On 21-03-17 20:13:59, Sanket Parmar wrote:
> 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@xxxxxx>
> Signed-off-by: Sanket Parmar <sparmar@xxxxxxxxxxx>
> ---
>
> Changelog:
> v2:
> - used dma_*_noncoherent() APIs
> - changed the commit log
>
> drivers/usb/cdns3/cdns3-gadget.c | 30 ++++++++++++++++++++++++------
> drivers/usb/cdns3/cdns3-gadget.h | 2 ++
> 2 files changed, 26 insertions(+), 6 deletions(-)
>
> diff --git a/drivers/usb/cdns3/cdns3-gadget.c b/drivers/usb/cdns3/cdns3-gadget.c
> index 0b892a2..126087b 100644
> --- 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 +945,18 @@ 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);
> +
> +
One more blank line.
Otherwise, it seems OK for me.
> priv_req->flags |= REQUEST_UNALIGNED;
> trace_cdns3_prepare_aligned_request(priv_req);
>
> @@ -3088,9 +3105,10 @@ 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 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;
> };
> --
> 2.4.5
>
--
Thanks,
Peter Chen
