usb: gadget: fsl_udc: fix dequeuing a request in progress

The original implementation of dequeuing a request in progress
is not correct.  Change to use a correct process and also clean
up the related functions a little bit.

Signed-off-by: Li Yang <leoli@freescale.com>
Acked-by: Peter Chen <peter.chen@freescale.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

2 files changed, 42 insertions, 36 deletions

diff --git a/drivers/usb/gadget/fsl_udc_core.c b/drivers/usb/gadget/fsl_udc_core.c
index bf1cd6e55ed9..dd28ef3def71 100644
--- a/drivers/usb/gadget/fsl_udc_core.c
+++ b/drivers/usb/gadget/fsl_udc_core.c
@@ -696,12 +696,31 @@ static void fsl_free_request(struct usb_ep *_ep, struct usb_request *_req)
                 kfree(req);
 }
 
-/*-------------------------------------------------------------------------*/
+/* Actually add a dTD chain to an empty dQH and let go */
+static void fsl_prime_ep(struct fsl_ep *ep, struct ep_td_struct *td)
+{
+        struct ep_queue_head *qh = get_qh_by_ep(ep);
+
+        /* Write dQH next pointer and terminate bit to 0 */
+        qh->next_dtd_ptr = cpu_to_hc32(td->td_dma
+                        & EP_QUEUE_HEAD_NEXT_POINTER_MASK);
+
+        /* Clear active and halt bit */
+        qh->size_ioc_int_sts &= cpu_to_hc32(~(EP_QUEUE_HEAD_STATUS_ACTIVE
+                                        | EP_QUEUE_HEAD_STATUS_HALT));
+
+        /* Ensure that updates to the QH will occur before priming. */
+        wmb();
+
+        /* Prime endpoint by writing correct bit to ENDPTPRIME */
+        fsl_writel(ep_is_in(ep) ? (1 << (ep_index(ep) + 16))
+                        : (1 << (ep_index(ep))), &dr_regs->endpointprime);
+}
+
+/* Add dTD chain to the dQH of an EP */
 static void fsl_queue_td(struct fsl_ep *ep, struct fsl_req *req)
 {
-        int i = ep_index(ep) * 2 + ep_is_in(ep);
         u32 temp, bitmask, tmp_stat;
-        struct ep_queue_head *dQH = &ep->udc->ep_qh[i];
 
         /* VDBG("QH addr Register 0x%8x", dr_regs->endpointlistaddr);
         VDBG("ep_qh[%d] addr is 0x%8x", i, (u32)&(ep->udc->ep_qh[i])); */
@@ -719,7 +738,7 @@ static void fsl_queue_td(struct fsl_ep *ep, struct fsl_req *req)
                         cpu_to_hc32(req->head->td_dma & DTD_ADDR_MASK);
                 /* Read prime bit, if 1 goto done */
                 if (fsl_readl(&dr_regs->endpointprime) & bitmask)
-                        goto out;
+                        return;
 
                 do {
                         /* Set ATDTW bit in USBCMD */
@@ -736,28 +755,10 @@ static void fsl_queue_td(struct fsl_ep *ep, struct fsl_req *req)
                 fsl_writel(temp & ~USB_CMD_ATDTW, &dr_regs->usbcmd);
 
                 if (tmp_stat)
-                        goto out;
+                        return;
         }
 
-        /* Write dQH next pointer and terminate bit to 0 */
-        temp = req->head->td_dma & EP_QUEUE_HEAD_NEXT_POINTER_MASK;
-        dQH->next_dtd_ptr = cpu_to_hc32(temp);
-
-        /* Clear active and halt bit */
-        temp = cpu_to_hc32(~(EP_QUEUE_HEAD_STATUS_ACTIVE
-                        | EP_QUEUE_HEAD_STATUS_HALT));
-        dQH->size_ioc_int_sts &= temp;
-
-        /* Ensure that updates to the QH will occur before priming. */
-        wmb();
-
-        /* Prime endpoint by writing 1 to ENDPTPRIME */
-        temp = ep_is_in(ep)
-                ? (1 << (ep_index(ep) + 16))
-                : (1 << (ep_index(ep)));
-        fsl_writel(temp, &dr_regs->endpointprime);
-out:
-        return;
+        fsl_prime_ep(ep, req->head);
 }
 
