1 files changed, 457 insertions, 0 deletions
diff --git a/drivers/infiniband/hw/hfi1/iowait.h b/drivers/infiniband/hw/hfi1/iowait.h
new file mode 100644
index 0000000000..4df0700cba
--- /dev/null
+++ b/drivers/infiniband/hw/hfi1/iowait.h
@@ -0,0 +1,457 @@
+/* SPDX-License-Identifier: GPL-2.0 or BSD-3-Clause */
+/*
+ * Copyright(c) 2015 - 2018 Intel Corporation.
+ */
+
+#ifndef _HFI1_IOWAIT_H
+#define _HFI1_IOWAIT_H
+
+#include <linux/list.h>
+#include <linux/workqueue.h>
+#include <linux/wait.h>
+#include <linux/sched.h>
+
+#include "sdma_txreq.h"
+
+/*
+ * typedef (*restart_t)() - restart callback
+ * @work: pointer to work structure
+ */
+typedef void (*restart_t)(struct work_struct *work);
+
+#define IOWAIT_PENDING_IB  0x0
+#define IOWAIT_PENDING_TID 0x1
+
+/*
+ * A QP can have multiple Send Engines (SEs).
+ *
+ * The current use case is for supporting a TID RDMA
+ * packet build/xmit mechanism independent from verbs.
+ */
+#define IOWAIT_SES 2
+#define IOWAIT_IB_SE 0
+#define IOWAIT_TID_SE 1
+
+struct sdma_txreq;
+struct sdma_engine;
+/**
+ * @iowork: the work struct
+ * @tx_head: list of prebuilt packets
+ * @iow: the parent iowait structure
+ *
+ * This structure is the work item (process) specific
+ * details associated with the each of the two SEs of the
+ * QP.
+ *
+ * The workstruct and the queued TXs are unique to each
+ * SE.
+ */
+struct iowait;
+struct iowait_work {
+	struct work_struct iowork;
+	struct list_head tx_head;
+	struct iowait *iow;
+};
+
+/**
+ * @list: used to add/insert into QP/PQ wait lists
+ * @tx_head: overflow list of sdma_txreq's
+ * @sleep: no space callback
+ * @wakeup: space callback wakeup
+ * @sdma_drained: sdma count drained
+ * @init_priority: callback to manipulate priority
+ * @lock: lock protected head of wait queue
+ * @iowork: workqueue overhead
+ * @wait_dma: wait for sdma_busy == 0
+ * @wait_pio: wait for pio_busy == 0
+ * @sdma_busy: # of packets in flight
+ * @count: total number of descriptors in tx_head'ed list
+ * @tx_limit: limit for overflow queuing
+ * @tx_count: number of tx entry's in tx_head'ed list
+ * @flags: wait flags (one per QP)
+ * @wait: SE array for multiple legs
+ *
+ * This is to be embedded in user's state structure
+ * (QP or PQ).
+ *
+ * The sleep and wakeup members are a
+ * bit misnamed.   They do not strictly
+ * speaking sleep or wake up, but they
+ * are callbacks for the ULP to implement
+ * what ever queuing/dequeuing of
+ * the embedded iowait and its containing struct
+ * when a resource shortage like SDMA ring space
+ * or PIO credit space is seen.
+ *
+ * Both potentially have locks help
+ * so sleeping is not allowed and it is not
+ * supported to submit txreqs from the wakeup
+ * call directly because of lock conflicts.
+ *
+ * The wait_dma member along with the iow
+ *
+ * The lock field is used by waiters to record
+ * the seqlock_t that guards the list head.
+ * Waiters explicity know that, but the destroy
+ * code that unwaits QPs does not.
+ */
+struct iowait {
+	struct list_head list;
+	int (*sleep)(
+		struct sdma_engine *sde,
+		struct iowait_work *wait,
+		struct sdma_txreq *tx,
+		uint seq,
+		bool pkts_sent
+		);
+	void (*wakeup)(struct iowait *wait, int reason);
+	void (*sdma_drained)(struct iowait *wait);
+	void (*init_priority)(struct iowait *wait);
+	seqlock_t *lock;
+	wait_queue_head_t wait_dma;
+	wait_queue_head_t wait_pio;
+	atomic_t sdma_busy;
+	atomic_t pio_busy;
+	u32 count;
+	u32 tx_limit;
+	u32 tx_count;
+	u8 starved_cnt;
+	u8 priority;
+	unsigned long flags;
+	struct iowait_work wait[IOWAIT_SES];
+};
+
+#define SDMA_AVAIL_REASON 0
+
+void iowait_set_flag(struct iowait *wait, u32 flag);
+bool iowait_flag_set(struct iowait *wait, u32 flag);
+void iowait_clear_flag(struct iowait *wait, u32 flag);
+
+void iowait_init(struct iowait *wait, u32 tx_limit,
+		 void (*func)(struct work_struct *work),
+		 void (*tidfunc)(struct work_struct *work),
+		 int (*sleep)(struct sdma_engine *sde,
+			      struct iowait_work *wait,
+			      struct sdma_txreq *tx,
+			      uint seq,
+			      bool pkts_sent),
+		 void (*wakeup)(struct iowait *wait, int reason),
+		 void (*sdma_drained)(struct iowait *wait),
+		 void (*init_priority)(struct iowait *wait));
+
+/**
+ * iowait_schedule() - schedule the default send engine work
+ * @wait: wait struct to schedule
+ * @wq: workqueue for schedule
+ * @cpu: cpu
+ */
+static inline bool iowait_schedule(struct iowait *wait,
+				   struct workqueue_struct *wq, int cpu)
+{
+	return !!queue_work_on(cpu, wq, &wait->wait[IOWAIT_IB_SE].iowork);
+}
+
+/**
+ * iowait_tid_schedule - schedule the tid SE
+ * @wait: the iowait structure
+ * @wq: the work queue
+ * @cpu: the cpu
+ */
+static inline bool iowait_tid_schedule(struct iowait *wait,
+				       struct workqueue_struct *wq, int cpu)
+{
+	return !!queue_work_on(cpu, wq, &wait->wait[IOWAIT_TID_SE].iowork);
+}
+
+/**
+ * iowait_sdma_drain() - wait for DMAs to drain
+ *
+ * @wait: iowait structure
+ *
+ * This will delay until the iowait sdmas have
+ * completed.
