Allocation of DMA coherent memory in atomic context using
dma_alloc_coherent() might fail on some platform. To fix it,
Replaced dma_alloc_coherent() with dma_pool API to allocate a
smaller chunk of DMA coherent memory for TRB rings.

Also in cdns3_prepare_aligned_request_buf(), replaced
dma_alloc_coherent() with kmalloc and dma_map API to allocate
aligned request buffer of dynamic length.

Fixes: commit 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 |  115 ++++++++++++++++++++++---------------
 drivers/usb/cdns3/cdns3-gadget.h |    3 +
 2 files changed, 71 insertions(+), 47 deletions(-)

diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
index 582bfec..5fd6993 100644
--- a/drivers/usb/cdns3/cdns3-gadget.c
+++ b/drivers/usb/cdns3/cdns3-gadget.c
@@ -59,6 +59,7 @@
 #include <linux/dma-mapping.h>
 #include <linux/usb/gadget.h>
 #include <linux/module.h>
+#include <linux/dmapool.h>
 #include <linux/iopoll.h>
 
 #include "core.h"
@@ -190,29 +191,13 @@ dma_addr_t cdns3_trb_virt_to_dma(struct cdns3_endpoint 
*priv_ep,
        return priv_ep->trb_pool_dma + offset;
 }
 
-static int cdns3_ring_size(struct cdns3_endpoint *priv_ep)
-{
-       switch (priv_ep->type) {
-       case USB_ENDPOINT_XFER_ISOC:
-               return TRB_ISO_RING_SIZE;
-       case USB_ENDPOINT_XFER_CONTROL:
-               return TRB_CTRL_RING_SIZE;
-       default:
-               if (priv_ep->use_streams)
-                       return TRB_STREAM_RING_SIZE;
-               else
-                       return TRB_RING_SIZE;
-       }
-}
-
 static void cdns3_free_trb_pool(struct cdns3_endpoint *priv_ep)
 {
        struct cdns3_device *priv_dev = priv_ep->cdns3_dev;
 
        if (priv_ep->trb_pool) {
-               dma_free_coherent(priv_dev->sysdev,
-                                 cdns3_ring_size(priv_ep),
-                                 priv_ep->trb_pool, priv_ep->trb_pool_dma);
+               dma_pool_free(priv_dev->eps_dma_pool,
+                               priv_ep->trb_pool, priv_ep->trb_pool_dma);
                priv_ep->trb_pool = NULL;
        }
 }
@@ -226,7 +211,7 @@ static void cdns3_free_trb_pool(struct cdns3_endpoint 
*priv_ep)
 int cdns3_allocate_trb_pool(struct cdns3_endpoint *priv_ep)
 {
        struct cdns3_device *priv_dev = priv_ep->cdns3_dev;
-       int ring_size = cdns3_ring_size(priv_ep);
+       int ring_size = TRB_RING_SIZE;
        int num_trbs = ring_size / TRB_SIZE;
        struct cdns3_trb *link_trb;
 
@@ -234,10 +219,10 @@ int cdns3_allocate_trb_pool(struct cdns3_endpoint 
*priv_ep)
                cdns3_free_trb_pool(priv_ep);
 
        if (!priv_ep->trb_pool) {
-               priv_ep->trb_pool = dma_alloc_coherent(priv_dev->sysdev,
-                                                      ring_size,
-                                                      &priv_ep->trb_pool_dma,
-                                                      GFP_DMA32 | GFP_ATOMIC);
+               priv_ep->trb_pool = dma_pool_alloc(priv_dev->eps_dma_pool,
+                                               GFP_DMA32 | GFP_ATOMIC,
+                                               &priv_ep->trb_pool_dma);
+
                if (!priv_ep->trb_pool)
                        return -ENOMEM;
 
@@ -833,10 +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 */
@@ -898,8 +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);
                }
@@ -925,27 +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);
        }
@@ -955,6 +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);
 
@@ -3103,16 +3113,17 @@ 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);
        }
 
        dma_free_coherent(priv_dev->sysdev, 8, priv_dev->setup_buf,
                          priv_dev->setup_dma);
+       dma_pool_destroy(priv_dev->eps_dma_pool);
 
        kfree(priv_dev->zlp_buf);
        usb_put_gadget(&priv_dev->gadget);
@@ -3185,6 +3196,14 @@ static int cdns3_gadget_start(struct cdns *cdns)
        /* initialize endpoint container */
        INIT_LIST_HEAD(&priv_dev->gadget.ep_list);
        INIT_LIST_HEAD(&priv_dev->aligned_buf_list);
+       priv_dev->eps_dma_pool = dma_pool_create("cdns3_eps_dma_pool",
+                                               priv_dev->sysdev,
+                                               TRB_RING_SIZE, 8, 0);
+       if (!priv_dev->eps_dma_pool) {
+               dev_err(priv_dev->dev, "Failed to create TRB dma pool\n");
+               ret = -ENOMEM;
+               goto err1;
+       }
 
        ret = cdns3_init_eps(priv_dev);
        if (ret) {
@@ -3235,6 +3254,8 @@ static int cdns3_gadget_start(struct cdns *cdns)
 err2:
        cdns3_free_all_eps(priv_dev);
 err1:
+       dma_pool_destroy(priv_dev->eps_dma_pool);
+
        usb_put_gadget(&priv_dev->gadget);
        cdns->gadget_dev = NULL;
        return ret;
diff --git a/drivers/usb/cdns3/cdns3-gadget.h b/drivers/usb/cdns3/cdns3-gadget.h
index 21fa461..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;
 };
@@ -1298,6 +1300,7 @@ struct cdns3_device {
 
        struct cdns3_usb_regs           __iomem *regs;
 
+       struct dma_pool                 *eps_dma_pool;
        struct usb_ctrlrequest          *setup_buf;
        dma_addr_t                      setup_dma;
        void                            *zlp_buf;
-- 
1.7.1

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