thunderbolt: Add MSI-X support

Intel Thunderbolt controllers support up to 16 MSI-X vectors. Using
MSI-X is preferred over MSI or legacy interrupt and may bring additional
performance because there is no need to check the status registers which
interrupt was triggered.

While there we convert comments in structs tb_ring and tb_nhi to follow
kernel-doc format more closely.

This code is based on the work done by Amir Levy and Michael Jamet.

Signed-off-by: Michael Jamet <michael.jamet@intel.com>
Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: Andreas Noever <andreas.noever@gmail.com>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>

1 files changed, 44 insertions, 12 deletions

diff --git a/drivers/thunderbolt/nhi.h b/drivers/thunderbolt/nhi.h
index 317242939b31..630f44140530 100644
--- a/drivers/thunderbolt/nhi.h
+++ b/drivers/thunderbolt/nhi.h
@@ -7,45 +7,75 @@
 #ifndef DSL3510_H_
 #define DSL3510_H_
 
+#include <linux/idr.h>
 #include <linux/mutex.h>
 #include <linux/workqueue.h>
 
 /**
  * struct tb_nhi - thunderbolt native host interface
+ * @lock: Must be held during ring creation/destruction. Is acquired by
+ *	  interrupt_work when dispatching interrupts to individual rings.
+ * @pdev: Pointer to the PCI device
+ * @iobase: MMIO space of the NHI
+ * @tx_rings: All Tx rings available on this host controller
+ * @rx_rings: All Rx rings available on this host controller
+ * @msix_ida: Used to allocate MSI-X vectors for rings
+ * @interrupt_work: Work scheduled to handle ring interrupt when no
+ *		    MSI-X is used.
+ * @hop_count: Number of rings (end point hops) supported by NHI.
  */
 struct tb_nhi {
-	struct mutex lock; /*
-			    * Must be held during ring creation/destruction.
-			    * Is acquired by interrupt_work when dispatching
-			    * interrupts to individual rings.
-			    **/
+	struct mutex lock;
 	struct pci_dev *pdev;
 	void __iomem *iobase;
 	struct tb_ring **tx_rings;
 	struct tb_ring **rx_rings;
+	struct ida msix_ida;
 	struct work_struct interrupt_work;
-	u32 hop_count; /* Number of rings (end point hops) supported by NHI. */
+	u32 hop_count;
 };
 
 /**
  * struct tb_ring - thunderbolt TX or RX ring associated with a NHI
+ * @lock: Lock serializing actions to this ring. Must be acquired after
+ *	  nhi->lock.
+ * @nhi: Pointer to the native host controller interface
+ * @size: Size of the ring
+ * @hop: Hop (DMA channel) associated with this ring
+ * @head: Head of the ring (write next descriptor here)
+ * @tail: Tail of the ring (complete next descriptor here)
+ * @descriptors: Allocated descriptors for this ring
+ * @queue: Queue holding frames to be transferred over this ring
+ * @in_flight: Queue holding frames that are currently in flight
+ * @work: Interrupt work structure
+ * @is_tx: Is the ring Tx or Rx
+ * @running: Is the ring running
+ * @irq: MSI-X irq number if the ring uses MSI-X. %0 otherwise.
+ * @vector: MSI-X vector number the ring uses (only set if @irq is > 0)
+ * @flags: Ring specific flags
  */
 struct tb_ring {
-	struct mutex lock; /* must be acquired after nhi->lock */
+	struct mutex lock;
 	struct tb_nhi *nhi;
 	int size;
 	int hop;
-	int head; /* write next descriptor here */
-	int tail; /* complete next descriptor here */
+	int head;
+	int tail;
 	struct ring_desc *descriptors;
 	dma_addr_t descriptors_dma;
 	struct list_head queue;
 	struct list_head in_flight;
 	struct work_struct work;
-	bool is_tx:1; /* rx otherwise */
+	bool is_tx:1;
 	bool running:1;
+	int irq;
+	u8 vector;
+	unsigned int flags;
 };
 
+/* Leave ring interrupt enabled on suspend */
+#define RING_FLAG_NO_SUSPEND	BIT(0)
+
 struct ring_frame;
 typedef void (*ring_cb)(struct tb_ring*, struct ring_frame*, bool canceled);
 
@@ -64,8 +94,10 @@ struct ring_frame {
 
 #define TB_FRAME_SIZE 0x100    /* minimum size for ring_rx */
 
-struct tb_ring *ring_alloc_tx(struct tb_nhi *nhi, int hop, int size);
-struct tb_ring *ring_alloc_rx(struct tb_nhi *nhi, int hop, int size);
+struct tb_ring *ring_alloc_tx(struct tb_nhi *nhi, int hop, int size,
+			      unsigned int flags);
+struct tb_ring *ring_alloc_rx(struct tb_nhi *nhi, int hop, int size,
+			      unsigned int flags);
 void ring_start(struct tb_ring *ring);
 void ring_stop(struct tb_ring *ring);
 void ring_free(struct tb_ring *ring);