| /* |
| * Copyright (C) 2001-2004 by David Brownell |
| * |
| * This program is free software; you can redistribute it and/or modify it |
| * under the terms of the GNU General Public License as published by the |
| * Free Software Foundation; either version 2 of the License, or (at your |
| * option) any later version. |
| * |
| * This program is distributed in the hope that it will be useful, but |
| * WITHOUT ANY WARRANTY; without even the implied warranty of MERCHANTABILITY |
| * or FITNESS FOR A PARTICULAR PURPOSE. See the GNU General Public License |
| * for more details. |
| * |
| * You should have received a copy of the GNU General Public License |
| * along with this program; if not, write to the Free Software Foundation, |
| * Inc., 675 Mass Ave, Cambridge, MA 02139, USA. |
| */ |
| |
| /* this file is part of ehci-hcd.c */ |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| /* |
| * EHCI hardware queue manipulation ... the core. QH/QTD manipulation. |
| * |
| * Control, bulk, and interrupt traffic all use "qh" lists. They list "qtd" |
| * entries describing USB transactions, max 16-20kB/entry (with 4kB-aligned |
| * buffers needed for the larger number). We use one QH per endpoint, queue |
| * multiple urbs (all three types) per endpoint. URBs may need several qtds. |
| * |
| * ISO traffic uses "ISO TD" (itd, and sitd) records, and (along with |
| * interrupts) needs careful scheduling. Performance improvements can be |
| * an ongoing challenge. That's in "ehci-sched.c". |
| * |
| * USB 1.1 devices are handled (a) by "companion" OHCI or UHCI root hubs, |
| * or otherwise through transaction translators (TTs) in USB 2.0 hubs using |
| * (b) special fields in qh entries or (c) split iso entries. TTs will |
| * buffer low/full speed data so the host collects it at high speed. |
| */ |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| /* fill a qtd, returning how much of the buffer we were able to queue up */ |
| |
| static int |
| qtd_fill(struct ehci_hcd *ehci, struct ehci_qtd *qtd, dma_addr_t buf, |
| size_t len, int token, int maxpacket) |
| { |
| int i, count; |
| u64 addr = buf; |
| |
| /* one buffer entry per 4K ... first might be short or unaligned */ |
| qtd->hw_buf[0] = cpu_to_hc32(ehci, (u32)addr); |
| qtd->hw_buf_hi[0] = cpu_to_hc32(ehci, (u32)(addr >> 32)); |
| count = 0x1000 - (buf & 0x0fff); /* rest of that page */ |
| if (likely (len < count)) /* ... iff needed */ |
| count = len; |
| else { |
| buf += 0x1000; |
| buf &= ~0x0fff; |
| |
| /* per-qtd limit: from 16K to 20K (best alignment) */ |
| for (i = 1; count < len && i < 5; i++) { |
| addr = buf; |
| qtd->hw_buf[i] = cpu_to_hc32(ehci, (u32)addr); |
| qtd->hw_buf_hi[i] = cpu_to_hc32(ehci, |
| (u32)(addr >> 32)); |
| buf += 0x1000; |
| if ((count + 0x1000) < len) |
| count += 0x1000; |
| else |
| count = len; |
| } |
| |
| /* short packets may only terminate transfers */ |
| if (count != len) |
| count -= (count % maxpacket); |
| } |
| qtd->hw_token = cpu_to_hc32(ehci, (count << 16) | token); |
| qtd->length = count; |
| |
| return count; |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| static inline void |
| qh_update (struct ehci_hcd *ehci, struct ehci_qh *qh, struct ehci_qtd *qtd) |
| { |
| struct ehci_qh_hw *hw = qh->hw; |
| |
| /* writes to an active overlay are unsafe */ |
| BUG_ON(qh->qh_state != QH_STATE_IDLE); |
| |
| hw->hw_qtd_next = QTD_NEXT(ehci, qtd->qtd_dma); |
| hw->hw_alt_next = EHCI_LIST_END(ehci); |
| |
| /* Except for control endpoints, we make hardware maintain data |
| * toggle (like OHCI) ... here (re)initialize the toggle in the QH, |
| * and set the pseudo-toggle in udev. Only usb_clear_halt() will |
| * ever clear it. |
| */ |
| if (!(hw->hw_info1 & cpu_to_hc32(ehci, QH_TOGGLE_CTL))) { |
| unsigned is_out, epnum; |
| |
| is_out = qh->is_out; |
| epnum = (hc32_to_cpup(ehci, &hw->hw_info1) >> 8) & 0x0f; |
| if (unlikely (!usb_gettoggle (qh->dev, epnum, is_out))) { |
| hw->hw_token &= ~cpu_to_hc32(ehci, QTD_TOGGLE); |
| usb_settoggle (qh->dev, epnum, is_out, 1); |
| } |
| } |
| |
| hw->hw_token &= cpu_to_hc32(ehci, QTD_TOGGLE | QTD_STS_PING); |
| } |
| |
| /* if it weren't for a common silicon quirk (writing the dummy into the qh |
| * overlay, so qh->hw_token wrongly becomes inactive/halted), only fault |
| * recovery (including urb dequeue) would need software changes to a QH... |
| */ |
| static void |
| qh_refresh (struct ehci_hcd *ehci, struct ehci_qh *qh) |
| { |
| struct ehci_qtd *qtd; |
| |
| if (list_empty (&qh->qtd_list)) |
| qtd = qh->dummy; |
| else { |
| qtd = list_entry (qh->qtd_list.next, |
| struct ehci_qtd, qtd_list); |
| /* first qtd may already be partially processed */ |
| if (cpu_to_hc32(ehci, qtd->qtd_dma) == qh->hw->hw_current) |
| qtd = NULL; |
| } |
| |
| if (qtd) |
| qh_update (ehci, qh, qtd); |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| static void qh_link_async(struct ehci_hcd *ehci, struct ehci_qh *qh); |
| |
| static void ehci_clear_tt_buffer_complete(struct usb_hcd *hcd, |
| struct usb_host_endpoint *ep) |
| { |
| struct ehci_hcd *ehci = hcd_to_ehci(hcd); |
