diff options
Diffstat (limited to 'drivers')
| -rw-r--r-- | drivers/usb/core/hcd.h | 8 | ||||
| -rw-r--r-- | drivers/usb/core/hub.c | 15 | ||||
| -rw-r--r-- | drivers/usb/host/ehci-hcd.c | 8 |
3 files changed, 29 insertions, 2 deletions
diff --git a/drivers/usb/core/hcd.h b/drivers/usb/core/hcd.h index 1396141274f..98e24194a4a 100644 --- a/drivers/usb/core/hcd.h +++ b/drivers/usb/core/hcd.h @@ -19,6 +19,8 @@ #ifdef __KERNEL__ +#include <linux/rwsem.h> + /* This file contains declarations of usbcore internals that are mostly * used or exposed by Host Controller Drivers. */ @@ -470,5 +472,9 @@ static inline void usbmon_urb_complete(struct usb_bus *bus, struct urb *urb, : (in_interrupt () ? "in_interrupt" : "can sleep")) -#endif /* __KERNEL__ */ +/* This rwsem is for use only by the hub driver and ehci-hcd. + * Nobody else should touch it. + */ +extern struct rw_semaphore ehci_cf_port_reset_rwsem; +#endif /* __KERNEL__ */ diff --git a/drivers/usb/core/hub.c b/drivers/usb/core/hub.c index 481dca641ea..d20cb545a6e 100644 --- a/drivers/usb/core/hub.c +++ b/drivers/usb/core/hub.c @@ -125,6 +125,12 @@ MODULE_PARM_DESC(use_both_schemes, "try the other device initialization scheme if the " "first one fails"); +/* Mutual exclusion for EHCI CF initialization. This interferes with + * port reset on some companion controllers. + */ +DECLARE_RWSEM(ehci_cf_port_reset_rwsem); +EXPORT_SYMBOL_GPL(ehci_cf_port_reset_rwsem); + static inline char *portspeed(int portstatus) { @@ -1581,6 +1587,11 @@ static int hub_port_reset(struct usb_hub *hub, int port1, { int i, status; + /* Block EHCI CF initialization during the port reset. + * Some companion controllers don't like it when they mix. + */ + down_read(&ehci_cf_port_reset_rwsem); + /* Reset the port */ for (i = 0; i < PORT_RESET_TRIES; i++) { status = set_port_feature(hub->hdev, @@ -1612,7 +1623,7 @@ static int hub_port_reset(struct usb_hub *hub, int port1, usb_set_device_state(udev, status ? USB_STATE_NOTATTACHED : USB_STATE_DEFAULT); - return status; + goto done; } dev_dbg (hub->intfdev, @@ -1625,6 +1636,8 @@ static int hub_port_reset(struct usb_hub *hub, int port1, "Cannot enable port %i. Maybe the USB cable is bad?\n", port1); + done: + up_read(&ehci_cf_port_reset_rwsem); return status; } diff --git a/drivers/usb/host/ehci-hcd.c b/drivers/usb/host/ehci-hcd.c index db00492588b..c1514442883 100644 --- a/drivers/usb/host/ehci-hcd.c +++ b/drivers/usb/host/ehci-hcd.c @@ -570,10 +570,18 @@ static int ehci_run (struct usb_hcd *hcd) * are explicitly handed to companion controller(s), so no TT is * involved with the root hub. (Except where one is integrated, * and there's no companion controller unless maybe for USB OTG.) + * + * Turning on the CF flag will transfer ownership of all ports + * from the companions to the EHCI controller. If any of the + * companions are in the middle of a port reset at the time, it + * could cause trouble. Write-locking ehci_cf_port_reset_rwsem + * guarantees that no resets are in progress. */ + down_write(&ehci_cf_port_reset_rwsem); hcd->state = HC_STATE_RUNNING; ehci_writel(ehci, FLAG_CF, &ehci->regs->configured_flag); ehci_readl(ehci, &ehci->regs->command); /* unblock posted writes */ + up_write(&ehci_cf_port_reset_rwsem); temp = HC_VERSION(ehci_readl(ehci, &ehci->caps->hc_capbase)); ehci_info (ehci, |