diff options
| author | David Brownell <david-b@pacbell.net> | 2007-05-17 12:21:19 -0700 |
|---|---|---|
| committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-07-12 16:29:47 -0700 |
| commit | 9c033e810eef0aff6d4d3bf028aa1e583c074f93 (patch) | |
| tree | b7dfa412f7882fa90fd6bb8c5e8cbc2185bd12cf /drivers/usb/host | |
| parent | 04d06ad0f1fdb499af84ae3d7969e2136a462f38 (diff) | |
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: Steven J. Hill <sjhill1@rockwellcollins.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host')
| -rw-r--r-- | drivers/usb/host/ehci-mem.c | 11 | ||||
| -rw-r--r-- | drivers/usb/host/ehci.h | 9 |
2 files changed, 14 insertions, 6 deletions
diff --git a/drivers/usb/host/ehci-mem.c b/drivers/usb/host/ehci-mem.c index bdb29e61805..8816d09903d 100644 --- a/drivers/usb/host/ehci-mem.c +++ b/drivers/usb/host/ehci-mem.c @@ -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); } /*-------------------------------------------------------------------------*/ diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h index 79ad2af5ef6..6ef9d775775 100644 --- a/drivers/usb/host/ehci.h +++ b/drivers/usb/host/ehci.h @@ -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; |