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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>
This commit is contained in:
Sanket Parmar 2021-03-22 11:26:30 +01:00 committed by Peter Chen
parent b9b1eae761
commit 8430e98f2c
No known key found for this signature in database
GPG Key ID: 4859298150D671BB
2 changed files with 25 additions and 6 deletions
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29
drivers/usb/cdns3/cdns3-gadget.c
View File

@ -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);

2
drivers/usb/cdns3/cdns3-gadget.h
View File

@ -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;
};