[PATCH 03/15] usb: xhci: call xhci_flush_cache where appropriate

[Ahmad Fatoum <a.fatoum@pengutronix.de>]

xhci_flush_cache() is a no-op in barebox, because we use dma-coherent
allocations. Nevertheless, we define a stub for xhci_flush_cache, which
is used should we ever want to change this behavior.

The original U-Boot code doesn't use dma-coherent allocations and has
run into a few cache invalidation issues. Import the xhci_flush_cache()
added in the meantime.

No functional change.

Signed-off-by: Ahmad Fatoum <a.fatoum@pengutronix.de>
---
 drivers/usb/host/xhci-mem.c  | 3 +++
 drivers/usb/host/xhci-ring.c | 4 ++++
 2 files changed, 7 insertions(+)

diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 5ae1512af53a..db38fd43f65a 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -408,6 +408,9 @@ static int xhci_scratchpad_alloc(struct xhci_ctrl *ctrl)
 		scratchpad->sp_array[i] = cpu_to_le64(ptr);
 	}
 
+	xhci_flush_cache((uintptr_t)scratchpad->sp_array,
+			 sizeof(u64) * num_sp);
+
 	return 0;
 
 fail_sp3:
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 804384e0307f..d725b71983cd 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -670,6 +670,9 @@ int xhci_bulk_tx(struct usb_device *udev, unsigned long pipe,
 
 	first_trb = true;
 
+	/* flush the buffer before use */
+	xhci_flush_cache((uintptr_t)buffer, length);
+
 	/* Queue the first TRB, even if it's zero-length */
 	do {
 		u32 remainder = 0;
@@ -913,6 +916,7 @@ int xhci_ctrl_tx(struct usb_device *udev, unsigned long pipe,
 		trb_fields[2] = length_field;
 		trb_fields[3] = field | ep_ring->cycle_state;
 
+		xhci_flush_cache((uintptr_t)buffer, length);
 		queue_trb(ctrl, ep_ring, true, trb_fields);
 	}
 
-- 
2.39.2