xhci: rework command timeout and cancellation,

Use one timer to control command timeout.

start/kick the timer every time a command is completed and a
new command is waiting, or a new command is added to a empty list.

If the timer runs out, then tag the current command as "aborted", and
start the xhci command abortion process.

Previously each function that submitted a command had its own timer.
If that command timed out, a new command structure for the
command was created and it was put on a cancel_cmd_list list,
then a pci write to abort the command ring was issued.

when the ring was aborted, it checked if the current command
was the one to be canceled, later when the ring was stopped the
driver got ownership of the TRBs in the command ring,
compared then to the TRBs in the cancel_cmd_list,
and turned them into No-ops.

Now, instead, at timeout we tag the status of the command in the
command queue to be aborted, and start the ring abortion.
Ring abortion stops the command ring and gives control of the
commands to us.
All the aborted commands are now turned into No-ops.

If the ring is already stopped when the command times outs its not possible
to start the ring abortion, in this case the command is turnd to No-op
right away.

All these changes allows us to remove the entire cancel_cmd_list code.

The functions waiting for a command to finish no longer have their own timeouts.
They will wait either until the command completes normally,
or until the whole command abortion is done.

Signed-off-by: Mathias Nyman <mathias.nyman@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 128 insertions, 250 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 3d60865a3d8f..d67ff71209f5 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -287,17 +287,7 @@ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci)
 
         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);
@@ -323,71 +313,6 @@ static int xhci_abort_cmd_ring(struct xhci_hcd *xhci)
         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,
@@ -1206,164 +1131,6 @@ static void xhci_handle_cmd_reset_ep(struct xhci_hcd *xhci, int slot_id,
         }
 }
 
