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path: root/drivers/usb/host/uhci-hcd.c
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Diffstat (limited to 'drivers/usb/host/uhci-hcd.c')
-rw-r--r--drivers/usb/host/uhci-hcd.c51
1 files changed, 29 insertions, 22 deletions
diff --git a/drivers/usb/host/uhci-hcd.c b/drivers/usb/host/uhci-hcd.c
index e0d4c2358b3..49b9d390b95 100644
--- a/drivers/usb/host/uhci-hcd.c
+++ b/drivers/usb/host/uhci-hcd.c
@@ -92,6 +92,34 @@ static void suspend_rh(struct uhci_hcd *uhci, enum uhci_rh_state new_state);
static void wakeup_rh(struct uhci_hcd *uhci);
static void uhci_get_current_frame_number(struct uhci_hcd *uhci);
+/*
+ * Calculate the link pointer DMA value for the first Skeleton QH in a frame.
+ */
+static __le32 uhci_frame_skel_link(struct uhci_hcd *uhci, int frame)
+{
+ int skelnum;
+
+ /*
+ * The interrupt queues will be interleaved as evenly as possible.
+ * There's not much to be done about period-1 interrupts; they have
+ * to occur in every frame. But we can schedule period-2 interrupts
+ * in odd-numbered frames, period-4 interrupts in frames congruent
+ * to 2 (mod 4), and so on. This way each frame only has two
+ * interrupt QHs, which will help spread out bandwidth utilization.
+ *
+ * ffs (Find First bit Set) does exactly what we need:
+ * 1,3,5,... => ffs = 0 => use skel_int2_qh = skelqh[8],
+ * 2,6,10,... => ffs = 1 => use skel_int4_qh = skelqh[7], etc.
+ * ffs >= 7 => not on any high-period queue, so use
+ * skel_int1_qh = skelqh[9].
+ * Add in UHCI_NUMFRAMES to insure at least one bit is set.
+ */
+ skelnum = 8 - (int) __ffs(frame | UHCI_NUMFRAMES);
+ if (skelnum <= 1)
+ skelnum = 9;
+ return UHCI_PTR_QH | cpu_to_le32(uhci->skelqh[skelnum]->dma_handle);
+}
+
#include "uhci-debug.c"
#include "uhci-q.c"
#include "uhci-hub.c"
@@ -631,32 +659,11 @@ static int uhci_start(struct usb_hcd *hcd)
/*
* Fill the frame list: make all entries point to the proper
* interrupt queue.
- *
- * The interrupt queues will be interleaved as evenly as possible.
- * There's not much to be done about period-1 interrupts; they have
- * to occur in every frame. But we can schedule period-2 interrupts
- * in odd-numbered frames, period-4 interrupts in frames congruent
- * to 2 (mod 4), and so on. This way each frame only has two
- * interrupt QHs, which will help spread out bandwidth utilization.
*/
for (i = 0; i < UHCI_NUMFRAMES; i++) {
- int irq;
-
- /*
- * ffs (Find First bit Set) does exactly what we need:
- * 1,3,5,... => ffs = 0 => use skel_int2_qh = skelqh[8],
- * 2,6,10,... => ffs = 1 => use skel_int4_qh = skelqh[7], etc.
- * ffs >= 7 => not on any high-period queue, so use
- * skel_int1_qh = skelqh[9].
- * Add UHCI_NUMFRAMES to insure at least one bit is set.
- */
- irq = 8 - (int) __ffs(i + UHCI_NUMFRAMES);
- if (irq <= 1)
- irq = 9;
/* Only place we don't use the frame list routines */
- uhci->frame[i] = UHCI_PTR_QH |
- cpu_to_le32(uhci->skelqh[irq]->dma_handle);
+ uhci->frame[i] = uhci_frame_skel_link(uhci, i);
}
/*