USB: xhci: Re-purpose xhci_quiesce().

xhci_quiesce() is basically a no-op right now.  It's only called if
HC_IS_RUNNING() is true, and the body of the function consists of a
BUG_ON if HC_IS_RUNNING() is false.  For the new xHCI watchdog timer, we
need a new function that clears the xHCI running bit in the command
register, but doesn't wait for the halt status to show up in the status
register.  Re-purpose xhci_quiesce() to do that.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 17 insertions, 34 deletions

diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
index 3a30db6d6abe..5839453d342b 100644
--- a/drivers/usb/host/xhci-hcd.c
+++ b/drivers/usb/host/xhci-hcd.c
@@ -67,22 +67,14 @@ static int handshake(struct xhci_hcd *xhci, void __iomem *ptr,
 }
 
 /*
- * Force HC into halt state.
- *
- * Disable any IRQs and clear the run/stop bit.
- * HC will complete any current and actively pipelined transactions, and
- * should halt within 16 microframes of the run/stop bit being cleared.
- * Read HC Halted bit in the status register to see when the HC is finished.
- * XXX: shouldn't we set HC_STATE_HALT here somewhere?
+ * Disable interrupts and begin the xHCI halting process.
  */
-int xhci_halt(struct xhci_hcd *xhci)
+void xhci_quiesce(struct xhci_hcd *xhci)
 {
         u32 halted;
         u32 cmd;
         u32 mask;
 
-        xhci_dbg(xhci, "// Halt the HC\n");
-        /* Disable all interrupts from the host controller */
         mask = ~(XHCI_IRQS);
         halted = xhci_readl(xhci, &xhci->op_regs->status) & STS_HALT;
         if (!halted)
@@ -91,6 +83,21 @@ int xhci_halt(struct xhci_hcd *xhci)
         cmd = xhci_readl(xhci, &xhci->op_regs->command);
         cmd &= mask;
         xhci_writel(xhci, cmd, &xhci->op_regs->command);
+}
+
+/*
+ * Force HC into halt state.
+ *
+ * Disable any IRQs and clear the run/stop bit.
+ * HC will complete any current and actively pipelined transactions, and
+ * should halt within 16 microframes of the run/stop bit being cleared.
+ * Read HC Halted bit in the status register to see when the HC is finished.
+ * XXX: shouldn't we set HC_STATE_HALT here somewhere?
+ */
+int xhci_halt(struct xhci_hcd *xhci)
+{
+        xhci_dbg(xhci, "// Halt the HC\n");
+        xhci_quiesce(xhci);
 
         return handshake(xhci, &xhci->op_regs->status,
                         STS_HALT, STS_HALT, XHCI_MAX_HALT_USEC);
@@ -124,28 +131,6 @@ int xhci_reset(struct xhci_hcd *xhci)
         return handshake(xhci, &xhci->op_regs->command, CMD_RESET, 0, 250 * 1000);
 }
 
-/*
- * Stop the HC from processing the endpoint queues.
- */
-static void xhci_quiesce(struct xhci_hcd *xhci)
-{
-        /*
-         * Queues are per endpoint, so we need to disable an endpoint or slot.
-         *
-         * To disable a slot, we need to insert a disable slot command on the
-         * command ring and ring the doorbell.  This will also free any internal
-         * resources associated with the slot (which might not be what we want).
-         *
-         * A Release Endpoint command sounds better - doesn't free internal HC
-         * memory, but removes the endpoints from the schedule and releases the
-         * bandwidth, disables the doorbells, and clears the endpoint enable
-         * flag.  Usually used prior to a set interface command.
-         *
-         * TODO: Implement after command ring code is done.
-         */
-        BUG_ON(!HC_IS_RUNNING(xhci_to_hcd(xhci)->state));
-        xhci_dbg(xhci, "Finished quiescing -- code not written yet\n");
-}
 
 #if 0
 /* Set up MSI-X table for entry 0 (may claim other entries later) */
@@ -490,8 +475,6 @@ void xhci_stop(struct usb_hcd *hcd)
         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 
         spin_lock_irq(&xhci->lock);
-        if (HC_IS_RUNNING(hcd->state))
-                xhci_quiesce(xhci);
         xhci_halt(xhci);
         xhci_reset(xhci);
         spin_unlock_irq(&xhci->lock);