[PATCH v2 0/3] usb: dwc2: Add USB DRD support on CV1800 Series SoC

[PATCH v2 0/3] usb: dwc2: Add USB DRD support on CV1800 Series SoC

[Inochi Amaoto]

The current DRD implementation of DRD will cause a interrupt flow on
CV1800 Series SoC. It has two reasons:
1. The DRD does not sync the phy mode when change the controller mode,
   it is a violation of the DRD as it does not rely on a OTG phy.
2. The CV1800 is entered with a Session End Detected interrupt, but the
   DRD code has no change on it, so the controller will enter the
   interrupt storm.

This patch add fixes for these two problem, and I have tested this on
a Huashan PI board (it has a CV1812H SoC).

Note: This patches set does not resolve all the problems, as
      usb_add_hcd() will override the role set by dwc2, but I am not
      sure whether it should change skip_phy_initialization of hcd.
      So I kept it as it is and users still needs to set the role
      in the userspace as "role-switch-default-mode" in devicetree
      takes no effect.

Changed from v1:
- https://lore.kernel.org/linux-usb/20261110070627.217946-1-inochiama@gmail.com
1. the DTS patch is dropped and will be sent separately.
patch 2:
1. fix wrong is_host check in dwc2_drd_init()
2. remove unnecessary role check before setting phy mode in
   dwc2_drd_role_sw_set()


Inochi Amaoto (3):
  usb: dwc2: gadget: honor pullup requests in core_connect
  usb: dwc2: drd: Sync the generic PHY mode with role requests
  usb: dwc2: Add USB DRD support on CV1800 series SoC

 drivers/usb/dwc2/core.h     |  5 ++-
 drivers/usb/dwc2/drd.c      | 75 ++++++++++++++++++++++++++++---------
 drivers/usb/dwc2/gadget.c   |  3 +-
 drivers/usb/dwc2/params.c   |  1 +
 drivers/usb/dwc2/platform.c |  4 +-
 5 files changed, 68 insertions(+), 20 deletions(-)

--
2.56.0

[PATCH v2 1/3] usb: dwc2: gadget: honor pullup requests in core_connect

[Inochi Amaoto]

The connector ID work initializes the peripheral controller and calls
dwc2_hsotg_core_connect() even when no gadget driver has requested a
connection. After a host-to-device role change, this clears SFTDISCON
and lets the host enumerate an unconfigured gadget.

Check enabled in the connection helper. So the device will keep
disconnect until the controller is ready

Fixes: 510ffaa48eac ("usb: dwc2: Initialize the USB core for peripheral mode")
Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 drivers/usb/dwc2/gadget.c | 3 ++-
 1 file changed, 2 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index 6c8a9f05fff0..5c8e85493289 100644
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -3664,7 +3664,8 @@ void dwc2_hsotg_core_disconnect(struct dwc2_hsotg *hsotg)
 void dwc2_hsotg_core_connect(struct dwc2_hsotg *hsotg)
 {
 	/* remove the soft-disconnect and let's go */
-	if (!hsotg->role_sw || (dwc2_readl(hsotg, GOTGCTL) & GOTGCTL_BSESVLD))
+	if (hsotg->enabled &&
+	    (!hsotg->role_sw || (dwc2_readl(hsotg, GOTGCTL) & GOTGCTL_BSESVLD)))
 		dwc2_clear_bit(hsotg, DCTL, DCTL_SFTDISCON);
 }
 
-- 
2.56.0

[PATCH v2 2/3] usb: dwc2: drd: Sync the generic PHY mode with role requests

[Inochi Amaoto]

The USB DRD does not reply on a OTG phy, which means the controller
should not reply on the switch behavior from PHY. Instead, it should
sync the phy state to avoid a brolen role.

