The DWC3-exynos eXtensible host controller on Exynos5420 SoC
is quirky in a way that the PHY needs to be tuned to get it
working at SuperSpeed.
By default this PHY works as High-speed phy and therefore
detects even Super-speed devices as high-speed ones.
So, the PHY needs to be tuned after controller has been reset.
Adding a xHCI quirk for this purpose.
Signed-off-by: Vivek Gautam <gautam.vivek@xxxxxxxxxxx>
---
drivers/usb/host/xhci-plat.c | 19 +++++++++++++++++++
drivers/usb/host/xhci.h | 1 +
2 files changed, 20 insertions(+), 0 deletions(-)
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index d9c169f..395c9e9 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -21,6 +21,25 @@
static void xhci_plat_quirks(struct device *dev, struct xhci_hcd *xhci)
{
+ struct device *parent_dev;
+ struct device *vendor_parent_dev;
+
+ parent_dev = dev->parent;
+ vendor_parent_dev = parent_dev->parent;
+
+ /*
+ * The DWC3-exynos host controller on Exynos5420 SoC is quirky
+ * in a way that the PHY needs to be tuned to get it working
+ * at SuperSpeed. By default this PHY works as High-speed phy
+ * and so detects even Super-speed devices as high-speed ones.
+ * Therefor the PHY needs to be tuned after controller
+ * has been reset, since a controller reset actually forces the
+ * PHY to fall back to its default state wherein it works as
+ * High-Speed PHY only.
+ */
+ if (!strstr(dev_name(vendor_parent_dev), "exynos"))
+ xhci->quirks |= XHCI_DWC3_EXYNOS;
+
/*
* As of now platform drivers don't provide MSI support so we ensure
* here that the generic code does not try to make a pci_dev from our
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 7807f62..f69af8c 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1560,6 +1560,7 @@ struct xhci_hcd {
#define XHCI_PLAT (1 << 16)
#define XHCI_SLOW_SUSPEND (1 << 17)
#define XHCI_SPURIOUS_WAKEUP (1 << 18)
+#define XHCI_DWC3_EXYNOS (1 << 19)
unsigned int num_active_eps;
unsigned int limit_active_eps;
/* There are two roothubs to keep track of bus suspend info for */
--
1.7.6.5
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