| struct ehci_qh *qh = ep->hcpriv; |
| unsigned long flags; |
| |
| spin_lock_irqsave(&ehci->lock, flags); |
| qh->clearing_tt = 0; |
| if (qh->qh_state == QH_STATE_IDLE && !list_empty(&qh->qtd_list) |
| && ehci->rh_state == EHCI_RH_RUNNING) |
| qh_link_async(ehci, qh); |
| spin_unlock_irqrestore(&ehci->lock, flags); |
| } |
| |
| static void ehci_clear_tt_buffer(struct ehci_hcd *ehci, struct ehci_qh *qh, |
| struct urb *urb, u32 token) |
| { |
| |
| /* If an async split transaction gets an error or is unlinked, |
| * the TT buffer may be left in an indeterminate state. We |
| * have to clear the TT buffer. |
| * |
| * Note: this routine is never called for Isochronous transfers. |
| */ |
| if (urb->dev->tt && !usb_pipeint(urb->pipe) && !qh->clearing_tt) { |
| #ifdef DEBUG |
| struct usb_device *tt = urb->dev->tt->hub; |
| dev_dbg(&tt->dev, |
| "clear tt buffer port %d, a%d ep%d t%08x\n", |
| urb->dev->ttport, urb->dev->devnum, |
| usb_pipeendpoint(urb->pipe), token); |
| #endif /* DEBUG */ |
| if (!ehci_is_TDI(ehci) |
| || urb->dev->tt->hub != |
| ehci_to_hcd(ehci)->self.root_hub) { |
| if (usb_hub_clear_tt_buffer(urb) == 0) |
| qh->clearing_tt = 1; |
| } else { |
| |
| /* REVISIT ARC-derived cores don't clear the root |
| * hub TT buffer in this way... |
| */ |
| } |
| } |
| } |
| |
| static int qtd_copy_status ( |
| struct ehci_hcd *ehci, |
| struct urb *urb, |
| size_t length, |
| u32 token |
| ) |
| { |
| int status = -EINPROGRESS; |
| |
| /* count IN/OUT bytes, not SETUP (even short packets) */ |
| if (likely (QTD_PID (token) != 2)) |
| urb->actual_length += length - QTD_LENGTH (token); |
| |
| /* don't modify error codes */ |
| if (unlikely(urb->unlinked)) |
| return status; |
| |
| /* force cleanup after short read; not always an error */ |
| if (unlikely (IS_SHORT_READ (token))) |
| status = -EREMOTEIO; |
| |
| /* serious "can't proceed" faults reported by the hardware */ |
| if (token & QTD_STS_HALT) { |
| if (token & QTD_STS_BABBLE) { |
| /* FIXME "must" disable babbling device's port too */ |
| status = -EOVERFLOW; |
| /* CERR nonzero + halt --> stall */ |
| } else if (QTD_CERR(token)) { |
| status = -EPIPE; |
| |
| /* In theory, more than one of the following bits can be set |
| * since they are sticky and the transaction is retried. |
| * Which to test first is rather arbitrary. |
| */ |
| } else if (token & QTD_STS_MMF) { |
| /* fs/ls interrupt xfer missed the complete-split */ |
| status = -EPROTO; |
| } else if (token & QTD_STS_DBE) { |
| status = (QTD_PID (token) == 1) /* IN ? */ |
| ? -ENOSR /* hc couldn't read data */ |
| : -ECOMM; /* hc couldn't write data */ |
| } else if (token & QTD_STS_XACT) { |
| /* timeout, bad CRC, wrong PID, etc */ |
| ehci_dbg(ehci, "devpath %s ep%d%s 3strikes\n", |
| urb->dev->devpath, |
| usb_pipeendpoint(urb->pipe), |
| usb_pipein(urb->pipe) ? "in" : "out"); |
| status = -EPROTO; |
| } else { /* unknown */ |
| status = -EPROTO; |
| } |
| |
| ehci_vdbg (ehci, |
| "dev%d ep%d%s qtd token %08x --> status %d\n", |
| usb_pipedevice (urb->pipe), |
| usb_pipeendpoint (urb->pipe), |
| usb_pipein (urb->pipe) ? "in" : "out", |
| token, status); |
| } |
| |
| return status; |
| } |
| |
| static void |
| ehci_urb_done(struct ehci_hcd *ehci, struct urb *urb, int status) |
| __releases(ehci->lock) |
| __acquires(ehci->lock) |
| { |
| if (likely (urb->hcpriv != NULL)) { |
| struct ehci_qh *qh = (struct ehci_qh *) urb->hcpriv; |
| |
| /* S-mask in a QH means it's an interrupt urb */ |
| if ((qh->hw->hw_info2 & cpu_to_hc32(ehci, QH_SMASK)) != 0) { |
| |
| /* ... update hc-wide periodic stats (for usbfs) */ |
| ehci_to_hcd(ehci)->self.bandwidth_int_reqs--; |
| } |
| } |
| |
| if (unlikely(urb->unlinked)) { |
| COUNT(ehci->stats.unlink); |
| } else { |
| /* report non-error and short read status as zero */ |
| if (status == -EINPROGRESS || status == -EREMOTEIO) |
| status = 0; |
| COUNT(ehci->stats.complete); |
| } |
| |
| #ifdef EHCI_URB_TRACE |
| ehci_dbg (ehci, |
| "%s %s urb %p ep%d%s status %d len %d/%d\n", |
| __func__, urb->dev->devpath, urb, |
| usb_pipeendpoint (urb->pipe), |
| usb_pipein (urb->pipe) ? "in" : "out", |
| status, |
| urb->actual_length, urb->transfer_buffer_length); |
| #endif |
| |
| /* complete() can reenter this HCD */ |
| usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb); |
| spin_unlock (&ehci->lock); |
| usb_hcd_giveback_urb(ehci_to_hcd(ehci), urb, status); |
| spin_lock (&ehci->lock); |
| } |
| |
| static int qh_schedule (struct ehci_hcd *ehci, struct ehci_qh *qh); |
| |
| /* |
| * Process and free completed qtds for a qh, returning URBs to drivers. |
| * Chases up to qh->hw_current. Returns number of completions called, |
| * indicating how much "real" work we did. |
| */ |
| static unsigned |
| qh_completions (struct ehci_hcd *ehci, struct ehci_qh *qh) |
| { |
| struct ehci_qtd *last, *end = qh->dummy; |
| struct list_head *entry, *tmp; |
| int last_status; |
| int stopped; |
| unsigned count = 0; |
| u8 state; |
| struct ehci_qh_hw *hw = qh->hw; |
| |
| if (unlikely (list_empty (&qh->qtd_list))) |
