usb: cdns3: Optimize DMA request buffer allocation

dma_alloc_coherent() might fail on the platform with a small
DMA region.

To avoid such failure in cdns3_prepare_aligned_request_buf(),
dma_alloc_coherent() is replaced with dma_alloc_noncoherent()
to allocate aligned request buffer of dynamic length.

Reported-by: Aswath Govindraju <a-govindraju@ti.com>
Signed-off-by: Sanket Parmar <sparmar@cadence.com>
Signed-off-by: Peter Chen <peter.chen@kernel.org>

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index 0b892a2b9cc81317a9186f525dfaea42ba664c37..9b1bd417cec0393c1097f96800abd9e8f5ad8f28 100644 (file)
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -819,9 +819,15 @@ void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep,
                                        priv_ep->dir);
 
        if ((priv_req->flags & REQUEST_UNALIGNED) &&
-           priv_ep->dir == USB_DIR_OUT && !request->status)
+           priv_ep->dir == USB_DIR_OUT && !request->status) {
+               /* Make DMA buffer CPU accessible */
+               dma_sync_single_for_cpu(priv_dev->sysdev,
+                       priv_req->aligned_buf->dma,
+                       priv_req->aligned_buf->size,
+                       priv_req->aligned_buf->dir);
                memcpy(request->buf, priv_req->aligned_buf->buf,
                       request->length);
+       }
 
        priv_req->flags &= ~(REQUEST_PENDING | REQUEST_UNALIGNED);
        /* All TRBs have finished, clear the counter */
@@ -883,8 +889,8 @@ static void cdns3_free_aligned_request_buf(struct work_struct *work)
                         * interrupts.
                         */
                        spin_unlock_irqrestore(&priv_dev->lock, flags);
-                       dma_free_coherent(priv_dev->sysdev, buf->size,
-                                         buf->buf, buf->dma);
+                       dma_free_noncoherent(priv_dev->sysdev, buf->size,
+                                         buf->buf, buf->dma, buf->dir);
                        kfree(buf);
                        spin_lock_irqsave(&priv_dev->lock, flags);
                }
@@ -911,10 +917,13 @@ static int cdns3_prepare_aligned_request_buf(struct cdns3_request *priv_req)
                        return -ENOMEM;
 
                buf->size = priv_req->request.length;
+               buf->dir = usb_endpoint_dir_in(priv_ep->endpoint.desc) ?
+                       DMA_TO_DEVICE : DMA_FROM_DEVICE;
 
-               buf->buf = dma_alloc_coherent(priv_dev->sysdev,
+               buf->buf = dma_alloc_noncoherent(priv_dev->sysdev,
                                              buf->size,
                                              &buf->dma,
+                                             buf->dir,
                                              GFP_ATOMIC);
                if (!buf->buf) {
                        kfree(buf);
@@ -936,10 +945,17 @@ static int cdns3_prepare_aligned_request_buf(struct cdns3_request *priv_req)
        }
 
        if (priv_ep->dir == USB_DIR_IN) {
+               /* Make DMA buffer CPU accessible */
+               dma_sync_single_for_cpu(priv_dev->sysdev,
+                       buf->dma, buf->size, buf->dir);
                memcpy(buf->buf, priv_req->request.buf,
                       priv_req->request.length);
        }
 
+       /* Transfer DMA buffer ownership back to device */
+       dma_sync_single_for_device(priv_dev->sysdev,
+                       buf->dma, buf->size, buf->dir);
+
        priv_req->flags |= REQUEST_UNALIGNED;
        trace_cdns3_prepare_aligned_request(priv_req);
 
@@ -3088,9 +3104,10 @@ static void cdns3_gadget_exit(struct cdns *cdns)
                struct cdns3_aligned_buf *buf;
 
                buf = cdns3_next_align_buf(&priv_dev->aligned_buf_list);
-               dma_free_coherent(priv_dev->sysdev, buf->size,
+               dma_free_noncoherent(priv_dev->sysdev, buf->size,
                                  buf->buf,
-                                 buf->dma);
+                                 buf->dma,
+                                 buf->dir);
 
                list_del(&buf->list);
                kfree(buf);

diff --git a/drivers/usb/cdns3/cdns3-gadget.h b/drivers/usb/cdns3/cdns3-gadget.h
index ecf9b91ccbb94be71177831ebb90c283fc29c313..c5660f2c4293ff2a34f81a57ac0b17f447564611 100644 (file)
--- a/drivers/usb/cdns3/cdns3-gadget.h
+++ b/drivers/usb/cdns3/cdns3-gadget.h
@@ -12,6 +12,7 @@
 #ifndef __LINUX_CDNS3_GADGET
 #define __LINUX_CDNS3_GADGET
 #include <linux/usb/gadget.h>
+#include <linux/dma-direction.h>
 
 /*
  * USBSS-DEV register interface.
@@ -1205,6 +1206,7 @@ struct cdns3_aligned_buf {
        void                    *buf;
        dma_addr_t              dma;
        u32                     size;
+       enum dma_data_direction dir;
        unsigned                in_use:1;
        struct list_head        list;
 };