[PATCH 5.10 132/199] ehci: fix EHCI host controller initialization sequence

Greg Kroah-Hartman
2021-01-25T19:17:57Z

From: Eugene Korenevsky <ekorenevsky@astralinux.ru>

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: 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>

---
drivers/usb/host/ehci-hcd.c | 12 ++++++++++++
1 file changed, 12 insertions(+)

--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -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));