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, 108 deletions

diff --git a/drivers/usb/gadget/omap_udc.c b/drivers/usb/gadget/omap_udc.c
index c4975a6cf777..9b0f0925dddf 100644
--- a/drivers/usb/gadget/omap_udc.c
+++ b/drivers/usb/gadget/omap_udc.c
@@ -296,111 +296,6 @@ omap_free_request(struct usb_ep *ep, struct usb_request *_req)
 
 /*-------------------------------------------------------------------------*/
 
-/*
- * dma-coherent memory allocation (for dma-capable endpoints)
- *
- * NOTE: the dma_*_coherent() API calls suck.  Most implementations are
- * (a) page-oriented, so small buffers lose big; and (b) asymmetric with
- * respect to calls with irqs disabled:  alloc is safe, free is not.
- * We currently work around (b), but not (a).
- */
-
-static void *
-omap_alloc_buffer(
-        struct usb_ep   *_ep,
-        unsigned        bytes,
-        dma_addr_t      *dma,
-        gfp_t           gfp_flags
-)
-{
-        void            *retval;
-        struct omap_ep  *ep;
-
-        if (!_ep)
-                return NULL;
-
-        ep = container_of(_ep, struct omap_ep, ep);
-        if (use_dma && ep->has_dma) {
-                static int      warned;
-                if (!warned && bytes < PAGE_SIZE) {
-                        dev_warn(ep->udc->gadget.dev.parent,
-                                "using dma_alloc_coherent for "
-                                "small allocations wastes memory\n");
-                        warned++;
-                }
-                return dma_alloc_coherent(ep->udc->gadget.dev.parent,
-                                bytes, dma, gfp_flags);
-        }
-
-        retval = kmalloc(bytes, gfp_flags);
-        if (retval)
-                *dma = virt_to_phys(retval);
-        return retval;
-}
-
-static DEFINE_SPINLOCK(buflock);
-static LIST_HEAD(buffers);
-
-struct free_record {
-        struct list_head        list;
-        struct device           *dev;
-        unsigned                bytes;
-        dma_addr_t              dma;
-};
-
-static void do_free(unsigned long ignored)
-{
-        spin_lock_irq(&buflock);
-        while (!list_empty(&buffers)) {
-                struct free_record      *buf;
-
-                buf = list_entry(buffers.next, struct free_record, list);
-                list_del(&buf->list);
-                spin_unlock_irq(&buflock);
-
-                dma_free_coherent(buf->dev, buf->bytes, buf, buf->dma);
-
-                spin_lock_irq(&buflock);
-        }
-        spin_unlock_irq(&buflock);
-}
-
-static DECLARE_TASKLET(deferred_free, do_free, 0);
-
-static void omap_free_buffer(
-        struct usb_ep   *_ep,
-        void            *buf,
-        dma_addr_t      dma,
-        unsigned        bytes
-)
-{
-        if (!_ep) {
-                WARN_ON(1);
-                return;
-        }
-
-        /* free memory into the right allocator */
-        if (dma != DMA_ADDR_INVALID) {
-                struct omap_ep          *ep;
-                struct free_record      *rec = buf;
-                unsigned long           flags;
-
-                ep = container_of(_ep, struct omap_ep, ep);
-
-                rec->dev = ep->udc->gadget.dev.parent;
-                rec->bytes = bytes;
-                rec->dma = dma;
-
-                spin_lock_irqsave(&buflock, flags);
-                list_add_tail(&rec->list, &buffers);
-                tasklet_schedule(&deferred_free);
-                spin_unlock_irqrestore(&buflock, flags);
-        } else
-                kfree(buf);
-}
-
-/*-------------------------------------------------------------------------*/
-
 static void
 done(struct omap_ep *ep, struct omap_req *req, int status)
 {
@@ -1271,9 +1166,6 @@ static struct usb_ep_ops omap_ep_ops = {
         .alloc_request  = omap_alloc_request,
         .free_request   = omap_free_request,
 
-        .alloc_buffer   = omap_alloc_buffer,
-        .free_buffer    = omap_free_buffer,
-
         .queue          = omap_ep_queue,
         .dequeue        = omap_ep_dequeue,