UHCI: fix bandwidth allocation

This patch (as840) fixes the bandwidth allocation mechanism in
uhci-hcd.  It has never worked correctly.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

diff --git a/drivers/usb/host/uhci-debug.c b/drivers/usb/host/uhci-debug.c
index 3fbb5ba..5d6c06b 100644 (file)
--- a/drivers/usb/host/uhci-debug.c
+++ b/drivers/usb/host/uhci-debug.c
@@ -168,9 +168,13 @@ static int uhci_show_qh(struct uhci_qh *qh, char *buf, int len, int space)
                        space, "", qh, qtype,
                        le32_to_cpu(qh->link), le32_to_cpu(element));
        if (qh->type == USB_ENDPOINT_XFER_ISOC)
-               out += sprintf(out, "%*s    period %d frame %x desc [%p]\n",
-                               space, "", qh->period, qh->iso_frame,
-                               qh->iso_packet_desc);
+               out += sprintf(out, "%*s    period %d phase %d load %d us, "
+                               "frame %x desc [%p]\n",
+                               space, "", qh->period, qh->phase, qh->load,
+                               qh->iso_frame, qh->iso_packet_desc);
+       else if (qh->type == USB_ENDPOINT_XFER_INT)
+               out += sprintf(out, "%*s    period %d phase %d load %d us\n",
+                               space, "", qh->period, qh->phase, qh->load);
 
        if (element & UHCI_PTR_QH)
                out += sprintf(out, "%*s  Element points to QH (bug?)\n", space, "");
@@ -352,6 +356,17 @@ static int uhci_sprint_schedule(struct uhci_hcd *uhci, char *buf, int len)
        out += uhci_show_root_hub_state(uhci, out, len - (out - buf));
        out += sprintf(out, "HC status\n");
        out += uhci_show_status(uhci, out, len - (out - buf));
+
+       out += sprintf(out, "Periodic load table\n");
+       for (i = 0; i < MAX_PHASE; ++i) {
+               out += sprintf(out, "\t%d", uhci->load[i]);
+               if (i % 8 == 7)
+                       *out++ = '\n';
+       }
+       out += sprintf(out, "Total: %d, #INT: %d, #ISO: %d\n",
+                       uhci->total_load,
+                       uhci_to_hcd(uhci)->self.bandwidth_int_reqs,
+                       uhci_to_hcd(uhci)->self.bandwidth_isoc_reqs);
        if (debug <= 1)
                return out - buf;
 

diff --git a/drivers/usb/host/uhci-hcd.h b/drivers/usb/host/uhci-hcd.h
index 108e3de..74469b5 100644 (file)
--- a/drivers/usb/host/uhci-hcd.h
+++ b/drivers/usb/host/uhci-hcd.h
@@ -83,6 +83,7 @@
 #define UHCI_MAX_SOF_NUMBER    2047    /* in an SOF packet */
 #define CAN_SCHEDULE_FRAMES    1000    /* how far in the future frames
                                         * can be scheduled */
+#define MAX_PHASE              32      /* Periodic scheduling length */
 
 /* When no queues need Full-Speed Bandwidth Reclamation,
  * delay this long before turning FSBR off */
@@ -141,6 +142,8 @@ struct uhci_qh {
        unsigned long advance_jiffies;  /* Time of last queue advance */
        unsigned int unlink_frame;      /* When the QH was unlinked */
        unsigned int period;            /* For Interrupt and Isochronous QHs */
+       short phase;                    /* Between 0 and period-1 */
+       short load;                     /* Periodic time requirement, in us */
        unsigned int iso_frame;         /* Frame # for iso_packet_desc */
        int iso_status;                 /* Status for Isochronous URBs */
 
@@ -153,6 +156,8 @@ struct uhci_qh {
        unsigned int needs_fixup:1;     /* Must fix the TD toggle values */
        unsigned int is_stopped:1;      /* Queue was stopped by error/unlink */
        unsigned int wait_expired:1;    /* QH_WAIT_TIMEOUT has expired */
+       unsigned int bandwidth_reserved:1;      /* Periodic bandwidth has
+                                                * been allocated */
 } __attribute__((aligned(16)));
 
 /*
@@ -414,6 +419,9 @@ struct uhci_hcd {
 
        wait_queue_head_t waitqh;               /* endpoint_disable waiters */
        int num_waiting;                        /* Number of waiters */
+
+       int total_load;                         /* Sum of array values */
+       short load[MAX_PHASE];                  /* Periodic allocations */
 };
 