 /* Fill in the dTD structure
@@ -973,25 +974,20 @@ static int fsl_ep_dequeue(struct usb_ep *_ep, struct usb_request *_req)
 
                 /* The request isn't the last request in this ep queue */
                 if (req->queue.next != &ep->queue) {
-                        struct ep_queue_head *qh;
                         struct fsl_req *next_req;
 
-                        qh = ep->qh;
                         next_req = list_entry(req->queue.next, struct fsl_req,
                                         queue);
 
-                        /* Point the QH to the first TD of next request */
-                        fsl_writel((u32) next_req->head, &qh->curr_dtd_ptr);
+                        /* prime with dTD of next request */
+                        fsl_prime_ep(ep, next_req->head);
                 }
-
-                /* The request hasn't been processed, patch up the TD chain */
+        /* The request hasn't been processed, patch up the TD chain */
         } else {
                 struct fsl_req *prev_req;
 
                 prev_req = list_entry(req->queue.prev, struct fsl_req, queue);
-                fsl_writel(fsl_readl(&req->tail->next_td_ptr),
-                                &prev_req->tail->next_td_ptr);
-
+                prev_req->tail->next_td_ptr = req->tail->next_td_ptr;
         }
 
         done(ep, req, -ECONNRESET);
@@ -1068,7 +1064,7 @@ static int fsl_ep_fifo_status(struct usb_ep *_ep)
         struct fsl_udc *udc;
         int size = 0;
         u32 bitmask;
-        struct ep_queue_head *d_qh;
+        struct ep_queue_head *qh;
 
         ep = container_of(_ep, struct fsl_ep, ep);
         if (!_ep || (!ep->desc && ep_index(ep) != 0))
@@ -1079,13 +1075,13 @@ static int fsl_ep_fifo_status(struct usb_ep *_ep)
         if (!udc->driver || udc->gadget.speed == USB_SPEED_UNKNOWN)
                 return -ESHUTDOWN;
 
-        d_qh = &ep->udc->ep_qh[ep_index(ep) * 2 + ep_is_in(ep)];
+        qh = get_qh_by_ep(ep);
 
         bitmask = (ep_is_in(ep)) ? (1 << (ep_index(ep) + 16)) :
             (1 << (ep_index(ep)));
 
         if (fsl_readl(&dr_regs->endptstatus) & bitmask)
-                size = (d_qh->size_ioc_int_sts & DTD_PACKET_SIZE)
+                size = (qh->size_ioc_int_sts & DTD_PACKET_SIZE)
                     >> DTD_LENGTH_BIT_POS;
 
         pr_debug("%s %u\n", __func__, size);
diff --git a/drivers/usb/gadget/fsl_usb2_udc.h b/drivers/usb/gadget/fsl_usb2_udc.h
index 1d51be83fda8..f781f5dec417 100644
--- a/drivers/usb/gadget/fsl_usb2_udc.h
+++ b/drivers/usb/gadget/fsl_usb2_udc.h
@@ -569,6 +569,16 @@ static void dump_msg(const char *label, const u8 * buf, unsigned int length)
                                         * 2 + ((windex & USB_DIR_IN) ? 1 : 0))
 #define get_pipe_by_ep(EP)      (ep_index(EP) * 2 + ep_is_in(EP))
 
+static inline struct ep_queue_head *get_qh_by_ep(struct fsl_ep *ep)
+{
+        /* we only have one ep0 structure but two queue heads */
+        if (ep_index(ep) != 0)
+                return ep->qh;
+        else
+                return &ep->udc->ep_qh[(ep->udc->ep0_dir ==
+                                USB_DIR_IN) ? 1 : 0];
+}
+
 struct platform_device;
 #ifdef CONFIG_ARCH_MXC
 int fsl_udc_clk_init(struct platform_device *pdev);