| return count; |
| |
| /* completions (or tasks on other cpus) must never clobber HALT |
| * till we've gone through and cleaned everything up, even when |
| * they add urbs to this qh's queue or mark them for unlinking. |
| * |
| * NOTE: unlinking expects to be done in queue order. |
| * |
| * It's a bug for qh->qh_state to be anything other than |
| * QH_STATE_IDLE, unless our caller is scan_async() or |
| * scan_intr(). |
| */ |
| state = qh->qh_state; |
| qh->qh_state = QH_STATE_COMPLETING; |
| stopped = (state == QH_STATE_IDLE); |
| |
| rescan: |
| last = NULL; |
| last_status = -EINPROGRESS; |
| qh->needs_rescan = 0; |
| |
| /* remove de-activated QTDs from front of queue. |
| * after faults (including short reads), cleanup this urb |
| * then let the queue advance. |
| * if queue is stopped, handles unlinks. |
| */ |
| list_for_each_safe (entry, tmp, &qh->qtd_list) { |
| struct ehci_qtd *qtd; |
| struct urb *urb; |
| u32 token = 0; |
| |
| qtd = list_entry (entry, struct ehci_qtd, qtd_list); |
| urb = qtd->urb; |
| |
| /* clean up any state from previous QTD ...*/ |
| if (last) { |
| if (likely (last->urb != urb)) { |
| ehci_urb_done(ehci, last->urb, last_status); |
| count++; |
| last_status = -EINPROGRESS; |
| } |
| ehci_qtd_free (ehci, last); |
| last = NULL; |
| } |
| |
| /* ignore urbs submitted during completions we reported */ |
| if (qtd == end) |
| break; |
| |
| /* hardware copies qtd out of qh overlay */ |
| rmb (); |
| token = hc32_to_cpu(ehci, qtd->hw_token); |
| |
| /* always clean up qtds the hc de-activated */ |
| retry_xacterr: |
| if ((token & QTD_STS_ACTIVE) == 0) { |
| |
| /* Report Data Buffer Error: non-fatal but useful */ |
| if (token & QTD_STS_DBE) |
| ehci_dbg(ehci, |
| "detected DataBufferErr for urb %p ep%d%s len %d, qtd %p [qh %p]\n", |
| urb, |
| usb_endpoint_num(&urb->ep->desc), |
| usb_endpoint_dir_in(&urb->ep->desc) ? "in" : "out", |
| urb->transfer_buffer_length, |
| qtd, |
| qh); |
| |
| /* on STALL, error, and short reads this urb must |
| * complete and all its qtds must be recycled. |
| */ |
| if ((token & QTD_STS_HALT) != 0) { |
| |
| /* retry transaction errors until we |
| * reach the software xacterr limit |
| */ |
| if ((token & QTD_STS_XACT) && |
| QTD_CERR(token) == 0 && |
| ++qh->xacterrs < QH_XACTERR_MAX && |
| !urb->unlinked) { |
| ehci_dbg(ehci, |
| "detected XactErr len %zu/%zu retry %d\n", |
| qtd->length - QTD_LENGTH(token), qtd->length, qh->xacterrs); |
| |
| /* reset the token in the qtd and the |
| * qh overlay (which still contains |
| * the qtd) so that we pick up from |
| * where we left off |
| */ |
| token &= ~QTD_STS_HALT; |
| token |= QTD_STS_ACTIVE | |
| (EHCI_TUNE_CERR << 10); |
| qtd->hw_token = cpu_to_hc32(ehci, |
| token); |
| wmb(); |
| hw->hw_token = cpu_to_hc32(ehci, |
| token); |
| goto retry_xacterr; |
| } |
| stopped = 1; |
| |
| /* magic dummy for some short reads; qh won't advance. |
| * that silicon quirk can kick in with this dummy too. |
| * |
| * other short reads won't stop the queue, including |
| * control transfers (status stage handles that) or |
| * most other single-qtd reads ... the queue stops if |
| * URB_SHORT_NOT_OK was set so the driver submitting |
| * the urbs could clean it up. |
| */ |
| } else if (IS_SHORT_READ (token) |
| && !(qtd->hw_alt_next |
| & EHCI_LIST_END(ehci))) { |
| stopped = 1; |
| } |
| |
| /* stop scanning when we reach qtds the hc is using */ |
| } else if (likely (!stopped |
| && ehci->rh_state >= EHCI_RH_RUNNING)) { |
| break; |
| |
| /* scan the whole queue for unlinks whenever it stops */ |
| } else { |
| stopped = 1; |
| |
| /* cancel everything if we halt, suspend, etc */ |
| if (ehci->rh_state < EHCI_RH_RUNNING) |
| last_status = -ESHUTDOWN; |
| |
| /* this qtd is active; skip it unless a previous qtd |
| * for its urb faulted, or its urb was canceled. |
| */ |
| else if (last_status == -EINPROGRESS && !urb->unlinked) |
| continue; |
| |
| /* qh unlinked; token in overlay may be most current */ |
| if (state == QH_STATE_IDLE |
| && cpu_to_hc32(ehci, qtd->qtd_dma) |
| == hw->hw_current) { |
| token = hc32_to_cpu(ehci, hw->hw_token); |
| |
| /* An unlink may leave an incomplete |
| * async transaction in the TT buffer. |
| * We have to clear it. |
| */ |
| ehci_clear_tt_buffer(ehci, qh, urb, token); |
| } |
| } |
| |
| /* unless we already know the urb's status, collect qtd status |
| * and update count of bytes transferred. in common short read |
| * cases with only one data qtd (including control transfers), |
| * queue processing won't halt. but with two or more qtds (for |
| * example, with a 32 KB transfer), when the first qtd gets a |
| * short read the second must be removed by hand. |
| */ |
| if (last_status == -EINPROGRESS) { |
| last_status = qtd_copy_status(ehci, urb, |
| qtd->length, token); |
| if (last_status == -EREMOTEIO |
| && (qtd->hw_alt_next |
| & EHCI_LIST_END(ehci))) |
| last_status = -EINPROGRESS; |
| |
| /* As part of low/full-speed endpoint-halt processing |
| * we must clear the TT buffer (11.17.5). |
| */ |
| if (unlikely(last_status != -EINPROGRESS && |
