usb gadget stack: remove usb_ep_*_buffer(), part 2

This patch removes controller driver infrastructure which supported
the now-removed usb_ep_{alloc,free}_buffer() calls.

As can be seen, many of the implementations of this were broken to
various degrees.  Many didn't properly return dma-coherent mappings;
those which did so were necessarily ugly because of bogosity in the
underlying dma_free_coherent() calls ... which on many platforms
can't be called from the same contexts (notably in_irq) from which
their dma_alloc_coherent() sibling can be called.

The main potential downside of removing this is that gadget drivers
wouldn't have specific knowledge that the controller drivers have:
endpoints that aren't dma-capable don't need any dma mappings at all.

Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 0 insertions, 48 deletions

diff --git a/drivers/usb/gadget/goku_udc.c b/drivers/usb/gadget/goku_udc.c
index ae931af05cef..dfadb643597b 100644
--- a/drivers/usb/gadget/goku_udc.c
+++ b/drivers/usb/gadget/goku_udc.c
@@ -296,51 +296,6 @@ goku_free_request(struct usb_ep *_ep, struct usb_request *_req)
 
 /*-------------------------------------------------------------------------*/
 
-/* allocating buffers this way eliminates dma mapping overhead, which
- * on some platforms will mean eliminating a per-io buffer copy.  with
- * some kinds of system caches, further tweaks may still be needed.
- */
-static void *
-goku_alloc_buffer(struct usb_ep *_ep, unsigned bytes,
-			dma_addr_t *dma, gfp_t gfp_flags)
-{
-	void		*retval;
-	struct goku_ep	*ep;
-
-	ep = container_of(_ep, struct goku_ep, ep);
-	if (!_ep)
-		return NULL;
-	*dma = DMA_ADDR_INVALID;
-
-	if (ep->dma) {
-		/* the main problem with this call is that it wastes memory
-		 * on typical 1/N page allocations: it allocates 1-N pages.
-		 */
-#warning Using dma_alloc_coherent even with buffers smaller than a page.
-		retval = dma_alloc_coherent(&ep->dev->pdev->dev,
-				bytes, dma, gfp_flags);
-	} else
-		retval = kmalloc(bytes, gfp_flags);
-	return retval;
-}
-
-static void
-goku_free_buffer(struct usb_ep *_ep, void *buf, dma_addr_t dma, unsigned bytes)
-{
-	/* free memory into the right allocator */
-	if (dma != DMA_ADDR_INVALID) {
-		struct goku_ep	*ep;
-
-		ep = container_of(_ep, struct goku_ep, ep);
-		if (!_ep)
-			return;
-		dma_free_coherent(&ep->dev->pdev->dev, bytes, buf, dma);
-	} else
-		kfree (buf);
-}
-
-/*-------------------------------------------------------------------------*/
-
 static void
 done(struct goku_ep *ep, struct goku_request *req, int status)
 {
@@ -1026,9 +981,6 @@ static struct usb_ep_ops goku_ep_ops = {
 	.alloc_request	= goku_alloc_request,
 	.free_request	= goku_free_request,
 
-	.alloc_buffer	= goku_alloc_buffer,
-	.free_buffer	= goku_free_buffer,
-
 	.queue		= goku_queue,
 	.dequeue	= goku_dequeue,