diff options
author | Alan Stern <stern@rowland.harvard.edu> | 2007-02-19 15:52:45 -0500 |
---|---|---|
committer | Greg Kroah-Hartman <gregkh@suse.de> | 2007-02-23 15:03:45 -0800 |
commit | 17230acdc71137622ca7dfd789b3944c75d39404 (patch) | |
tree | 67eb75c5e8d254b2d5490ea9982efe73952f90d5 /drivers/usb/host/uhci-q.c | |
parent | 28b9325e6ae45ffb5e99fedcafe00f25fcaacf06 (diff) |
UHCI: Eliminate asynchronous skeleton Queue Headers
This patch (as856) attempts to improve the performance of uhci-hcd by
removing the asynchronous skeleton Queue Headers. They don't contain
any useful information but the controller has to read through them at
least once every millisecond, incurring a non-zero DMA overhead.
Now all the asynchronous queues are combined, along with the period-1
interrupt queue, into a single list with a single skeleton QH. The
start of the low-speed control, full-speed control, and bulk sublists
is determined by linear search. Since there should rarely be more
than a couple of QHs in the list, the searches should incur a much
smaller total load than keeping the skeleton QHs.
Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
Diffstat (limited to 'drivers/usb/host/uhci-q.c')
-rw-r--r-- | drivers/usb/host/uhci-q.c | 193 |
1 files changed, 171 insertions, 22 deletions
diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c index a0c6bf6128a..f4ebdb3e488 100644 --- a/drivers/usb/host/uhci-q.c +++ b/drivers/usb/host/uhci-q.c @@ -13,7 +13,7 @@ * (C) Copyright 2000 Yggdrasil Computing, Inc. (port of new PCI interface * support from usb-ohci.c by Adam Richter, adam@yggdrasil.com). * (C) Copyright 1999 Gregory P. Smith (from usb-ohci.c) - * (C) Copyright 2004-2006 Alan Stern, stern@rowland.harvard.edu + * (C) Copyright 2004-2007 Alan Stern, stern@rowland.harvard.edu */ @@ -45,14 +45,43 @@ static inline void uhci_clear_next_interrupt(struct uhci_hcd *uhci) */ static void uhci_fsbr_on(struct uhci_hcd *uhci) { + struct uhci_qh *fsbr_qh, *lqh, *tqh; + uhci->fsbr_is_on = 1; - uhci->skel_term_qh->link = LINK_TO_QH(uhci->skel_fs_control_qh); + lqh = list_entry(uhci->skel_async_qh->node.prev, + struct uhci_qh, node); + + /* Find the first FSBR QH. Linear search through the list is + * acceptable because normally FSBR gets turned on as soon as + * one QH needs it. */ + fsbr_qh = NULL; + list_for_each_entry_reverse(tqh, &uhci->skel_async_qh->node, node) { + if (tqh->skel < SKEL_FSBR) + break; + fsbr_qh = tqh; + } + + /* No FSBR QH means we must insert the terminating skeleton QH */ + if (!fsbr_qh) { + uhci->skel_term_qh->link = LINK_TO_QH(uhci->skel_term_qh); + wmb(); + lqh->link = uhci->skel_term_qh->link; + + /* Otherwise loop the last QH to the first FSBR QH */ + } else + lqh->link = LINK_TO_QH(fsbr_qh); } static void uhci_fsbr_off(struct uhci_hcd *uhci) { + struct uhci_qh *lqh; + uhci->fsbr_is_on = 0; - uhci->skel_term_qh->link = UHCI_PTR_TERM; + lqh = list_entry(uhci->skel_async_qh->node.prev, + struct uhci_qh, node); + + /* End the async list normally and unlink the terminating QH */ + lqh->link = uhci->skel_term_qh->link = UHCI_PTR_TERM; } static void uhci_add_fsbr(struct uhci_hcd *uhci, struct urb *urb) @@ -404,12 +433,81 @@ static void uhci_fixup_toggles(struct uhci_qh *qh, int skip_first) } /* - * Put a QH on the schedule in both hardware and software + * Link an