usb: orion-ehci: Add support for the Armada 3700

- Add a new compatible string for the Armada 3700 SoCs

- add sbuscfg support for orion usb controller driver. For the SoCs
  without hlock, need to program BAWR/BARD/AHBBRST fields in the sbuscfg
  register to guarantee the AHB master's burst would not overrun or
  underrun the FIFO.

- the sbuscfg register has to be set after the usb controller reset,
  otherwise the value would be overridden to 0. In order to do this, the
  reset callback is registered.

[gregory.clement@free-electrons.com: - reword commit and comments
				     - fix error path in ehci_orion_drv_reset()
				     - fix checkpatch warning]
Signed-off-by: Hua Jing <jinghua@marvell.com>
Signed-off-by: Gregory CLEMENT <gregory.clement@free-electrons.com>
Reviewed-by: Andrew Lunn <andrew@lunn.ch>
Acked-by: Rob Herring <robh@kernel.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

Documentation/devicetree/bindings/usb/ehci-orion.txt

 * EHCI controller, Orion Marvell variants
 
 Required properties:
-- compatible: must be "marvell,orion-ehci"
+- compatible: must be one of the following
+	"marvell,orion-ehci"
+	"marvell,armada-3700-ehci"
 - reg: physical base address of the controller and length of memory mapped
   region.
 - interrupts: The EHCI interrupt

drivers/usb/host/ehci-orion.c

@@ -47,6 +47,18 @@
 #define USB_PHY_IVREF_CTRL	0x440
 #define USB_PHY_TST_GRP_CTRL	0x450
 
+#define USB_SBUSCFG		0x90
+
+/* BAWR = BARD = 3 : Align read/write bursts packets larger than 128 bytes */
+#define USB_SBUSCFG_BAWR_ALIGN_128B	(0x3 << 6)
+#define USB_SBUSCFG_BARD_ALIGN_128B	(0x3 << 3)
+/* AHBBRST = 3	   : Align AHB Burst to INCR16 (64 bytes) */
+#define USB_SBUSCFG_AHBBRST_INCR16	(0x3 << 0)
+
+#define USB_SBUSCFG_DEF_VAL (USB_SBUSCFG_BAWR_ALIGN_128B	\
+			     | USB_SBUSCFG_BARD_ALIGN_128B	\
+			     | USB_SBUSCFG_AHBBRST_INCR16)
+
 #define DRIVER_DESC "EHCI orion driver"
 
 #define hcd_to_orion_priv(h) ((struct orion_ehci_hcd *)hcd_to_ehci(h)->priv)
@@ -151,8 +163,31 @@ ehci_orion_conf_mbus_windows(struct usb_hcd *hcd,
 	}
 }
 
+static int ehci_orion_drv_reset(struct usb_hcd *hcd)
+{
+	struct device *dev = hcd->self.controller;
+	int ret;
+
+	ret = ehci_setup(hcd);
+	if (ret)
+		return ret;
+
+	/*
+	 * For SoC without hlock, need to program sbuscfg value to guarantee
+	 * AHB master's burst would not overrun or underrun FIFO.
+	 *
+	 * sbuscfg reg has to be set after usb controller reset, otherwise
+	 * the value would be override to 0.
+	 */
+	if (of_device_is_compatible(dev->of_node, "marvell,armada-3700-ehci"))
+		wrl(USB_SBUSCFG, USB_SBUSCFG_DEF_VAL);
+
+	return ret;
+}
+
 static const struct ehci_driver_overrides orion_overrides __initconst = {
 	.extra_priv_size =	sizeof(struct orion_ehci_hcd),
+	.reset = ehci_orion_drv_reset,
 };
 
 static int ehci_orion_drv_probe(struct platform_device *pdev)
@@ -310,6 +345,7 @@ static int ehci_orion_drv_remove(struct platform_device *pdev)
 
 static const struct of_device_id ehci_orion_dt_ids[] = {
 	{ .compatible = "marvell,orion-ehci", },
+	{ .compatible = "marvell,armada-3700-ehci", },
 	{},
 };
 MODULE_DEVICE_TABLE(of, ehci_orion_dt_ids);