[U-Boot] [PATCH v2 2/3] rockchip: rk3399-puma: implement usb_hub_reset_devices for puma-rk3399

[Philipp Tomsich]

For some versions of the RK3399-Q7 (at least revisions v1.1 and v1.2
are affected), we need to turn on the power for the port connected to
the on-module USB hub only when the device is probed for the first
time to ensure that the hub does not enter a low-power mode (that
U-Boot's USB stack can't deal with).

Note that this is needed for U-Boot only, as Linux eventually manages
to attach the hub even when it has entered into its low-power state
(when the hub wakes up the next time) after a few seconds.

Signed-off-by: Philipp Tomsich <philipp.tomsich at theobroma-systems.com>

---

Changes in v2:
- moved the power-control logic from xhci.c into the board-specific
  file for the RK3399-Q7, hooking it up via usb_hub_reset_devices

 board/theobroma-systems/puma_rk3399/puma-rk3399.c | 70 ++++++++++++++++++++++-
 1 file changed, 69 insertions(+), 1 deletion(-)

diff --git a/board/theobroma-systems/puma_rk3399/puma-rk3399.c b/board/theobroma-systems/puma_rk3399/puma-rk3399.c
index 2b4988e..7f2dd65 100644
--- a/board/theobroma-systems/puma_rk3399/puma-rk3399.c
+++ b/board/theobroma-systems/puma_rk3399/puma-rk3399.c
@@ -7,12 +7,13 @@
 #include <common.h>
 #include <dm.h>
 #include <misc.h>
+#include <spl.h>
+#include <usb.h>
 #include <dm/pinctrl.h>
 #include <dm/uclass-internal.h>
 #include <asm/setup.h>
 #include <asm/arch/periph.h>
 #include <power/regulator.h>
-#include <spl.h>
 #include <u-boot/sha256.h>
 
 DECLARE_GLOBAL_DATA_PTR;
@@ -158,3 +159,70 @@ void get_board_serial(struct tag_serialnr *serialnr)
 	serialnr->low = (u32)(serial & 0xffffffff);
 }
 #endif
+
+/**
+ * Switch power at an external regulator (for our root hub).
+ *
+ * @param ctrl pointer to the xHCI controller
+ * @param port port number as in the control message (one-based)
+ * @param enable boolean indicating whether to enable or disable power
+ * @return returns 0 on success, an error-code on failure
+ */
+static int board_usb_port_power_set(struct udevice *dev, int port,
+				    bool enable)
+{
+#if CONFIG_IS_ENABLED(OF_CONTROL) && CONFIG_IS_ENABLED(DM_REGULATOR)
+	/* We start counting ports at 0, while USB counts from 1. */
+	int index = port - 1;
+	const char *regname = NULL;
+	struct udevice *regulator;
+	const char *prop = "tsd,usb-port-power";
+	int ret;
+
+	debug("%s: ctrl '%s' port %d enable %s\n", __func__,
+	      dev_read_name(dev), port, enable ? "true" : "false");
+
+	ret = dev_read_string_index(dev, prop, index, &regname);
+	if (ret < 0) {
+		debug("%s: ctrl '%s' port %d: no entry in '%s'\n",
+		      __func__, dev_read_name(dev), port, prop);
+		return ret;
+	}
+
+	ret = regulator_get_by_platname(regname, &regulator);
+	if (ret) {
+		debug("%s: ctrl '%s' port %d: could not get regulator '%s'\n",
+		      __func__, dev_read_name(dev), port, regname);
+		return ret;
+	}
+
+	regulator_set_enable(regulator, enable);
+	return 0;
+#else
+	return -ENOTSUPP;
+#endif
+}
+
+void usb_hub_reset_devices(struct usb_hub_device *hub, int port)
+{
+	struct udevice *dev = hub->pusb_dev->dev;
+	struct udevice *ctrl;
+
+	/* We are only interested in our root-hubs */
+	if (usb_hub_is_root_hub(dev) == false)
+		return;
+
+	ctrl = usb_get_bus(dev);
+	if (!ctrl) {
+		debug("%s: could not retrieve ctrl for hub\n", __func__);
+		return;
+	}
+
+	/*
+	 * To work around an incompatibility between the single-threaded
+	 * USB stack in U-Boot and (a strange low-power mode of) the USB
+	 * hub we have on-module, we need to delay powering on the hub
+	 * until the first time the port is probed.
+	 */
+	board_usb_port_power_set(ctrl, port, true);
+}
-- 
2.1.4