thunderbolt: Export ring handling functions to modules

These are used by Thunderbolt services to send and receive frames over
the high-speed DMA rings.

We also put the functions to tb_ namespace to make sure we do not
collide with others and add missing kernel-doc comments for the exported
functions.

Signed-off-by: Mika Westerberg <mika.westerberg@linux.intel.com>
Reviewed-by: Michael Jamet <michael.jamet@intel.com>
Reviewed-by: Yehezkel Bernat <yehezkel.bernat@intel.com>
Reviewed-by: Andy Shevchenko <andriy.shevchenko@linux.intel.com>
Signed-off-by: David S. Miller <davem@davemloft.net>

1 files changed, 158 insertions, 0 deletions

diff --git a/include/linux/thunderbolt.h b/include/linux/thunderbolt.h
index 18c0e3d5e85c..9ddb83ad890f 100644
--- a/include/linux/thunderbolt.h
+++ b/include/linux/thunderbolt.h
@@ -15,10 +15,12 @@
 #define THUNDERBOLT_H_
 
 #include <linux/device.h>
+#include <linux/idr.h>
 #include <linux/list.h>
 #include <linux/mutex.h>
 #include <linux/mod_devicetable.h>
 #include <linux/uuid.h>
+#include <linux/workqueue.h>
 
 enum tb_cfg_pkg_type {
 	TB_CFG_PKG_READ = 1,
@@ -397,4 +399,160 @@ static inline struct tb_xdomain *tb_service_parent(struct tb_service *svc)
 	return tb_to_xdomain(svc->dev.parent);
 }
 
+/**
+ * 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
+ * @going_away: The host controller device is about to disappear so when
+ *		this flag is set, avoid touching the hardware anymore.
+ * @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;
+	struct pci_dev *pdev;
+	void __iomem *iobase;
+	struct tb_ring **tx_rings;
+	struct tb_ring **rx_rings;
+	struct ida msix_ida;
+	bool going_away;
+	struct work_struct interrupt_work;
+	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
+ * @sof_mask: Bit mask used to detect start of frame PDF
+ * @eof_mask: Bit mask used to detect end of frame PDF
+ */
+struct tb_ring {
+	struct mutex lock;
+	struct tb_nhi *nhi;
+	int size;
+	int hop;
+	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;
+	bool running:1;
+	int irq;
+	u8 vector;
+	unsigned int flags;
+	u16 sof_mask;
+	u16 eof_mask;
+};
+
+/* Leave ring interrupt enabled on suspend */
+#define RING_FLAG_NO_SUSPEND	BIT(0)
+/* Configure the ring to be in frame mode */
+#define RING_FLAG_FRAME		BIT(1)
+/* Enable end-to-end flow control */
+#define RING_FLAG_E2E		BIT(2)
+
+struct ring_frame;
+typedef void (*ring_cb)(struct tb_ring *, struct ring_frame *, bool canceled);
+
+/**
+ * struct ring_frame - For use with ring_rx/ring_tx
+ * @buffer_phy: DMA mapped address of the frame
+ * @callback: Callback called when the frame is finished
+ * @list: Frame is linked to a queue using this
+ * @size: Size of the frame in bytes (%0 means %4096)
+ * @flags: Flags for the frame (see &enum ring_desc_flags)
+ * @eof: End of frame protocol defined field
+ * @sof: Start of frame protocol defined field
+ */
+struct ring_frame {
+	dma_addr_t buffer_phy;
+	ring_cb callback;
+	struct list_head list;
+	u32 size:12;
+	u32 flags:12;
+	u32 eof:4;
+	u32 sof:4;
+};
+
+/* Minimum size for ring_rx */
+#define TB_FRAME_SIZE		0x100
+
+struct tb_ring *tb_ring_alloc_tx(struct tb_nhi *nhi, int hop, int size,
+				 unsigned int flags);
+struct tb_ring *tb_ring_alloc_rx(struct tb_nhi *nhi, int hop, int size,
+				 unsigned int flags, u16 sof_mask,
+				 u16 eof_mask);
+void tb_ring_start(struct tb_ring *ring);
+void tb_ring_stop(struct tb_ring *ring);
+void tb_ring_free(struct tb_ring *ring);
+
+int __tb_ring_enqueue(struct tb_ring *ring, struct ring_frame *frame);
+
+/**
+ * tb_ring_rx() - enqueue a frame on an RX ring
+ * @ring: Ring to enqueue the frame
+ * @frame: Frame to enqueue
+ *
+ * @frame->buffer, @frame->buffer_phy and @frame->callback have to be set. The
+ * buffer must contain at least %TB_FRAME_SIZE bytes.
+ *
+ * @frame->callback will be invoked with @frame->size, @frame->flags,
+ * @frame->eof, @frame->sof set once the frame has been received.
+ *
+ * If ring_stop() is called after the packet has been enqueued
+ * @frame->callback will be called with canceled set to true.
+ *
+ * Return: Returns %-ESHUTDOWN if ring_stop has been called. Zero otherwise.
+ */
+static inline int tb_ring_rx(struct tb_ring *ring, struct ring_frame *frame)
+{
+	WARN_ON(ring->is_tx);
+	return __tb_ring_enqueue(ring, frame);
+}
+
+/**
+ * tb_ring_tx() - enqueue a frame on an TX ring
+ * @ring: Ring the enqueue the frame
+ * @frame: Frame to enqueue
+ *
+ * @frame->buffer, @frame->buffer_phy, @frame->callback, @frame->size,
+ * @frame->eof and @frame->sof have to be set.
+ *
+ * @frame->callback will be invoked with once the frame has been transmitted.
+ *
+ * If ring_stop() is called after the packet has been enqueued @frame->callback
+ * will be called with canceled set to true.
+ *
+ * Return: Returns %-ESHUTDOWN if ring_stop has been called. Zero otherwise.
+ */
+static inline int tb_ring_tx(struct tb_ring *ring, struct ring_frame *frame)
+{
+	WARN_ON(!ring->is_tx);
+	return __tb_ring_enqueue(ring, frame);
+}
+
 #endif /* THUNDERBOLT_H_ */