xhci_abort_cmd_ring() spins for up to five seconds while waiting for a
register read to show that the command ring is stopped. It is holding
the xhci->spinlock with IRQs disabled, which is not good on xHCI hosts
that share legacy PCI interrupts with other PCI devices.
Make the xhci_abort_cmd_ring() simply return true if we need to wait on
the command ring to stop, and make xhci_cancel_cmd() drop the spinlock
and wait on the command ring, if necessary.
This patch should be backported to stable kernels as old as 3.0, that
contain the commit b92cc66c047ff7cf587b318fe377061a353c120f "xHCI: add
aborting command ring function".
Signed-off-by: Sarah Sharp <sarah.a.sharp@xxxxxxxxxxxxxxx>
Cc: Elric Fu <elricfu1@xxxxxxxxx>
Cc: stable@xxxxxxxxxxxxxxx
---
drivers/usb/host/xhci-ring.c | 71 +++++++++++++++++++++--------------------
1 files changed, 36 insertions(+), 35 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 8828754..0e32e19 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -289,10 +289,10 @@ void xhci_ring_cmd_db(struct xhci_hcd *xhci)
xhci_readl(xhci, &xhci->dba->doorbell[0]);
}
+/* Returns 1 if we need to wait on the command ring stop write. */
static int xhci_abort_cmd_ring(struct xhci_hcd *xhci)
{
u64 temp_64;
- int ret;
xhci_dbg(xhci, "Abort command ring\n");
@@ -311,25 +311,7 @@ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci)
xhci_write_64(xhci, temp_64 | CMD_RING_ABORT,
&xhci->op_regs->cmd_ring);
- /* Section 4.6.1.2 of xHCI 1.0 spec says software should
- * time the completion od all xHCI commands, including
- * the Command Abort operation. If software doesn't see
- * CRR negated in a timely manner (e.g. longer than 5
- * seconds), then it should assume that the there are
- * larger problems with the xHC and assert HCRST.
- */
- ret = xhci_handshake(xhci, &xhci->op_regs->cmd_ring,
- CMD_RING_RUNNING, 0, 5 * 1000 * 1000);
- if (ret < 0) {
- xhci_err(xhci, "Stopped the command ring failed, "
- "maybe the host is dead\n");
- xhci->xhc_state |= XHCI_STATE_DYING;
- xhci_quiesce(xhci);
- xhci_halt(xhci);
- return -ESHUTDOWN;
- }
-
- return 0;
+ return 1;
}
static int xhci_queue_cd(struct xhci_hcd *xhci,
@@ -369,32 +351,51 @@ int xhci_cancel_cmd(struct xhci_hcd *xhci, struct xhci_command *command,
if (xhci->xhc_state & XHCI_STATE_DYING) {
xhci_warn(xhci, "Abort the command ring,"
" but the xHCI is dead.\n");
- retval = -ESHUTDOWN;
- goto fail;
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ return -ESHUTDOWN;
}
/* queue the cmd desriptor to cancel_cmd_list */
retval = xhci_queue_cd(xhci, command, cmd_trb);
if (retval) {
xhci_warn(xhci, "Queuing command descriptor failed.\n");
- goto fail;
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ return retval;
}
-
/* abort command ring */
retval = xhci_abort_cmd_ring(xhci);
- if (retval) {
- xhci_err(xhci, "Abort command ring failed\n");
- if (unlikely(retval == -ESHUTDOWN)) {
- spin_unlock_irqrestore(&xhci->lock, flags);
- usb_hc_died(xhci_to_hcd(xhci)->primary_hcd);
- xhci_dbg(xhci, "xHCI host controller is dead.\n");
- return retval;
- }
- }
+ spin_unlock_irqrestore(&xhci->lock, flags);
+
+ if (!retval)
+ return 0;
+
+ /* Section 4.6.1.2 of xHCI 1.0 spec says software should
+ * time the completion od all xHCI commands, including
+ * the Command Abort operation. If software doesn't see
+ * CRR negated in a timely manner (e.g. longer than 5
+ * seconds), then it should assume that the there are
+ * larger problems with the xHC and assert HCRST.
+ */
+ retval = xhci_handshake(xhci, &xhci->op_regs->cmd_ring,
+ CMD_RING_RUNNING, 0, 5 * 1000 * 1000);
+ if (retval == 0)
+ return 0;
+
+ xhci_err(xhci, "Stopped the command ring failed, "
+ "maybe the host is dead\n");
-fail:
+ spin_lock_irqsave(&xhci->lock, flags);
+ xhci->xhc_state |= XHCI_STATE_DYING;
spin_unlock_irqrestore(&xhci->lock, flags);
- return retval;
+
+ xhci_quiesce(xhci);
+ xhci_halt(xhci);
+
+ xhci_err(xhci, "Abort command ring failed\n");
+ usb_hc_died(xhci_to_hcd(xhci)->primary_hcd);
+ xhci_dbg(xhci, "xHCI host controller is dead.\n");
+
+ return -ESHUTDOWN;
}
void xhci_ring_ep_doorbell(struct xhci_hcd *xhci,
--
1.7.9
--
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