diff options
Diffstat (limited to 'drivers/usb')
| -rw-r--r-- | drivers/usb/host/Kconfig | 20 | ||||
| -rw-r--r-- | drivers/usb/host/ehci-sched.c | 216 |
2 files changed, 234 insertions, 2 deletions
diff --git a/drivers/usb/host/Kconfig b/drivers/usb/host/Kconfig index e27b79a3c05..c060eb9b3b1 100644 --- a/drivers/usb/host/Kconfig +++ b/drivers/usb/host/Kconfig @@ -47,7 +47,25 @@ config USB_EHCI_ROOT_HUB_TT controller is needed. It's safe to say "y" even if your controller doesn't support this feature. - This supports the EHCI implementation from TransDimension Inc. + This supports the EHCI implementation that's originally + from ARC, and has since changed hands a few times. + +config USB_EHCI_TT_NEWSCHED + bool "Improved Transaction Translator scheduling (EXPERIMENTAL)" + depends on USB_EHCI_HCD && EXPERIMENTAL + ---help--- + This changes the periodic scheduling code to fill more of the low + and full speed bandwidth available from the Transaction Translator + (TT) in USB 2.0 hubs. Without this, only one transfer will be + issued in each microframe, significantly reducing the number of + periodic low/fullspeed transfers possible. + + If you have multiple periodic low/fullspeed devices connected to a + highspeed USB hub which is connected to a highspeed USB Host + Controller, and some of those devices will not work correctly + (possibly due to "ENOSPC" or "-28" errors), say Y. + + If unsure, say N. config USB_ISP116X_HCD tristate "ISP116X HCD support" diff --git a/drivers/usb/host/ehci-sched.c b/drivers/usb/host/ehci-sched.c index 5871944e614..4859900bd13 100644 --- a/drivers/usb/host/ehci-sched.c +++ b/drivers/usb/host/ehci-sched.c @@ -163,6 +163,190 @@ static int same_tt (struct usb_device *dev1, struct usb_device *dev2) return 1; } +#ifdef CONFIG_USB_EHCI_TT_NEWSCHED + +/* Which uframe does the low/fullspeed transfer start in? + * + * The parameter is the mask of ssplits in "H-frame" terms + * and this returns the transfer start uframe in "B-frame" terms, + * which allows both to match, e.g. a ssplit in "H-frame" uframe 0 + * will cause a transfer in "B-frame" uframe 0. "B-frames" lag + * "H-frames" by 1 uframe. See the EHCI spec sec 4.5 and figure 4.7. + */ +static inline unsigned char tt_start_uframe(struct ehci_hcd *ehci, __le32 mask) +{ + unsigned char smask = QH_SMASK & le32_to_cpu(mask); + if (!smask) { + ehci_err(ehci, "invalid empty smask!\n"); + /* uframe 7 can't have bw so this will indicate failure */ + return 7; + } + return ffs(smask) - 1; +} + +static const unsigned char +max_tt_usecs[] = { 125, 125, 125, 125, 125, 125, 30, 0 }; + +/* carryover low/fullspeed bandwidth that crosses uframe boundries */ +static inline void carryover_tt_bandwidth(unsigned short tt_usecs[8]) +{ + int i; + for (i=0; i<7; i++) { + if (max_tt_usecs[i] < tt_usecs[i]) { + tt_usecs[i+1] += tt_usecs[i] - max_tt_usecs[i]; + tt_usecs[i] = max_tt_usecs[i]; + } + } +} + +/* How many of the tt's periodic downstream 1000 usecs are allocated? + * + * While this measures the bandwidth in terms of usecs/uframe, + * the low/fullspeed bus has no notion of uframes, so any particular + * low/fullspeed transfer can "carry over" from one uframe to the next, + * since the TT just performs downstream transfers in sequence. + * + * For example two seperate 100 usec transfers can start in the same uframe, + * and the second one would "carry over" 75 usecs into the next uframe. + */ +static void +periodic_tt_usecs ( + struct ehci_hcd *ehci, + struct usb_device *dev, + unsigned frame, + unsigned short tt_usecs[8] +) +{ + __le32 *hw_p = &ehci->periodic [frame]; + union ehci_shadow *q = &ehci->pshadow [frame]; + unsigned char uf; + + memset(tt_usecs, 0, 16); + + while (q->ptr) { + switch (Q_NEXT_TYPE(*hw_p)) { + case Q_TYPE_ITD: + hw_p = &q->itd->hw_next; + q = &q->itd->itd_next; + continue; + case Q_TYPE_QH: + if (same_tt(dev, q->qh->dev)) { + uf = tt_start_uframe(ehci, q->qh->hw_info2); + tt_usecs[uf] += q->qh->tt_usecs; + } + hw_p = &q->qh->hw_next; + q = &q->qh->qh_next; + continue; + case Q_TYPE_SITD: + if (same_tt(dev, q->sitd->urb->dev)) { + uf = tt_start_uframe(ehci, q->sitd->hw_uframe); + tt_usecs[uf] += q->sitd->stream->tt_usecs; + } + hw_p = &q->sitd->hw_next; + q = &q->sitd->sitd_next; + continue; + // case Q_TYPE_FSTN: + default: + ehci_dbg(ehci, + "ignoring periodic frame %d FSTN\n", frame); + hw_p = &q->fstn->hw_next; + q = &q->fstn->fstn_next; + } + } + + carryover_tt_bandwidth(tt_usecs); + + if (max_tt_usecs[7] < tt_usecs[7]) + ehci_err(ehci, "frame %d tt sched overrun: %d usecs\n", + frame, tt_usecs[7] - max_tt_usecs[7]); +} + +/* + * Return true if the device's tt's downstream bus is available for a + * periodic transfer of the specified length (usecs), starting at the + * specified frame/uframe. Note that (as summarized in section 11.19 + * of the usb 2.0 spec) TTs can buffer multiple transactions for each + * uframe. + * + * The uframe parameter is when the fullspeed/lowspeed transfer + * should be executed in "B-frame" terms, which is the same as the + * highspeed ssplit's uframe (which is in "H-frame" terms). For example + * a ssplit in "H-frame" 0 causes a transfer in "B-frame" 0. + * See the EHCI spec sec 4.5 and fig 4.7. + * + * This checks if the full/lowspeed bus, at the specified starting uframe, + * has the specified bandwidth available, according to rules listed + * in USB 2.0 spec section 11.18.1 fig 11-60. + * + * This does not check if the transfer would exceed the max ssplit + * limit of 16, specified in USB 2.0 spec section 11.18.4 requirement #4, + * since proper scheduling limits ssplits to less than 16 per uframe. + */ +static int tt_available ( + struct ehci_hcd *ehci, + unsigned period, + struct usb_device *dev, + unsigned frame, + unsigned uframe, + u16 usecs +) +{ + if ((period == 0) || (uframe >= 7)) /* error */ + return 0; + + for (; frame < ehci->periodic_size; frame += period) { + unsigned short tt_usecs[8]; + + periodic_tt_usecs (ehci, dev, frame, tt_usecs); + + ehci_vdbg(ehci, "tt frame %d check %d usecs start uframe %d in" + " schedule %d/%d/%d/%d/%d/%d/%d/%d\n", + frame, usecs, uframe, + tt_usecs[0], tt_usecs[1], tt_usecs[2], tt_usecs[3], + tt_usecs[4], tt_usecs[5], tt_usecs[6], tt_usecs[7]); + + if (max_tt_usecs[uframe] <= tt_usecs[uframe]) { + ehci_vdbg(ehci, "frame %d uframe %d fully scheduled\n", + frame, uframe); + return 0; + } + + /* special case for isoc transfers larger than 125us: + * the first and each subsequent fully used uframe + * must be empty, so as to not illegally delay + * already scheduled transactions + */ + if (125 < usecs) { + int ufs = (usecs / 125) - 1; + int i; + for (i = uframe; i < (uframe + ufs) && i < 8; i++) + if (0 < tt_usecs[i]) { + ehci_vdbg(ehci, + "multi-uframe xfer can't fit " + "in frame %d uframe %d\n", + frame, i); + return 0; + } + } + + tt_usecs[uframe] += usecs; + + carryover_tt_bandwidth(tt_usecs); + + /* fail if the carryover pushed bw past the last uframe's limit */ + if (max_tt_usecs[7] < tt_usecs[7]) { + ehci_vdbg(ehci, + "tt unavailable usecs %d frame %d uframe %d\n", + usecs, frame, uframe); + return 0; + } + } + + return 1; +} + +#else + /* return true iff the device's transaction translator is available * for a periodic transfer starting at the specified frame, using * all the uframes in the mask. @@ -237,6 +421,8 @@ static int tt_no_collision ( return 1; } +#endif /* CONFIG_USB_EHCI_TT_NEWSCHED */ + /*-------------------------------------------------------------------------*/ static int enable_periodic (struct ehci_hcd *ehci) @@ -481,7 +667,7 @@ static int check_intr_schedule ( ) { int retval = -ENOSPC; - u8 mask; + u8 mask = 0; if (qh->c_usecs && uframe >= 6) /* FSTN territory? */ goto done; @@ -494,6 +680,24 @@ static int check_intr_schedule ( goto done; } +#ifdef CONFIG_USB_EHCI_TT_NEWSCHED + if (tt_available (ehci, qh->period, qh->dev, frame, uframe, + qh->tt_usecs)) { + unsigned i; + + /* TODO : this may need FSTN for SSPLIT in uframe 5. */ + for (i=uframe+1; i<8 && i<uframe+4; i++) + if (!check_period (ehci, frame, i, + qh->period, qh->c_usecs)) + goto done; + else + mask |= 1 << i; + + retval = 0; + + *c_maskp = cpu_to_le32 (mask << 8); + } +#else /* Make sure this tt's buffer is also available for CSPLITs. * We pessimize a bit; probably the typical full speed case * doesn't need the second CSPLIT. @@ -514,6 +718,7 @@ static int check_intr_schedule ( goto done; retval = 0; } +#endif done: return retval; } @@ -1047,12 +1252,21 @@ sitd_slot_ok ( frame = uframe >> 3; uf = uframe & 7; +#ifdef CONFIG_USB_EHCI_TT_NEWSCHED + /* The tt's fullspeed bus bandwidth must be available. + * tt_available scheduling guarantees 10+% for control/bulk. + */ + if (!tt_available (ehci, period_uframes << 3, + stream->udev, frame, uf, stream->tt_usecs)) + return 0; +#else /* tt must be idle for start(s), any gap, and csplit. * assume scheduling slop leaves 10+% for control/bulk. */ if (!tt_no_collision (ehci, period_uframes << 3, stream->udev, frame, mask)) return 0; +#endif /* check starts (OUT uses more than one) */ max_used = 100 - stream->usecs; |