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USB: EHCI: fix up locking

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This patch (as1588) adjusts the locking in ehci-hcd's various halt,
shutdown, and suspend/resume pathways.  We want to hold the spinlock
while writing device registers and accessing shared variables, but not
while polling in a loop.

In addition, there's no need to call ehci_work() at times when no URBs
can be active, i.e., in ehci_stop() and ehci_bus_suspend().

Finally, ehci_adjust_port_wakeup_flags() is called only in situations
where interrupts are enabled; therefore it can use spin_lock_irq
rather than spin_lock_irqsave.

Signed-off-by: Alan Stern <stern@rowland.harvard.edu>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
This commit is contained in:
Alan Stern
2012-07-11 11:23:10 -04:00
committed by Greg Kroah-Hartman
parent f428907822
commit c4f3476436
3 changed files with 65 additions and 31 deletions
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41
drivers/usb/host/ehci-hub.c
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@@ -59,6 +59,7 @@ static void ehci_handover_companion_ports(struct ehci_hcd *ehci)
/* Give the connections some time to appear */
msleep(20);
spin_lock_irq(&ehci->lock);
port = HCS_N_PORTS(ehci->hcs_params);
while (port--) {
if (test_bit(port, &ehci->owned_ports)) {
@@ -70,23 +71,30 @@ static void ehci_handover_companion_ports(struct ehci_hcd *ehci)
clear_bit(port, &ehci->owned_ports);
else if (test_bit(port, &ehci->companion_ports))
ehci_writel(ehci, status & ~PORT_PE, reg);
else
else {
spin_unlock_irq(&ehci->lock);
ehci_hub_control(hcd, SetPortFeature,
USB_PORT_FEAT_RESET, port + 1,
NULL, 0);
spin_lock_irq(&ehci->lock);
}
}
}
spin_unlock_irq(&ehci->lock);
if (!ehci->owned_ports)
return;
msleep(90); /* Wait for resets to complete */
spin_lock_irq(&ehci->lock);
port = HCS_N_PORTS(ehci->hcs_params);
while (port--) {
if (test_bit(port, &ehci->owned_ports)) {
spin_unlock_irq(&ehci->lock);
ehci_hub_control(hcd, GetPortStatus,
0, port + 1,
(char *) &buf, sizeof(buf));
spin_lock_irq(&ehci->lock);
/* The companion should now own the port,
* but if something went wrong the port must not
@@ -105,6 +113,7 @@ static void ehci_handover_companion_ports(struct ehci_hcd *ehci)
}
ehci->owned_ports = 0;
spin_unlock_irq(&ehci->lock);
}
static int ehci_port_change(struct ehci_hcd *ehci)
@@ -133,7 +142,6 @@ static void ehci_adjust_port_wakeup_flags(struct ehci_hcd *ehci,
{
int port;
u32 temp;
unsigned long flags;
/* If remote wakeup is enabled for the root hub but disabled
* for the controller, we must adjust all the port wakeup flags
@@ -143,7 +151,7 @@ static void ehci_adjust_port_wakeup_flags(struct ehci_hcd *ehci,
if (!ehci_to_hcd(ehci)->self.root_hub->do_remote_wakeup || do_wakeup)
return;
spin_lock_irqsave(&ehci->lock, flags);
spin_lock_irq(&ehci->lock);
/* clear phy low-power mode before changing wakeup flags */
if (ehci->has_hostpc) {
@@ -154,9 +162,9 @@ static void ehci_adjust_port_wakeup_flags(struct ehci_hcd *ehci,
temp = ehci_readl(ehci, hostpc_reg);
ehci_writel(ehci, temp & ~HOSTPC_PHCD, hostpc_reg);
}
spin_unlock_irqrestore(&ehci->lock, flags);
spin_unlock_irq(&ehci->lock);
msleep(5);
spin_lock_irqsave(&ehci->lock, flags);
spin_lock_irq(&ehci->lock);
}
port = HCS_N_PORTS(ehci->hcs_params);
@@ -194,7 +202,7 @@ static void ehci_adjust_port_wakeup_flags(struct ehci_hcd *ehci,
if (!suspending && ehci_port_change(ehci))
usb_hcd_resume_root_hub(ehci_to_hcd(ehci));
spin_unlock_irqrestore(&ehci->lock, flags);
spin_unlock_irq(&ehci->lock);
}
static int ehci_bus_suspend (struct usb_hcd *hcd)
@@ -209,6 +217,9 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
if (time_before (jiffies, ehci->next_statechange))
msleep(5);
/* stop the schedules */
ehci_quiesce(ehci);
spin_lock_irq (&ehci->lock);
/* Once the controller is stopped, port resumes that are already
@@ -224,10 +235,6 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
}
}
/* stop schedules, clean any completed work */
ehci_quiesce(ehci);
ehci_work(ehci);
/* Unlike other USB host controller types, EHCI doesn't have
* any notion of "global" or bus-wide suspend. The driver has
* to manually suspend all the active unsuspended ports, and
@@ -289,6 +296,7 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
"succeeded" : "failed");
}
}
spin_unlock_irq(&ehci->lock);
/* Apparently some devices need a >= 1-uframe delay here */
if (ehci->bus_suspended)
@@ -296,6 +304,8 @@ static int ehci_bus_suspend (struct usb_hcd *hcd)
/* turn off now-idle HC */
ehci_halt (ehci);
spin_lock_irq(&ehci->lock);
ehci->rh_state = EHCI_RH_SUSPENDED;
end_unlink_async(ehci);
@@ -424,13 +434,14 @@ static int ehci_bus_resume (struct usb_hcd *hcd)
}
ehci->next_statechange = jiffies + msecs_to_jiffies(5);
spin_unlock_irq(&ehci->lock);
ehci_handover_companion_ports(ehci);
/* Now we can safely re-enable irqs */
ehci_writel(ehci, INTR_MASK, &ehci->regs->intr_enable);
(void) ehci_readl(ehci, &ehci->regs->intr_enable);
spin_unlock_irq (&ehci->lock);
ehci_handover_companion_ports(ehci);
return 0;
}
@@ -1018,7 +1029,9 @@ static int ehci_hub_control (
case USB_PORT_FEAT_TEST:
if (!selector || selector > 5)
goto error;
spin_unlock_irqrestore(&ehci->lock, flags);
ehci_quiesce(ehci);
spin_lock_irqsave(&ehci->lock, flags);
/* Put all enabled ports into suspend */
while (ports--) {
@@ -1030,7 +1043,11 @@ static int ehci_hub_control (
ehci_writel(ehci, temp | PORT_SUSPEND,
sreg);
}
spin_unlock_irqrestore(&ehci->lock, flags);
ehci_halt(ehci);
spin_lock_irqsave(&ehci->lock, flags);
temp = ehci_readl(ehci, status_reg);
temp |= selector << 16;
ehci_writel(ehci, temp, status_reg);