According to xHCI spec section 4.6.1.1 and section 4.6.1.2,
after aborting a command on the command ring, xHC will
generate a command completion event with its completion
code set to Command Ring Stopped at least. If a command is
currently executing at the time of aborting a command, xHC
also generate a command completion event with its completion
code set to Command Abort. When the command ring is stopped,
software may remove, add, or rearrage Command Descriptors.
To cancel a command, software will initialize a command
descriptor for the cancel command, and add it into a
cancel_cmd_list of xhci. When the command ring is stopped,
software will find the command trbs described by command
descriptors in cancel_cmd_list and modify it to No Op
command. If software can't find the matched trbs, we can
think it had been finished.
Signed-off-by: Elric Fu <elricfu1@xxxxxxxxx>
---
drivers/usb/host/xhci-ring.c | 171 ++++++++++++++++++++++++++++++++++++++++--
1 files changed, 165 insertions(+), 6 deletions(-)
diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index aa514cc..9aec89f 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -1151,6 +1151,20 @@ static void handle_reset_ep_completion(struct xhci_hcd *xhci,
}
}
+/* 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);
+}
+
+
/* Check to see if a command in the device's command queue matches this one.
* Signal the completion or free the command, and return 1. Return 0 if the
* completed command isn't at the head of the command list.
@@ -1169,15 +1183,144 @@ static int handle_cmd_in_cmd_wait_list(struct xhci_hcd *xhci,
if (xhci->cmd_ring->dequeue != command->command_trb)
return 0;
- command->status = GET_COMP_CODE(le32_to_cpu(event->status));
- list_del(&command->cmd_list);
- if (command->completion)
- complete(command->completion);
- else
- xhci_free_command(xhci, command);
+ xhci_complete_cmd_in_cmd_wait_list(xhci, command,
+ GET_COMP_CODE(le32_to_cpu(event->status)));
return 1;
}
+/*
+ * 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);
+
+ /* 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 handle_cmd_completion(struct xhci_hcd *xhci,
struct xhci_event_cmd *event)
{
@@ -1203,6 +1346,22 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
xhci->error_bitmask |= 1 << 5;
return;
}
+
+ if ((GET_COMP_CODE(le32_to_cpu(event->status)) == COMP_CMD_ABORT) ||
+ (GET_COMP_CODE(le32_to_cpu(event->status)) == 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,
+ GET_COMP_CODE(le32_to_cpu(event->status)))) {
+ inc_deq(xhci, xhci->cmd_ring);
+ return;
+ }
+ }
+
switch (le32_to_cpu(xhci->cmd_ring->dequeue->generic.field[3])
& TRB_TYPE_BITMASK) {
case TRB_TYPE(TRB_ENABLE_SLOT):
--
1.7.9.1
--
To unsubscribe from this list: send the line "unsubscribe linux-usb" in
the body of a message to majordomo@xxxxxxxxxxxxxxx
More majordomo info at http://vger.kernel.org/majordomo-info.html