 /* Convert between a usb_hcd pointer and the corresponding uhci_hcd */

diff --git a/drivers/usb/host/uhci-q.c b/drivers/usb/host/uhci-q.c
index 5afcc52..2cbb239 100644 (file)
--- a/drivers/usb/host/uhci-q.c
+++ b/drivers/usb/host/uhci-q.c
@@ -261,6 +261,14 @@ static struct uhci_qh *uhci_alloc_qh(struct uhci_hcd *uhci,
                qh->udev = udev;
                hep->hcpriv = qh;
 
+               if (qh->type == USB_ENDPOINT_XFER_INT ||
+                               qh->type == USB_ENDPOINT_XFER_ISOC)
+                       qh->load = usb_calc_bus_time(udev->speed,
+                                       usb_endpoint_dir_in(&hep->desc),
+                                       qh->type == USB_ENDPOINT_XFER_ISOC,
+                                       le16_to_cpu(hep->desc.wMaxPacketSize))
+                               / 1000 + 1;
+
        } else {                /* Skeleton QH */
                qh->state = QH_STATE_ACTIVE;
                qh->type = -1;
@@ -496,6 +504,121 @@ static void uhci_make_qh_idle(struct uhci_hcd *uhci, struct uhci_qh *qh)
                wake_up_all(&uhci->waitqh);
 }
 
+/*
+ * Find the highest existing bandwidth load for a given phase and period.
+ */
+static int uhci_highest_load(struct uhci_hcd *uhci, int phase, int period)
+{
+       int highest_load = uhci->load[phase];
+
+       for (phase += period; phase < MAX_PHASE; phase += period)
+               highest_load = max_t(int, highest_load, uhci->load[phase]);
+       return highest_load;
+}
+
+/*
+ * Set qh->phase to the optimal phase for a periodic transfer and
+ * check whether the bandwidth requirement is acceptable.
+ */
+static int uhci_check_bandwidth(struct uhci_hcd *uhci, struct uhci_qh *qh)
+{
+       int minimax_load;
+
+       /* Find the optimal phase (unless it is already set) and get
+        * its load value. */
+       if (qh->phase >= 0)
+               minimax_load = uhci_highest_load(uhci, qh->phase, qh->period);
+       else {
+               int phase, load;
+               int max_phase = min_t(int, MAX_PHASE, qh->period);
+
+               qh->phase = 0;
+               minimax_load = uhci_highest_load(uhci, qh->phase, qh->period);
+               for (phase = 1; phase < max_phase; ++phase) {
+                       load = uhci_highest_load(uhci, phase, qh->period);
+                       if (load < minimax_load) {
+                               minimax_load = load;
+                               qh->phase = phase;
+                       }
+               }
+       }
+
+       /* Maximum allowable periodic bandwidth is 90%, or 900 us per frame */
+       if (minimax_load + qh->load > 900) {
+               dev_dbg(uhci_dev(uhci), "bandwidth allocation failed: "
+                               "period %d, phase %d, %d + %d us\n",
+                               qh->period, qh->phase, minimax_load, qh->load);
+               return -ENOSPC;
+       }
+       return 0;
+}
+
+/*
+ * Reserve a periodic QH's bandwidth in the schedule
+ */
+static void uhci_reserve_bandwidth(struct uhci_hcd *uhci, struct uhci_qh *qh)
+{
+       int i;
+       int load = qh->load;
+       char *p = "??";
+
+       for (i = qh->phase; i < MAX_PHASE; i += qh->period) {
+               uhci->load[i] += load;
+               uhci->total_load += load;
+       }
+       uhci_to_hcd(uhci)->self.bandwidth_allocated =
+                       uhci->total_load / MAX_PHASE;
+       switch (qh->type) {
+       case USB_ENDPOINT_XFER_INT:
+               ++uhci_to_hcd(uhci)->self.bandwidth_int_reqs;
+               p = "INT";
+               break;
+       case USB_ENDPOINT_XFER_ISOC:
+               ++uhci_to_hcd(uhci)->self.bandwidth_isoc_reqs;
+               p = "ISO";
+               break;
+       }
+       qh->bandwidth_reserved = 1;
+       dev_dbg(uhci_dev(uhci),
+                       "%s dev %d ep%02x-%s, period %d, phase %d, %d us\n",
+                       "reserve", qh->udev->devnum,
+                       qh->hep->desc.bEndpointAddress, p,
+                       qh->period, qh->phase, load);
+}
+
+/*
+ * Release a periodic QH's bandwidth reservation
+ */
+static void uhci_release_bandwidth(struct uhci_hcd *uhci, struct uhci_qh *qh)
+{
+       int i;
+       int load = qh->load;
+       char *p = "??";
+
+       for (i = qh->phase; i < MAX_PHASE; i += qh->period) {
+               uhci->load[i] -= load;
+               uhci->total_load -= load;
+       }
+       uhci_to_hcd(uhci)->self.bandwidth_allocated =
+                       uhci->total_load / MAX_PHASE;
+       switch (qh->type) {
+       case USB_ENDPOINT_XFER_INT:
+               --uhci_to_hcd(uhci)->self.bandwidth_int_reqs;
+               p = "INT";
+               break;
+       case USB_ENDPOINT_XFER_ISOC:
+               --uhci_to_hcd(uhci)->self.bandwidth_isoc_reqs;
+               p = "ISO";
+               break;
+       }
+       qh->bandwidth_reserved = 0;
+       dev_dbg(uhci_dev(uhci),
+                       "%s dev %d ep%02x-%s, period %d, phase %d, %d us\n",
+                       "release", qh->udev->devnum,
+                       qh->hep->desc.bEndpointAddress, p,
+                       qh->period, qh->phase, load);
+}
+
 static inline struct urb_priv *uhci_alloc_urb_priv(struct uhci_hcd *uhci,
                struct urb *urb)
 {
@@ -799,7 +922,6 @@ static int uhci_submit_common(struct uhci_hcd *uhci, struct urb *urb,
        wmb();
        qh->dummy_td->status |= __constant_cpu_to_le32(TD_CTRL_ACTIVE);
        qh->dummy_td = td;
-       qh->period = urb->interval;
 