| last_status != -EREMOTEIO)) { |
| /* The TT's in some hubs malfunction when they |
| * receive this request following a STALL (they |
| * stop sending isochronous packets). Since a |
| * STALL can't leave the TT buffer in a busy |
| * state (if you believe Figures 11-48 - 11-51 |
| * in the USB 2.0 spec), we won't clear the TT |
| * buffer in this case. Strictly speaking this |
| * is a violation of the spec. |
| */ |
| if (last_status != -EPIPE) |
| ehci_clear_tt_buffer(ehci, qh, urb, |
| token); |
| } |
| } |
| |
| /* if we're removing something not at the queue head, |
| * patch the hardware queue pointer. |
| */ |
| if (stopped && qtd->qtd_list.prev != &qh->qtd_list) { |
| last = list_entry (qtd->qtd_list.prev, |
| struct ehci_qtd, qtd_list); |
| last->hw_next = qtd->hw_next; |
| } |
| |
| /* remove qtd; it's recycled after possible urb completion */ |
| list_del (&qtd->qtd_list); |
| last = qtd; |
| |
| /* reinit the xacterr counter for the next qtd */ |
| qh->xacterrs = 0; |
| } |
| |
| /* last urb's completion might still need calling */ |
| if (likely (last != NULL)) { |
| ehci_urb_done(ehci, last->urb, last_status); |
| count++; |
| ehci_qtd_free (ehci, last); |
| } |
| |
| /* Do we need to rescan for URBs dequeued during a giveback? */ |
| if (unlikely(qh->needs_rescan)) { |
| /* If the QH is already unlinked, do the rescan now. */ |
| if (state == QH_STATE_IDLE) |
| goto rescan; |
| |
| /* Otherwise we have to wait until the QH is fully unlinked. |
| * Our caller will start an unlink if qh->needs_rescan is |
| * set. But if an unlink has already started, nothing needs |
| * to be done. |
| */ |
| if (state != QH_STATE_LINKED) |
| qh->needs_rescan = 0; |
| } |
| |
| /* restore original state; caller must unlink or relink */ |
| qh->qh_state = state; |
| |
| /* be sure the hardware's done with the qh before refreshing |
| * it after fault cleanup, or recovering from silicon wrongly |
| * overlaying the dummy qtd (which reduces DMA chatter). |
| */ |
| if (stopped != 0 || hw->hw_qtd_next == EHCI_LIST_END(ehci)) { |
| switch (state) { |
| case QH_STATE_IDLE: |
| qh_refresh(ehci, qh); |
| break; |
| case QH_STATE_LINKED: |
| /* We won't refresh a QH that's linked (after the HC |
| * stopped the queue). That avoids a race: |
| * - HC reads first part of QH; |
| * - CPU updates that first part and the token; |
| * - HC reads rest of that QH, including token |
| * Result: HC gets an inconsistent image, and then |
| * DMAs to/from the wrong memory (corrupting it). |
| * |
| * That should be rare for interrupt transfers, |
| * except maybe high bandwidth ... |
| */ |
| |
| /* Tell the caller to start an unlink */ |
| qh->needs_rescan = 1; |
| break; |
| /* otherwise, unlink already started */ |
| } |
| } |
| |
| return count; |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| // high bandwidth multiplier, as encoded in highspeed endpoint descriptors |
| #define hb_mult(wMaxPacketSize) (1 + (((wMaxPacketSize) >> 11) & 0x03)) |
| // ... and packet size, for any kind of endpoint descriptor |
| #define max_packet(wMaxPacketSize) ((wMaxPacketSize) & 0x07ff) |
| |
| /* |
| * reverse of qh_urb_transaction: free a list of TDs. |
| * used for cleanup after errors, before HC sees an URB's TDs. |
| */ |
| static void qtd_list_free ( |
| struct ehci_hcd *ehci, |
| struct urb *urb, |
| struct list_head *qtd_list |
| ) { |
| struct list_head *entry, *temp; |
| |
| list_for_each_safe (entry, temp, qtd_list) { |
| struct ehci_qtd *qtd; |
| |
| qtd = list_entry (entry, struct ehci_qtd, qtd_list); |
| list_del (&qtd->qtd_list); |
| ehci_qtd_free (ehci, qtd); |
| } |
| } |
| |
| /* |
| * create a list of filled qtds for this URB; won't link into qh. |
| */ |
| static struct list_head * |
| qh_urb_transaction ( |
| struct ehci_hcd *ehci, |
| struct urb *urb, |
| struct list_head *head, |
| gfp_t flags |
| ) { |
| struct ehci_qtd *qtd, *qtd_prev; |
| dma_addr_t buf; |
| int len, this_sg_len, maxpacket; |
| int is_input; |
| u32 token; |
| int i; |
| struct scatterlist *sg; |
| |
| /* |
| * URBs map to sequences of QTDs: one logical transaction |
| */ |
| qtd = ehci_qtd_alloc (ehci, flags); |
| if (unlikely (!qtd)) |
| return NULL; |
| list_add_tail (&qtd->qtd_list, head); |
| qtd->urb = urb; |
| |
| token = QTD_STS_ACTIVE; |
| token |= (EHCI_TUNE_CERR << 10); |
| /* for split transactions, SplitXState initialized to zero */ |
| |
| len = urb->transfer_buffer_length; |
| is_input = usb_pipein (urb->pipe); |
| if (usb_pipecontrol (urb->pipe)) { |
| /* SETUP pid */ |
| qtd_fill(ehci, qtd, urb->setup_dma, |
| sizeof (struct usb_ctrlrequest), |
| token | (2 /* "setup" */ << 8), 8); |
| |
| /* ... and always at least one more pid */ |
| token ^= QTD_TOGGLE; |
| qtd_prev = qtd; |
| qtd = ehci_qtd_alloc (ehci, flags); |
| if (unlikely (!qtd)) |
| goto cleanup; |
| qtd->urb = urb; |
| qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma); |
| list_add_tail (&qtd->qtd_list, head); |
| |
| /* for zero length DATA stages, STATUS is always IN */ |
| if (len == 0) |
| token |= (1 /* "in" */ << 8); |
