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USB: ehci shutdown refactored 

This patch refactors some shutdown code so it can be shared between
ehci_stop() and ehci_shutdown().

This also fixes a couple potential bugs:
 - ehci_shutdown() was not locking ehci->lock before halting the HC.
 - ehci_shutdown() didn't disable the watchdog and IAA timers.
 - ehci_stop() was resetting the host controller when it may have been
   running, which the EHCI spec says "may result in undefined behavior".

ehci_stop() was calling port_power() to turn off the ports, which waited
20ms after applying the port change.  The msleep was for the case where
the HC might take 20ms to turn the ports on; since we're shutting them
off, we can avoid the msleep and just use ehci_turn_off_ports().

ehci_stop() doesn't need to clear the intr_enable register or revert
ownership of the companion controllers to the BIOS, because the host
controller reset should have done that.  There might be a buggy host
controller that doesn't follow the reset rules, but for now we assume
it's redundant code and remove it.

[ A subsequent patch will cancel the timers later ... this version
carries forward existing bugs where timers could get re-armed
after they're canceled. ]

Signed-off-by: Sarah Sharp <sarah.a.sharp@intel.com>
Signed-off-by: David Brownell <dbrownell@users.sourceforge.net>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>
This commit is contained in:
Sarah Sharp 2008-04-08 14:30:18 -07:00 committed by Greg Kroah-Hartman
parent 3cf2723432
commit 21da84a893
1 changed files with 25 additions and 16 deletions
Show Stats Download Patch File Download Diff File Expand all files Collapse all files

41
drivers/usb/host/ehci-hcd.c
View File

@ -331,17 +331,13 @@ static void ehci_turn_off_all_ports(struct ehci_hcd *ehci)
&ehci->regs->port_status[port]);
}
/* ehci_shutdown kick in for silicon on any bus (not just pci, etc).
* This forcibly disables dma and IRQs, helping kexec and other cases
* where the next system software may expect clean state.
/*
* Halt HC, turn off all ports, and let the BIOS use the companion controllers.
* Should be called with ehci->lock held.
*/
static void
ehci_shutdown (struct usb_hcd *hcd)
static void ehci_silence_controller(struct ehci_hcd *ehci)
{
struct ehci_hcd *ehci;
ehci = hcd_to_ehci (hcd);
(void) ehci_halt (ehci);
ehci_halt(ehci);
ehci_turn_off_all_ports(ehci);
/* make BIOS/etc use companion controller during reboot */
@ -351,6 +347,22 @@ ehci_shutdown (struct usb_hcd *hcd)
ehci_readl(ehci, &ehci->regs->configured_flag);
}
/* ehci_shutdown kick in for silicon on any bus (not just pci, etc).
* This forcibly disables dma and IRQs, helping kexec and other cases
* where the next system software may expect clean state.
*/
static void ehci_shutdown(struct usb_hcd *hcd)
{
struct ehci_hcd *ehci = hcd_to_ehci(hcd);
del_timer_sync(&ehci->watchdog);
del_timer_sync(&ehci->iaa_watchdog);
spin_lock_irq(&ehci->lock);
ehci_silence_controller(ehci);
spin_unlock_irq(&ehci->lock);
}
static void ehci_port_power (struct ehci_hcd *ehci, int is_on)
{
unsigned port;
@ -401,15 +413,15 @@ static void ehci_work (struct ehci_hcd *ehci)
timer_action (ehci, TIMER_IO_WATCHDOG);
}
/*
* Called when the ehci_hcd module is removed.
*/
static void ehci_stop (struct usb_hcd *hcd)
{
struct ehci_hcd *ehci = hcd_to_ehci (hcd);
ehci_dbg (ehci, "stop\n");
/* Turn off port power on all root hub ports. */
ehci_port_power (ehci, 0);
/* no more interrupts ... */
del_timer_sync (&ehci->watchdog);
del_timer_sync(&ehci->iaa_watchdog);
@ -418,13 +430,10 @@ static void ehci_stop (struct usb_hcd *hcd)
if (HC_IS_RUNNING (hcd->state))
ehci_quiesce (ehci);
ehci_silence_controller(ehci);
ehci_reset (ehci);
ehci_writel(ehci, 0, &ehci->regs->intr_enable);
spin_unlock_irq(&ehci->lock);
/* let companion controllers work when we aren't */
ehci_writel(ehci, 0, &ehci->regs->configured_flag);
remove_companion_file(ehci);
remove_debug_files (ehci);