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Commit e4183329 authored by Eugene Korenevsky's avatar Eugene Korenevsky Committed by Greg Kroah-Hartman
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ehci: fix EHCI host controller initialization sequence 

commit 280a9045bb18833db921b316a5527d2b565e9f2e upstream.

According to EHCI spec, EHCI HC clears USBSTS.HCHalted whenever
USBCMD.RS=1.

However, it is a good practice to wait some time after setting USBCMD.RS
(approximately 100ms) until USBSTS.HCHalted become zero.

Without this waiting, VirtualBox's EHCI virtual HC accidentally hangs
(see BugLink).

BugLink: https://bugzilla.kernel.org/show_bug.cgi?id=211095


Acked-by: default avatarAlan Stern <stern@rowland.harvard.edu>
Signed-off-by: default avatarEugene Korenevsky <ekorenevsky@astralinux.ru>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210110173609.GA17313@himera.home


Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@linuxfoundation.org>
parent 186a03e3

drivers/usb/host/ehci-hcd.c

+12 −0
Original line number Diff line number Diff line
@@ -587,6 +587,7 @@ static int ehci_run (struct usb_hcd *hcd) 
	struct ehci_hcd		*ehci = hcd_to_ehci (hcd);

	u32			temp;

	u32			hcc_params;

	int			rc;



	hcd->uses_new_polling = 1;
@@ -642,9 +643,20 @@ static int ehci_run (struct usb_hcd *hcd) 
	down_write(&ehci_cf_port_reset_rwsem);

	ehci->rh_state = EHCI_RH_RUNNING;

	ehci_writel(ehci, FLAG_CF, &ehci->regs->configured_flag);



	/* Wait until HC become operational */

	ehci_readl(ehci, &ehci->regs->command);	/* unblock posted writes */

	msleep(5);

	rc = ehci_handshake(ehci, &ehci->regs->status, STS_HALT, 0, 100 * 1000);



	up_write(&ehci_cf_port_reset_rwsem);



	if (rc) {

		ehci_err(ehci, "USB %x.%x, controller refused to start: %d\n",

			 ((ehci->sbrn & 0xf0)>>4), (ehci->sbrn & 0x0f), rc);

		return rc;

	}



	ehci->last_periodic_enable = ktime_get_real();



	temp = HC_VERSION(ehci, ehci_readl(ehci, &ehci->caps->hc_capbase));