| } |
| |
| /* |
| * data transfer stage: buffer setup |
| */ |
| i = urb->num_mapped_sgs; |
| if (len > 0 && i > 0) { |
| sg = urb->sg; |
| buf = sg_dma_address(sg); |
| |
| /* urb->transfer_buffer_length may be smaller than the |
| * size of the scatterlist (or vice versa) |
| */ |
| this_sg_len = min_t(int, sg_dma_len(sg), len); |
| } else { |
| sg = NULL; |
| buf = urb->transfer_dma; |
| this_sg_len = len; |
| } |
| |
| if (is_input) |
| token |= (1 /* "in" */ << 8); |
| /* else it's already initted to "out" pid (0 << 8) */ |
| |
| maxpacket = max_packet(usb_maxpacket(urb->dev, urb->pipe, !is_input)); |
| |
| /* |
| * buffer gets wrapped in one or more qtds; |
| * last one may be "short" (including zero len) |
| * and may serve as a control status ack |
| */ |
| for (;;) { |
| int this_qtd_len; |
| |
| this_qtd_len = qtd_fill(ehci, qtd, buf, this_sg_len, token, |
| maxpacket); |
| this_sg_len -= this_qtd_len; |
| len -= this_qtd_len; |
| buf += this_qtd_len; |
| |
| /* |
| * short reads advance to a "magic" dummy instead of the next |
| * qtd ... that forces the queue to stop, for manual cleanup. |
| * (this will usually be overridden later.) |
| */ |
| if (is_input) |
| qtd->hw_alt_next = ehci->async->hw->hw_alt_next; |
| |
| /* qh makes control packets use qtd toggle; maybe switch it */ |
| if ((maxpacket & (this_qtd_len + (maxpacket - 1))) == 0) |
| token ^= QTD_TOGGLE; |
| |
| if (likely(this_sg_len <= 0)) { |
| if (--i <= 0 || len <= 0) |
| break; |
| sg = sg_next(sg); |
| buf = sg_dma_address(sg); |
| this_sg_len = min_t(int, sg_dma_len(sg), len); |
| } |
| |
| qtd_prev = qtd; |
| qtd = ehci_qtd_alloc (ehci, flags); |
| if (unlikely (!qtd)) |
| goto cleanup; |
| qtd->urb = urb; |
| qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma); |
| list_add_tail (&qtd->qtd_list, head); |
| } |
| |
| /* |
| * unless the caller requires manual cleanup after short reads, |
| * have the alt_next mechanism keep the queue running after the |
| * last data qtd (the only one, for control and most other cases). |
| */ |
| if (likely ((urb->transfer_flags & URB_SHORT_NOT_OK) == 0 |
| || usb_pipecontrol (urb->pipe))) |
| qtd->hw_alt_next = EHCI_LIST_END(ehci); |
| |
| /* |
| * control requests may need a terminating data "status" ack; |
| * other OUT ones may need a terminating short packet |
| * (zero length). |
| */ |
| if (likely (urb->transfer_buffer_length != 0)) { |
| int one_more = 0; |
| |
| if (usb_pipecontrol (urb->pipe)) { |
| one_more = 1; |
| token ^= 0x0100; /* "in" <--> "out" */ |
| token |= QTD_TOGGLE; /* force DATA1 */ |
| } else if (usb_pipeout(urb->pipe) |
| && (urb->transfer_flags & URB_ZERO_PACKET) |
| && !(urb->transfer_buffer_length % maxpacket)) { |
| one_more = 1; |
| } |
| if (one_more) { |
| qtd_prev = qtd; |
| qtd = ehci_qtd_alloc (ehci, flags); |
| if (unlikely (!qtd)) |
| goto cleanup; |
| qtd->urb = urb; |
| qtd_prev->hw_next = QTD_NEXT(ehci, qtd->qtd_dma); |
| list_add_tail (&qtd->qtd_list, head); |
| |
| /* never any data in such packets */ |
| qtd_fill(ehci, qtd, 0, 0, token, 0); |
| } |
| } |
| |
| /* by default, enable interrupt on urb completion */ |
| if (likely (!(urb->transfer_flags & URB_NO_INTERRUPT))) |
| qtd->hw_token |= cpu_to_hc32(ehci, QTD_IOC); |
| return head; |
| |
| cleanup: |
| qtd_list_free (ehci, urb, head); |
| return NULL; |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| // Would be best to create all qh's from config descriptors, |
| // when each interface/altsetting is established. Unlink |
| // any previous qh and cancel its urbs first; endpoints are |
| // implicitly reset then (data toggle too). |
| // That'd mean updating how usbcore talks to HCDs. (2.7?) |
| |
| |
| /* |
| * Each QH holds a qtd list; a QH is used for everything except iso. |
| * |
| * For interrupt urbs, the scheduler must set the microframe scheduling |
| * mask(s) each time the QH gets scheduled. For highspeed, that's |
| * just one microframe in the s-mask. For split interrupt transactions |
| * there are additional complications: c-mask, maybe FSTNs. |
| */ |
| static struct ehci_qh * |
| qh_make ( |
| struct ehci_hcd *ehci, |
| struct urb *urb, |
| gfp_t flags |
| ) { |
| struct ehci_qh *qh = ehci_qh_alloc (ehci, flags); |
| u32 info1 = 0, info2 = 0; |
| int is_input, type; |
| int maxp = 0; |
| struct usb_tt *tt = urb->dev->tt; |
| struct ehci_qh_hw *hw; |
| |
| if (!qh) |
| return qh; |
| |
| /* |
| * init endpoint/device data for this QH |
| */ |
| info1 |= usb_pipeendpoint (urb->pipe) << 8; |
| info1 |= usb_pipedevice (urb->pipe) << 0; |
| |
| is_input = usb_pipein (urb->pipe); |
| type = usb_pipetype (urb->pipe); |
| maxp = usb_maxpacket (urb->dev, urb->pipe, !is_input); |
| |
| /* 1024 byte maxpacket is a hardware ceiling. High bandwidth |
| * acts like up to 3KB, but is built from smaller packets. |
| */ |
| if (max_packet(maxp) > 1024) { |
| ehci_dbg(ehci, "bogus qh maxpacket %d\n", max_packet(maxp)); |
| goto done; |
| } |
| |
| /* Compute interrupt scheduling parameters just once, and save. |
| * - allowing for high bandwidth, how many nsec/uframe are used? |
