On 21-03-09 06:19:39, Sanket Parmar wrote:
> Allocation of DMA coherent memory in atomic context using
> dma_alloc_coherent() might fail on platforms with smaller
> DMA region.
>
> To fix it, dma_alloc_coherent() is replaced with dma_pool
> API to allocate a smaller chunk of DMA coherent memory for
> TRB rings.
>
> Fixes: 7733f6c32e36 ("usb: cdns3: Add Cadence USB3 DRD Driver")
The patch is ok, but I don't think it is a bug-fix, it is an
improvement for smaller DMA region use case.
I will apply it with deletion of above Fixes tag if you have no
more opinion.
Peter
> Reported-by: Aswath Govindraju <a-govindr...@ti.com>
> Signed-off-by: Sanket Parmar <spar...@cadence.com>
> ---
> drivers/usb/cdns3/cdns3-gadget.c | 42 +++++++++++++++++--------------------
> drivers/usb/cdns3/cdns3-gadget.h | 1 +
> 2 files changed, 20 insertions(+), 23 deletions(-)
>
> diff --git a/drivers/usb/cdns3/cdns3-gadget.c
> b/drivers/usb/cdns3/cdns3-gadget.c
> index 582bfec..5f51215 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;
>
> @@ -3113,6 +3098,7 @@ static void cdns3_gadget_exit(struct cdns *cdns)
>
> 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 +3171,14 @@ 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 +3229,8 @@ 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..ecf9b91 100644
> --- a/drivers/usb/cdns3/cdns3-gadget.h
> +++ b/drivers/usb/cdns3/cdns3-gadget.h
> @@ -1298,6 +1298,7 @@ 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
>
--
Thanks,
Peter Chen
