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 kmalloc and dma_map API to
allocate aligned request buffer of dynamic length.

Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
Reported-by: Aswath Govindraju <a-govindr...@ti.com>
Signed-off-by: Sanket Parmar <spar...@cadence.com>
---
 drivers/usb/cdns3/cdns3-gadget.c |   73 +++++++++++++++++++++++++------------
 drivers/usb/cdns3/cdns3-gadget.h |    2 +
 2 files changed, 51 insertions(+), 24 deletions(-)

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index 5f51215..b4955ce 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -818,10 +818,26 @@ void cdns3_gadget_giveback(struct cdns3_endpoint *priv_ep,
        usb_gadget_unmap_request_by_dev(priv_dev->sysdev, request,
                                        priv_ep->dir);
 
-       if ((priv_req->flags & REQUEST_UNALIGNED) &&
-           priv_ep->dir == USB_DIR_OUT && !request->status)
-               memcpy(request->buf, priv_req->aligned_buf->buf,
-                      request->length);
+       if ((priv_req->flags & REQUEST_UNALIGNED) && priv_req->aligned_buf) {
+               struct cdns3_aligned_buf *buf;
+
+               buf = priv_req->aligned_buf;
+               dma_unmap_single(priv_dev->sysdev, buf->dma, buf->size,
+                       buf->dir);
+               priv_req->flags &= ~REQUEST_UNALIGNED;
+
+               if (priv_ep->dir == USB_DIR_OUT && !request->status) {
+                       memcpy(request->buf, priv_req->aligned_buf->buf,
+                              request->length);
+               }
+
+               trace_cdns3_free_aligned_request(priv_req);
+               priv_req->aligned_buf->in_use = 0;
+               queue_work(system_freezable_wq,
+                          &priv_dev->aligned_buf_wq);
+               priv_req->aligned_buf = NULL;
+
+       }
 
        priv_req->flags &= ~(REQUEST_PENDING | REQUEST_UNALIGNED);
        /* All TRBs have finished, clear the counter */
@@ -883,8 +899,7 @@ 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);
+                       kfree(buf->buf);
                        kfree(buf);
                        spin_lock_irqsave(&priv_dev->lock, flags);
                }
@@ -910,27 +925,16 @@ static int cdns3_prepare_aligned_request_buf(struct 
cdns3_request *priv_req)
                if (!buf)
                        return -ENOMEM;
 
-               buf->size = priv_req->request.length;
+               buf->size = usb_endpoint_dir_out(priv_ep->endpoint.desc) ?
+                               usb_ep_align(&(priv_ep->endpoint), 
priv_req->request.length)
+                               : priv_req->request.length;
 
-               buf->buf = dma_alloc_coherent(priv_dev->sysdev,
-                                             buf->size,
-                                             &buf->dma,
-                                             GFP_ATOMIC);
+               buf->buf = kmalloc(buf->size, GFP_ATOMIC);
                if (!buf->buf) {
                        kfree(buf);
                        return -ENOMEM;
                }
 
-               if (priv_req->aligned_buf) {
-                       trace_cdns3_free_aligned_request(priv_req);
-                       priv_req->aligned_buf->in_use = 0;
-                       queue_work(system_freezable_wq,
-                                  &priv_dev->aligned_buf_wq);
-               }
-
-               buf->in_use = 1;
-               priv_req->aligned_buf = buf;
-
                list_add_tail(&buf->list,
                              &priv_dev->aligned_buf_list);
        }
@@ -940,6 +944,27 @@ static int cdns3_prepare_aligned_request_buf(struct 
cdns3_request *priv_req)
                       priv_req->request.length);
        }
 
+       if (priv_req->aligned_buf) {
+               trace_cdns3_free_aligned_request(priv_req);
+               priv_req->aligned_buf->in_use = 0;
+               queue_work(system_freezable_wq,
+                          &priv_dev->aligned_buf_wq);
+       }
+
+       buf->dir =  priv_ep->dir ? DMA_TO_DEVICE : DMA_FROM_DEVICE;
+       buf->in_use = 1;
+       priv_req->aligned_buf = buf;
+
+       buf->dma = dma_map_single(priv_dev->sysdev, buf->buf, buf->size,
+                               buf->dir);
+
+       if (dma_mapping_error(priv_dev->sysdev, buf->dma)) {
+               dev_err(priv_dev->dev, "Failed to map buffer\n");
+               kfree(buf->buf);
+               kfree(buf);
+               return -EFAULT;
+       }
+
        priv_req->flags |= REQUEST_UNALIGNED;
        trace_cdns3_prepare_aligned_request(priv_req);
 
@@ -3088,11 +3113,11 @@ 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,
-                                 buf->buf,
-                                 buf->dma);
+               dma_unmap_single(priv_dev->sysdev, buf->dma, buf->size,
+                       buf->dir);
 
                list_del(&buf->list);
+               kfree(buf->buf);
                kfree(buf);
        }
 
diff --git a/drivers/usb/cdns3/cdns3-gadget.h b/drivers/usb/cdns3/cdns3-gadget.h
index ecf9b91..c5660f2 100644
--- 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;
 };
-- 
1.7.1

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