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, 76 insertions, 0 deletions

diff --git a/drivers/usb/host/xhci-dbg.c b/drivers/usb/host/xhci-dbg.c
index 5724683cef1..6dbf7d856f8 100644
--- a/drivers/usb/host/xhci-dbg.c
+++ b/drivers/usb/host/xhci-dbg.c
@@ -230,6 +230,64 @@ void xhci_print_registers(struct xhci_hcd *xhci)
 	xhci_print_op_regs(xhci);
 }
 
+void xhci_print_trb_offsets(struct xhci_hcd *xhci, union xhci_trb *trb)
+{
+	int i;
+	for (i = 0; i < 4; ++i)
+		xhci_dbg(xhci, "Offset 0x%x = 0x%x\n",
+				i*4, trb->generic.field[i]);
+}
+
+/**
+ * Debug a transfer request block (TRB).
+ */
+void xhci_debug_trb(struct xhci_hcd *xhci, union xhci_trb *trb)
+{
+	u64	address;
+	u32	type = xhci_readl(xhci, &trb->link.control) & TRB_TYPE_BITMASK;
+
+	switch (type) {
+	case TRB_TYPE(TRB_LINK):
+		xhci_dbg(xhci, "Link TRB:\n");
+		xhci_print_trb_offsets(xhci, trb);
+
+		address = trb->link.segment_ptr[0] +
+			(((u64) trb->link.segment_ptr[1]) << 32);
+		xhci_dbg(xhci, "Next ring segment DMA address = 0x%llx\n", address);
+
+		xhci_dbg(xhci, "Interrupter target = 0x%x\n",
+				GET_INTR_TARGET(trb->link.intr_target));
+		xhci_dbg(xhci, "Cycle bit = %u\n",
+				(unsigned int) (trb->link.control & TRB_CYCLE));
+		xhci_dbg(xhci, "Toggle cycle bit = %u\n",
+				(unsigned int) (trb->link.control & LINK_TOGGLE));
+		xhci_dbg(xhci, "No Snoop bit = %u\n",
+				(unsigned int) (trb->link.control & TRB_NO_SNOOP));
+		break;
+	case TRB_TYPE(TRB_TRANSFER):
+		address = trb->trans_event.buffer[0] +
+			(((u64) trb->trans_event.buffer[1]) << 32);
+		/*
+		 * FIXME: look at flags to figure out if it's an address or if
+		 * the data is directly in the buffer field.
+		 */
+		xhci_dbg(xhci, "DMA address or buffer contents= %llu\n", address);
+		break;
+	case TRB_TYPE(TRB_COMPLETION):
+		address = trb->event_cmd.cmd_trb[0] +
+			(((u64) trb->event_cmd.cmd_trb[1]) << 32);
+		xhci_dbg(xhci, "Command TRB pointer = %llu\n", address);
+		xhci_dbg(xhci, "Completion status = %u\n",
+				(unsigned int) GET_COMP_CODE(trb->event_cmd.status));
+		xhci_dbg(xhci, "Flags = 0x%x\n", (unsigned int) trb->event_cmd.flags);
+		break;
+	default:
+		xhci_dbg(xhci, "Unknown TRB with TRB type ID %u\n",
+				(unsigned int) type>>10);
+		xhci_print_trb_offsets(xhci, trb);
+		break;
+	}
+}
 
 /**
  * Debug a segment with an xHCI ring.
@@ -261,6 +319,20 @@ void xhci_debug_segment(struct xhci_hcd *xhci, struct xhci_segment *seg)
 	}
 }
 
+void xhci_dbg_ring_ptrs(struct xhci_hcd *xhci, struct xhci_ring *ring)
+{
+	xhci_dbg(xhci, "Ring deq = 0x%x (virt), 0x%x (dma)\n",
+			(unsigned int) ring->dequeue,
+			trb_virt_to_dma(ring->deq_seg, ring->dequeue));
+	xhci_dbg(xhci, "Ring deq updated %u times\n",
+			ring->deq_updates);
+	xhci_dbg(xhci, "Ring enq = 0x%x (virt), 0x%x (dma)\n",
+			(unsigned int) ring->enqueue,
+			trb_virt_to_dma(ring->enq_seg, ring->enqueue));
+	xhci_dbg(xhci, "Ring enq updated %u times\n",
+			ring->enq_updates);
+}
+
 /**
  * Debugging for an xHCI ring, which is a queue broken into multiple segments.
  *
@@ -277,6 +349,10 @@ void xhci_debug_ring(struct xhci_hcd *xhci, struct xhci_ring *ring)
 	struct xhci_segment *first_seg = ring->first_seg;
 	xhci_debug_segment(xhci, first_seg);
 
+	if (!ring->enq_updates && !ring->deq_updates) {
+		xhci_dbg(xhci, "  Ring has not been updated\n");
+		return;
+	}
 	for (seg = first_seg->next; seg != first_seg; seg = seg->next)
 		xhci_debug_segment(xhci, seg);
 }