USB: EHCI: fix up locking
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>
diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c
index 340c9c4..ac4c8dd 100644
--- a/drivers/usb/host/ehci-hcd.c
+++ b/drivers/usb/host/ehci-hcd.c
@@ -167,21 +167,24 @@
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 @@
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 @@
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 @@
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 @@
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 @@
/*
* 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 @@
/* 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 @@
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 @@
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 @@
/* 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);