        usb_settoggle(urb->dev, usb_pipeendpoint(urb->pipe),
                        usb_pipeout(urb->pipe), toggle);
@@ -830,28 +952,42 @@ static inline int uhci_submit_bulk(struct uhci_hcd *uhci, struct urb *urb,
 static int uhci_submit_interrupt(struct uhci_hcd *uhci, struct urb *urb,
                struct uhci_qh *qh)
 {
-       int exponent;
+       int ret;
 
        /* USB 1.1 interrupt transfers only involve one packet per interval.
         * Drivers can submit URBs of any length, but longer ones will need
         * multiple intervals to complete.
         */
 
-       /* Figure out which power-of-two queue to use */
-       for (exponent = 7; exponent >= 0; --exponent) {
-               if ((1 << exponent) <= urb->interval)
-                       break;
-       }
-       if (exponent < 0)
-               return -EINVAL;
-       urb->interval = 1 << exponent;
+       if (!qh->bandwidth_reserved) {
+               int exponent;
 
-       if (qh->period == 0)
+               /* Figure out which power-of-two queue to use */
+               for (exponent = 7; exponent >= 0; --exponent) {
+                       if ((1 << exponent) <= urb->interval)
+                               break;
+               }
+               if (exponent < 0)
+                       return -EINVAL;
+               qh->period = 1 << exponent;
                qh->skel = uhci->skelqh[UHCI_SKEL_INDEX(exponent)];
-       else if (qh->period != urb->interval)
-               return -EINVAL;         /* Can't change the period */
 
-       return uhci_submit_common(uhci, urb, qh);
+               /* For now, interrupt phase is fixed by the layout
+                * of the QH lists. */
+               qh->phase = (qh->period / 2) & (MAX_PHASE - 1);
+               ret = uhci_check_bandwidth(uhci, qh);
+               if (ret)
+                       return ret;
+       } else if (qh->period > urb->interval)
+               return -EINVAL;         /* Can't decrease the period */
+
+       ret = uhci_submit_common(uhci, urb, qh);
+       if (ret == 0) {
+               urb->interval = qh->period;
+               if (!qh->bandwidth_reserved)
+                       uhci_reserve_bandwidth(uhci, qh);
+       }
+       return ret;
 }
 
 /*
@@ -998,15 +1134,32 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
                return -EFBIG;
 
        /* Check the period and figure out the starting frame number */
-       if (qh->period == 0) {
+       if (!qh->bandwidth_reserved) {
+               qh->period = urb->interval;
                if (urb->transfer_flags & URB_ISO_ASAP) {
+                       qh->phase = -1;         /* Find the best phase */
+                       i = uhci_check_bandwidth(uhci, qh);
+                       if (i)
+                               return i;
+
+                       /* Allow a little time to allocate the TDs */
                        uhci_get_current_frame_number(uhci);
-                       urb->start_frame = uhci->frame_number + 10;
+                       frame = uhci->frame_number + 10;
+
+                       /* Move forward to the first frame having the
+                        * correct phase */
+                       urb->start_frame = frame + ((qh->phase - frame) &
+                                       (qh->period - 1));
                } else {
                        i = urb->start_frame - uhci->last_iso_frame;
                        if (i <= 0 || i >= UHCI_NUMFRAMES)
                                return -EINVAL;
+                       qh->phase = urb->start_frame & (qh->period - 1);
+                       i = uhci_check_bandwidth(uhci, qh);
+                       if (i)
+                               return i;
                }
+
        } else if (qh->period != urb->interval) {
                return -EINVAL;         /* Can't change the period */
 
