This commit adds a bit-array to xhci bus_state for keeping track of
which ports are undergoing a resume transition. If any of the bits
are set when xhci_hub_status_data() is called, the routine will return
a non-zero value even if no ports have any status changes pending.
This will allow usbcore to handle races between root-hub suspend and
port wakeup.
Signed-off-by: Andiry Xu <andiry.xu@xxxxxxx>
Cc: Alan Stern <stern@xxxxxxxxxxxxxxxxxxx>
---
drivers/usb/host/xhci-hub.c | 22 ++++++++++++----------
drivers/usb/host/xhci-ring.c | 1 +
drivers/usb/host/xhci.c | 12 ++++++++++--
drivers/usb/host/xhci.h | 2 ++
4 files changed, 25 insertions(+), 12 deletions(-)
diff --git a/drivers/usb/host/xhci-hub.c b/drivers/usb/host/xhci-hub.c
index 673ad12..89850a8 100644
--- a/drivers/usb/host/xhci-hub.c
+++ b/drivers/usb/host/xhci-hub.c
@@ -558,6 +558,7 @@ int xhci_hub_control(struct usb_hcd *hcd, u16 typeReq, u16 wValue,
xhci_dbg(xhci, "Resume USB2 port %d\n",
wIndex + 1);
bus_state->resume_done[wIndex] = 0;
+ clear_bit(wIndex, &bus_state->resuming_ports);
xhci_set_link_state(xhci, port_array, wIndex,
XDEV_U0);
xhci_dbg(xhci, "set port %d resume\n",
@@ -845,7 +846,12 @@ int xhci_hub_status_data(struct usb_hcd *hcd, char *buf)
/* Initial status is no changes */
retval = (max_ports + 8) / 8;
memset(buf, 0, retval);
- status = 0;
+
+ /*
+ * Inform the usbcore about resume-in-progress by returning
+ * a non-zero value even if there are no status changes.
+ */
+ status = bus_state->resuming_ports;
mask = PORT_CSC | PORT_PEC | PORT_OCC | PORT_PLC | PORT_WRC;
@@ -885,15 +891,11 @@ int xhci_bus_suspend(struct usb_hcd *hcd)
spin_lock_irqsave(&xhci->lock, flags);
if (hcd->self.root_hub->do_remote_wakeup) {
- port_index = max_ports;
- while (port_index--) {
- if (bus_state->resume_done[port_index] != 0) {
- spin_unlock_irqrestore(&xhci->lock, flags);
- xhci_dbg(xhci, "suspend failed because "
- "port %d is resuming\n",
- port_index + 1);
- return -EBUSY;
- }
+ if (bus_state->resuming_ports) {
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ xhci_dbg(xhci, "suspend failed because "
+ "a port is resuming\n");
+ return -EBUSY;
}
}
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 3d9422f..cb1de11 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1377,6 +1377,7 @@ static void handle_port_status(struct xhci_hcd *xhci,
xhci_dbg(xhci, "resume HS port %d\n", port_id);
bus_state->resume_done[faked_port_index] = jiffies +
msecs_to_jiffies(20);
+ set_bit(faked_port_index, &bus_state->resuming_ports);
mod_timer(&hcd->rh_timer,
bus_state->resume_done[faked_port_index]);
/* Do the rest in GetPortStatus */
diff --git a/drivers/usb/host/xhci.c b/drivers/usb/host/xhci.c
index 36641a7..5910048 100644
--- a/drivers/usb/host/xhci.c
+++ b/drivers/usb/host/xhci.c
@@ -152,7 +152,7 @@ int xhci_reset(struct xhci_hcd *xhci)
{
u32 command;
u32 state;
- int ret;
+ int ret, i;
state = xhci_readl(xhci, &xhci->op_regs->status);
if ((state & STS_HALT) == 0) {
@@ -175,7 +175,15 @@ int xhci_reset(struct xhci_hcd *xhci)
* xHCI cannot write to any doorbells or operational registers other
* than status until the "Controller Not Ready" flag is cleared.
*/
- return handshake(xhci, &xhci->op_regs->status, STS_CNR, 0, 250 * 1000);
+ ret = handshake(xhci, &xhci->op_regs->status, STS_CNR, 0, 250 * 1000);
+
+ for (i = 0; i < 2; ++i) {
+ xhci->bus_state[i].port_c_suspend = 0;
+ xhci->bus_state[i].suspended_ports = 0;
+ xhci->bus_state[i].resuming_ports = 0;
+ }
+
+ return ret;
}
#ifdef CONFIG_PCI
diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 3d69c4b..ce1edd7 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -1362,6 +1362,8 @@ struct xhci_bus_state {
u32 suspended_ports;
u32 port_remote_wakeup;
unsigned long resume_done[USB_MAXCHILDREN];
+ /* which ports have started to resume */
+ unsigned long resuming_ports;
};
static inline unsigned int hcd_index(struct usb_hcd *hcd)
--
1.7.4.1
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