usb: dwc2: gadget: add unaligned buffers support

When using DMA, dwc2 requires buffers to be 4 bytes aligned. Use
bounce buffers if they are not.

Tested-by: Robert Baldyga <r.baldyga@samsung.com>
Acked-by: John Youn <johnyoun@synopsys.com>
Signed-off-by: Mian Yousaf Kaukab <yousaf.kaukab@intel.com>
Signed-off-by: Felipe Balbi <balbi@ti.com>

diff --git a/drivers/usb/dwc2/core.h b/drivers/usb/dwc2/core.h
index c750fd3d88b330603a842a04e8e0baa08939b842..485b195126e728d0d6f3a1f0f11213dbbdb58f7f 100644 (file)
--- a/drivers/usb/dwc2/core.h
+++ b/drivers/usb/dwc2/core.h
@@ -158,10 +158,12 @@ struct s3c_hsotg_ep {
  * struct s3c_hsotg_req - data transfer request
  * @req: The USB gadget request
  * @queue: The list of requests for the endpoint this is queued for.
+ * @saved_req_buf: variable to save req.buf when bounce buffers are used.
  */
 struct s3c_hsotg_req {
        struct usb_request      req;
        struct list_head        queue;
+       void *saved_req_buf;
 };
 
 #if IS_ENABLED(CONFIG_USB_DWC2_PERIPHERAL) || IS_ENABLED(CONFIG_USB_DWC2_DUAL_ROLE)

diff --git a/drivers/usb/dwc2/gadget.c b/drivers/usb/dwc2/gadget.c
index fc9462aff67f72f6381f6e7ce38289374b346308..5e91cf154bba33589a8dfe67785e8fa3055478fe 100644 (file)
--- a/drivers/usb/dwc2/gadget.c
+++ b/drivers/usb/dwc2/gadget.c
@@ -726,6 +726,59 @@ dma_error:
        return -EIO;
 }
 
+static int s3c_hsotg_handle_unaligned_buf_start(struct dwc2_hsotg *hsotg,
+       struct s3c_hsotg_ep *hs_ep, struct s3c_hsotg_req *hs_req)
+{
+       void *req_buf = hs_req->req.buf;
+
+       /* If dma is not being used or buffer is aligned */
+       if (!using_dma(hsotg) || !((long)req_buf & 3))
+               return 0;
+
+       WARN_ON(hs_req->saved_req_buf);
+
+       dev_dbg(hsotg->dev, "%s: %s: buf=%p length=%d\n", __func__,
+                       hs_ep->ep.name, req_buf, hs_req->req.length);
+
+       hs_req->req.buf = kmalloc(hs_req->req.length, GFP_ATOMIC);
+       if (!hs_req->req.buf) {
+               hs_req->req.buf = req_buf;
+               dev_err(hsotg->dev,
+                       "%s: unable to allocate memory for bounce buffer\n",
+                       __func__);
+               return -ENOMEM;
+       }
+
+       /* Save actual buffer */
+       hs_req->saved_req_buf = req_buf;
+
+       if (hs_ep->dir_in)
+               memcpy(hs_req->req.buf, req_buf, hs_req->req.length);
+       return 0;
+}
+
+static void s3c_hsotg_handle_unaligned_buf_complete(struct dwc2_hsotg *hsotg,
+       struct s3c_hsotg_ep *hs_ep, struct s3c_hsotg_req *hs_req)
+{
+       /* If dma is not being used or buffer was aligned */
+       if (!using_dma(hsotg) || !hs_req->saved_req_buf)
+               return;
+
+       dev_dbg(hsotg->dev, "%s: %s: status=%d actual-length=%d\n", __func__,
+               hs_ep->ep.name, hs_req->req.status, hs_req->req.actual);
+
+       /* Copy data from bounce buffer on successful out transfer */
+       if (!hs_ep->dir_in && !hs_req->req.status)
+               memcpy(hs_req->saved_req_buf, hs_req->req.buf,
+                                                       hs_req->req.actual);
+
+       /* Free bounce buffer */
+       kfree(hs_req->req.buf);
+
+       hs_req->req.buf = hs_req->saved_req_buf;
+       hs_req->saved_req_buf = NULL;
+}
+
 static int s3c_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
                              gfp_t gfp_flags)
 {
@@ -733,6 +786,7 @@ static int s3c_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
        struct s3c_hsotg_ep *hs_ep = our_ep(ep);
        struct dwc2_hsotg *hs = hs_ep->parent;
        bool first;
+       int ret;
 
        dev_dbg(hs->dev, "%s: req %p: %d@%p, noi=%d, zero=%d, snok=%d\n",
                ep->name, req, req->length, req->buf, req->no_interrupt,
@@ -743,9 +797,13 @@ static int s3c_hsotg_ep_queue(struct usb_ep *ep, struct usb_request *req,
        req->actual = 0;
        req->status = -EINPROGRESS;
 
+       ret = s3c_hsotg_handle_unaligned_buf_start(hs, hs_ep, hs_req);
+       if (ret)
+               return ret;
+
        /* if we're using DMA, sync the buffers as necessary */
        if (using_dma(hs)) {
-               int ret = s3c_hsotg_map_dma(hs, hs_ep, req);
+               ret = s3c_hsotg_map_dma(hs, hs_ep, req);
                if (ret)
                        return ret;
        }
@@ -1326,6 +1384,8 @@ static void s3c_hsotg_complete_request(struct dwc2_hsotg *hsotg,
        if (hs_req->req.status == -EINPROGRESS)
                hs_req->req.status = result;
 
+       s3c_hsotg_handle_unaligned_buf_complete(hsotg, hs_ep, hs_req);
+
        hs_ep->req = NULL;
        list_del_init(&hs_req->queue);