usb: dwc3: core: Prevent phy suspend during init

GUSB3PIPECTL.SUSPENDENABLE and GUSB2PHYCFG.SUSPHY should be cleared
during initialization. Suspend during initialization can result in
undefined behavior due to clock synchronization failure, which often
seen as core soft reset timeout.

The programming guide recommended these bits to be cleared during
initialization for DWC_usb3.0 version 1.94 and above (along with
DWC_usb31 and DWC_usb32). The current check in the driver does not
account if it's set by default setting from coreConsultant.

This is especially the case for DRD when switching mode to ensure the
phy clocks are available to change mode. Depending on the
platforms/design, some may be affected more than others. This is noted
in the DWC_usb3x programming guide under the above registers.

Let's just disable them during driver load and mode switching. Restore
them when the controller initialization completes.

Note that some platforms workaround this issue by disabling phy suspend
through "snps,dis_u3_susphy_quirk" and "snps,dis_u2_susphy_quirk" when
they should not need to.

Cc: [email protected]
Fixes: 9ba3aca ("usb: dwc3: Disable phy suspend after power-on reset")
Signed-off-by: Thinh Nguyen <[email protected]>
Link: https://lore.kernel.org/r/20da4e5a0c4678c9587d3da23f83bdd6d77353e9.1713394973.git.Thinh.Nguyen@synopsys.com
Signed-off-by: Greg Kroah-Hartman <[email protected]>

Author: Thinh Nguyen

drivers/usb/dwc3/core.c

@@ -104,6 +104,27 @@ static int dwc3_get_dr_mode(struct dwc3 *dwc)
 	return 0;
 }
 
+void dwc3_enable_susphy(struct dwc3 *dwc, bool enable)
+{
+	u32 reg;
+
+	reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
+	if (enable && !dwc->dis_u3_susphy_quirk)
+		reg |= DWC3_GUSB3PIPECTL_SUSPHY;
+	else
+		reg &= ~DWC3_GUSB3PIPECTL_SUSPHY;
+
+	dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);
+
+	reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
+	if (enable && !dwc->dis_u2_susphy_quirk)
+		reg |= DWC3_GUSB2PHYCFG_SUSPHY;
+	else
+		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
+
+	dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
+}
+
 void dwc3_set_prtcap(struct dwc3 *dwc, u32 mode)
 {
 	u32 reg;
@@ -585,11 +606,8 @@ static int dwc3_core_ulpi_init(struct dwc3 *dwc)
  */
 static int dwc3_phy_setup(struct dwc3 *dwc)
 {
-	unsigned int hw_mode;
 	u32 reg;
 
-	hw_mode = DWC3_GHWPARAMS0_MODE(dwc->hwparams.hwparams0);
-
 	reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
 
 	/*
@@ -599,21 +617,16 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
 	reg &= ~DWC3_GUSB3PIPECTL_UX_EXIT_PX;
 
 	/*
-	 * Above 1.94a, it is recommended to set DWC3_GUSB3PIPECTL_SUSPHY
-	 * to '0' during coreConsultant configuration. So default value
-	 * will be '0' when the core is reset. Application needs to set it
-	 * to '1' after the core initialization is completed.
-	 */
-	if (!DWC3_VER_IS_WITHIN(DWC3, ANY, 194A))
-		reg |= DWC3_GUSB3PIPECTL_SUSPHY;
-
-	/*
-	 * For DRD controllers, GUSB3PIPECTL.SUSPENDENABLE must be cleared after
-	 * power-on reset, and it can be set after core initialization, which is
-	 * after device soft-reset during initialization.
+	 * Above DWC_usb3.0 1.94a, it is recommended to set
+	 * DWC3_GUSB3PIPECTL_SUSPHY to '0' during coreConsultant configuration.
+	 * So default value will be '0' when the core is reset. Application
+	 * needs to set it to '1' after the core initialization is completed.
+	 *
+	 * Similarly for DRD controllers, GUSB3PIPECTL.SUSPENDENABLE must be
+	 * cleared after power-on reset, and it can be set after core
+	 * initialization.
 	 */
-	if (hw_mode == DWC3_GHWPARAMS0_MODE_DRD)
-		reg &= ~DWC3_GUSB3PIPECTL_SUSPHY;
+	reg &= ~DWC3_GUSB3PIPECTL_SUSPHY;
 
 	if (dwc->u2ss_inp3_quirk)
 		reg |= DWC3_GUSB3PIPECTL_U2SSINP3OK;
@@ -639,9 +652,6 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
 	if (dwc->tx_de_emphasis_quirk)
 		reg |= DWC3_GUSB3PIPECTL_TX_DEEPH(dwc->tx_de_emphasis);
 
-	if (dwc->dis_u3_susphy_quirk)
-		reg &= ~DWC3_GUSB3PIPECTL_SUSPHY;
-
 	if (dwc->dis_del_phy_power_chg_quirk)
 		reg &= ~DWC3_GUSB3PIPECTL_DEPOCHANGE;
 
