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From: Neil Armstrong <narmstrong@baylibre.com>
To: kishon@ti.com, balbi@kernel.org, khilman@baylibre.com,
	martin.blumenstingl@googlemail.com
Cc: linux-amlogic@lists.infradead.org, linux-usb@vger.kernel.org,
	linux-kernel@vger.kernel.org,
	linux-arm-kernel@lists.infradead.org,
	Neil Armstrong <narmstrong@baylibre.com>
Subject: [PATCH v2 08/14] usb: dwc3: meson-g12a: support the GXL/GXM DWC3 host phy disconnect
Date: Thu, 26 Mar 2020 14:45:00 +0100
Message-ID: <20200326134507.4808-9-narmstrong@baylibre.com> (raw)
In-Reply-To: <20200326134507.4808-1-narmstrong@baylibre.com>

On the Amlogic GXL/GXM SoCs, the OTG PHY status signals are always
connected to the DWC3 controller, thus crashing the controller when
switching to OTG mode when port is not populated with a device/cable to
Host.

Amlogic added a bit to disconnect the OTG PHY status signals from the DWC3
to be used when switching the OTG PHY as Device to the DWC2 controller.

The drawback is that it makes the DWC3 port state machine stall and needs
a full reset of the DWC3 controller to get connect status to the port
connected to the OTG PHY, but not the other one.

Signed-off-by: Neil Armstrong <narmstrong@baylibre.com>
---
 drivers/usb/dwc3/dwc3-meson-g12a.c | 34 ++++++++++++++++++++++++++++++
 1 file changed, 34 insertions(+)

diff --git a/drivers/usb/dwc3/dwc3-meson-g12a.c b/drivers/usb/dwc3/dwc3-meson-g12a.c
index 43b398b7b1f7..f3f247d38606 100644
--- a/drivers/usb/dwc3/dwc3-meson-g12a.c
+++ b/drivers/usb/dwc3/dwc3-meson-g12a.c
@@ -131,6 +131,7 @@ struct dwc3_meson_g12a;
 
 struct dwc3_meson_g12a_drvdata {
 	bool otg_switch_supported;
+	bool otg_phy_host_port_disable;
 	struct clk_bulk_data *clks;
 	int num_clks;
 	const char **phy_names;
@@ -155,6 +156,19 @@ static int dwc3_meson_g12a_set_phy_mode(struct dwc3_meson_g12a *priv,
 
 static int dwc3_meson_g12a_usb_init(struct dwc3_meson_g12a *priv);
 
+/*
+ * For GXL and GXM SoCs:
+ * USB Phy muxing between the DWC2 Device controller and the DWC3 Host
+ * controller is buggy when switching from Device to Host when USB port
+ * is unpopulated, it causes the DWC3 to hard crash.
+ * When populated (including OTG switching with ID pin), the switch works
+ * like a charm like on the G12A platforms.
+ * In order to still switch from Host to Device on an USB Type-A port,
+ * an U2_PORT_DISABLE bit has been added to disconnect the DWC3 Host
+ * controller from the port, but when used the DWC3 controller must be
+ * reset to recover usage of the port.
+ */
+
 static struct dwc3_meson_g12a_drvdata g12a_drvdata = {
 	.otg_switch_supported = true,
 	.clks = meson_g12a_clocks,
@@ -290,6 +304,13 @@ static void dwc3_meson_g12a_usb_otg_apply_mode(struct dwc3_meson_g12a *priv,
 					       enum phy_mode mode)
 {
 	if (mode == PHY_MODE_USB_DEVICE) {
+		if (priv->otg_mode != USB_DR_MODE_OTG &&
+		    priv->drvdata->otg_phy_host_port_disable)
+			/* Isolate the OTG PHY port from the Host Controller */
+			regmap_update_bits(priv->usb_glue_regmap, USB_R1,
+				USB_R1_U3H_HOST_U2_PORT_DISABLE_MASK,
+				FIELD_PREP(USB_R1_U3H_HOST_U2_PORT_DISABLE_MASK,
+					   BIT(USB2_OTG_PHY)));
 		regmap_update_bits(priv->usb_glue_regmap, USB_R0,
 				USB_R0_U2D_ACT, USB_R0_U2D_ACT);
 		regmap_update_bits(priv->usb_glue_regmap, USB_R0,
@@ -297,6 +318,12 @@ static void dwc3_meson_g12a_usb_otg_apply_mode(struct dwc3_meson_g12a *priv,
 		regmap_update_bits(priv->usb_glue_regmap, USB_R4,
 				USB_R4_P21_SLEEP_M0, USB_R4_P21_SLEEP_M0);
 	} else {
+		if (priv->otg_mode != USB_DR_MODE_OTG &&
+		    priv->drvdata->otg_phy_host_port_disable) {
+			regmap_update_bits(priv->usb_glue_regmap, USB_R1,
+				USB_R1_U3H_HOST_U2_PORT_DISABLE_MASK, 0);
+			msleep(500);
+		}
 		regmap_update_bits(priv->usb_glue_regmap, USB_R0,
 				USB_R0_U2D_ACT, 0);
 		regmap_update_bits(priv->usb_glue_regmap, USB_R4,
@@ -429,6 +456,13 @@ static int dwc3_meson_g12a_role_set(struct device *dev, enum usb_role role)
 	if (mode == priv->otg_phy_mode)
 		return 0;
 
