4 files changed, 138 insertions, 2 deletions

diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index bc94822f4c5d..f8fed163a23a 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -30,8 +30,7 @@
 #include <linux/vmalloc.h>
 #include <linux/errno.h>
 #include <linux/init.h>
-#include <linux/timer.h>
-#include <linux/ktime.h>
+#include <linux/hrtimer.h>
 #include <linux/list.h>
 #include <linux/interrupt.h>
 #include <linux/usb.h>
@@ -380,6 +379,7 @@ static void ehci_quiesce (struct ehci_hcd *ehci)
 static void end_unlink_async(struct ehci_hcd *ehci);
 static void ehci_work(struct ehci_hcd *ehci);
 
+#include "ehci-timer.c"
 #include "ehci-hub.c"
 #include "ehci-lpm.c"
 #include "ehci-mem.c"
@@ -494,7 +494,10 @@ static void ehci_shutdown(struct usb_hcd *hcd)
         spin_lock_irq(&ehci->lock);
         ehci->rh_state = EHCI_RH_STOPPING;
         ehci_silence_controller(ehci);
+        ehci->enabled_hrtimer_events = 0;
         spin_unlock_irq(&ehci->lock);
+
+        hrtimer_cancel(&ehci->hrtimer);
 }
 
 static void ehci_port_power (struct ehci_hcd *ehci, int is_on)
@@ -561,12 +564,14 @@ static void ehci_stop (struct usb_hcd *hcd)
         del_timer_sync(&ehci->iaa_watchdog);
 
         spin_lock_irq(&ehci->lock);
+        ehci->enabled_hrtimer_events = 0;
         ehci_quiesce(ehci);
 
         ehci_silence_controller(ehci);
         ehci_reset (ehci);
         spin_unlock_irq(&ehci->lock);
 
+        hrtimer_cancel(&ehci->hrtimer);
         remove_sysfs_files(ehci);
         remove_debug_files (ehci);
 
@@ -615,6 +620,10 @@ static int ehci_init(struct usb_hcd *hcd)
         ehci->iaa_watchdog.function = ehci_iaa_watchdog;
         ehci->iaa_watchdog.data = (unsigned long) ehci;
 
+        hrtimer_init(&ehci->hrtimer, CLOCK_MONOTONIC, HRTIMER_MODE_ABS);
+        ehci->hrtimer.function = ehci_hrtimer_func;
+        ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;
+
         hcc_params = ehci_readl(ehci, &ehci->caps->hcc_params);
 
         /*
@@ -954,6 +963,8 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd)
                 dbg_status(ehci, "fatal", status);
                 ehci_halt(ehci);
 dead:
+                ehci->enabled_hrtimer_events = 0;
+                hrtimer_try_to_cancel(&ehci->hrtimer);
                 ehci_reset(ehci);
                 ehci_writel(ehci, 0, &ehci->regs->configured_flag);
                 usb_hc_died(hcd);
diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c
index fb1b99e74937..25329e4b844f 100644
--- a/drivers/usb/host/ehci-hub.c
+++ b/drivers/usb/host/ehci-hub.c
@@ -311,12 +311,15 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
         ehci_readl(ehci, &ehci->regs->intr_enable);
 
         ehci->next_statechange = jiffies + msecs_to_jiffies(10);
+        ehci->enabled_hrtimer_events = 0;
+        ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;
         spin_unlock_irq (&ehci->lock);
 
         /* ehci_work() may have re-enabled the watchdog timer, which we do not
          * want, and so we must delete any pending watchdog timer events.
          */
         del_timer_sync(&ehci->watchdog);
+        hrtimer_cancel(&ehci->hrtimer);
         return 0;
 }
 
diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c
new file mode 100644
index 000000000000..f6279e2883a8
--- /dev/null
+++ b/drivers/usb/host/ehci-timer.c
@@ -0,0 +1,106 @@
+/*
+ * Copyright (C) 2012 by Alan Stern
+ *
+ * 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.
+ */
+
+/* This file is part of ehci-hcd.c */
+
+/*-------------------------------------------------------------------------*/
+
+/*
+ * EHCI timer support...  Now using hrtimers.
+ *
+ * Lots of different events are triggered from ehci->hrtimer.  Whenever
+ * the timer routine runs, it checks each possible event; events that are
+ * currently enabled and whose expiration time has passed get handled.
+ * The set of enabled events is stored as a collection of bitflags in
+ * ehci->enabled_hrtimer_events, and they are numbered in order of
+ * increasing delay values (ranging between 1 ms and 100 ms).
+ *
+ * Rather than implementing a sorted list or tree of all pending events,
+ * we keep track only of the lowest-numbered pending event, in
+ * ehci->next_hrtimer_event.  Whenever ehci->hrtimer gets restarted, its
+ * expiration time is set to the timeout value for this event.
+ *
+ * As a result, events might not get handled right away; the actual delay
+ * could be anywhere up to twice the requested delay.  This doesn't
+ * matter, because none of the events are especially time-critical.  The
+ * ones that matter most all have a delay of 1 ms, so they will be
+ * handled after 2 ms at most, which is okay.  In addition to this, we
+ * allow for an expiration range of 1 ms.
+ */
+
+/*
+ * Delay lengths for the hrtimer event types.
+ * Keep this list sorted by delay length, in the same order as
+ * the event types indexed by enum ehci_hrtimer_event in ehci.h.
+ */
+static unsigned event_delays_ns[] = {
+};
+
+/* Enable a pending hrtimer event */
+static void ehci_enable_event(struct ehci_hcd *ehci, unsigned event,
+                bool resched)
+{
+        ktime_t         *timeout = &ehci->hr_timeouts[event];
+
+        if (resched)
+                *timeout = ktime_add(ktime_get(),
+                                ktime_set(0, event_delays_ns[event]));
+        ehci->enabled_hrtimer_events |= (1 << event);
+
+        /* Track only the lowest-numbered pending event */
+        if (event < ehci->next_hrtimer_event) {
+                ehci->next_hrtimer_event = event;
+                hrtimer_start_range_ns(&ehci->hrtimer, *timeout,
+                                NSEC_PER_MSEC, HRTIMER_MODE_ABS);
+        }
+}
+
+
+/*
+ * Handler functions for the hrtimer event types.
+ * Keep this array in the same order as the event types indexed by
+ * enum ehci_hrtimer_event in ehci.h.
+ */
+static void (*event_handlers[])(struct ehci_hcd *) = {
+};
+
+static enum hrtimer_restart ehci_hrtimer_func(struct hrtimer *t)
+{
+        struct ehci_hcd *ehci = container_of(t, struct ehci_hcd, hrtimer);
+        ktime_t         now;
+        unsigned long   events;
+        unsigned long   flags;
+        unsigned        e;
+
+        spin_lock_irqsave(&ehci->lock, flags);
+
+        events = ehci->enabled_hrtimer_events;
+        ehci->enabled_hrtimer_events = 0;
+        ehci->next_hrtimer_event = EHCI_HRTIMER_NO_EVENT;
+
+        /*
+         * Check each pending event.  If its time has expired, handle
+         * the event; otherwise re-enable it.
+         */
+        now = ktime_get();
+        for_each_set_bit(e, &events, EHCI_HRTIMER_NUM_EVENTS) {
+                if (now.tv64 >= ehci->hr_timeouts[e].tv64)
+                        event_handlers[e](ehci);
+                else
+                        ehci_enable_event(ehci, e, false);
+        }
+
+        spin_unlock_irqrestore(&ehci->lock, flags);
+        return HRTIMER_NORESTART;
+}
diff --git a/drivers/usb/host/ehci.h b/drivers/usb/host/ehci.h
index 9e8e82ecce58..070be83028d5 100644
--- a/drivers/usb/host/ehci.h
+++ b/drivers/usb/host/ehci.h
@@ -73,7 +73,23 @@ enum ehci_rh_state {
         EHCI_RH_STOPPING
 };
 
+/*
+ * Timer events, ordered by increasing delay length.
+ * Always update event_delays_ns[] and event_handlers[] (defined in
+ * ehci-timer.c) in parallel with this list.
+ */
+enum ehci_hrtimer_event {
+        EHCI_HRTIMER_NUM_EVENTS         /* Must come last */
+};
+#define EHCI_HRTIMER_NO_EVENT   99
+
 struct ehci_hcd {                       /* one per controller */
+        /* timing support */
+        enum ehci_hrtimer_event next_hrtimer_event;
+        unsigned                enabled_hrtimer_events;
+        ktime_t                 hr_timeouts[EHCI_HRTIMER_NUM_EVENTS];
+        struct hrtimer          hrtimer;
+
         /* glue to PCI and HCD framework */
         struct ehci_caps __iomem *caps;
         struct ehci_regs __iomem *regs;