@@ -689,24 +699,15 @@ static int dwc3_phy_setup(struct dwc3 *dwc)
 	}
 
 	/*
-	 * Above 1.94a, it is recommended to set DWC3_GUSB2PHYCFG_SUSPHY to
-	 * '0' during coreConsultant configuration. So default value will
-	 * be '0' when the core is reset. Application needs to set it to
-	 * '1' after the core initialization is completed.
-	 */
-	if (!DWC3_VER_IS_WITHIN(DWC3, ANY, 194A))
-		reg |= DWC3_GUSB2PHYCFG_SUSPHY;
-
-	/*
-	 * For DRD controllers, GUSB2PHYCFG.SUSPHY must be cleared after
-	 * power-on reset, and it can be set after core initialization, which is
-	 * after device soft-reset during initialization.
+	 * Above DWC_usb3.0 1.94a, it is recommended to set
+	 * DWC3_GUSB2PHYCFG_SUSPHY to '0' during coreConsultant configuration.
+	 * So default value will be '0' when the core is reset. Application
+	 * needs to set it to '1' after the core initialization is completed.
+	 *
+	 * Similarly for DRD controllers, GUSB2PHYCFG.SUSPHY must be cleared
+	 * after power-on reset, and it can be set after core initialization.
 	 */
-	if (hw_mode == DWC3_GHWPARAMS0_MODE_DRD)
-		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
-
-	if (dwc->dis_u2_susphy_quirk)
-		reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
+	reg &= ~DWC3_GUSB2PHYCFG_SUSPHY;
 
 	if (dwc->dis_enblslpm_quirk)
 		reg &= ~DWC3_GUSB2PHYCFG_ENBLSLPM;
@@ -1227,21 +1228,6 @@ static int dwc3_core_init(struct dwc3 *dwc)
 	if (ret)
 		goto err_exit_phy;
 
-	if (hw_mode == DWC3_GHWPARAMS0_MODE_DRD &&
-	    !DWC3_VER_IS_WITHIN(DWC3, ANY, 194A)) {
-		if (!dwc->dis_u3_susphy_quirk) {
-			reg = dwc3_readl(dwc->regs, DWC3_GUSB3PIPECTL(0));
-			reg |= DWC3_GUSB3PIPECTL_SUSPHY;
-			dwc3_writel(dwc->regs, DWC3_GUSB3PIPECTL(0), reg);
-		}
-
-		if (!dwc->dis_u2_susphy_quirk) {
-			reg = dwc3_readl(dwc->regs, DWC3_GUSB2PHYCFG(0));
-			reg |= DWC3_GUSB2PHYCFG_SUSPHY;
-			dwc3_writel(dwc->regs, DWC3_GUSB2PHYCFG(0), reg);
-		}
-	}
-
 	dwc3_core_setup_global_control(dwc);
 	dwc3_core_num_eps(dwc);
 

drivers/usb/dwc3/core.h

@@ -1580,6 +1580,7 @@ int dwc3_event_buffers_setup(struct dwc3 *dwc);
 void dwc3_event_buffers_cleanup(struct dwc3 *dwc);
 
 int dwc3_core_soft_reset(struct dwc3 *dwc);
+void dwc3_enable_susphy(struct dwc3 *dwc, bool enable);
 
 #if IS_ENABLED(CONFIG_USB_DWC3_HOST) || IS_ENABLED(CONFIG_USB_DWC3_DUAL_ROLE)
 int dwc3_host_init(struct dwc3 *dwc);

drivers/usb/dwc3/gadget.c

@@ -2924,6 +2924,7 @@ static int __dwc3_gadget_start(struct dwc3 *dwc)
 	dwc3_ep0_out_start(dwc);
 
 	dwc3_gadget_enable_irq(dwc);
+	dwc3_enable_susphy(dwc, true);
 
 	return 0;
 
@@ -4690,6 +4691,7 @@ void dwc3_gadget_exit(struct dwc3 *dwc)
 	if (!dwc->gadget)
 		return;
 
+	dwc3_enable_susphy(dwc, false);
 	usb_del_gadget(dwc->gadget);
 	dwc3_gadget_free_endpoints(dwc);
 	usb_put_gadget(dwc->gadget);

drivers/usb/dwc3/host.c

@@ -10,10 +10,13 @@
 #include <linux/irq.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/usb.h>
+#include <linux/usb/hcd.h>
 
 #include "../host/xhci-port.h"
 #include "../host/xhci-ext-caps.h"
 #include "../host/xhci-caps.h"
+#include "../host/xhci-plat.h"
 #include "core.h"
 
 #define XHCI_HCSPARAMS1		0x4
@@ -57,6 +60,24 @@ static void dwc3_power_off_all_roothub_ports(struct dwc3 *dwc)
 	}
 }
 
+static void dwc3_xhci_plat_start(struct usb_hcd *hcd)
+{
+	struct platform_device *pdev;
+	struct dwc3 *dwc;
+
+	if (!usb_hcd_is_primary_hcd(hcd))
+		return;
+
+	pdev = to_platform_device(hcd->self.controller);
+	dwc = dev_get_drvdata(pdev->dev.parent);
+
+	dwc3_enable_susphy(dwc, true);
+}
+
+static const struct xhci_plat_priv dwc3_xhci_plat_quirk = {
+	.plat_start = dwc3_xhci_plat_start,
+};
+
 static void dwc3_host_fill_xhci_irq_res(struct dwc3 *dwc,
 					int irq, char *name)
 {
@@ -167,6 +188,11 @@ int dwc3_host_init(struct dwc3 *dwc)
 		}
 	}
 
+	ret = platform_device_add_data(xhci, &dwc3_xhci_plat_quirk,
+				       sizeof(struct xhci_plat_priv));
+	if (ret)
+		goto err;
+
 	ret = platform_device_add(xhci);
 	if (ret) {
 		dev_err(dwc->dev, "failed to register xHCI device\n");
@@ -192,6 +218,7 @@ void dwc3_host_exit(struct dwc3 *dwc)
 	if (dwc->sys_wakeup)
 		device_init_wakeup(&dwc->xhci->dev, false);
 
+	dwc3_enable_susphy(dwc, false);
 	platform_device_unregister(dwc->xhci);
 	dwc->xhci = NULL;
 }