+	if (priv->drvdata->otg_phy_host_port_disable)
+		dev_warn_once(priv->dev, "Manual OTG switch is broken on this "\
+					 "SoC, when manual switching from "\
+					 "Host to device, DWC3 controller "\
+					 "will need to be resetted in order "\
+					 "to recover usage of the Host port");
+
 	return dwc3_meson_g12a_otg_mode_set(priv, mode);
 }
 
-- 
2.22.0


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Thread overview: 22+ messages / expand[flat|nested]  mbox.gz  Atom feed  top
2020-03-26 13:44 [PATCH v2 00/14] usb: dwc3: meson: add OTG support for GXL/GXM Neil Armstrong
2020-03-26 13:44 ` [PATCH v2 01/14] dt-bindings: usb: amlogic, meson-g12a-usb-ctrl: add the Amlogic GXL and GXM Families USB Glue Bindings Neil Armstrong
2020-03-26 13:44 ` [PATCH v2 02/14] usb: dwc3: meson-g12a: specify phy names in soc data Neil Armstrong
2020-03-26 13:44 ` [PATCH v2 03/14] usb: dwc3: meson-g12a: handle the phy and glue registers separately Neil Armstrong
2020-03-26 13:44 ` [PATCH v2 04/14] usb: dwc3: meson-g12a: get the reset as shared Neil Armstrong
2020-03-26 13:44 ` [PATCH v2 05/14] usb: dwc3: meson-g12a: check return of dwc3_meson_g12a_usb_init Neil Armstrong
2020-03-26 22:57   ` Martin Blumenstingl
2020-03-26 13:44 ` [PATCH v2 06/14] usb: dwc3: meson-g12a: refactor usb2 phy init Neil Armstrong
2020-03-26 23:08   ` Martin Blumenstingl
2020-03-29 10:35     ` Felipe Balbi
2020-03-26 13:44 ` [PATCH v2 07/14] usb: dwc3: meson-g12a: refactor usb init Neil Armstrong
2020-03-26 23:26   ` Martin Blumenstingl
2020-03-31  8:44     ` Neil Armstrong
2020-03-26 13:45 ` Neil Armstrong [this message]
2020-03-26 13:45 ` [PATCH v2 09/14] usb: dwc3: meson-g12a: add support for GXL and GXM SoCs Neil Armstrong
2020-03-26 13:45 ` [PATCH v2 10/14] arm64: dts: amlogic: use the new USB control driver for GXL and GXM Neil Armstrong
2020-03-26 13:45 ` [PATCH v2 11/14] phy: amlogic: meson-gxl-usb3: remove code for non-existing PHY Neil Armstrong
2020-03-26 13:45 ` [PATCH v2 12/14] usb: dwc3: of-simple: remove Amlogic GXL and AXG compatibles Neil Armstrong
2020-03-26 13:45 ` [PATCH v2 13/14] doc: dt: bindings: usb: dwc3: remove amlogic compatible entries Neil Armstrong
2020-03-26 13:45 ` [PATCH v2 14/14] dt-bindings: usb: dwc3: remove old DWC3 wrapper Neil Armstrong
2020-03-29 10:36 ` [PATCH v2 00/14] usb: dwc3: meson: add OTG support for GXL/GXM Felipe Balbi
2020-03-31  8:40   ` Neil Armstrong

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