descriptors)
> +			if (true)
>  				cdev->gadget->max_speed =
>  					USB_SPEED_HIGH;
>  		}
> 
> Note that I have 'phy-imx8mq-usb.c' enabled in my config and device tree. I
> tried various quirks as well, to me the PHY seems fine, but something is still
> strange with DWC3 on iMX95 when using SuperSpeed.
> 
> Thanks and kind regards,
> Ernest

Hi Ernest,

Sorry for the late reply - I was away on holiday leave.

Thank you for sharing your findings and the detailed analysis. However, I'm seeing slightly different results with fastboot on my end.

In my testing, fastboot boot Image works reliably without forcing the gadget to High-Speed mode. Even with SuperSpeed enabled, the download and boot sequence completes successfully. To verify the actual negotiated USB link speed, I ran lsusb -t on the host side, which confirmed that the device is negotiating SuperSpeed (5 Gbps) correctly. Fastboot continues to work as expected in this mode on my setup.

If you have a specific sequence or condition that reproduces the issue on your side, I'd be happy to run the same test on my setup and compare results.

Best regards,
Alice Guo

Re: [PATCH V2 4/4] usb: dwc3: core: improve reset sequence

[Mattijs Korpershoek]

Hi Chris,

Thank you for the patch.

On Thu, Jan 15, 2026 at 17:01, Chris Morgan <macroalpha82@gmail.com> wrote:

> From: Chris Morgan <macromorgan@hotmail.com>
>
> According to Synopsys Databook, we shouldn't be
> relying on GCTL.CORESOFTRESET bit as that's only for
> debugging purposes. Instead, let's use DCTL.CSFTRST
> if we're OTG or PERIPHERAL mode.
>
> Host side block will be reset by XHCI driver if
> necessary. Note that this reduces amount of time
> spent on dwc3_probe() by a long margin.
>
> We're still gonna wait for reset to finish for a
> long time (default to 1ms max), but tests show that
> the reset polling loop executed at most 19 times
> (modprobe dwc3 && modprobe -r dwc3 executed 1000
> times in a row).
>
> Note that this patch was submitted to Linux in 2016 [1], however I can
> confirm it is needed to support gadget mode in U-Boot on my device.
> While I am referencing this patch from Linux I am in fact taking the
> full existing dwc3_core_soft_reset() function from Linux as it exists
> in v6.19-rc5, so it may differ slightly from the information in the
> 2016 patch.
>
> [1] https://git.kernel.org/pub/scm/linux/kernel/git/torvalds/linux.git/patch/drivers/usb/dwc3?id=f59dcab176293b646e1358144c93c58c3cda2813
>
> Suggested-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
> Signed-off-by: Felipe Balbi <felipe.balbi@linux.intel.com>
> Signed-off-by: Chris Morgan <macromorgan@hotmail.com>

Reviewed-by: Mattijs Korpershoek <mkorpershoek@kernel.org>

> ---
>  drivers/usb/dwc3/core.c | 66 ++++++++++++++++++++++++-----------------
>  1 file changed, 39 insertions(+), 27 deletions(-)
>

Re: [PATCH V2 0/4] USB Fixes for Gadget Mode on DWC3

[Mattijs Korpershoek]

Hi,

On Thu, 15 Jan 2026 17:01:31 -0600, Chris Morgan wrote:
> From: Chris Morgan <macromorgan@hotmail.com>
> 
> In order to get gadget mode functional (for fastboot and ums) I need to
> pull two patches in from mainline Linux. After applying these two
> patches to U-Boot I am able to use ums and fastboot on my Anbernic
> RG353P device for testing purposes.
> 
> [...]

Thanks, Applied to https://source.denx.de/u-boot/custodians/u-boot-dfu (u-boot-dfu)

[1/4] usb: dwc3: core: Add ip and version_type support from Linux
      https://source.denx.de/u-boot/custodians/u-boot-dfu/-/commit/add7152eb071619efa150e4b7503f9f333133dbb
[2/4] usb: dwc3: Increase DWC3 controller halt timeout
      https://source.denx.de/u-boot/custodians/u-boot-dfu/-/commit/7590f29e2cd72fb8ed50efde3cdb786d74dc1f10
[3/4] usb: dwc3: gadget: Don't send unintended link state change
      https://source.denx.de/u-boot/custodians/u-boot-dfu/-/commit/de69f14a0991f3b9afe78dc0721a9184d297e303
[4/4] usb: dwc3: core: improve reset sequence
      https://source.denx.de/u-boot/custodians/u-boot-dfu/-/commit/aef270254f0feaad54837d3fbbc04ad0c060d3fa

--
Mattijs