@@ -265,6 +265,9 @@ int xhci_plat_probe(struct platform_device *pdev, struct device *sysdev, const s
if (device_property_read_bool(tmpdev, "xhci-skip-phy-init-quirk"))
xhci->quirks |= XHCI_SKIP_PHY_INIT;
+ if (device_property_read_bool(tmpdev, "xhci-full-reset-on-remove-quirk"))
+ xhci->quirks |= XHCI_FULL_RESET_ON_REMOVE;
+
device_property_read_u32(tmpdev, "imod-interval-ns",
&xhci->imod_interval);
}
@@ -198,6 +198,7 @@ int xhci_reset(struct xhci_hcd *xhci, u64 timeout_us)
u32 command;
u32 state;
int ret;
+ unsigned int exit_state;
state = readl(&xhci->op_regs->status);
@@ -226,8 +227,13 @@ int xhci_reset(struct xhci_hcd *xhci, u64 timeout_us)
if (xhci->quirks & XHCI_INTEL_HOST)
udelay(1000);
+ if (xhci->quirks & XHCI_FULL_RESET_ON_REMOVE)
+ exit_state = 0;
+ else
+ exit_state = XHCI_STATE_REMOVING;
+
ret = xhci_handshake_check_state(xhci, &xhci->op_regs->command,
- CMD_RESET, 0, timeout_us, XHCI_STATE_REMOVING);
+ CMD_RESET, 0, timeout_us, exit_state);
if (ret)
return ret;
@@ -1637,6 +1637,7 @@ struct xhci_hcd {
#define XHCI_WRITE_64_HI_LO BIT_ULL(47)
#define XHCI_CDNS_SCTX_QUIRK BIT_ULL(48)
#define XHCI_ETRON_HOST BIT_ULL(49)
+#define XHCI_FULL_RESET_ON_REMOVE BIT_ULL(50)
unsigned int num_active_eps;
unsigned int limit_active_eps;
Commit 6ccb83d6c497 ("usb: xhci: Implement xhci_handshake_check_state() helper") introduced an optimization to xhci_reset() during xhci removal, allowing it to bail out early without waiting for the reset to complete. This behavior can cause issues on SNPS DWC3 USB controller with dual-role capability. When the DWC3 controller exits host mode and removes xhci while a reset is still in progress, and then tries to configure its hardware for device mode, the ongoing reset leads to register access issues; specifically, all register reads returns 0. These issues extend beyond the xhci register space (which is expected during a reset) and affect the entire DWC3 IP block, causing the DWC3 device mode to malfunction. To address this, introduce the `XHCI_FULL_RESET_ON_REMOVE` quirk. When this quirk is set, xhci_reset() always completes its reset handshake, ensuring the controller is in a fully reset state before proceeding. Cc: stable@vger.kernel.org Fixes: 6ccb83d6c497 ("usb: xhci: Implement xhci_handshake_check_state() helper") Signed-off-by: Roy Luo <royluo@google.com> --- drivers/usb/host/xhci-plat.c | 3 +++ drivers/usb/host/xhci.c | 8 +++++++- drivers/usb/host/xhci.h | 1 + 3 files changed, 11 insertions(+), 1 deletion(-)