[PATCH] usb: ehci-hcd: initialize ehci->qh_list[] with zeros

Peter Mamonov pmamonov at gmail.com
Tue Aug 25 03:33:56 PDT 2015


Without this initialization ehci->qh_list[0].qh_endpt2 is left uninitialized,
which causes problems with some EHCI host controllers.

Das u-boot uses the same strategy:

	static int ehci_common_init(struct ehci_ctrl *ctrl, uint tweaks)
	{
		...
		qh_list = &ctrl->qh_list;

		/* Set head of reclaim list */
		memset(qh_list, 0, sizeof(*qh_list));
		qh_list->qh_link = cpu_to_hc32((unsigned long)qh_list | QH_LINK_TYPE_QH);
		qh_list->qh_endpt1 = cpu_to_hc32(QH_ENDPT1_H(1) |
							QH_ENDPT1_EPS(USB_SPEED_HIGH));
		qh_list->qh_overlay.qt_next = cpu_to_hc32(QT_NEXT_TERMINATE);
		qh_list->qh_overlay.qt_altnext = cpu_to_hc32(QT_NEXT_TERMINATE);
		qh_list->qh_overlay.qt_token =
				cpu_to_hc32(QT_TOKEN_STATUS(QT_TOKEN_STATUS_HALTED));
		...
	}

Signed-off-by: Peter Mamonov <pmamonov at gmail.com>
---
 drivers/usb/host/ehci-hcd.c | 2 ++
 1 file changed, 2 insertions(+)

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index a9039c6..58c22db 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -772,6 +772,8 @@ static int ehci_init(struct usb_host *host)
 			return ret;
 	}
 
+	memset(ehci->qh_list, 0, sizeof(struct QH) * NUM_TD);
+
 	ehci->qh_list->qh_link = cpu_to_hc32((uint32_t)ehci->qh_list | QH_LINK_TYPE_QH);
 	ehci->qh_list->qh_endpt1 = cpu_to_hc32((1 << 15) | (USB_SPEED_HIGH << 12));
 	ehci->qh_list->qh_curtd = cpu_to_hc32(QT_NEXT_TERMINATE);
-- 
2.1.4




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