| * - split transactions need a second CSPLIT uframe; same question |
| * - splits also need a schedule gap (for full/low speed I/O) |
| * - qh has a polling interval |
| * |
| * For control/bulk requests, the HC or TT handles these. |
| */ |
| if (type == PIPE_INTERRUPT) { |
| qh->usecs = NS_TO_US(usb_calc_bus_time(USB_SPEED_HIGH, |
| is_input, 0, |
| hb_mult(maxp) * max_packet(maxp))); |
| qh->start = NO_FRAME; |
| |
| if (urb->dev->speed == USB_SPEED_HIGH) { |
| qh->c_usecs = 0; |
| qh->gap_uf = 0; |
| |
| qh->period = urb->interval >> 3; |
| if (qh->period == 0 && urb->interval != 1) { |
| /* NOTE interval 2 or 4 uframes could work. |
| * But interval 1 scheduling is simpler, and |
| * includes high bandwidth. |
| */ |
| urb->interval = 1; |
| } else if (qh->period > ehci->periodic_size) { |
| qh->period = ehci->periodic_size; |
| urb->interval = qh->period << 3; |
| } |
| } else { |
| int think_time; |
| |
| /* gap is f(FS/LS transfer times) */ |
| qh->gap_uf = 1 + usb_calc_bus_time (urb->dev->speed, |
| is_input, 0, maxp) / (125 * 1000); |
| |
| /* FIXME this just approximates SPLIT/CSPLIT times */ |
| if (is_input) { // SPLIT, gap, CSPLIT+DATA |
| qh->c_usecs = qh->usecs + HS_USECS (0); |
| qh->usecs = HS_USECS (1); |
| } else { // SPLIT+DATA, gap, CSPLIT |
| qh->usecs += HS_USECS (1); |
| qh->c_usecs = HS_USECS (0); |
| } |
| |
| think_time = tt ? tt->think_time : 0; |
| qh->tt_usecs = NS_TO_US (think_time + |
| usb_calc_bus_time (urb->dev->speed, |
| is_input, 0, max_packet (maxp))); |
| qh->period = urb->interval; |
| if (qh->period > ehci->periodic_size) { |
| qh->period = ehci->periodic_size; |
| urb->interval = qh->period; |
| } |
| } |
| } |
| |
| /* support for tt scheduling, and access to toggles */ |
| qh->dev = urb->dev; |
| |
| /* using TT? */ |
| switch (urb->dev->speed) { |
| case USB_SPEED_LOW: |
| info1 |= QH_LOW_SPEED; |
| /* FALL THROUGH */ |
| |
| case USB_SPEED_FULL: |
| /* EPS 0 means "full" */ |
| if (type != PIPE_INTERRUPT) |
| info1 |= (EHCI_TUNE_RL_TT << 28); |
| if (type == PIPE_CONTROL) { |
| info1 |= QH_CONTROL_EP; /* for TT */ |
| info1 |= QH_TOGGLE_CTL; /* toggle from qtd */ |
| } |
| info1 |= maxp << 16; |
| |
| info2 |= (EHCI_TUNE_MULT_TT << 30); |
| |
| /* Some Freescale processors have an erratum in which the |
| * port number in the queue head was 0..N-1 instead of 1..N. |
| */ |
| if (ehci_has_fsl_portno_bug(ehci)) |
| info2 |= (urb->dev->ttport-1) << 23; |
| else |
| info2 |= urb->dev->ttport << 23; |
| |
| /* set the address of the TT; for TDI's integrated |
| * root hub tt, leave it zeroed. |
| */ |
| if (tt && tt->hub != ehci_to_hcd(ehci)->self.root_hub) |
| info2 |= tt->hub->devnum << 16; |
| |
| /* NOTE: if (PIPE_INTERRUPT) { scheduler sets c-mask } */ |
| |
| break; |
| |
| case USB_SPEED_HIGH: /* no TT involved */ |
| info1 |= QH_HIGH_SPEED; |
| if (type == PIPE_CONTROL) { |
| info1 |= (EHCI_TUNE_RL_HS << 28); |
| info1 |= 64 << 16; /* usb2 fixed maxpacket */ |
| info1 |= QH_TOGGLE_CTL; /* toggle from qtd */ |
| info2 |= (EHCI_TUNE_MULT_HS << 30); |
| } else if (type == PIPE_BULK) { |
| info1 |= (EHCI_TUNE_RL_HS << 28); |
| /* The USB spec says that high speed bulk endpoints |
| * always use 512 byte maxpacket. But some device |
| * vendors decided to ignore that, and MSFT is happy |
| * to help them do so. So now people expect to use |
| * such nonconformant devices with Linux too; sigh. |
| */ |
| info1 |= max_packet(maxp) << 16; |
| info2 |= (EHCI_TUNE_MULT_HS << 30); |
| } else { /* PIPE_INTERRUPT */ |
| info1 |= max_packet (maxp) << 16; |
| info2 |= hb_mult (maxp) << 30; |
| } |
| break; |
| default: |
| ehci_dbg(ehci, "bogus dev %p speed %d\n", urb->dev, |
| urb->dev->speed); |
| done: |
| qh_destroy(ehci, qh); |
| return NULL; |
| } |
| |
| /* NOTE: if (PIPE_INTERRUPT) { scheduler sets s-mask } */ |
| |
| /* init as live, toggle clear, advance to dummy */ |
| qh->qh_state = QH_STATE_IDLE; |
| hw = qh->hw; |
| hw->hw_info1 = cpu_to_hc32(ehci, info1); |
| hw->hw_info2 = cpu_to_hc32(ehci, info2); |
| qh->is_out = !is_input; |
| usb_settoggle (urb->dev, usb_pipeendpoint (urb->pipe), !is_input, 1); |
| qh_refresh (ehci, qh); |
| return qh; |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| static void enable_async(struct ehci_hcd *ehci) |
| { |
| if (ehci->async_count++) |
| return; |
| |
| /* Stop waiting to turn off the async schedule */ |
| ehci->enabled_hrtimer_events &= ~BIT(EHCI_HRTIMER_DISABLE_ASYNC); |
| |
| /* Don't start the schedule until ASS is 0 */ |
| ehci_poll_ASS(ehci); |
| turn_on_io_watchdog(ehci); |
| } |
| |
| static void disable_async(struct ehci_hcd *ehci) |
| { |
| if (--ehci->async_count) |
| return; |
| |
| /* The async schedule and async_unlink list are supposed to be empty */ |
| WARN_ON(ehci->async->qh_next.qh || ehci->async_unlink); |
| |
| /* Don't turn off the schedule until ASS is 1 */ |
| ehci_poll_ASS(ehci); |
| } |
| |
| /* move qh (and its qtds) onto async queue; maybe enable queue. */ |
| |
| static void qh_link_async (struct ehci_hcd *ehci, struct ehci_qh *qh) |
| { |
