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Commit 9c033e81 authored by David Brownell's avatar David Brownell Committed by Greg Kroah-Hartman
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USB: ehci refcounts work on ppc7448 



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: default avatarSteven J. Hill <sjhill1@rockwellcollins.com>
Signed-off-by: default avatarDavid Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: default avatarGreg Kroah-Hartman <gregkh@suse.de>
parent 04d06ad0

drivers/usb/host/ehci-mem.c

+6 −5
Original line number Original line Diff line number Diff line
@@ -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;

	struct ehci_hcd *ehci = qh->ehci;





	/* clean qtds first, and know this is not linked */

	/* 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;

		return qh;





	memset (qh, 0, sizeof *qh);

	memset (qh, 0, sizeof *qh);

	kref_init(&qh->kref);

	qh->refcount = 1;

	qh->ehci = ehci;

	qh->ehci = ehci;

	qh->qh_dma = dma;

	qh->qh_dma = dma;

	// INIT_LIST_HEAD (&qh->qh_list);

	// 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) */

/* to share a qh (cpu threads, or hc) */

static inline struct ehci_qh *qh_get (struct ehci_qh *qh)

static inline struct ehci_qh *qh_get (struct ehci_qh *qh)

{

{

	kref_get(&qh->kref);

	WARN_ON(!qh->refcount);

	qh->refcount++;

	return qh;

	return qh;

}

}





static inline void qh_put (struct ehci_qh *qh)

static inline void qh_put (struct ehci_qh *qh)

{

{

	kref_put(&qh->kref, qh_destroy);

	if (!--qh->refcount)

		qh_destroy(qh);

}

}





/*-------------------------------------------------------------------------*/

/*-------------------------------------------------------------------------*/

drivers/usb/host/ehci.h

+8 −1
Original line number Original line Diff line number Diff line
@@ -457,7 +457,14 @@ struct ehci_qh { 
	struct ehci_qh		*reclaim;	/* next to reclaim */

	struct ehci_qh		*reclaim;	/* next to reclaim */





	struct ehci_hcd		*ehci;

	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;

	unsigned		stamp;





	u8			qh_state;

	u8			qh_state;