USB: xhci: Change how xHCI commands are handled.

Some commands to the xHCI hardware cannot be allowed to fail due to out of
memory issues or the command ring being full.

Add a way to reserve a TRB on the command ring, and make all command
queueing functions indicate whether they are using a reserved TRB.

Add a way to pre-allocate all the memory a command might need.  A command
needs an input context, a variable to store the status, and (optionally) a
completion for the caller to wait on.  Change all code that assumes the
input device context, status, and completion for a command is stored in
the xhci virtual USB device structure (xhci_virt_device).

Store pending completions in a FIFO in xhci_virt_device.  Make the event
handler for a configure endpoint command check to see whether a pending
command in the list has completed.  We need to use separate input device
contexts for some configure endpoint commands, since multiple drivers can
submit requests at the same time that require a configure endpoint
command.

Signed-off-by: Sarah Sharp <sarah.a.sharp@linux.intel.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@suse.de>

1 files changed, 54 insertions, 14 deletions

diff --git a/drivers/usb/host/xhci-ring.c b/drivers/usb/host/xhci-ring.c
index 6a72d2022b45..a9379b3bebaf 100644
--- a/drivers/usb/host/xhci-ring.c
+++ b/drivers/usb/host/xhci-ring.c
@@ -675,7 +675,8 @@ static void handle_reset_ep_completion(struct xhci_hcd *xhci,
 	if (xhci->quirks & XHCI_RESET_EP_QUIRK) {
 		xhci_dbg(xhci, "Queueing configure endpoint command\n");
 		xhci_queue_configure_endpoint(xhci,
-				xhci->devs[slot_id]->in_ctx->dma, slot_id);
+				xhci->devs[slot_id]->in_ctx->dma, slot_id,
+				false);
 		xhci_ring_cmd_db(xhci);
 	} else {
 		/* Clear our internal halted state and restart the ring */
@@ -691,6 +692,7 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
 	u64 cmd_dma;
 	dma_addr_t cmd_dequeue_dma;
 	struct xhci_input_control_ctx *ctrl_ctx;
+	struct xhci_virt_device *virt_dev;
 	unsigned int ep_index;
 	struct xhci_ring *ep_ring;
 	unsigned int ep_state;
@@ -721,6 +723,25 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
 			xhci_free_virt_device(xhci, slot_id);
 		break;
 	case TRB_TYPE(TRB_CONFIG_EP):
+		virt_dev = xhci->devs[slot_id];
+		/* Check to see if a command in the device's command queue
+		 * matches this one.  Signal the completion or free the command.
+		 */
+		if (!list_empty(&virt_dev->cmd_list)) {
+			struct xhci_command *command;
+			command = list_entry(virt_dev->cmd_list.next,
+					struct xhci_command, cmd_list);
+			if (xhci->cmd_ring->dequeue == command->command_trb) {
+				command->status =
+					GET_COMP_CODE(event->status);
+				list_del(&command->cmd_list);
+				if (command->completion)
+					complete(command->completion);
+				else
+					xhci_free_command(xhci, command);
+			}
+			break;
+		}
 		/*
 		 * Configure endpoint commands can come from the USB core
 		 * configuration or alt setting changes, or because the HW
@@ -729,7 +750,7 @@ static void handle_cmd_completion(struct xhci_hcd *xhci,
 		 * not waiting on the configure endpoint command.
 		 */
 		ctrl_ctx = xhci_get_input_control_ctx(xhci,
-				xhci->devs[slot_id]->in_ctx);
+				virt_dev->in_ctx);
 		/* Input ctx add_flags are the endpoint index plus one */
 		ep_index = xhci_last_valid_endpoint(ctrl_ctx->add_flags) - 1;
 		ep_ring = xhci->devs[slot_id]->eps[ep_index].ring;
@@ -1858,12 +1879,27 @@ int xhci_queue_ctrl_tx(struct xhci_hcd *xhci, gfp_t mem_flags,
 
