From c4f3476436f7452b97c8accb5dd7d53219a11a3f Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Wed, 11 Jul 2012 11:23:10 -0400 Subject: [PATCH] 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 Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-hcd.c | 48 ++++++++++++++++++++++++----------- drivers/usb/host/ehci-hub.c | 41 +++++++++++++++++++++--------- drivers/usb/host/ehci-tegra.c | 5 ++-- 3 files changed, 64 insertions(+), 30 deletions(-) diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index 340c9c4894bf..ac4c8ddde20a 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -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); diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c index 05490d387fd2..ffc5f27df725 100644 --- a/drivers/usb/host/ehci-hub.c +++ b/drivers/usb/host/ehci-hub.c @@ -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); diff --git a/drivers/usb/host/ehci-tegra.c b/drivers/usb/host/ehci-tegra.c index f7f3ce3275b8..65360945df78 100644 --- a/drivers/usb/host/ehci-tegra.c +++ b/drivers/usb/host/ehci-tegra.c @@ -445,12 +445,11 @@ static int controller_suspend(struct device *dev) if (time_before(jiffies, ehci->next_statechange)) msleep(10); - spin_lock_irqsave(&ehci->lock, flags); + ehci_halt(ehci); + spin_lock_irqsave(&ehci->lock, flags); tegra->port_speed = (readl(&hw->port_status[0]) >> 26) & 0x3; - ehci_halt(ehci); clear_bit(HCD_FLAG_HW_ACCESSIBLE, &hcd->flags); - spin_unlock_irqrestore(&ehci->lock, flags); tegra_ehci_power_down(hcd); -- 2.34.1