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authorElric Fu <elricfu1@gmail.com>2012-06-27 16:31:12 +0800
committerGreg Kroah-Hartman <gregkh@linuxfoundation.org>2012-10-28 10:02:14 -0700
commitbc47204b268516ae4085ebdc81a34ddda71b77c4 (patch)
treec2adf3cab42a559fe127dff07ea031210a4acb11 /drivers/usb/host/xhci-ring.c
parentc76e4de05c23fea3d6ad6df63876a9397dd7c85a (diff)
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xHCI: add aborting command ring function
commit b92cc66c047ff7cf587b318fe377061a353c120f upstream. Software have to abort command ring and cancel command when a command is failed or hang. Otherwise, the command ring will hang up and can't handle the others. An example of a command that may hang is the Address Device Command, because waiting for a SET_ADDRESS request to be acknowledged by a USB device is outside of the xHC's ability to control. To cancel a command, software will initialize a command descriptor for the cancel command, and add it into a cancel_cmd_list of xhci. Sarah: Fixed missing newline on "Have the command ring been stopped?" debugging statement. This patch should be backported to kernels as old as 3.0, that contain the commit 7ed603ecf8b68ab81f4c83097d3063d43ec73bb8 "xhci: Add an assertion to check for virt_dev=0 bug." That commit papers over a NULL pointer dereference, and this patch fixes the underlying issue that caused the NULL pointer dereference. Signed-off-by: Elric Fu <elricfu1@gmail.com> Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com> Tested-by: Miroslav Sabljic <miroslav.sabljic@avl.com> Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
Diffstat (limited to 'drivers/usb/host/xhci-ring.c')
-rw-r--r--drivers/usb/host/xhci-ring.c108
1 files changed, 108 insertions, 0 deletions
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 4027779..058004b 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -320,6 +320,114 @@ void xhci_ring_cmd_db(struct xhci_hcd *xhci)
xhci_readl(xhci, &xhci->dba->doorbell[0]);
}
+static int xhci_abort_cmd_ring(struct xhci_hcd *xhci)
+{
+ u64 temp_64;
+ int ret;
+
+ xhci_dbg(xhci, "Abort command ring\n");
+
+ if (!(xhci->cmd_ring_state & CMD_RING_STATE_RUNNING)) {
+ xhci_dbg(xhci, "The command ring isn't running, "
+ "Have the command ring been stopped?\n");
+ return 0;
+ }
+
+ temp_64 = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
+ if (!(temp_64 & CMD_RING_RUNNING)) {
+ xhci_dbg(xhci, "Command ring had been stopped\n");
+ return 0;
+ }
+ xhci->cmd_ring_state = CMD_RING_STATE_ABORTED;
+ 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 = 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;
+}
+
+static int xhci_queue_cd(struct xhci_hcd *xhci,
+ struct xhci_command *command,
+ union xhci_trb *cmd_trb)
+{
+ struct xhci_cd *cd;
+ cd = kzalloc(sizeof(struct xhci_cd), GFP_ATOMIC);
+ if (!cd)
+ return -ENOMEM;
+ INIT_LIST_HEAD(&cd->cancel_cmd_list);
+
+ cd->command = command;
+ cd->cmd_trb = cmd_trb;
+ list_add_tail(&cd->cancel_cmd_list, &xhci->cancel_cmd_list);
+
+ return 0;
+}
+
+/*
+ * Cancel the command which has issue.
+ *
+ * Some commands may hang due to waiting for acknowledgement from
+ * usb device. It is outside of the xHC's ability to control and
+ * will cause the command ring is blocked. When it occurs software
+ * should intervene to recover the command ring.
+ * See Section 4.6.1.1 and 4.6.1.2
+ */
+int xhci_cancel_cmd(struct xhci_hcd *xhci, struct xhci_command *command,
+ union xhci_trb *cmd_trb)
+{
+ int retval = 0;
+ unsigned long flags;
+
+ spin_lock_irqsave(&xhci->lock, flags);
+
+ if (xhci->xhc_state & XHCI_STATE_DYING) {
+ xhci_warn(xhci, "Abort the command ring,"
+ " but the xHCI is dead.\n");
+ retval = -ESHUTDOWN;
+ goto fail;
+ }
+
+ /* 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;
+ }
+
+ /* 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;
+ }
+ }
+
+fail:
+ spin_unlock_irqrestore(&xhci->lock, flags);
+ return retval;
+}
+
void xhci_ring_ep_doorbell(struct xhci_hcd *xhci,
unsigned int slot_id,
unsigned int ep_index,