usb: dwc3: add support for USB 2.0-only core configuration
Newer DWC3 controllers can be built for USB 2.0-only mode, where
most of the USB 3.0 circuitry is left out. To support this mode,
the driver must limit the speed programmed into the DCFG register
to Hi-Speed or lower.
Reads and writes to the PIPECTL register are left as-is, since
they should be no-ops in USB 2.0-only mode. Calls to phy_init()
etc. for the USB3 phy are also left as-is, since the no-op USB3
phy should be used for USB 2.0-only mode controllers.
Signed-off-by: Paul Zimmerman <paulz@synopsys.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
diff --git a/drivers/usb/dwc3/core.c b/drivers/usb/dwc3/core.c
index fbe4463..b769c1f 100644
--- a/drivers/usb/dwc3/core.c
+++ b/drivers/usb/dwc3/core.c
@@ -386,6 +386,13 @@
}
dwc->revision = reg;
+ /* Handle USB2.0-only core configuration */
+ if (DWC3_GHWPARAMS3_SSPHY_IFC(dwc->hwparams.hwparams3) ==
+ DWC3_GHWPARAMS3_SSPHY_IFC_DIS) {
+ if (dwc->maximum_speed == USB_SPEED_SUPER)
+ dwc->maximum_speed = USB_SPEED_HIGH;
+ }
+
/* issue device SoftReset too */
timeout = jiffies + msecs_to_jiffies(500);
dwc3_writel(dwc->regs, DWC3_DCTL, DWC3_DCTL_CSFTRST);