USB: xhci: No-op command queueing and irq handler.

xHCI host controllers can optionally implement a no-op test.  This
simple test ensures the OS has correctly setup all basic data structures
and can correctly respond to interrupts from the host controller
hardware.

There are two rings exercised by the no-op test:  the command ring, and
the event ring.

The host controller driver writes a no-op command TRB to the command
ring, and rings the doorbell for the command ring (the first entry in
the doorbell array).  The hardware receives this event, places a command
completion event on the event ring, and fires an interrupt.

The host controller driver sees the interrupt, and checks the event ring
for TRBs it can process, and sees the command completion event.  (See
the rules in xhci-ring.c for who "owns" a TRB.  This is a simplified set
of rules, and may not contain all the details that are in the xHCI 0.95
spec.)

A timer fires every 60 seconds to debug the state of the hardware and
command and event rings.  This timer only runs if
CONFIG_USB_XHCI_HCD_DEBUGGING is 'y'.

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

1 files changed, 151 insertions, 1 deletions

diff --git a/drivers/usb/host/xhci-hcd.c b/drivers/usb/host/xhci-hcd.c
index 011f47810665..a99c119e9fd9 100644
--- a/drivers/usb/host/xhci-hcd.c
+++ b/drivers/usb/host/xhci-hcd.c
@@ -218,6 +218,120 @@ int xhci_init(struct usb_hcd *hcd)
 }
 
 /*
+ * Called in interrupt context when there might be work
+ * queued on the event ring
+ *
+ * xhci->lock must be held by caller.
+ */
+static void xhci_work(struct xhci_hcd *xhci)
+{
+        u32 temp;
+
+        /*
+         * Clear the op reg interrupt status first,
+         * so we can receive interrupts from other MSI-X interrupters.
+         * Write 1 to clear the interrupt status.
+         */
+        temp = xhci_readl(xhci, &xhci->op_regs->status);
+        temp |= STS_EINT;
+        xhci_writel(xhci, temp, &xhci->op_regs->status);
+        /* FIXME when MSI-X is supported and there are multiple vectors */
+        /* Clear the MSI-X event interrupt status */
+
+        /* Acknowledge the interrupt */
+        temp = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+        temp |= 0x3;
+        xhci_writel(xhci, temp, &xhci->ir_set->irq_pending);
+        /* Flush posted writes */
+        xhci_readl(xhci, &xhci->ir_set->irq_pending);
+
+        /* FIXME this should be a delayed service routine that clears the EHB */
+        handle_event(xhci);
+
+        /* Clear the event handler busy flag; the event ring should be empty. */
+        temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[0]);
+        xhci_writel(xhci, temp & ~ERST_EHB, &xhci->ir_set->erst_dequeue[0]);
+        /* Flush posted writes -- FIXME is this necessary? */
+        xhci_readl(xhci, &xhci->ir_set->irq_pending);
+}
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * xHCI spec says we can get an interrupt, and if the HC has an error condition,
+ * we might get bad data out of the event ring.  Section 4.10.2.7 has a list of
+ * indicators of an event TRB error, but we check the status *first* to be safe.
+ */
+irqreturn_t xhci_irq(struct usb_hcd *hcd)
+{
+        struct xhci_hcd *xhci = hcd_to_xhci(hcd);
+        u32 temp, temp2;
+
+        spin_lock(&xhci->lock);
+        /* Check if the xHC generated the interrupt, or the irq is shared */
+        temp = xhci_readl(xhci, &xhci->op_regs->status);
+        temp2 = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+        if (!(temp & STS_EINT) && !ER_IRQ_PENDING(temp2)) {
+                spin_unlock(&xhci->lock);
+                return IRQ_NONE;
+        }
+
+        temp = xhci_readl(xhci, &xhci->op_regs->status);
+        if (temp & STS_FATAL) {
+                xhci_warn(xhci, "WARNING: Host System Error\n");
+                xhci_halt(xhci);
+                xhci_to_hcd(xhci)->state = HC_STATE_HALT;
+                return -ESHUTDOWN;
+        }
+
+        xhci_work(xhci);
+        spin_unlock(&xhci->lock);
+
+        return IRQ_HANDLED;
+}
+
+#ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
+void event_ring_work(unsigned long arg)
+{
+        unsigned long flags;
+        int temp;
+        struct xhci_hcd *xhci = (struct xhci_hcd *) arg;
+        int i, j;
+
+        xhci_dbg(xhci, "Poll event ring: %lu\n", jiffies);
+
+        spin_lock_irqsave(&xhci->lock, flags);
+        temp = xhci_readl(xhci, &xhci->op_regs->status);
+        xhci_dbg(xhci, "op reg status = 0x%x\n", temp);
+        temp = xhci_readl(xhci, &xhci->ir_set->irq_pending);
+        xhci_dbg(xhci, "ir_set 0 pending = 0x%x\n", temp);
+        xhci_dbg(xhci, "No-op commands handled = %d\n", xhci->noops_handled);
+        xhci_dbg(xhci, "HC error bitmask = 0x%x\n", xhci->error_bitmask);
+        xhci->error_bitmask = 0;
+        xhci_dbg(xhci, "Event ring:\n");
+        xhci_debug_segment(xhci, xhci->event_ring->deq_seg);
+        xhci_dbg_ring_ptrs(xhci, xhci->event_ring);
+        temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[0]);
+        temp &= ERST_PTR_MASK;
+        xhci_dbg(xhci, "ERST deq = 0x%x\n", temp);
+        xhci_dbg(xhci, "Command ring:\n");
+        xhci_debug_segment(xhci, xhci->cmd_ring->deq_seg);
+        xhci_dbg_ring_ptrs(xhci, xhci->cmd_ring);
+        xhci_dbg_cmd_ptrs(xhci);
+
+        if (xhci->noops_submitted != NUM_TEST_NOOPS)
+                if (setup_one_noop(xhci))
+                        ring_cmd_db(xhci);
+        spin_unlock_irqrestore(&xhci->lock, flags);
+
+        if (!xhci->zombie)
+                mod_timer(&xhci->event_ring_timer, jiffies + POLL_TIMEOUT * HZ);
+        else
+                xhci_dbg(xhci, "Quit polling the event ring.\n");
+}
+#endif
+
+/*
  * Start the HC after it was halted.
  *
  * This function is called by the USB core when the HC driver is added.
@@ -233,8 +347,9 @@ int xhci_run(struct usb_hcd *hcd)
 {
         u32 temp;
         struct xhci_hcd *xhci = hcd_to_xhci(hcd);
-        xhci_dbg(xhci, "xhci_run\n");
+        void (*doorbell)(struct xhci_hcd *) = NULL;
 
