1 files changed, 11 insertions, 1 deletions

diff --git a/drivers/usb/gadget/s3c-hsotg.c b/drivers/usb/gadget/s3c-hsotg.c
index 4a251458c61d..354fd456f8cc 100644
--- a/drivers/usb/gadget/s3c-hsotg.c
+++ b/drivers/usb/gadget/s3c-hsotg.c
@@ -91,7 +91,9 @@ struct s3c_hsotg_req;
  * For periodic IN endpoints, we have fifo_size and fifo_load to try
  * and keep track of the amount of data in the periodic FIFO for each
  * of these as we don't have a status register that tells us how much
- * is in each of them.
+ * is in each of them. (note, this may actually be useless information
+ * as in shared-fifo mode periodic in acts like a single-frame packet
+ * buffer than a fifo)
  */
 struct s3c_hsotg_ep {
         struct usb_ep           ep;
@@ -474,6 +476,14 @@ static int s3c_hsotg_write_fifo(struct s3c_hsotg *hsotg,
 
                 size_left = S3C_DxEPTSIZ_XferSize_GET(epsize);
 
+                /* if shared fifo, we cannot write anything until the
+                 * previous data has been completely sent.
+                 */
+                if (hs_ep->fifo_load != 0) {
+                        s3c_hsotg_en_gsint(hsotg, S3C_GINTSTS_PTxFEmp);
+                        return -ENOSPC;
+                }
+
                 dev_dbg(hsotg->dev, "%s: left=%d, load=%d, fifo=%d, size %d\n",
                         __func__, size_left,
                         hs_ep->size_loaded, hs_ep->fifo_load, hs_ep->fifo_size);