| __hc32 dma = QH_NEXT(ehci, qh->qh_dma); |
| struct ehci_qh *head; |
| |
| /* Don't link a QH if there's a Clear-TT-Buffer pending */ |
| if (unlikely(qh->clearing_tt)) |
| return; |
| |
| WARN_ON(qh->qh_state != QH_STATE_IDLE); |
| |
| /* clear halt and/or toggle; and maybe recover from silicon quirk */ |
| qh_refresh(ehci, qh); |
| |
| /* splice right after start */ |
| head = ehci->async; |
| qh->qh_next = head->qh_next; |
| qh->hw->hw_next = head->hw->hw_next; |
| wmb (); |
| |
| head->qh_next.qh = qh; |
| head->hw->hw_next = dma; |
| |
| qh->xacterrs = 0; |
| qh->qh_state = QH_STATE_LINKED; |
| /* qtd completions reported later by interrupt */ |
| |
| enable_async(ehci); |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| /* |
| * For control/bulk/interrupt, return QH with these TDs appended. |
| * Allocates and initializes the QH if necessary. |
| * Returns null if it can't allocate a QH it needs to. |
| * If the QH has TDs (urbs) already, that's great. |
| */ |
| static struct ehci_qh *qh_append_tds ( |
| struct ehci_hcd *ehci, |
| struct urb *urb, |
| struct list_head *qtd_list, |
| int epnum, |
| void **ptr |
| ) |
| { |
| struct ehci_qh *qh = NULL; |
| __hc32 qh_addr_mask = cpu_to_hc32(ehci, 0x7f); |
| |
| qh = (struct ehci_qh *) *ptr; |
| if (unlikely (qh == NULL)) { |
| /* can't sleep here, we have ehci->lock... */ |
| qh = qh_make (ehci, urb, GFP_ATOMIC); |
| *ptr = qh; |
| } |
| if (likely (qh != NULL)) { |
| struct ehci_qtd *qtd; |
| |
| if (unlikely (list_empty (qtd_list))) |
| qtd = NULL; |
| else |
| qtd = list_entry (qtd_list->next, struct ehci_qtd, |
| qtd_list); |
| |
| /* control qh may need patching ... */ |
| if (unlikely (epnum == 0)) { |
| |
| /* usb_reset_device() briefly reverts to address 0 */ |
| if (usb_pipedevice (urb->pipe) == 0) |
| qh->hw->hw_info1 &= ~qh_addr_mask; |
| } |
| |
| /* just one way to queue requests: swap with the dummy qtd. |
| * only hc or qh_refresh() ever modify the overlay. |
| */ |
| if (likely (qtd != NULL)) { |
| struct ehci_qtd *dummy; |
| dma_addr_t dma; |
| __hc32 token; |
| |
| /* to avoid racing the HC, use the dummy td instead of |
| * the first td of our list (becomes new dummy). both |
| * tds stay deactivated until we're done, when the |
| * HC is allowed to fetch the old dummy (4.10.2). |
| */ |
| token = qtd->hw_token; |
| qtd->hw_token = HALT_BIT(ehci); |
| |
| dummy = qh->dummy; |
| |
| dma = dummy->qtd_dma; |
| *dummy = *qtd; |
| dummy->qtd_dma = dma; |
| |
| list_del (&qtd->qtd_list); |
| list_add (&dummy->qtd_list, qtd_list); |
| list_splice_tail(qtd_list, &qh->qtd_list); |
| |
| ehci_qtd_init(ehci, qtd, qtd->qtd_dma); |
| qh->dummy = qtd; |
| |
| /* hc must see the new dummy at list end */ |
| dma = qtd->qtd_dma; |
| qtd = list_entry (qh->qtd_list.prev, |
| struct ehci_qtd, qtd_list); |
| qtd->hw_next = QTD_NEXT(ehci, dma); |
| |
| /* let the hc process these next qtds */ |
| wmb (); |
| dummy->hw_token = token; |
| |
| urb->hcpriv = qh; |
| } |
| } |
| return qh; |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| static int |
| submit_async ( |
| struct ehci_hcd *ehci, |
| struct urb *urb, |
| struct list_head *qtd_list, |
| gfp_t mem_flags |
| ) { |
| int epnum; |
| unsigned long flags; |
| struct ehci_qh *qh = NULL; |
| int rc; |
| |
| epnum = urb->ep->desc.bEndpointAddress; |
| |
| #ifdef EHCI_URB_TRACE |
| { |
| struct ehci_qtd *qtd; |
| qtd = list_entry(qtd_list->next, struct ehci_qtd, qtd_list); |
| ehci_dbg(ehci, |
| "%s %s urb %p ep%d%s len %d, qtd %p [qh %p]\n", |
| __func__, urb->dev->devpath, urb, |
| epnum & 0x0f, (epnum & USB_DIR_IN) ? "in" : "out", |
| urb->transfer_buffer_length, |
| qtd, urb->ep->hcpriv); |
| } |
| #endif |
| |
| spin_lock_irqsave (&ehci->lock, flags); |
| if (unlikely(!HCD_HW_ACCESSIBLE(ehci_to_hcd(ehci)))) { |
| rc = -ESHUTDOWN; |
| goto done; |
| } |
| rc = usb_hcd_link_urb_to_ep(ehci_to_hcd(ehci), urb); |
| if (unlikely(rc)) |
| goto done; |
| |
| qh = qh_append_tds(ehci, urb, qtd_list, epnum, &urb->ep->hcpriv); |
| if (unlikely(qh == NULL)) { |
| usb_hcd_unlink_urb_from_ep(ehci_to_hcd(ehci), urb); |
| rc = -ENOMEM; |
| goto done; |
| } |
| |
| /* Control/bulk operations through TTs don't need scheduling, |
| * the HC and TT handle it when the TT has a buffer ready. |
| */ |
| if (likely (qh->qh_state == QH_STATE_IDLE)) |
| qh_link_async(ehci, qh); |
| done: |
| spin_unlock_irqrestore (&ehci->lock, flags); |
| if (unlikely (qh == NULL)) |
| qtd_list_free (ehci, urb, qtd_list); |
| return rc; |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| static void single_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh) |
| { |
| struct ehci_qh *prev; |
| |
| /* Add to the end of the list of QHs waiting for the next IAAD */ |
| qh->qh_state = QH_STATE_UNLINK; |
| if (ehci->async_unlink) |
| ehci->async_unlink_last->unlink_next = qh; |
| else |
| ehci->async_unlink = qh; |
| ehci->async_unlink_last = qh; |
| |
| /* Unlink it from the schedule */ |
| prev = ehci->async; |
| while (prev->qh_next.qh != qh) |
| prev = prev->qh_next.qh; |
| |
| prev->hw->hw_next = qh->hw->hw_next; |