@@ -1052,9 +1205,6 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
        /* Set the interrupt-on-completion flag on the last packet. */
        td->status |= __constant_cpu_to_le32(TD_CTRL_IOC);
 
-       qh->skel = uhci->skel_iso_qh;
-       qh->period = urb->interval;
-
        /* Add the TDs to the frame list */
        frame = urb->start_frame;
        list_for_each_entry(td, &urbp->td_list, list) {
@@ -1068,6 +1218,9 @@ static int uhci_submit_isochronous(struct uhci_hcd *uhci, struct urb *urb,
                qh->iso_status = 0;
        }
 
+       qh->skel = uhci->skel_iso_qh;
+       if (!qh->bandwidth_reserved)
+               uhci_reserve_bandwidth(uhci, qh);
        return 0;
 }
 
@@ -1122,7 +1275,6 @@ static int uhci_urb_enqueue(struct usb_hcd *hcd,
        unsigned long flags;
        struct urb_priv *urbp;
        struct uhci_qh *qh;
-       int bustime;
 
        spin_lock_irqsave(&uhci->lock, flags);
 
@@ -1152,35 +1304,11 @@ static int uhci_urb_enqueue(struct usb_hcd *hcd,
                ret = uhci_submit_bulk(uhci, urb, qh);
                break;
        case USB_ENDPOINT_XFER_INT:
-               if (list_empty(&qh->queue)) {
-                       bustime = usb_check_bandwidth(urb->dev, urb);
-                       if (bustime < 0)
-                               ret = bustime;
-                       else {
-                               ret = uhci_submit_interrupt(uhci, urb, qh);
-                               if (ret == 0)
-                                       usb_claim_bandwidth(urb->dev, urb, bustime, 0);
-                       }
-               } else {        /* inherit from parent */
-                       struct urb_priv *eurbp;
-
-                       eurbp = list_entry(qh->queue.prev, struct urb_priv,
-                                       node);
-                       urb->bandwidth = eurbp->urb->bandwidth;
-                       ret = uhci_submit_interrupt(uhci, urb, qh);
-               }
+               ret = uhci_submit_interrupt(uhci, urb, qh);
                break;
        case USB_ENDPOINT_XFER_ISOC:
                urb->error_count = 0;
-               bustime = usb_check_bandwidth(urb->dev, urb);
-               if (bustime < 0) {
-                       ret = bustime;
-                       break;
-               }
-
                ret = uhci_submit_isochronous(uhci, urb, qh);
-               if (ret == 0)
-                       usb_claim_bandwidth(urb->dev, urb, bustime, 1);
                break;
        }
        if (ret != 0)
@@ -1277,24 +1405,6 @@ __acquires(uhci->lock)
 
        uhci_free_urb_priv(uhci, urbp);
 
-       switch (qh->type) {
-       case USB_ENDPOINT_XFER_ISOC:
-               /* Release bandwidth for Interrupt or Isoc. transfers */
-               if (urb->bandwidth)
-                       usb_release_bandwidth(urb->dev, urb, 1);
-               break;
-       case USB_ENDPOINT_XFER_INT:
-               /* Release bandwidth for Interrupt or Isoc. transfers */
-               /* Make sure we don't release if we have a queued URB */
-               if (list_empty(&qh->queue) && urb->bandwidth)
-                       usb_release_bandwidth(urb->dev, urb, 0);
-               else
-                       /* bandwidth was passed on to queued URB, */
-                       /* so don't let usb_unlink_urb() release it */
-                       urb->bandwidth = 0;
-               break;
-       }
-
        spin_unlock(&uhci->lock);
        usb_hcd_giveback_urb(uhci_to_hcd(uhci), urb);
        spin_lock(&uhci->lock);
@@ -1303,9 +1413,8 @@ __acquires(uhci->lock)
         * reserved bandwidth. */
        if (list_empty(&qh->queue)) {
                uhci_unlink_qh(uhci, qh);
-
-               /* Bandwidth stuff not yet implemented */
-               qh->period = 0;
+               if (qh->bandwidth_reserved)
+                       uhci_release_bandwidth(uhci, qh);
        }
 }