-/* Complete the command and detele it from the devcie's command queue.
- */
-static void xhci_complete_cmd_in_cmd_wait_list(struct xhci_hcd *xhci,
-                struct xhci_command *command, u32 status)
-{
-        command->status = status;
-        list_del(&command->cmd_list);
-        if (command->completion)
-                complete(command->completion);
-        else
-                xhci_free_command(xhci, command);
-}
-
-
-/*
- * Finding the command trb need to be cancelled and modifying it to
- * NO OP command. And if the command is in device's command wait
- * list, finishing and freeing it.
- *
- * If we can't find the command trb, we think it had already been
- * executed.
- */
-static void xhci_cmd_to_noop(struct xhci_hcd *xhci, struct xhci_cd *cur_cd)
-{
-        struct xhci_segment *cur_seg;
-        union xhci_trb *cmd_trb;
-        u32 cycle_state;
-
-        if (xhci->cmd_ring->dequeue == xhci->cmd_ring->enqueue)
-                return;
-
-        /* find the current segment of command ring */
-        cur_seg = find_trb_seg(xhci->cmd_ring->first_seg,
-                        xhci->cmd_ring->dequeue, &cycle_state);
-
-        if (!cur_seg) {
-                xhci_warn(xhci, "Command ring mismatch, dequeue = %p %llx (dma)\n",
-                                xhci->cmd_ring->dequeue,
-                                (unsigned long long)
-                                xhci_trb_virt_to_dma(xhci->cmd_ring->deq_seg,
-                                        xhci->cmd_ring->dequeue));
-                xhci_debug_ring(xhci, xhci->cmd_ring);
-                xhci_dbg_ring_ptrs(xhci, xhci->cmd_ring);
-                return;
-        }
-
-        /* find the command trb matched by cd from command ring */
-        for (cmd_trb = xhci->cmd_ring->dequeue;
-                        cmd_trb != xhci->cmd_ring->enqueue;
-                        next_trb(xhci, xhci->cmd_ring, &cur_seg, &cmd_trb)) {
-                /* If the trb is link trb, continue */
-                if (TRB_TYPE_LINK_LE32(cmd_trb->generic.field[3]))
-                        continue;
-
-                if (cur_cd->cmd_trb == cmd_trb) {
-
-                        /* If the command in device's command list, we should
-                         * finish it and free the command structure.
-                         */
-                        if (cur_cd->command)
-                                xhci_complete_cmd_in_cmd_wait_list(xhci,
-                                        cur_cd->command, COMP_CMD_STOP);
-
-                        /* get cycle state from the origin command trb */
-                        cycle_state = le32_to_cpu(cmd_trb->generic.field[3])
-                                & TRB_CYCLE;
-
-                        /* modify the command trb to NO OP command */
-                        cmd_trb->generic.field[0] = 0;
-                        cmd_trb->generic.field[1] = 0;
-                        cmd_trb->generic.field[2] = 0;
-                        cmd_trb->generic.field[3] = cpu_to_le32(
-                                        TRB_TYPE(TRB_CMD_NOOP) | cycle_state);
-                        break;
-                }
-        }
-}
-
-static void xhci_cancel_cmd_in_cd_list(struct xhci_hcd *xhci)
-{
-        struct xhci_cd *cur_cd, *next_cd;
-
-        if (list_empty(&xhci->cancel_cmd_list))
-                return;
-
-        list_for_each_entry_safe(cur_cd, next_cd,
-                        &xhci->cancel_cmd_list, cancel_cmd_list) {
-                xhci_cmd_to_noop(xhci, cur_cd);
-                list_del(&cur_cd->cancel_cmd_list);
-                kfree(cur_cd);
-        }
-}
-
-/*
- * traversing the cancel_cmd_list. If the command descriptor according
- * to cmd_trb is found, the function free it and return 1, otherwise
- * return 0.
- */
-static int xhci_search_cmd_trb_in_cd_list(struct xhci_hcd *xhci,
-                union xhci_trb *cmd_trb)
-{
-        struct xhci_cd *cur_cd, *next_cd;
-
-        if (list_empty(&xhci->cancel_cmd_list))
-                return 0;
-
-        list_for_each_entry_safe(cur_cd, next_cd,
-                        &xhci->cancel_cmd_list, cancel_cmd_list) {
-                if (cur_cd->cmd_trb == cmd_trb) {
-                        if (cur_cd->command)
-                                xhci_complete_cmd_in_cmd_wait_list(xhci,
-                                        cur_cd->command, COMP_CMD_STOP);
-                        list_del(&cur_cd->cancel_cmd_list);
-                        kfree(cur_cd);
-                        return 1;
-                }
-        }
-
-        return 0;
-}
-
-/*
- * If the cmd_trb_comp_code is COMP_CMD_ABORT, we just check whether the
- * trb pointed by the command ring dequeue pointer is the trb we want to
- * cancel or not. And if the cmd_trb_comp_code is COMP_CMD_STOP, we will
- * traverse the cancel_cmd_list to trun the all of the commands according
- * to command descriptor to NO-OP trb.
- */
-static int handle_stopped_cmd_ring(struct xhci_hcd *xhci,
-                int cmd_trb_comp_code)
-{
-        int cur_trb_is_good = 0;
-
-        /* Searching the cmd trb pointed by the command ring dequeue
-         * pointer in command descriptor list. If it is found, free it.
-         */
-        cur_trb_is_good = xhci_search_cmd_trb_in_cd_list(xhci,
-                        xhci->cmd_ring->dequeue);
-
-        if (cmd_trb_comp_code == COMP_CMD_ABORT)
-                xhci->cmd_ring_state = CMD_RING_STATE_STOPPED;
-        else if (cmd_trb_comp_code == COMP_CMD_STOP) {
-                /* traversing the cancel_cmd_list and canceling
-                 * the command according to command descriptor
-                 */
-                xhci_cancel_cmd_in_cd_list(xhci);
-
-                xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;
-                /*
-                 * ring command ring doorbell again to restart the
-                 * command ring
-                 */
-                if (xhci->cmd_ring->dequeue != xhci->cmd_ring->enqueue)
-                        xhci_ring_cmd_db(xhci);
-        }
-        return cur_trb_is_good;
-}
-
 static void xhci_handle_cmd_enable_slot(struct xhci_hcd *xhci, int slot_id,
                 u32 cmd_comp_code)
 {
@@ -1480,6 +1247,97 @@ void xhci_cleanup_command_queue(struct xhci_hcd *xhci)
                 xhci_complete_del_and_free_cmd(cur_cmd, COMP_CMD_ABORT);
 }
 