| prev->qh_next = qh->qh_next; |
| if (ehci->qh_scan_next == qh) |
| ehci->qh_scan_next = qh->qh_next.qh; |
| } |
| |
| static void start_iaa_cycle(struct ehci_hcd *ehci, bool nested) |
| { |
| /* |
| * Do nothing if an IAA cycle is already running or |
| * if one will be started shortly. |
| */ |
| if (ehci->async_iaa || ehci->async_unlinking) |
| return; |
| |
| /* Do all the waiting QHs at once */ |
| ehci->async_iaa = ehci->async_unlink; |
| ehci->async_unlink = NULL; |
| |
| /* If the controller isn't running, we don't have to wait for it */ |
| if (unlikely(ehci->rh_state < EHCI_RH_RUNNING)) { |
| if (!nested) /* Avoid recursion */ |
| end_unlink_async(ehci); |
| |
| /* Otherwise start a new IAA cycle */ |
| } else if (likely(ehci->rh_state == EHCI_RH_RUNNING)) { |
| /* Make sure the unlinks are all visible to the hardware */ |
| wmb(); |
| |
| ehci_writel(ehci, ehci->command | CMD_IAAD, |
| &ehci->regs->command); |
| ehci_readl(ehci, &ehci->regs->command); |
| ehci_enable_event(ehci, EHCI_HRTIMER_IAA_WATCHDOG, true); |
| } |
| } |
| |
| /* the async qh for the qtds being unlinked are now gone from the HC */ |
| |
| static void end_unlink_async(struct ehci_hcd *ehci) |
| { |
| struct ehci_qh *qh; |
| |
| if (ehci->has_synopsys_hc_bug) |
| ehci_writel(ehci, (u32) ehci->async->qh_dma, |
| &ehci->regs->async_next); |
| |
| /* Process the idle QHs */ |
| restart: |
| ehci->async_unlinking = true; |
| while (ehci->async_iaa) { |
| qh = ehci->async_iaa; |
| ehci->async_iaa = qh->unlink_next; |
| qh->unlink_next = NULL; |
| |
| qh->qh_state = QH_STATE_IDLE; |
| qh->qh_next.qh = NULL; |
| |
| qh_completions(ehci, qh); |
| if (!list_empty(&qh->qtd_list) && |
| ehci->rh_state == EHCI_RH_RUNNING) |
| qh_link_async(ehci, qh); |
| disable_async(ehci); |
| } |
| ehci->async_unlinking = false; |
| |
| /* Start a new IAA cycle if any QHs are waiting for it */ |
| if (ehci->async_unlink) { |
| start_iaa_cycle(ehci, true); |
| if (unlikely(ehci->rh_state < EHCI_RH_RUNNING)) |
| goto restart; |
| } |
| } |
| |
| static void unlink_empty_async(struct ehci_hcd *ehci) |
| { |
| struct ehci_qh *qh, *next; |
| bool stopped = (ehci->rh_state < EHCI_RH_RUNNING); |
| bool check_unlinks_later = false; |
| |
| /* Unlink all the async QHs that have been empty for a timer cycle */ |
| next = ehci->async->qh_next.qh; |
| while (next) { |
| qh = next; |
| next = qh->qh_next.qh; |
| |
| if (list_empty(&qh->qtd_list) && |
| qh->qh_state == QH_STATE_LINKED) { |
| if (!stopped && qh->unlink_cycle == |
| ehci->async_unlink_cycle) |
| check_unlinks_later = true; |
| else |
| single_unlink_async(ehci, qh); |
| } |
| } |
| |
| /* Start a new IAA cycle if any QHs are waiting for it */ |
| if (ehci->async_unlink) |
| start_iaa_cycle(ehci, false); |
| |
| /* QHs that haven't been empty for long enough will be handled later */ |
| if (check_unlinks_later) { |
| ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true); |
| ++ehci->async_unlink_cycle; |
| } |
| } |
| |
| /* makes sure the async qh will become idle */ |
| /* caller must own ehci->lock */ |
| |
| static void start_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh) |
| { |
| /* |
| * If the QH isn't linked then there's nothing we can do |
| * unless we were called during a giveback, in which case |
| * qh_completions() has to deal with it. |
| */ |
| if (qh->qh_state != QH_STATE_LINKED) { |
| if (qh->qh_state == QH_STATE_COMPLETING) |
| qh->needs_rescan = 1; |
| return; |
| } |
| |
| single_unlink_async(ehci, qh); |
| start_iaa_cycle(ehci, false); |
| } |
| |
| /*-------------------------------------------------------------------------*/ |
| |
| static void scan_async (struct ehci_hcd *ehci) |
| { |
| struct ehci_qh *qh; |
| bool check_unlinks_later = false; |
| |
| ehci->qh_scan_next = ehci->async->qh_next.qh; |
| while (ehci->qh_scan_next) { |
| qh = ehci->qh_scan_next; |
| ehci->qh_scan_next = qh->qh_next.qh; |
| rescan: |
| /* clean any finished work for this qh */ |
| if (!list_empty(&qh->qtd_list)) { |
| int temp; |
| |
| /* |
| * Unlinks could happen here; completion reporting |
| * drops the lock. That's why ehci->qh_scan_next |
| * always holds the next qh to scan; if the next qh |
| * gets unlinked then ehci->qh_scan_next is adjusted |
| * in single_unlink_async(). |
| */ |
| temp = qh_completions(ehci, qh); |
| if (qh->needs_rescan) { |
| start_unlink_async(ehci, qh); |
| } else if (list_empty(&qh->qtd_list) |
| && qh->qh_state == QH_STATE_LINKED) { |
| qh->unlink_cycle = ehci->async_unlink_cycle; |
| check_unlinks_later = true; |
| } else if (temp != 0) |
| goto rescan; |
| } |
| } |
| |
| /* |
| * Unlink empty entries, reducing DMA usage as well |
| * as HCD schedule-scanning costs. Delay for any qh |
| * we just scanned, there's a not-unusual case that it |
| * doesn't stay idle for long. |
| */ |
| if (check_unlinks_later && ehci->rh_state == EHCI_RH_RUNNING && |
| !(ehci->enabled_hrtimer_events & |
| BIT(EHCI_HRTIMER_ASYNC_UNLINKS))) { |
| ehci_enable_event(ehci, EHCI_HRTIMER_ASYNC_UNLINKS, true); |
| ++ehci->async_unlink_cycle; |
| } |
| } |