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xhci: Introduce helper to turn one TRB into a no-op 

Useful for turning both transfer and command trbs
into no-ops.

Based on earlier code by Felipe Balbi <felipe.balbi@linux.intel.com>

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Mathias Nyman 2017-01-23 14:20:15 +02:00 committed by Greg Kroah-Hartman
parent a60f2f2ffa
commit ae1e3f0732
1 changed files with 17 additions and 12 deletions
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29
drivers/usb/host/xhci-ring.c
View File

@ -129,6 +129,21 @@ static void inc_td_cnt(struct urb *urb)
urb_priv->td_cnt++;
}
static void trb_to_noop(union xhci_trb *trb, u32 noop_type)
{
if (trb_is_link(trb)) {
/* unchain chained link TRBs */
trb->link.control &= cpu_to_le32(~TRB_CHAIN);
} else {
trb->generic.field[0] = 0;
trb->generic.field[1] = 0;
trb->generic.field[2] = 0;
/* Preserve only the cycle bit of this TRB */
trb->generic.field[3] &= cpu_to_le32(TRB_CYCLE);
trb->generic.field[3] |= cpu_to_le32(TRB_TYPE(noop_type));
}
}
/* Updates trb to point to the next TRB in the ring, and updates seg if the next
* TRB is in a new segment. This does not skip over link TRBs, and it does not
* effect the ring dequeue or enqueue pointers.
@ -592,18 +607,8 @@ static void td_to_noop(struct xhci_hcd *xhci, struct xhci_ring *ep_ring,
union xhci_trb *trb = td->first_trb;
while (1) {
if (trb_is_link(trb)) {
/* unchain chained link TRBs */
trb->link.control &= cpu_to_le32(~TRB_CHAIN);
} else {
trb->generic.field[0] = 0;
trb->generic.field[1] = 0;
trb->generic.field[2] = 0;
/* Preserve only the cycle bit of this TRB */
trb->generic.field[3] &= cpu_to_le32(TRB_CYCLE);
trb->generic.field[3] |= cpu_to_le32(
TRB_TYPE(TRB_TR_NOOP));
}
trb_to_noop(trb, TRB_TR_NOOP);
/* flip cycle if asked to */
if (flip_cycle && trb != td->first_trb && trb != td->last_trb)
trb->generic.field[3] ^= cpu_to_le32(TRB_CYCLE);