usb: xhci: Acknowledge pending events in secondary event ring

As part of bus suspend if xHC is halted when there are pending
events in the event ring, xHC stops responding to xhci commands
upon host or device initiated bus resume. Fix this issue by
going over all the pending events and writing address of xHC
event ring enqueue pointer to ERDP register. This indicates to
xHC that system software has processed all Events in the ring.

Change-Id: I0c1fafb03c9848d043599fcee19e9bf07c3a3acd
Signed-off-by: Hemant Kumar <hemantk@codeaurora.org>

2 files changed, 78 insertions, 26 deletions

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 29dc6ab252b1..8308838d62d5 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -1786,11 +1786,84 @@ void xhci_free_command(struct xhci_hcd *xhci,
 	kfree(command);
 }
 
+void xhci_handle_sec_intr_events(struct xhci_hcd *xhci, int intr_num)
+{
+	union xhci_trb *erdp_trb, *current_trb;
+	struct xhci_segment	*seg;
+	u64 erdp_reg;
+	u32 iman_reg;
+	dma_addr_t deq;
+	unsigned long segment_offset;
+
+	/* disable irq, ack pending interrupt and ack all pending events */
+
+	iman_reg =
+		readl_relaxed(&xhci->sec_ir_set[intr_num]->irq_pending);
+	iman_reg &= ~IMAN_IE;
+	writel_relaxed(iman_reg,
+			&xhci->sec_ir_set[intr_num]->irq_pending);
+	iman_reg =
+		readl_relaxed(&xhci->sec_ir_set[intr_num]->irq_pending);
+	if (iman_reg & IMAN_IP)
+		writel_relaxed(iman_reg,
+			&xhci->sec_ir_set[intr_num]->irq_pending);
+
+	/* last acked event trb is in erdp reg  */
+	erdp_reg =
+		xhci_read_64(xhci, &xhci->sec_ir_set[intr_num]->erst_dequeue);
+	deq = (dma_addr_t)(erdp_reg & ~ERST_PTR_MASK);
+	if (!deq) {
+		pr_debug("%s: event ring handling not required\n", __func__);
+		return;
+	}
+
+	seg = xhci->sec_event_ring[intr_num]->first_seg;
+	segment_offset = deq - seg->dma;
+
+	/* find out virtual address of the last acked event trb */
+	erdp_trb = current_trb = &seg->trbs[0] +
+				(segment_offset/sizeof(*current_trb));
+
+	/* read cycle state of the last acked trb to find out CCS */
+	xhci->sec_event_ring[intr_num]->cycle_state =
+				(current_trb->event_cmd.flags & TRB_CYCLE);
+
+	 while (1) {
+		/* last trb of the event ring: toggle cycle state */
+		if (current_trb == &seg->trbs[TRBS_PER_SEGMENT - 1]) {
+			xhci->sec_event_ring[intr_num]->cycle_state ^= 1;
+			current_trb = &seg->trbs[0];
+		} else {
+			current_trb++;
+		}
+
+		/* cycle state transition */
+		if ((le32_to_cpu(current_trb->event_cmd.flags) & TRB_CYCLE) !=
+		    xhci->sec_event_ring[intr_num]->cycle_state)
+			break;
+	}
+
+	if (erdp_trb != current_trb) {
+		deq =
+		xhci_trb_virt_to_dma(xhci->sec_event_ring[intr_num]->deq_seg,
+					current_trb);
+		if (deq == 0)
+			xhci_warn(xhci,
+				"WARN ivalid SW event ring dequeue ptr.\n");
+		/* Update HC event ring dequeue pointer */
+		erdp_reg &= ERST_PTR_MASK;
+		erdp_reg |= ((u64) deq & (u64) ~ERST_PTR_MASK);
+	}
+
+	/* Clear the event handler busy flag (RW1C); event ring is empty. */
+	erdp_reg |= ERST_EHB;
+	xhci_write_64(xhci, erdp_reg,
+			&xhci->sec_ir_set[intr_num]->erst_dequeue);
+}
+
 int xhci_sec_event_ring_cleanup(struct usb_hcd *hcd, unsigned intr_num)
 {
 	int size;
-	u32 iman_reg;
-	u64 erdp_reg;
 	struct xhci_hcd *xhci = hcd_to_xhci(hcd);
 	struct device	*dev = xhci_to_hcd(xhci)->self.controller;
 
@@ -1803,28 +1876,7 @@ int xhci_sec_event_ring_cleanup(struct usb_hcd *hcd, unsigned intr_num)
 	size =
 	sizeof(struct xhci_erst_entry)*(xhci->sec_erst[intr_num].num_entries);
 	if (xhci->sec_erst[intr_num].entries) {
-		/*
-		 * disable irq, ack pending interrupt and clear EHB for xHC to
-		 * generate interrupt again when new event ring is setup
-		 */
-		iman_reg =
-			readl_relaxed(&xhci->sec_ir_set[intr_num]->irq_pending);
-		iman_reg &= ~IMAN_IE;
-		writel_relaxed(iman_reg,
-				&xhci->sec_ir_set[intr_num]->irq_pending);
-		iman_reg =
-			readl_relaxed(&xhci->sec_ir_set[intr_num]->irq_pending);
-		if (iman_reg & IMAN_IP)
-			writel_relaxed(iman_reg,
-				&xhci->sec_ir_set[intr_num]->irq_pending);
-		/* make sure IP gets cleared before clearing EHB */
-		mb();
-
-		erdp_reg = xhci_read_64(xhci,
-				&xhci->sec_ir_set[intr_num]->erst_dequeue);
-		xhci_write_64(xhci, erdp_reg | ERST_EHB,
-				&xhci->sec_ir_set[intr_num]->erst_dequeue);
-
+		xhci_handle_sec_intr_events(xhci, intr_num);
 		dma_free_coherent(dev, size, xhci->sec_erst[intr_num].entries,
 				xhci->sec_erst[intr_num].erst_dma_addr);
 		xhci->sec_erst[intr_num].entries = NULL;
diff --git a/drivers/usb/host/xhci-plat.c b/drivers/usb/host/xhci-plat.c
index fcb9b4b822aa..1221a80e0bdc 100644
--- a/drivers/usb/host/xhci-plat.c
+++ b/drivers/usb/host/xhci-plat.c
@@ -336,7 +336,7 @@ static int xhci_plat_runtime_suspend(struct device *dev)
 
 	dev_dbg(dev, "xhci-plat runtime suspend\n");
 
-	return 0;
+	return xhci_suspend(xhci, true);
 }
 
 static int xhci_plat_runtime_resume(struct device *dev)
@@ -350,7 +350,7 @@ static int xhci_plat_runtime_resume(struct device *dev)
 
 	dev_dbg(dev, "xhci-plat runtime resume\n");
 
-	ret = 0;
+	ret = xhci_resume(xhci, false);
 	pm_runtime_mark_last_busy(dev);
 
 	return ret;