Set the generic PHY mode after resolving the default role and before
updating the controller. And disable the controller clock if there
is a failure and it is disabled.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 drivers/usb/dwc2/core.h     |  2 +-
 drivers/usb/dwc2/drd.c      | 46 +++++++++++++++++++++++++++++--------
 drivers/usb/dwc2/platform.c |  4 +++-
 3 files changed, 41 insertions(+), 11 deletions(-)

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 015a5fb7842d..298b418e6859 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -1400,7 +1400,7 @@ static inline int dwc2_is_device_mode(struct dwc2_hsotg *hsotg)
 
 int dwc2_drd_init(struct dwc2_hsotg *hsotg);
 void dwc2_drd_suspend(struct dwc2_hsotg *hsotg);
-void dwc2_drd_resume(struct dwc2_hsotg *hsotg);
+int dwc2_drd_resume(struct dwc2_hsotg *hsotg);
 void dwc2_drd_exit(struct dwc2_hsotg *hsotg);
 
 /*
diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
index 1ad8fa3f862a..3dc194657e82 100644
--- a/drivers/usb/dwc2/drd.c
+++ b/drivers/usb/dwc2/drd.c
@@ -9,6 +9,7 @@
 
 #include <linux/clk.h>
 #include <linux/iopoll.h>
+#include <linux/phy/phy.h>
 #include <linux/platform_device.h>
 #include <linux/usb/role.h>
 #include "core.h"
@@ -88,6 +89,7 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 	struct dwc2_hsotg *hsotg = usb_role_switch_get_drvdata(sw);
 	unsigned long flags;
 	int already = 0;
+	int ret = 0;
 
 	/* Skip session not in line with dr_mode */
 	if ((role == USB_ROLE_DEVICE && hsotg->dr_mode == USB_DR_MODE_HOST) ||
@@ -111,14 +113,11 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 	 * mode and sessions. It is the case if cable is plugged at boot.
 	 */
 	if (!hsotg->ll_hw_enabled && hsotg->clk) {
-		int ret = clk_prepare_enable(hsotg->clk);
-
+		ret = clk_prepare_enable(hsotg->clk);
 		if (ret)
 			return ret;
 	}
 
-	spin_lock_irqsave(&hsotg->lock, flags);
-
 	if (role == USB_ROLE_NONE) {
 		/* default operation mode when usb role is USB_ROLE_NONE */
 		if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
@@ -127,6 +126,13 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 			role = USB_ROLE_DEVICE;
 	}
 
+	ret = phy_set_mode(hsotg->phy, role == USB_ROLE_HOST ?
+				PHY_MODE_USB_HOST : PHY_MODE_USB_DEVICE);
+	if (ret)
+		goto out_clk;
+
+	spin_lock_irqsave(&hsotg->lock, flags);
+
 	if ((IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) ||
 	     IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)) &&
 	     dwc2_is_device_mode(hsotg) &&
@@ -160,26 +166,40 @@ static int dwc2_drd_role_sw_set(struct usb_role_switch *sw, enum usb_role role)
 		/* This will raise a Connector ID Status Change Interrupt */
 		dwc2_force_mode(hsotg, role == USB_ROLE_HOST);
 
-	if (!hsotg->ll_hw_enabled && hsotg->clk)
-		clk_disable_unprepare(hsotg->clk);
-
 	dev_dbg(hsotg->dev, "%s-session valid\n",
 		role == USB_ROLE_NONE ? "No" :
 		role == USB_ROLE_HOST ? "A" : "B");
 
-	return 0;
+out_clk:
+	if (!hsotg->ll_hw_enabled && hsotg->clk)
+		clk_disable_unprepare(hsotg->clk);
+
+	return ret;
 }
 
 int dwc2_drd_init(struct dwc2_hsotg *hsotg)
 {
 	struct usb_role_switch_desc role_sw_desc = {0};
 	struct usb_role_switch *role_sw;
+	bool is_host;
 	int ret;
 
 	if (!device_property_read_bool(hsotg->dev, "usb-role-switch"))
 		return 0;
 
 	hsotg->role_sw_default_mode = usb_get_role_switch_default_mode(hsotg->dev);
+
+	if (hsotg->role_sw_default_mode != USB_DR_MODE_UNKNOWN)
+		is_host = hsotg->role_sw_default_mode == USB_DR_MODE_HOST;
+	else
+		is_host = hsotg->dr_mode == USB_DR_MODE_HOST;
+
+	ret = phy_set_mode(hsotg->phy,
+			   is_host ? PHY_MODE_USB_HOST : PHY_MODE_USB_DEVICE);
+	if (ret)
+		return dev_err_probe(hsotg->dev, ret,
+				     "failed to set default PHY mode\n");
+
 	role_sw_desc.driver_data = hsotg;
 	role_sw_desc.fwnode = dev_fwnode(hsotg->dev);
 	role_sw_desc.set = dwc2_drd_role_sw_set;
@@ -214,10 +234,11 @@ void dwc2_drd_suspend(struct dwc2_hsotg *hsotg)
 	}
 }
 
