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, 31 insertions, 3 deletions

diff --git a/drivers/usb/host/xhci.h b/drivers/usb/host/xhci.h
index 627092286d1b..36f7d4f91d9f 100644
--- a/drivers/usb/host/xhci.h
+++ b/drivers/usb/host/xhci.h
@@ -620,6 +620,22 @@ struct xhci_input_control_ctx {
 	u32	rsvd2[6];
 };
 
+/* Represents everything that is needed to issue a command on the command ring.
+ * It's useful to pre-allocate these for commands that cannot fail due to
+ * out-of-memory errors, like freeing streams.
+ */
+struct xhci_command {
+	/* Input context for changing device state */
+	struct xhci_container_ctx	*in_ctx;
+	u32				status;
+	/* If completion is null, no one is waiting on this command
+	 * and the structure can be freed after the command completes.
+	 */
+	struct completion		*completion;
+	union xhci_trb			*command_trb;
+	struct list_head		cmd_list;
+};
+
 /* drop context bitmasks */
 #define	DROP_EP(x)	(0x1 << x)
 /* add context bitmasks */
@@ -658,6 +674,7 @@ struct xhci_virt_device {
 	struct completion		cmd_completion;
 	/* Status of the last command issued for this device */
 	u32				cmd_status;
+	struct list_head		cmd_list;
 };
 
 
@@ -920,6 +937,8 @@ union xhci_trb {
  * It must also be greater than 16.
  */
 #define TRBS_PER_SEGMENT	64
+/* Allow two commands + a link TRB, along with any reserved command TRBs */
+#define MAX_RSVD_CMD_TRBS	(TRBS_PER_SEGMENT - 3)
 #define SEGMENT_SIZE		(TRBS_PER_SEGMENT*16)
 /* TRB buffer pointers can't cross 64KB boundaries */
 #define TRB_MAX_BUFF_SHIFT		16
@@ -1040,6 +1059,7 @@ struct xhci_hcd {
 	/* data structures */
 	struct xhci_device_context_array *dcbaa;
 	struct xhci_ring	*cmd_ring;
+	unsigned int		cmd_ring_reserved_trbs;
 	struct xhci_ring	*event_ring;
 	struct xhci_erst	erst;
 	/* Scratchpad */
@@ -1178,12 +1198,20 @@ unsigned int xhci_get_endpoint_flag_from_index(unsigned int ep_index);
 unsigned int xhci_last_valid_endpoint(u32 added_ctxs);
 void xhci_endpoint_zero(struct xhci_hcd *xhci, struct xhci_virt_device *virt_dev, struct usb_host_endpoint *ep);
 void xhci_endpoint_copy(struct xhci_hcd *xhci,
-		struct xhci_virt_device *vdev, unsigned int ep_index);
-void xhci_slot_copy(struct xhci_hcd *xhci, struct xhci_virt_device *vdev);
+		struct xhci_container_ctx *in_ctx,
+		struct xhci_container_ctx *out_ctx,
+		unsigned int ep_index);
+void xhci_slot_copy(struct xhci_hcd *xhci,
+		struct xhci_container_ctx *in_ctx,
+		struct xhci_container_ctx *out_ctx);
 int xhci_endpoint_init(struct xhci_hcd *xhci, struct xhci_virt_device *virt_dev,
 		struct usb_device *udev, struct usb_host_endpoint *ep,
 		gfp_t mem_flags);
 void xhci_ring_free(struct xhci_hcd *xhci, struct xhci_ring *ring);
+struct xhci_command *xhci_alloc_command(struct xhci_hcd *xhci,
+		bool allocate_completion, gfp_t mem_flags);
+void xhci_free_command(struct xhci_hcd *xhci,
+		struct xhci_command *command);
 
 #ifdef CONFIG_PCI
 /* xHCI PCI glue */
@@ -1229,7 +1257,7 @@ int xhci_queue_bulk_tx(struct xhci_hcd *xhci, gfp_t mem_flags, struct urb *urb,
 int xhci_queue_intr_tx(struct xhci_hcd *xhci, gfp_t mem_flags, struct urb *urb,
 		int slot_id, unsigned int ep_index);
 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);
 int xhci_queue_evaluate_context(struct xhci_hcd *xhci, dma_addr_t in_ctx_ptr,
 		u32 slot_id);
 int xhci_queue_reset_ep(struct xhci_hcd *xhci, int slot_id,