 /****		Command Ring Operations		****/
 
-/* Generic function for queueing a command TRB on the command ring */
-static int queue_command(struct xhci_hcd *xhci, u32 field1, u32 field2, u32 field3, u32 field4)
+/* Generic function for queueing a command TRB on the command ring.
+ * Check to make sure there's room on the command ring for one command TRB.
+ * Also check that there's room reserved for commands that must not fail.
+ * If this is a command that must not fail, meaning command_must_succeed = TRUE,
+ * then only check for the number of reserved spots.
+ * Don't decrement xhci->cmd_ring_reserved_trbs after we've queued the TRB
+ * because the command event handler may want to resubmit a failed command.
+ */
+static int queue_command(struct xhci_hcd *xhci, u32 field1, u32 field2,
+		u32 field3, u32 field4, bool command_must_succeed)
 {
-	if (!room_on_ring(xhci, xhci->cmd_ring, 1)) {
+	int reserved_trbs = xhci->cmd_ring_reserved_trbs;
+	if (!command_must_succeed)
+		reserved_trbs++;
+
+	if (!room_on_ring(xhci, xhci->cmd_ring, reserved_trbs)) {
 		if (!in_interrupt())
 			xhci_err(xhci, "ERR: No room for command on command ring\n");
+		if (command_must_succeed)
+			xhci_err(xhci, "ERR: Reserved TRB counting for "
+					"unfailable commands failed.\n");
 		return -ENOMEM;
 	}
 	queue_trb(xhci, xhci->cmd_ring, false, field1, field2, field3,
@@ -1874,7 +1910,7 @@ static int queue_command(struct xhci_hcd *xhci, u32 field1, u32 field2, u32 fiel
 /* Queue a no-op command on the command ring */
 static int queue_cmd_noop(struct xhci_hcd *xhci)
 {
-	return queue_command(xhci, 0, 0, 0, TRB_TYPE(TRB_CMD_NOOP));
+	return queue_command(xhci, 0, 0, 0, TRB_TYPE(TRB_CMD_NOOP), false);
 }
 
 /*
@@ -1893,7 +1929,7 @@ void *xhci_setup_one_noop(struct xhci_hcd *xhci)
 int xhci_queue_slot_control(struct xhci_hcd *xhci, u32 trb_type, u32 slot_id)
 {
 	return queue_command(xhci, 0, 0, 0,
-			TRB_TYPE(trb_type) | SLOT_ID_FOR_TRB(slot_id));
+			TRB_TYPE(trb_type) | SLOT_ID_FOR_TRB(slot_id), false);
 }
 
 /* Queue an address device command TRB */
@@ -1902,16 +1938,18 @@ int xhci_queue_address_device(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 {
 	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
 			upper_32_bits(in_ctx_ptr), 0,
-			TRB_TYPE(TRB_ADDR_DEV) | SLOT_ID_FOR_TRB(slot_id));
+			TRB_TYPE(TRB_ADDR_DEV) | SLOT_ID_FOR_TRB(slot_id),
+			false);
 }
 
 /* Queue a configure endpoint command TRB */
 int xhci_queue_configure_endpoint(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
-		u32 slot_id)
+		u32 slot_id, bool command_must_succeed)
 {
 	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
 			upper_32_bits(in_ctx_ptr), 0,
-			TRB_TYPE(TRB_CONFIG_EP) | SLOT_ID_FOR_TRB(slot_id));
+			TRB_TYPE(TRB_CONFIG_EP) | SLOT_ID_FOR_TRB(slot_id),
+			command_must_succeed);
 }
 
 /* Queue an evaluate context command TRB */
@@ -1920,7 +1958,8 @@ int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 {
 	return queue_command(xhci, lower_32_bits(in_ctx_ptr),
 			upper_32_bits(in_ctx_ptr), 0,
-			TRB_TYPE(TRB_EVAL_CONTEXT) | SLOT_ID_FOR_TRB(slot_id));
+			TRB_TYPE(TRB_EVAL_CONTEXT) | SLOT_ID_FOR_TRB(slot_id),
+			false);
 }
 
 int xhci_queue_stop_endpoint(struct xhci_hcd *xhci, int slot_id,
@@ -1931,7 +1970,7 @@ int xhci_queue_stop_endpoint(struct xhci_hcd *xhci, int slot_id,
 	u32 type = TRB_TYPE(TRB_STOP_RING);
 
 	return queue_command(xhci, 0, 0, 0,
-			trb_slot_id | trb_ep_index | type);
+			trb_slot_id | trb_ep_index | type, false);
 }
 
 /* Set Transfer Ring Dequeue Pointer command.
@@ -1955,7 +1994,7 @@ static int queue_set_tr_deq(struct xhci_hcd *xhci, int slot_id,
 	}
 	return queue_command(xhci, lower_32_bits(addr) | cycle_state,
 			upper_32_bits(addr), 0,
-			trb_slot_id | trb_ep_index | type);
+			trb_slot_id | trb_ep_index | type, false);
 }
 
 int xhci_queue_reset_ep(struct xhci_hcd *xhci, int slot_id,
@@ -1965,5 +2004,6 @@ int xhci_queue_reset_ep(struct xhci_hcd *xhci, int slot_id,
 	u32 trb_ep_index = EP_ID_FOR_TRB(ep_index);
 	u32 type = TRB_TYPE(TRB_RESET_EP);
 
-	return queue_command(xhci, 0, 0, 0, trb_slot_id | trb_ep_index | type);
+	return queue_command(xhci, 0, 0, 0, trb_slot_id | trb_ep_index | type,
+			false);
 }