+/*
+ * Turn all commands on command ring with status set to "aborted" to no-op trbs.
+ * If there are other commands waiting then restart the ring and kick the timer.
+ * This must be called with command ring stopped and xhci->lock held.
+ */
+static void xhci_handle_stopped_cmd_ring(struct xhci_hcd *xhci,
+                                         struct xhci_command *cur_cmd)
+{
+        struct xhci_command *i_cmd, *tmp_cmd;
+        u32 cycle_state;
+
+        /* Turn all aborted commands in list to no-ops, then restart */
+        list_for_each_entry_safe(i_cmd, tmp_cmd, &xhci->cmd_list,
+                                 cmd_list) {
+
+                if (i_cmd->status != COMP_CMD_ABORT)
+                        continue;
+
+                i_cmd->status = COMP_CMD_STOP;
+
+                xhci_dbg(xhci, "Turn aborted command %p to no-op\n",
+                         i_cmd->command_trb);
+                /* get cycle state from the original cmd trb */
+                cycle_state = le32_to_cpu(
+                        i_cmd->command_trb->generic.field[3]) & TRB_CYCLE;
+                /* modify the command trb to no-op command */
+                i_cmd->command_trb->generic.field[0] = 0;
+                i_cmd->command_trb->generic.field[1] = 0;
+                i_cmd->command_trb->generic.field[2] = 0;
+                i_cmd->command_trb->generic.field[3] = cpu_to_le32(
+                        TRB_TYPE(TRB_CMD_NOOP) | cycle_state);
+
+                /*
+                 * caller waiting for completion is called when command
+                 *  completion event is received for these no-op commands
+                 */
+        }
+
+        xhci->cmd_ring_state = CMD_RING_STATE_RUNNING;
+
+        /* ring command ring doorbell to restart the command ring */
+        if ((xhci->cmd_ring->dequeue != xhci->cmd_ring->enqueue) &&
+            !(xhci->xhc_state & XHCI_STATE_DYING)) {
+                xhci->current_cmd = cur_cmd;
+                mod_timer(&xhci->cmd_timer, jiffies + XHCI_CMD_DEFAULT_TIMEOUT);
+                xhci_ring_cmd_db(xhci);
+        }
+        return;
+}
+
+
+void xhci_handle_command_timeout(unsigned long data)
+{
+        struct xhci_hcd *xhci;
+        int ret;
+        unsigned long flags;
+        u64 hw_ring_state;
+        struct xhci_command *cur_cmd = NULL;
+        xhci = (struct xhci_hcd *) data;
+
+        /* mark this command to be cancelled */
+        spin_lock_irqsave(&xhci->lock, flags);
+        if (xhci->current_cmd) {
+                cur_cmd = xhci->current_cmd;
+                cur_cmd->status = COMP_CMD_ABORT;
+        }
+
+
+        /* Make sure command ring is running before aborting it */
+        hw_ring_state = xhci_read_64(xhci, &xhci->op_regs->cmd_ring);
+        if ((xhci->cmd_ring_state & CMD_RING_STATE_RUNNING) &&
+            (hw_ring_state & CMD_RING_RUNNING))  {
+
+                spin_unlock_irqrestore(&xhci->lock, flags);
+                xhci_dbg(xhci, "Command timeout\n");
+                ret = xhci_abort_cmd_ring(xhci);
+                if (unlikely(ret == -ESHUTDOWN)) {
+                        xhci_err(xhci, "Abort command ring failed\n");
+                        xhci_cleanup_command_queue(xhci);
+                        usb_hc_died(xhci_to_hcd(xhci)->primary_hcd);
+                        xhci_dbg(xhci, "xHCI host controller is dead.\n");
+                }
+                return;
+        }
+        /* command timeout on stopped ring, ring can't be aborted */
+        xhci_dbg(xhci, "Command timeout on stopped ring\n");
+        xhci_handle_stopped_cmd_ring(xhci, xhci->current_cmd);
+        spin_unlock_irqrestore(&xhci->lock, flags);
+        return;
+}
+
 static void handle_cmd_completion(struct xhci_hcd *xhci,
                 struct xhci_event_cmd *event)
 {
@@ -1513,26 +1371,28 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
                          "Command completion event does not match command\n");
                 return;
         }
+
+        del_timer(&xhci->cmd_timer);
+
         trace_xhci_cmd_completion(cmd_trb, (struct xhci_generic_trb *) event);
 
