[U-Boot] [PATCH] sunxi: A64: OHCI: prevent turning off shared USB clock

[Andre Przywara]

On the A64 the clock for the first USB controller is actually the parent
of the clock for the second controller, so turning them off in that order
makes the system hang.
Fix this by *not* turning off any clock for OHCI0, but both clocks when
OHCI1 is brought down.

Signed-off-by: Andre Przywara <andre.przywara at arm.com>
---
Hi,

this is a new approach to fix the USB hang we see with mainline U-Boot.
Compared to the previous patch it just deals with the USB clock (the AHB
gate was a red herring), and it eventually turns both clocks off instead
of leaving them running. Please have a test on A64 boards!

Cheers,
Andre.

 drivers/usb/host/ohci-sunxi.c | 13 ++++++++++++-
 1 file changed, 12 insertions(+), 1 deletion(-)

diff --git a/drivers/usb/host/ohci-sunxi.c b/drivers/usb/host/ohci-sunxi.c
index 0ddbdbe460..8f108b48a8 100644
--- a/drivers/usb/host/ohci-sunxi.c
+++ b/drivers/usb/host/ohci-sunxi.c
@@ -114,6 +114,7 @@ no_phy:
 static int ohci_usb_remove(struct udevice *dev)
 {
 	struct ohci_sunxi_priv *priv = dev_get_priv(dev);
+	fdt_addr_t base_addr = devfdt_get_addr(dev);
 	int ret;
 
 	if (generic_phy_valid(&priv->phy)) {
@@ -130,7 +131,17 @@ static int ohci_usb_remove(struct udevice *dev)
 
 	if (priv->cfg->has_reset)
 		clrbits_le32(priv->reset0_cfg, priv->ahb_gate_mask);
-	clrbits_le32(&priv->ccm->usb_clk_cfg, priv->usb_gate_mask);
+	/*
+	 * On the A64 CLK_USB_OHCI0 is the parent of CLK_USB_OHCI1, so
+	 * we have to bring down none for OHCI0, but both for OHCI1.
+	 */
+	if (!priv->cfg->extra_usb_gate_mask || base_addr >= SUNXI_USB2_BASE) {
+		u32 usb_gate_mask = priv->usb_gate_mask;
+
+		usb_gate_mask |= priv->cfg->extra_usb_gate_mask;
+		clrbits_le32(&priv->ccm->usb_clk_cfg, usb_gate_mask);
+	}
+
 	clrbits_le32(&priv->ccm->ahb_gate0, priv->ahb_gate_mask);
 
 	return 0;
-- 
2.14.4