Isochronous QH into its skeleton's list */ -static void uhci_activate_qh(struct uhci_hcd *uhci, struct uhci_qh *qh) +static inline void link_iso(struct uhci_hcd *uhci, struct uhci_qh *qh) +{ + list_add_tail(&qh->node, &uhci->skel_iso_qh->node); + + /* Isochronous QHs aren't linked by the hardware */ +} + +/* + * Link a high-period interrupt QH into the schedule at the end of its + * skeleton's list + */ +static void link_interrupt(struct uhci_hcd *uhci, struct uhci_qh *qh) { struct uhci_qh *pqh; + list_add_tail(&qh->node, &uhci->skelqh[qh->skel]->node); + + pqh = list_entry(qh->node.prev, struct uhci_qh, node); + qh->link = pqh->link; + wmb(); + pqh->link = LINK_TO_QH(qh); +} + +/* + * Link a period-1 interrupt or async QH into the schedule at the + * correct spot in the async skeleton's list, and update the FSBR link + */ +static void link_async(struct uhci_hcd *uhci, struct uhci_qh *qh) +{ + struct uhci_qh *pqh, *lqh; + __le32 link_to_new_qh; + __le32 *extra_link = &link_to_new_qh; + + /* Find the predecessor QH for our new one and insert it in the list. + * The list of QHs is expected to be short, so linear search won't + * take too long. */ + list_for_each_entry_reverse(pqh, &uhci->skel_async_qh->node, node) { + if (pqh->skel <= qh->skel) + break; + } + list_add(&qh->node, &pqh->node); + qh->link = pqh->link; + + link_to_new_qh = LINK_TO_QH(qh); + + /* If this is now the first FSBR QH, take special action */ + if (uhci->fsbr_is_on && pqh->skel < SKEL_FSBR && + qh->skel >= SKEL_FSBR) { + lqh = list_entry(uhci->skel_async_qh->node.prev, + struct uhci_qh, node); + + /* If the new QH is also the last one, we must unlink + * the terminating skeleton QH and make the new QH point + * back to itself. */ + if (qh == lqh) { + qh->link = link_to_new_qh; + extra_link = &uhci->skel_term_qh->link; + + /* Otherwise the last QH must point to the new QH */ + } else + extra_link = &lqh->link; + } + + /* Link it into the schedule */ + wmb(); + *extra_link = pqh->link = link_to_new_qh; +} + +/* + * Put a QH on the schedule in both hardware and software + */ +static void uhci_activate_qh(struct uhci_hcd *uhci, struct uhci_qh *qh) +{ WARN_ON(list_empty(&qh->queue)); /* Set the element pointer if it isn't set already. @@ -431,18 +529,64 @@ static void uhci_activate_qh(struct uhci_hcd *uhci, struct uhci_qh *qh) return; qh->state = QH_STATE_ACTIVE; - /* Move the QH from its old list to the end of the appropriate + /* Move the QH from its old list to the correct spot in the appropriate * skeleton's list */ if (qh == uhci->next_qh) uhci->next_qh = list_entry(qh->node.next, struct uhci_qh, node); - list_move_tail(&qh->node, &qh->skel->node); + list_del(&qh->node); + + if (qh->skel == SKEL_ISO) + link_iso(uhci, qh); + else if (qh->skel < SKEL_ASYNC) + link_interrupt(uhci, qh); + else + link_async(uhci, qh); +} + +/* + * Unlink a high-period interrupt QH from the schedule + */ +static void unlink_interrupt(struct uhci_hcd *uhci, struct uhci_qh *qh) +{ + struct uhci_qh *pqh; - /* Link it into the schedule */ pqh = list_entry(qh->node.prev, struct uhci_qh, node); - qh->link = pqh->link; - wmb(); - pqh->link = LINK_TO_QH(qh); + pqh->link = qh->link; + mb(); +} + +/* + * Unlink a period-1 interrupt or async QH from the schedule + */ +static void unlink_async(struct uhci_hcd *uhci, struct uhci_qh *qh) +{ + struct uhci_qh *pqh, *lqh; + __le32 link_to_next_qh = qh->link; + + pqh = list_entry(qh->node.prev, struct uhci_qh, node); + + /* If this is the first FSBQ QH, take special action */ + if (uhci->fsbr_is_on && pqh->skel < SKEL_FSBR && + qh->skel >= SKEL_FSBR) { + lqh = list_entry(uhci->skel_async_qh->node.prev, + struct uhci_qh, node); + + /* If this QH is also the last one, we must link in + * the terminating skeleton QH. */ + if (qh == lqh) { + link_to_next_qh = LINK_TO_QH(uhci->skel_term_qh); + uhci->skel_term_qh->link = link_to_next_qh; + wmb(); + qh->link = link_to_next_qh; + + /* Otherwise the last QH must point to the new first FSBR QH */ + } else + lqh->link = link_to_next_qh; + } + + pqh->link = link_to_next_qh; + mb(); } /* @@ -450,17 +594,18 @@ static void uhci_activate_qh(struct uhci_hcd *uhci, struct uhci_qh *qh) */ static void uhci_unlink_qh(struct uhci_hcd *uhci, struct uhci_qh *qh) { - struct uhci_qh *pqh; - if (qh->state == QH_STATE_UNLINKING) return; WARN_ON(qh->state != QH_STATE_ACTIVE || !qh->udev); qh->state = QH_STATE_UNLINKING; /* Unlink the QH from the schedule and record when we did it */ - pqh = list_entry(qh->node.prev, struct uhci_qh, node); - pqh->link = qh->link; - mb(); + if (qh->skel == SKEL_ISO) + ; + else if (qh->skel < SKEL_ASYNC) + unlink_interrupt(uhci, qh); + else + unlink_async(uhci, qh); uhci_get_current_frame_number(uhci); qh->unlink_frame = uhci->frame_number; @@ -696,6 +841,7 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb, dma_addr_t data = urb->transfer_dma; __le32 *plink; struct urb_priv *urbp = urb->hcpriv; + int skel; /* The "pipe" thing contains the destination in bits 8--18 */ destination = (urb->pipe & PIPE_DEVEP_MASK) | USB_PID_SETUP; @@ -796,11 +942,13 @@ static int uhci_submit_control(struct uhci_hcd *uhci, struct urb *urb, * isn't in the CONFIGURED state. */ if (urb->dev->speed == USB_SPEED_LOW || urb->dev->state != USB_STATE_CONFIGURED) - qh->skel = uhci->skel_ls_control_qh; + skel = SKEL_LS_CONTROL; else { - qh->skel = uhci->skel_fs_control_qh; + skel = SKEL_FS_CONTROL; uhci_add_fsbr(uhci, urb); } + if (qh->state != QH_STATE_ACTIVE) + qh->skel = skel; urb->actual_length = -8; /* Account for the SETUP packet */ return 0; @@ -930,7 +1078,7 @@ nomem: return -ENOMEM; } -static inline int uhci_submit_bulk(struct uhci_hcd *uhci, struct urb *urb, +static int uhci_submit_bulk(struct uhci_hcd *uhci, struct urb *urb, struct uhci_qh *qh) { int ret; @@ -939,7 +1087,8 @@ static inline int uhci_submit_bulk(struct uhci_hcd *uhci, struct urb *urb, if (urb->dev->speed == USB_SPEED_LOW) return -EINVAL; - qh->skel = uhci->skel_bulk_qh; + if (qh->state != QH_STATE_ACTIVE) + qh->skel = SKEL_BULK; ret = uhci_submit_common(uhci, urb, qh); if (ret == 0) uhci_add_fsbr(uhci, urb); @@ -967,7 +1116,7 @@ static int uhci_submit_interrupt(struct uhci_hcd *uhci, struct urb *urb, if (exponent < 0) return -EINVAL; qh->period = 1 << exponent; - qh->skel = uhci->skelqh[UHCI_SKEL_INDEX(exponent)]; + qh->skel = SKEL_INDEX(exponent); /* For now, interrupt phase is fixed by the layout * of the QH lists. */ @@ -1215,7 +1364,7 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb, qh->iso_status = 0; } - qh->skel = uhci->skel_iso_qh; + qh->skel = SKEL_ISO; if (!qh->bandwidth_reserved) uhci_reserve_bandwidth(uhci, qh); return 0; |