+        xhci_dbg(xhci, "xhci_run\n");
 #if 0   /* FIXME: MSI not setup yet */
         /* Do this at the very last minute */
         ret = xhci_setup_msix(xhci);
@@ -243,6 +358,17 @@ int xhci_run(struct usb_hcd *hcd)
 
         return -ENOSYS;
 #endif
+#ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
+        init_timer(&xhci->event_ring_timer);
+        xhci->event_ring_timer.data = (unsigned long) xhci;
+        xhci->event_ring_timer.function = event_ring_work;
+        /* Poll the event ring */
+        xhci->event_ring_timer.expires = jiffies + POLL_TIMEOUT * HZ;
+        xhci->zombie = 0;
+        xhci_dbg(xhci, "Setting event ring polling timer\n");
+        add_timer(&xhci->event_ring_timer);
+#endif
+
         xhci_dbg(xhci, "// Set the interrupt modulation register\n");
         temp = xhci_readl(xhci, &xhci->ir_set->irq_control);
         temp &= 0xffff;
@@ -266,10 +392,24 @@ int xhci_run(struct usb_hcd *hcd)
                         &xhci->ir_set->irq_pending);
         xhci_print_ir_set(xhci, xhci->ir_set, 0);
 
+        if (NUM_TEST_NOOPS > 0)
+                doorbell = setup_one_noop(xhci);
+
         xhci_dbg(xhci, "Command ring memory map follows:\n");
         xhci_debug_ring(xhci, xhci->cmd_ring);
+        xhci_dbg_ring_ptrs(xhci, xhci->cmd_ring);
+        xhci_dbg_cmd_ptrs(xhci);
+
         xhci_dbg(xhci, "ERST memory map follows:\n");
         xhci_dbg_erst(xhci, &xhci->erst);
+        xhci_dbg(xhci, "Event ring:\n");
+        xhci_debug_ring(xhci, xhci->event_ring);
+        xhci_dbg_ring_ptrs(xhci, xhci->event_ring);
+        temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[1]);
+        xhci_dbg(xhci, "ERST deq upper = 0x%x\n", temp);
+        temp = xhci_readl(xhci, &xhci->ir_set->erst_dequeue[0]);
+        temp &= ERST_PTR_MASK;
+        xhci_dbg(xhci, "ERST deq = 0x%x\n", temp);
 
         temp = xhci_readl(xhci, &xhci->op_regs->command);
         temp |= (CMD_RUN);
@@ -280,6 +420,8 @@ int xhci_run(struct usb_hcd *hcd)
         temp = xhci_readl(xhci, &xhci->op_regs->command);
         xhci_dbg(xhci, "// @%x = 0x%x\n",
                         (unsigned int) &xhci->op_regs->command, temp);
+        if (doorbell)
+                (*doorbell)(xhci);
 
         xhci_dbg(xhci, "Finished xhci_run\n");
         return 0;
@@ -309,6 +451,12 @@ void xhci_stop(struct usb_hcd *hcd)
 #if 0   /* No MSI yet */
         xhci_cleanup_msix(xhci);
 #endif
+#ifdef CONFIG_USB_XHCI_HCD_DEBUGGING
+        /* Tell the event ring poll function not to reschedule */
+        xhci->zombie = 1;
+        del_timer_sync(&xhci->event_ring_timer);
+#endif
+
         xhci_dbg(xhci, "// Disabling event ring interrupts\n");
         temp = xhci_readl(xhci, &xhci->op_regs->status);
         xhci_writel(xhci, temp & ~STS_EINT, &xhci->op_regs->status);
@@ -346,6 +494,8 @@ void xhci_shutdown(struct usb_hcd *hcd)
                     xhci_readl(xhci, &xhci->op_regs->status));
 }
 
+/*-------------------------------------------------------------------------*/
+
 int xhci_get_frame(struct usb_hcd *hcd)
 {
         struct xhci_hcd *xhci = hcd_to_xhci(hcd);