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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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48
drivers/usb/host/ehci-hcd.c
View file

@ -167,21 +167,24 @@ static int tdi_in_host_mode (struct ehci_hcd *ehci)
return (tmp & 3) == USBMODE_CM_HC;
}
/* force HC to halt state from unknown (EHCI spec section 2.3) */
/*
* Force HC to halt state from unknown (EHCI spec section 2.3).
* Must be called with interrupts enabled and the lock not held.
*/
static int ehci_halt (struct ehci_hcd *ehci)
{
u32 temp = ehci_readl(ehci, &ehci->regs->status);
u32 temp;
spin_lock_irq(&ehci->lock);
/* disable any irqs left enabled by previous code */
ehci_writel(ehci, 0, &ehci->regs->intr_enable);
if (ehci_is_TDI(ehci) && tdi_in_host_mode(ehci) == 0) {
if (ehci_is_TDI(ehci) && !tdi_in_host_mode(ehci)) {
spin_unlock_irq(&ehci->lock);
return 0;
}
if ((temp & STS_HALT) != 0)
return 0;
/*
* This routine gets called during probe before ehci->command
* has been initialized, so we can't rely on its value.
@ -190,7 +193,11 @@ static int ehci_halt (struct ehci_hcd *ehci)
temp = ehci_readl(ehci, &ehci->regs->command);
temp &= ~(CMD_RUN | CMD_IAAD);
ehci_writel(ehci, temp, &ehci->regs->command);
return handshake (ehci, &ehci->regs->status,
spin_unlock_irq(&ehci->lock);
synchronize_irq(ehci_to_hcd(ehci)->irq);
return handshake(ehci, &ehci->regs->status,
STS_HALT, STS_HALT, 16 * 125);
}
@ -210,7 +217,10 @@ static void tdi_reset (struct ehci_hcd *ehci)
ehci_writel(ehci, tmp, &ehci->regs->usbmode);
}
/* reset a non-running (STS_HALT == 1) controller */
/*
* Reset a non-running (STS_HALT == 1) controller.
* Must be called with interrupts enabled and the lock not held.
*/
static int ehci_reset (struct ehci_hcd *ehci)
{
int retval;
@ -248,7 +258,10 @@ static int ehci_reset (struct ehci_hcd *ehci)
return retval;
}
/* idle the controller (from running) */
/*
* Idle the controller (turn off the schedules).
* Must be called with interrupts enabled and the lock not held.
*/
static void ehci_quiesce (struct ehci_hcd *ehci)
{
u32 temp;
@ -261,8 +274,10 @@ static void ehci_quiesce (struct ehci_hcd *ehci)
handshake(ehci, &ehci->regs->status, STS_ASS | STS_PSS, temp, 16 * 125);
/* then disable anything that's still active */
spin_lock_irq(&ehci->lock);
ehci->command &= ~(CMD_ASE | CMD_PSE);
ehci_writel(ehci, ehci->command, &ehci->regs->command);
spin_unlock_irq(&ehci->lock);
/* hardware can take 16 microframes to turn off ... */
handshake(ehci, &ehci->regs->status, STS_ASS | STS_PSS, 0, 16 * 125);
@ -301,11 +316,14 @@ static void ehci_turn_off_all_ports(struct ehci_hcd *ehci)
/*
* Halt HC, turn off all ports, and let the BIOS use the companion controllers.
* Should be called with ehci->lock held.
* Must be called with interrupts enabled and the lock not held.
*/
static void ehci_silence_controller(struct ehci_hcd *ehci)
{
ehci_halt(ehci);
spin_lock_irq(&ehci->lock);
ehci->rh_state = EHCI_RH_HALTED;
ehci_turn_off_all_ports(ehci);
/* make BIOS/etc use companion controller during reboot */
@ -313,6 +331,7 @@ static void ehci_silence_controller(struct ehci_hcd *ehci)
/* unblock posted writes */
ehci_readl(ehci, &ehci->regs->configured_flag);
spin_unlock_irq(&ehci->lock);
}
/* ehci_shutdown kick in for silicon on any bus (not just pci, etc).
@ -325,10 +344,11 @@ 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);
ehci_silence_controller(ehci);
hrtimer_cancel(&ehci->hrtimer);
}
@ -400,11 +420,11 @@ static void ehci_stop (struct usb_hcd *hcd)
spin_lock_irq(&ehci->lock);
ehci->enabled_hrtimer_events = 0;
ehci_quiesce(ehci);
spin_unlock_irq(&ehci->lock);
ehci_quiesce(ehci);
ehci_silence_controller(ehci);
ehci_reset (ehci);
spin_unlock_irq(&ehci->lock);
hrtimer_cancel(&ehci->hrtimer);
remove_sysfs_files(ehci);
@ -412,8 +432,6 @@ static void ehci_stop (struct usb_hcd *hcd)
/* root hub is shut down separately (first, when possible) */
spin_lock_irq (&ehci->lock);
if (ehci->async)
ehci_work (ehci);
end_free_itds(ehci);
spin_unlock_irq (&ehci->lock);
ehci_mem_cleanup (ehci);