-void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
+int dwc2_drd_resume(struct dwc2_hsotg *hsotg)
 {
 	u32 gintsts, gintmsk;
 	enum usb_role role;
+	int ret;
 
 	if (hsotg->role_sw) {
 		/* get last known role (as the get ops isn't implemented by this driver) */
@@ -230,6 +251,11 @@ void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
 				role = USB_ROLE_DEVICE;
 		}
 
+		ret = phy_set_mode(hsotg->phy, role == USB_ROLE_HOST ?
+				   PHY_MODE_USB_HOST : PHY_MODE_USB_DEVICE);
+		if (ret)
+			return ret;
+
 		/* restore last role that may have been lost */
 		if (role == USB_ROLE_HOST)
 			dwc2_ovr_avalid(hsotg, true);
@@ -250,6 +276,8 @@ void dwc2_drd_resume(struct dwc2_hsotg *hsotg)
 		gintmsk |= GINTSTS_CONIDSTSCHNG;
 		dwc2_writel(hsotg, gintmsk, GINTMSK);
 	}
+
+	return 0;
 }
 
 void dwc2_drd_exit(struct dwc2_hsotg *hsotg)
diff --git a/drivers/usb/dwc2/platform.c b/drivers/usb/dwc2/platform.c
index ef0d73077034..ab39d6b36b19 100644
--- a/drivers/usb/dwc2/platform.c
+++ b/drivers/usb/dwc2/platform.c
@@ -783,7 +783,9 @@ static int __maybe_unused dwc2_resume(struct device *dev)
 		/* Need to restore FORCEDEVMODE/FORCEHOSTMODE */
 		dwc2_force_dr_mode(dwc2);
 	} else {
-		dwc2_drd_resume(dwc2);
+		ret = dwc2_drd_resume(dwc2);
+		if (ret)
+			return ret;
 	}
 
 	if (dwc2_is_device_mode(dwc2))
-- 
2.56.0

[PATCH v2 3/3] usb: dwc2: Add USB DRD support on CV1800 series SoC

[Inochi Amaoto]

On CV1800 series SoC, it has a problem that it enters the role switch
with a persistent Session End Detected interrupt. As a result, GOTGINT
bit 2 remains set after write-one-to-clear accesses and prevents a
normal boot.

Keeping the BVALID override asserted in host mode avoids the observed
interrupt storm while allowing host enumeration and device operation.
As the BVALOVAL field is device only in the datasheet, this change is
added as a quirk.

Signed-off-by: Inochi Amaoto <inochiama@gmail.com>
---
 drivers/usb/dwc2/core.h   |  3 +++
 drivers/usb/dwc2/drd.c    | 29 +++++++++++++++++++++--------
 drivers/usb/dwc2/params.c |  1 +
 3 files changed, 25 insertions(+), 8 deletions(-)

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index 298b418e6859..52ac64f67f41 100644
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -357,6 +357,8 @@ enum dwc2_ep0_state {
  *                      case.
  *                      0 - No (default)
  *                      1 - Yes
+ * @force_bvalid_in_host: Set the BVALID override value to 1 in host mode to
+ *                       avoid persistent Session End Detected interrupts.
  * @power_down:         Specifies whether the controller support power_down.
  *			If power_down is enabled, the controller will enter
  *			power_down in both peripheral and host mode when
@@ -460,6 +462,7 @@ struct dwc2_core_params {
 	bool reload_ctl;
 	bool uframe_sched;
 	bool external_id_pin_ctl;
+	bool force_bvalid_in_host;
 
