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USB: ehci refcounts work on ppc7448

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Remove atomic operations on the reference counter for EHCI queue heads.
On various platforms (including ppc7448), atomic operations are unusable
with dma-coherent memory.

Signed-off-by: Steven J. Hill <sjhill1@rockwellcollins.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
David Brownell 2007-05-17 12:21:19 -07:00 committed by Greg Kroah-Hartman
parent 04d06ad0f1
commit 9c033e810e
2 changed files with 14 additions and 6 deletions
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11
drivers/usb/host/ehci-mem.c
View file

@ -64,9 +64,8 @@ static inline void ehci_qtd_free (struct ehci_hcd *ehci, struct ehci_qtd *qtd)
}
static void qh_destroy (struct kref *kref)
static void qh_destroy(struct ehci_qh *qh)
{
struct ehci_qh *qh = container_of(kref, struct ehci_qh, kref);
struct ehci_hcd *ehci = qh->ehci;
/* clean qtds first, and know this is not linked */
@ -90,7 +89,7 @@ static struct ehci_qh *ehci_qh_alloc (struct ehci_hcd *ehci, gfp_t flags)
return qh;
memset (qh, 0, sizeof *qh);
kref_init(&qh->kref);
qh->refcount = 1;
qh->ehci = ehci;
qh->qh_dma = dma;
// INIT_LIST_HEAD (&qh->qh_list);
@ -112,13 +111,15 @@ static struct ehci_qh *ehci_qh_alloc (struct ehci_hcd *ehci, gfp_t flags)
/* to share a qh (cpu threads, or hc) */
static inline struct ehci_qh *qh_get (struct ehci_qh *qh)
{
kref_get(&qh->kref);
WARN_ON(!qh->refcount);
qh->refcount++;
return qh;
}
static inline void qh_put (struct ehci_qh *qh)
{
kref_put(&qh->kref, qh_destroy);
if (!--qh->refcount)
qh_destroy(qh);
}
/*-------------------------------------------------------------------------*/

9
drivers/usb/host/ehci.h
View file

@ -457,7 +457,14 @@ struct ehci_qh {
struct ehci_qh *reclaim; /* next to reclaim */
struct ehci_hcd *ehci;
struct kref kref;
/*
* Do NOT use atomic operations for QH refcounting. On some CPUs
* (PPC7448 for example), atomic operations cannot be performed on
* memory that is cache-inhibited (i.e. being used for DMA).
* Spinlocks are used to protect all QH fields.
*/
u32 refcount;
unsigned stamp;
u8 qh_state;