         cmd_comp_code = GET_COMP_CODE(le32_to_cpu(event->status));
-        if (cmd_comp_code == COMP_CMD_ABORT || cmd_comp_code == COMP_CMD_STOP) {
-                /* If the return value is 0, we think the trb pointed by
-                 * command ring dequeue pointer is a good trb. The good
-                 * trb means we don't want to cancel the trb, but it have
-                 * been stopped by host. So we should handle it normally.
-                 * Otherwise, driver should invoke inc_deq() and return.
-                 */
-                if (handle_stopped_cmd_ring(xhci, cmd_comp_code)) {
-                        inc_deq(xhci, xhci->cmd_ring);
-                        return;
-                }
-                /* There is no command to handle if we get a stop event when the
-                 * command ring is empty, event->cmd_trb points to the next
-                 * unset command
-                 */
-                if (xhci->cmd_ring->dequeue == xhci->cmd_ring->enqueue)
-                        return;
+
+        /* If CMD ring stopped we own the trbs between enqueue and dequeue */
+        if (cmd_comp_code == COMP_CMD_STOP) {
+                xhci_handle_stopped_cmd_ring(xhci, cmd);
+                return;
+        }
+        /*
+         * Host aborted the command ring, check if the current command was
+         * supposed to be aborted, otherwise continue normally.
+         * The command ring is stopped now, but the xHC will issue a Command
+         * Ring Stopped event which will cause us to restart it.
+         */
+        if (cmd_comp_code == COMP_CMD_ABORT) {
+                xhci->cmd_ring_state = CMD_RING_STATE_STOPPED;
+                if (cmd->status == COMP_CMD_ABORT)
+                        goto event_handled;
         }
 
         cmd_type = TRB_FIELD_TO_TYPE(le32_to_cpu(cmd_trb->generic.field[3]));
@@ -1563,6 +1423,9 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
                 xhci_handle_cmd_set_deq(xhci, slot_id, cmd_trb, cmd_comp_code);
                 break;
         case TRB_CMD_NOOP:
+                /* Is this an aborted command turned to NO-OP? */
+                if (cmd->status == COMP_CMD_STOP)
+                        cmd_comp_code = COMP_CMD_STOP;
                 break;
         case TRB_RESET_EP:
                 WARN_ON(slot_id != TRB_TO_SLOT_ID(
@@ -1583,6 +1446,14 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
                 break;
         }
 
+        /* restart timer if this wasn't the last command */
+        if (cmd->cmd_list.next != &xhci->cmd_list) {
+                xhci->current_cmd = list_entry(cmd->cmd_list.next,
+                                               struct xhci_command, cmd_list);
+                mod_timer(&xhci->cmd_timer, jiffies + XHCI_CMD_DEFAULT_TIMEOUT);
+        }
+
+event_handled:
         xhci_complete_del_and_free_cmd(cmd, cmd_comp_code);
 
         inc_deq(xhci, xhci->cmd_ring);
@@ -3988,6 +3859,13 @@ static int queue_command(struct xhci_hcd *xhci, struct xhci_command *cmd,
         cmd->command_trb = xhci->cmd_ring->enqueue;
         list_add_tail(&cmd->cmd_list, &xhci->cmd_list);
 
+        /* if there are no other commands queued we start the timeout timer */
+        if (xhci->cmd_list.next == &cmd->cmd_list &&
+            !timer_pending(&xhci->cmd_timer)) {
+                xhci->current_cmd = cmd;
+                mod_timer(&xhci->cmd_timer, jiffies + XHCI_CMD_DEFAULT_TIMEOUT);
+        }
+
         queue_trb(xhci, xhci->cmd_ring, false, field1, field2, field3,
                         field4 | xhci->cmd_ring->cycle_state);
         return 0;