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ehci: fix EHCI host controller initialization sequence 

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: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Eugene Korenevsky <ekorenevsky@astralinux.ru>
Cc: stable <stable@vger.kernel.org>
Link: https://lore.kernel.org/r/20210110173609.GA17313@himera.home
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
master
Eugene Korenevsky 2021-01-10 20:36:09 +03:00 committed by Greg Kroah-Hartman
parent 5f8e084026
commit 280a9045bb
1 changed files with 12 additions and 0 deletions
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12
drivers/usb/host/ehci-hcd.c
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@ -574,6 +574,7 @@ 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;
@ -629,9 +630,20 @@ 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));