usb: xhci: Set 'Average TRB Length' to 8 for control endpoints
Update the codes to conform with xHCI spec chapter 6.2.3.
Signed-off-by: Bin Meng <bmeng.cn@gmail.com>
diff --git a/drivers/usb/host/xhci-mem.c b/drivers/usb/host/xhci-mem.c
index 84982a9..0582a9b 100644
--- a/drivers/usb/host/xhci-mem.c
+++ b/drivers/usb/host/xhci-mem.c
@@ -850,6 +850,12 @@
trb_64 = (uintptr_t)virt_dev->eps[0].ring->first_seg->trbs;
ep0_ctx->deq = cpu_to_le64(trb_64 | virt_dev->eps[0].ring->cycle_state);
+ /*
+ * xHCI spec 6.2.3:
+ * software shall set 'Average TRB Length' to 8 for control endpoints.
+ */
+ ep0_ctx->tx_info = cpu_to_le32(EP_AVG_TRB_LENGTH(8));
+
/* Steps 7 and 8 were done in xhci_alloc_virt_device() */
xhci_flush_cache((uintptr_t)ep0_ctx, sizeof(struct xhci_ep_ctx));
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 93737b0..4673738 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -601,6 +601,12 @@
ep_ctx[ep_index]->deq = cpu_to_le64(trb_64 |
virt_dev->eps[ep_index].ring->cycle_state);
+ /*
+ * xHCI spec 6.2.3:
+ * 'Average TRB Length' should be 8 for control endpoints.
+ */
+ if (usb_endpoint_xfer_control(endpt_desc))
+ avg_trb_len = 8;
ep_ctx[ep_index]->tx_info =
cpu_to_le32(EP_MAX_ESIT_PAYLOAD_LO(max_esit_payload) |
EP_AVG_TRB_LENGTH(avg_trb_len));