[U-Boot] [PATCH 4/4] usb: ci_udc: complete ep0 direction handling

Stephen Warren
2014-05-29T20:53:03Z

handle_setup() currently assumes that the response to a Setup transaction
will be an OUT transaction, and any subsequent packet (if any) will be an
IN transaction. This appears to be valid in many cases; both USB
enumeration and Mass Storage work OK with this restriction. However, DFU
uses ep0 to transfer data in both directions. This renders the assumption
invalid; when sending data from device to host, the Data Stage is an IN
transaction, and the Status Stage is an OUT transaction. Enhance
handle_setup() to deduce the correct direction for the USB transactions
based on Setup transaction data.

ep0's request object only needs to be automatically re-queued when the
Data Stage completes, in order to implement the Status Stage. Once the
Status Stage transaction is complete, there is no need to re-queue the
USB request, so don't do that.

Don't sent USB request completion callbacks for Status Stage transactions.
These were queued by ci_udc itself, and only serve to confuse the USB
function code. For example, f_dfu attempts to interpret the 0-length data
buffers for Status Stage transactions as DFU packets. These buffers
contain stale data from the previous transaction. This causes f_dfu to
complain about a sequence number mismatch.

Signed-off-by: Stephen Warren <swarren@nvidia.com>
---
drivers/usb/gadget/ci_udc.c | 48 ++++++++++++++++++++++++++++++++++++++-------
drivers/usb/gadget/ci_udc.h | 1 +
2 files changed, 42 insertions(+), 7 deletions(-)

diff --git a/drivers/usb/gadget/ci_udc.c b/drivers/usb/gadget/ci_udc.c
index 03ad23164fe1..6dc20c6c954c 100644
--- a/drivers/usb/gadget/ci_udc.c
+++ b/drivers/usb/gadget/ci_udc.c
@@ -428,6 +428,17 @@ static int ci_ep_queue(struct usb_ep *ep,
return 0;
}

+static void flip_ep0_direction(void)
+{
+ if (ep0_desc.bEndpointAddress == USB_DIR_IN) {
+ DBG("%s: Flipping ep0 ot OUT\n", __func__);
+ ep0_desc.bEndpointAddress = 0;
+ } else {
+ DBG("%s: Flipping ep0 ot IN\n", __func__);
+ ep0_desc.bEndpointAddress = USB_DIR_IN;
+ }
+}
+
static void handle_ep_complete(struct ci_ep *ep)
{
struct ept_queue_item *item;
@@ -436,8 +447,6 @@ static void handle_ep_complete(struct ci_ep *ep)

num = ep->desc->bEndpointAddress & USB_ENDPOINT_NUMBER_MASK;
in = (ep->desc->bEndpointAddress & USB_DIR_IN) != 0;
- if (num == 0)
- ep0_desc.bEndpointAddress = 0;
item = ci_get_qtd(num, in);
ci_invalidate_qtd(num);

@@ -458,11 +467,18 @@ static void handle_ep_complete(struct ci_ep *ep)

DBG("ept%d %s req %p, complete %x\n",
num, in ? "in" : "out", ci_req, len);
- ci_req->req.complete(&ep->ep, &ci_req->req);
- if (num == 0) {
+ if (num != 0 || controller.ep0_data_phase)
+ ci_req->req.complete(&ep->ep, &ci_req->req);
+ if (num == 0 && controller.ep0_data_phase) {
+ /*
+ * Data Stage is complete, so flip ep0 dir for Status Stage,
+ * which always transfers a packet in the opposite direction.
+ */
+ DBG("%s: flip ep0 dir for Status Stage\n", __func__);
+ flip_ep0_direction();
+ controller.ep0_data_phase = false;
ci_req->req.length = 0;
usb_ep_queue(&ep->ep, &ci_req->req, 0);
- ep0_desc.bEndpointAddress = USB_DIR_IN;
}
}

@@ -491,8 +507,26 @@ static void handle_setup(void)
#else
writel(EPT_RX(0), &udc->epstat);
#endif
- DBG("handle setup %s, %x, %x index %x value %x\n", reqname(r.bRequest),
- r.bRequestType, r.bRequest, r.wIndex, r.wValue);
+ DBG("handle setup %s, %x, %x index %x value %x length %x\n",
+ reqname(r.bRequest), r.bRequestType, r.bRequest, r.wIndex,
+ r.wValue, r.wLength);
+
+ /* Set EP0 dir for Data Stage based on Setup Stage data */
+ if (r.bRequestType & USB_DIR_IN) {
+ DBG("%s: Set ep0 to IN for Data Stage\n", __func__);
+ ep0_desc.bEndpointAddress = USB_DIR_IN;
+ } else {
+ DBG("%s: Set ep0 to OUT for Data Stage\n", __func__);
+ ep0_desc.bEndpointAddress = 0;
+ }
+ if (r.wLength) {
+ controller.ep0_data_phase = true;
+ } else {
+ /* 0 length -> no Data Stage. Flip dir for Status Stage */
+ DBG("%s: 0 length: flip ep0 dir for Status Stage\n", __func__);
+ flip_ep0_direction();
+ controller.ep0_data_phase = false;
+ }

list_del_init(&ci_req->queue);
ci_ep->req_primed = false;
diff --git a/drivers/usb/gadget/ci_udc.h b/drivers/usb/gadget/ci_udc.h
index 7d76af84f037..c2144021e675 100644
--- a/drivers/usb/gadget/ci_udc.h
+++ b/drivers/usb/gadget/ci_udc.h
@@ -98,6 +98,7 @@ struct ci_ep {
struct ci_drv {
struct usb_gadget gadget;
struct ci_req *ep0_req;
+ bool ep0_data_phase;
struct usb_gadget_driver *driver;
struct ehci_ctrl *ctrl;
struct ept_queue_head *epts;
--
1.8.1.5