 	int power_down;
 #define DWC2_POWER_DOWN_PARAM_NONE		0
diff --git a/drivers/usb/dwc2/drd.c b/drivers/usb/dwc2/drd.c
index 3dc194657e82..3df63c0b88d8 100644
--- a/drivers/usb/dwc2/drd.c
+++ b/drivers/usb/dwc2/drd.c
@@ -28,10 +28,13 @@ static void dwc2_ovr_init(struct dwc2_hsotg *hsotg)
 	gotgctl = dwc2_readl(hsotg, GOTGCTL);
 	dwc2_ovr_gotgctl(gotgctl);
 	gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
-	if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST)
+	if (hsotg->role_sw_default_mode == USB_DR_MODE_HOST) {
 		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
-	else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL)
+		if (hsotg->params.force_bvalid_in_host)
+			gotgctl |= GOTGCTL_BVALOVAL;
+	} else if (hsotg->role_sw_default_mode == USB_DR_MODE_PERIPHERAL) {
 		gotgctl |= GOTGCTL_BVALOVAL | GOTGCTL_VBVALOVAL;
+	}
 	dwc2_writel(hsotg, gotgctl, GOTGCTL);
 
 	spin_unlock_irqrestore(&hsotg->lock, flags);
@@ -45,18 +48,26 @@ static int dwc2_ovr_avalid(struct dwc2_hsotg *hsotg, bool valid)
 	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
 
 	/* Check if A-Session is already in the right state */
-	if ((valid && (gotgctl & GOTGCTL_ASESVLD)) ||
+	if ((valid && (gotgctl & GOTGCTL_ASESVLD) &&
+	     (!hsotg->params.force_bvalid_in_host ||
+	      (dwc2_is_host_mode(hsotg) && (gotgctl & GOTGCTL_BVALOVAL) &&
+	       (gotgctl & GOTGCTL_AVALOVAL)))) ||
 	    (!valid && !(gotgctl & GOTGCTL_ASESVLD)))
 		return -EALREADY;
 
 	/* Always enable overrides to handle the resume case */
 	dwc2_ovr_gotgctl(gotgctl);
 
-	gotgctl &= ~GOTGCTL_BVALOVAL;
-	if (valid)
+	if (valid) {
 		gotgctl |= GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL;
-	else
-		gotgctl &= ~(GOTGCTL_AVALOVAL | GOTGCTL_VBVALOVAL);
+		if (hsotg->params.force_bvalid_in_host)
+			gotgctl |= GOTGCTL_BVALOVAL;
+		else
+			gotgctl &= ~GOTGCTL_BVALOVAL;
+	} else {
+		gotgctl &= ~(GOTGCTL_BVALOVAL | GOTGCTL_AVALOVAL |
+			     GOTGCTL_VBVALOVAL);
+	}
 	dwc2_writel(hsotg, gotgctl, GOTGCTL);
 
 	return 0;
@@ -67,7 +78,9 @@ static int dwc2_ovr_bvalid(struct dwc2_hsotg *hsotg, bool valid)
 	u32 gotgctl = dwc2_readl(hsotg, GOTGCTL);
 
 	/* Check if B-Session is already in the right state */
-	if ((valid && (gotgctl & GOTGCTL_BSESVLD)) ||
+	if ((valid && (gotgctl & GOTGCTL_BSESVLD) &&
+	     (!hsotg->params.force_bvalid_in_host ||
+	      (dwc2_is_device_mode(hsotg) && !(gotgctl & GOTGCTL_AVALOVAL)))) ||
 	    (!valid && !(gotgctl & GOTGCTL_BSESVLD)))
 		return -EALREADY;
 
diff --git a/drivers/usb/dwc2/params.c b/drivers/usb/dwc2/params.c
index 091bfcfef753..16db9c3c1991 100644
--- a/drivers/usb/dwc2/params.c
+++ b/drivers/usb/dwc2/params.c
@@ -222,6 +222,7 @@ static void dwc2_set_cv1800_params(struct dwc2_hsotg *hsotg)
 {
 	struct dwc2_core_params *p = &hsotg->params;
 
+	p->force_bvalid_in_host = true;
 	p->otg_caps.hnp_support = false;
 	p->otg_caps.srp_support = false;
 	p->host_dma = false;
-- 
2.56.0