usb: ehci: Add support for SINGLE_STEP_SET_FEATURE test of EHSET

The USB Embedded High-speed Host Electrical Test (EHSET) defines the
SINGLE_STEP_SET_FEATURE test as follows:

1) The host enumerates the test device with VID:0x1A0A, PID:0x0108
2) The host sends the SETUP stage of a GetDescriptor(Device)
3) The device ACKs the request
4) The host issues SOFs for 15 seconds allowing the test operator to
   raise the scope trigger just above the SOF voltage level
5) The host sends the IN packet
6) The device sends data in response, triggering the scope
7) The host sends an ACK in response to the data

This patch adds additional handling to the EHCI hub driver and allows
the EHSET driver to initiate this test mode by issuing a a SetFeature
request to the root hub with a Test Selector value of 0x06. From there
it mimics ehci_urb_enqueue() but separately submits QTDs for the
SETUP and DATA/STATUS stages in order to insert a delay in between.

Signed-off-by: Manu Gautam <mgautam@codeaurora.org>
Acked-by: Alan Stern <stern@rowland.harvard.edu>
[jackp@codeaurora.org: imported from commit c2084930 on codeaurora.org;
 minor cleanup and updated author email]
Signed-off-by: Jack Pham <jackp@codeaurora.org>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 101 insertions, 0 deletions

diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c
index b637a65..903d00d 100644
--- a/drivers/usb/host/ehci-q.c
+++ b/drivers/usb/host/ehci-q.c
@@ -1139,6 +1139,107 @@ submit_async (
 }
 
 /*-------------------------------------------------------------------------*/
+/*
+ * This function creates the qtds and submits them for the
+ * SINGLE_STEP_SET_FEATURE Test.
+ * This is done in two parts: first SETUP req for GetDesc is sent then
+ * 15 seconds later, the IN stage for GetDesc starts to req data from dev
+ *
+ * is_setup : i/p arguement decides which of the two stage needs to be
+ * performed; TRUE - SETUP and FALSE - IN+STATUS
+ * Returns 0 if success
+ */
+static int submit_single_step_set_feature(
+	struct usb_hcd  *hcd,
+	struct urb      *urb,
+	int             is_setup
+) {
+	struct ehci_hcd		*ehci = hcd_to_ehci(hcd);
+	struct list_head	qtd_list;
+	struct list_head	*head;
+
+	struct ehci_qtd		*qtd, *qtd_prev;
+	dma_addr_t		buf;
+	int			len, maxpacket;
+	u32			token;
+
+	INIT_LIST_HEAD(&qtd_list);
+	head = &qtd_list;
+
+	/* URBs map to sequences of QTDs:  one logical transaction */
+	qtd = ehci_qtd_alloc(ehci, GFP_KERNEL);
+	if (unlikely(!qtd))
+		return -1;
+	list_add_tail(&qtd->qtd_list, head);
+	qtd->urb = urb;
+
+	token = QTD_STS_ACTIVE;
+	token |= (EHCI_TUNE_CERR << 10);
+
+	len = urb->transfer_buffer_length;
+	/*
+	 * Check if the request is to perform just the SETUP stage (getDesc)
+	 * as in SINGLE_STEP_SET_FEATURE test, DATA stage (IN) happens
+	 * 15 secs after the setup
+	 */
+	if (is_setup) {
+		/* SETUP pid */
+		qtd_fill(ehci, qtd, urb->setup_dma,
+				sizeof(struct usb_ctrlrequest),
+				token | (2 /* "setup" */ << 8), 8);
+
+		submit_async(ehci, urb, &qtd_list, GFP_ATOMIC);
+		return 0; /*Return now; we shall come back after 15 seconds*/
+	}
+
+	/*
+	 * IN: data transfer stage:  buffer setup : start the IN txn phase for
+	 * the get_Desc SETUP which was sent 15seconds back
+	 */
+	token ^= QTD_TOGGLE;   /*We need to start IN with DATA-1 Pid-sequence*/
+	buf = urb->transfer_dma;
+
+	token |= (1 /* "in" */ << 8);  /*This is IN stage*/
+
+	maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, 0));
+
+	qtd_fill(ehci, qtd, buf, len, token, maxpacket);
+
+	/*
+	 * Our IN phase shall always be a short read; so keep the queue running
+	 * and let it advance to the next qtd which zero length OUT status
+	 */
+	qtd->hw_alt_next = EHCI_LIST_END(ehci);
+
+	/* STATUS stage for GetDesc control request */
+	token ^= 0x0100;        /* "in" <--> "out"  */
+	token |= QTD_TOGGLE;    /* force DATA1 */
+
+	qtd_prev = qtd;
+	qtd = ehci_qtd_alloc(ehci, GFP_ATOMIC);
+	if (unlikely(!qtd))
+		goto cleanup;
+	qtd->urb = urb;
+	qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma);
+	list_add_tail(&qtd->qtd_list, head);
+
+	/* dont fill any data in such packets */
+	qtd_fill(ehci, qtd, 0, 0, token, 0);
+
+	/* by default, enable interrupt on urb completion */
+	if (likely(!(urb->transfer_flags & URB_NO_INTERRUPT)))
+		qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC);
+
+	submit_async(ehci, urb, &qtd_list, GFP_KERNEL);
+
+	return 0;
+
+cleanup:
+	qtd_list_free(ehci, urb, head);
+	return -1;
+}
+
+/*-------------------------------------------------------------------------*/
 
 static void single_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh)
 {