usb: host: xhci: mvebu: make USB 3.0 PHY optional for Armada 3720

Older ATF does not provide SMC call for USB 3.0 phy power on functionality
and therefore initialization of xhci-hcd is failing when older version of
ATF is used. In this case phy_power_on() function returns -EOPNOTSUPP.

[ 3.108467] mvebu-a3700-comphy d0018300.phy: unsupported SMC call, try updating your firmware
[ 3.117250] phy phy-d0018300.phy.0: phy poweron failed --> -95
[ 3.123465] xhci-hcd: probe of d0058000.usb failed with error -95

This patch introduces a new plat_setup callback for xhci platform drivers
which is called prior calling usb_add_hcd() function. This function at its
beginning skips PHY init if hcd->skip_phy_initialization is set.

Current init_quirk callback for xhci platform drivers is called from
xhci_plat_setup() function which is called after chip reset completes.
It happens in the middle of the usb_add_hcd() function and therefore this
callback cannot be used for setting if PHY init should be skipped or not.

For Armada 3720 this patch introduce a new xhci_mvebu_a3700_plat_setup()
function configured as a xhci platform plat_setup callback. This new
function calls phy_power_on() and in case it returns -EOPNOTSUPP then
XHCI_SKIP_PHY_INIT quirk is set to instruct xhci-plat to skip PHY
initialization.

This patch fixes above failure by ignoring 'not supported' error in
xhci-hcd driver. In this case it is expected that phy is already power on.

It fixes initialization of xhci-hcd on Espressobin boards where is older
Marvell's Arm Trusted Firmware without SMC call for USB 3.0 phy power.

This is regression introduced in commit bd3d25b07342 ("arm64: dts: marvell:
armada-37xx: link USB hosts with their PHYs") where USB 3.0 phy was defined
and therefore xhci-hcd on Espressobin with older ATF started failing.

Fixes: bd3d25b07342 ("arm64: dts: marvell: armada-37xx: link USB hosts with their PHYs")
Cc: <[e-mail]> # 5.1+: ea17a0f153af: phy: marvell: comphy: Convert internal SMCC firmware return codes to errno
Cc: <[e-mail]> # 5.1+: f768e718911e: usb: host: xhci-plat: add priv quirk for skip PHY initialization
Tested-by: Tomasz Maciej Nowak <[e-mail]>
Tested-by: Yoshihiro Shimoda <[e-mail]> # On R-Car
Reviewed-by: Yoshihiro Shimoda <[e-mail]> # xhci-plat
Acked-by: Mathias Nyman <[e-mail]>
Signed-off-by: Pali Rohár <[e-mail]>
Link: https://lore.kernel.org/r/[e-mail]
Signed-off-by: Greg Kroah-Hartman <[e-mail]>

drivers/usb/host/xhci-mvebu.c

···
 #include <linux/mbus.h>
 #include <linux/of.h>
 #include <linux/platform_device.h>
+#include <linux/phy/phy.h>
 
 #include <linux/usb.h>
 #include <linux/usb/hcd.h>
···
 	 * windows, and is therefore no longer useful.
 	 */
 	iounmap(base);
+
+	return 0;
+}
+
+int xhci_mvebu_a3700_plat_setup(struct usb_hcd *hcd)
+{
+	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+	struct device *dev = hcd->self.controller;
+	struct phy *phy;
+	int ret;
+
+	/* Old bindings miss the PHY handle */
+	phy = of_phy_get(dev->of_node, "usb3-phy");
+	if (IS_ERR(phy) && PTR_ERR(phy) == -EPROBE_DEFER)
+		return -EPROBE_DEFER;
+	else if (IS_ERR(phy))
+		goto phy_out;
+
+	ret = phy_init(phy);
+	if (ret)
+		goto phy_put;
+
+	ret = phy_set_mode(phy, PHY_MODE_USB_HOST_SS);
+	if (ret)
+		goto phy_exit;
+
+	ret = phy_power_on(phy);
+	if (ret == -EOPNOTSUPP) {
+		/* Skip initializatin of XHCI PHY when it is unsupported by firmware */
+		dev_warn(dev, "PHY unsupported by firmware\n");
+		xhci->quirks |= XHCI_SKIP_PHY_INIT;
+	}
+	if (ret)
+		goto phy_exit;
+
+	phy_power_off(phy);
+phy_exit:
+	phy_exit(phy);
+phy_put:
+	of_phy_put(phy);
+phy_out:
 
 	return 0;
 }

drivers/usb/host/xhci-mvebu.h

···
 
 #if IS_ENABLED(CONFIG_USB_XHCI_MVEBU)
 int xhci_mvebu_mbus_init_quirk(struct usb_hcd *hcd);
+int xhci_mvebu_a3700_plat_setup(struct usb_hcd *hcd);
 int xhci_mvebu_a3700_init_quirk(struct usb_hcd *hcd);
 #else
 static inline int xhci_mvebu_mbus_init_quirk(struct usb_hcd *hcd)
+{
+	return 0;
+}
+
+static inline int xhci_mvebu_a3700_plat_setup(struct usb_hcd *hcd)
 {
 	return 0;
 }

drivers/usb/host/xhci-plat.c

···
 		priv->plat_start(hcd);
 }
 
+static int xhci_priv_plat_setup(struct usb_hcd *hcd)
+{
+	struct xhci_plat_priv *priv = hcd_to_xhci_priv(hcd);
+
+	if (!priv->plat_setup)
+		return 0;
+
+	return priv->plat_setup(hcd);
+}
+
 static int xhci_priv_init_quirk(struct usb_hcd *hcd)
 {
 	struct xhci_plat_priv *priv = hcd_to_xhci_priv(hcd);
···
 };
 
 static const struct xhci_plat_priv xhci_plat_marvell_armada3700 = {
+	.plat_setup = xhci_mvebu_a3700_plat_setup,
 	.init_quirk = xhci_mvebu_a3700_init_quirk,
 };
 
···
 
 	hcd->tpl_support = of_usb_host_tpl_support(sysdev->of_node);
 	xhci->shared_hcd->tpl_support = hcd->tpl_support;
-	if (priv && (priv->quirks & XHCI_SKIP_PHY_INIT))
+
+	if (priv) {
+		ret = xhci_priv_plat_setup(hcd);
+		if (ret)
+			goto disable_usb_phy;
+	}
+
+	if ((xhci->quirks & XHCI_SKIP_PHY_INIT) || (priv && (priv->quirks & XHCI_SKIP_PHY_INIT)))
 		hcd->skip_phy_initialization = 1;
 
 	if (priv && (priv->quirks & XHCI_SG_TRB_CACHE_SIZE_QUIRK))

drivers/usb/host/xhci-plat.h

···
 struct xhci_plat_priv {
 	const char *firmware_name;
 	unsigned long long quirks;
+	int (*plat_setup)(struct usb_hcd *);
 	void (*plat_start)(struct usb_hcd *);
 	int (*init_quirk)(struct usb_hcd *);
 	int (*suspend_quirk)(struct usb_hcd *);