x86: dfi-bt700: Add xHCI USB support

Change from EHCI to xHCI on the DFI BayTrail SoM.

The xHCI USB hub is connected to an GPIO on the DFI BayTrail SoM. For
correct operation, it needs to get reset upon power-up. Otherwise it
may happen that the hub is not detected after a software reboot. This
patch also configures this GPIO in the dts for correct operation.

Signed-off-by: Stefan Roese <sr@denx.de>
Cc: Simon Glass <sjg@chromium.org>
Reviewed-by: Bin Meng <bmeng.cn@gmail.com>

arch/x86/dts/dfi-bt700.dtsi

@@ -47,6 +47,15 @@
 			pad-offset = <0x3a0>;
 			mode-func = <1>;
 		};
+
+		xhci_hub_reset: usb_ulpi_stp@0 {
+			gpio-offset = <0xa0 10>;
+			pad-offset = <0x23b0>;
+			mode-func = <0>;
+			mode-gpio;
+			output-value = <1>;
+			direction = <PIN_OUTPUT>;
+		};
 	};
 
 	chosen {
@@ -261,6 +270,9 @@
 		fsp,enable-spi;
 		fsp,enable-sata;
 		fsp,sata-mode = <SATA_MODE_AHCI>;
+#ifdef CONFIG_USB_XHCI_HCD
+		fsp,enable-xhci;
+#endif
 		fsp,lpe-mode = <LPE_MODE_PCI>;
 		fsp,lpss-sio-mode = <LPSS_SIO_MODE_PCI>;
 		fsp,enable-dma0;

board/dfi/dfi-bt700/Kconfig

@@ -21,6 +21,7 @@ config BOARD_SPECIFIC_OPTIONS # dummy
 	select X86_RESET_VECTOR if !EFI_STUB
 	select INTEL_BAYTRAIL
 	select BOARD_ROMSIZE_KB_8192
+	select BOARD_LATE_INIT
 
 config PCIE_ECAM_BASE
 	default 0xe0000000

board/dfi/dfi-bt700/dfi-bt700.c

@@ -28,3 +28,30 @@ int board_early_init_f(void)
 
 	return 0;
 }
+
+int board_late_init(void)
+{
+	struct gpio_desc desc;
+	int ret;
+
+	ret = dm_gpio_lookup_name("F10", &desc);
+	if (ret)
+		debug("gpio ret=%d\n", ret);
+	ret = dm_gpio_request(&desc, "xhci_hub_reset");
+	if (ret)
+		debug("gpio_request ret=%d\n", ret);
+	ret = dm_gpio_set_dir_flags(&desc, GPIOD_IS_OUT);
+	if (ret)
+		debug("gpio dir ret=%d\n", ret);
+
+	/* Pull xHCI hub reset to low (active low) */
+	dm_gpio_set_value(&desc, 0);
+
+	/* Wait at least 5 ms, so lets choose 10 to be safe */
+	mdelay(10);
+
+	/* Pull xHCI hub reset to high (active low) */
+	dm_gpio_set_value(&desc, 1);
+
+	return 0;
+}