From f96fba0dbf8f6b0eaa313b4c230f93c9bb0dd759 Mon Sep 17 00:00:00 2001 From: Alan Stern Date: Mon, 25 Jan 2016 15:44:16 -0500 Subject: [PATCH] USB: EHCI: improve handling of the ehci->iaa_in_progress flag This patch improves the way ehci-hcd handles the iaa_in_progress flag. The current code is somewhat careless in this regard: The flag is meaningless when the root hub isn't running, most particularly after the root hub has been suspended. But in start_iaa_cycle(), the driver checks the flag before checking the root hub's state. They should be checked in the opposite order. That routine also sets the flag too early, before it has definitely committed to starting an IAA cycle. The flag is turned off in end_unlink_async(). Upcoming changes will call that routine at other times, not just at the end of an IAA cycle. The two actions are logically separate (although related), so we separate out a new routine to be called in place of end_unlink_async() whenever an IAA cycle ends: end_iaa_cycle(). iaa_in_progress should be turned off when the root hub is suspended -- we certainly don't want it still to be set when the root hub resumes. Therefore the call to end_unlink_async() in ehci_bus_suspend() should also be replaced with a call to end_iaa_cycle(). Signed-off-by: Alan Stern Signed-off-by: Greg Kroah-Hartman --- drivers/usb/host/ehci-hcd.c | 3 ++- drivers/usb/host/ehci-hub.c | 3 ++- drivers/usb/host/ehci-q.c | 28 +++++++++++++++------------- drivers/usb/host/ehci-timer.c | 2 +- 4 files changed, 20 insertions(+), 16 deletions(-) diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index c5465bf9a798..84c41262109c 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -306,6 +306,7 @@ static void ehci_quiesce (struct ehci_hcd *ehci) /*-------------------------------------------------------------------------*/ +static void end_iaa_cycle(struct ehci_hcd *ehci); static void end_unlink_async(struct ehci_hcd *ehci); static void unlink_empty_async(struct ehci_hcd *ehci); static void unlink_empty_async_suspended(struct ehci_hcd *ehci); @@ -758,7 +759,7 @@ static irqreturn_t ehci_irq (struct usb_hcd *hcd) ehci_dbg(ehci, "IAA with IAAD still set?\n"); if (ehci->iaa_in_progress) COUNT(ehci->stats.iaa); - end_unlink_async(ehci); + end_iaa_cycle(ehci); } /* remote wakeup [4.3.1] */ diff --git a/drivers/usb/host/ehci-hub.c b/drivers/usb/host/ehci-hub.c index 086a7115d263..6d84ce2edc27 100644 --- a/drivers/usb/host/ehci-hub.c +++ b/drivers/usb/host/ehci-hub.c @@ -347,7 +347,8 @@ static int ehci_bus_suspend (struct usb_hcd *hcd) goto done; ehci->rh_state = EHCI_RH_SUSPENDED; - end_unlink_async(ehci); + /* Any IAA cycle that started before the suspend is now invalid */ + end_iaa_cycle(ehci); unlink_empty_async_suspended(ehci); ehci_handle_start_intr_unlinks(ehci); ehci_handle_intr_unlinks(ehci); diff --git a/drivers/usb/host/ehci-q.c b/drivers/usb/host/ehci-q.c index 1b42bcb59743..15dcae8f0631 100644 --- a/drivers/usb/host/ehci-q.c +++ b/drivers/usb/host/ehci-q.c @@ -1283,17 +1283,13 @@ static void single_unlink_async(struct ehci_hcd *ehci, struct ehci_qh *qh) static void start_iaa_cycle(struct ehci_hcd *ehci) { - /* Do nothing if an IAA cycle is already running */ - if (ehci->iaa_in_progress) - return; - ehci->iaa_in_progress = true; - /* If the controller isn't running, we don't have to wait for it */ if (unlikely(ehci->rh_state < EHCI_RH_RUNNING)) { end_unlink_async(ehci); - /* Otherwise start a new IAA cycle */ - } else if (likely(ehci->rh_state == EHCI_RH_RUNNING)) { + /* Otherwise start a new IAA cycle if one isn't already running */ + } else if (ehci->rh_state == EHCI_RH_RUNNING && + !ehci->iaa_in_progress) { /* Make sure the unlinks are all visible to the hardware */ wmb(); @@ -1301,17 +1297,13 @@ static void start_iaa_cycle(struct ehci_hcd *ehci) ehci_writel(ehci, ehci->command | CMD_IAAD, &ehci->regs->command); ehci_readl(ehci, &ehci->regs->command); + ehci->iaa_in_progress = true; ehci_enable_event(ehci, EHCI_HRTIMER_IAA_WATCHDOG, true); } } -/* the async qh for the qtds being unlinked are now gone from the HC */ - -static void end_unlink_async(struct ehci_hcd *ehci) +static void end_iaa_cycle(struct ehci_hcd *ehci) { - struct ehci_qh *qh; - bool early_exit; - if (ehci->has_synopsys_hc_bug) ehci_writel(ehci, (u32) ehci->async->qh_dma, &ehci->regs->async_next); @@ -1319,6 +1311,16 @@ static void end_unlink_async(struct ehci_hcd *ehci) /* The current IAA cycle has ended */ ehci->iaa_in_progress = false; + end_unlink_async(ehci); +} + +/* See if the async qh for the qtds being unlinked are now gone from the HC */ + +static void end_unlink_async(struct ehci_hcd *ehci) +{ + struct ehci_qh *qh; + bool early_exit; + if (list_empty(&ehci->async_unlink)) return; qh = list_first_entry(&ehci->async_unlink, struct ehci_qh, diff --git a/drivers/usb/host/ehci-timer.c b/drivers/usb/host/ehci-timer.c index 37a3e0dece84..6bea4d553ec5 100644 --- a/drivers/usb/host/ehci-timer.c +++ b/drivers/usb/host/ehci-timer.c @@ -361,7 +361,7 @@ static void ehci_iaa_watchdog(struct ehci_hcd *ehci) } ehci_dbg(ehci, "IAA watchdog: status %x cmd %x\n", status, cmd); - end_unlink_async(ehci); + end_iaa_cycle(ehci); } -- 2.20.1