+ */
+static inline void iowait_sdma_drain(struct iowait *wait)
+{
+	wait_event(wait->wait_dma, !atomic_read(&wait->sdma_busy));
+}
+
+/**
+ * iowait_sdma_pending() - return sdma pending count
+ *
+ * @wait: iowait structure
+ *
+ */
+static inline int iowait_sdma_pending(struct iowait *wait)
+{
+	return atomic_read(&wait->sdma_busy);
+}
+
+/**
+ * iowait_sdma_inc - note sdma io pending
+ * @wait: iowait structure
+ */
+static inline void iowait_sdma_inc(struct iowait *wait)
+{
+	atomic_inc(&wait->sdma_busy);
+}
+
+/**
+ * iowait_sdma_add - add count to pending
+ * @wait: iowait structure
+ */
+static inline void iowait_sdma_add(struct iowait *wait, int count)
+{
+	atomic_add(count, &wait->sdma_busy);
+}
+
+/**
+ * iowait_sdma_dec - note sdma complete
+ * @wait: iowait structure
+ */
+static inline int iowait_sdma_dec(struct iowait *wait)
+{
+	if (!wait)
+		return 0;
+	return atomic_dec_and_test(&wait->sdma_busy);
+}
+
+/**
+ * iowait_pio_drain() - wait for pios to drain
+ *
+ * @wait: iowait structure
+ *
+ * This will delay until the iowait pios have
+ * completed.
+ */
+static inline void iowait_pio_drain(struct iowait *wait)
+{
+	wait_event_timeout(wait->wait_pio,
+			   !atomic_read(&wait->pio_busy),
+			   HZ);
+}
+
+/**
+ * iowait_pio_pending() - return pio pending count
+ *
+ * @wait: iowait structure
+ *
+ */
+static inline int iowait_pio_pending(struct iowait *wait)
+{
+	return atomic_read(&wait->pio_busy);
+}
+
+/**
+ * iowait_pio_inc - note pio pending
+ * @wait: iowait structure
+ */
+static inline void iowait_pio_inc(struct iowait *wait)
+{
+	atomic_inc(&wait->pio_busy);
+}
+
+/**
+ * iowait_pio_dec - note pio complete
+ * @wait: iowait structure
+ */
+static inline int iowait_pio_dec(struct iowait *wait)
+{
+	if (!wait)
+		return 0;
+	return atomic_dec_and_test(&wait->pio_busy);
+}
+
+/**
+ * iowait_drain_wakeup() - trigger iowait_drain() waiter
+ *
+ * @wait: iowait structure
+ *
+ * This will trigger any waiters.
+ */
+static inline void iowait_drain_wakeup(struct iowait *wait)
+{
+	wake_up(&wait->wait_dma);
+	wake_up(&wait->wait_pio);
+	if (wait->sdma_drained)
+		wait->sdma_drained(wait);
+}
+
+/**
+ * iowait_get_txhead() - get packet off of iowait list
+ *
+ * @wait: iowait_work structure
+ */
+static inline struct sdma_txreq *iowait_get_txhead(struct iowait_work *wait)
+{
+	struct sdma_txreq *tx = NULL;
+
+	if (!list_empty(&wait->tx_head)) {
+		tx = list_first_entry(
+			&wait->tx_head,
+			struct sdma_txreq,
+			list);
+		list_del_init(&tx->list);
+	}
+	return tx;
+}
+
+static inline u16 iowait_get_desc(struct iowait_work *w)
+{
+	u16 num_desc = 0;
+	struct sdma_txreq *tx = NULL;
+
+	if (!list_empty(&w->tx_head)) {
+		tx = list_first_entry(&w->tx_head, struct sdma_txreq,
+				      list);
+		num_desc = tx->num_desc;
+		if (tx->flags & SDMA_TXREQ_F_VIP)
+			w->iow->priority++;
+	}
+	return num_desc;
+}
+
+static inline u32 iowait_get_all_desc(struct iowait *w)
+{
+	u32 num_desc = 0;
+
+	num_desc = iowait_get_desc(&w->wait[IOWAIT_IB_SE]);
+	num_desc += iowait_get_desc(&w->wait[IOWAIT_TID_SE]);
+	return num_desc;
+}
+
+static inline void iowait_update_priority(struct iowait_work *w)
+{
+	struct sdma_txreq *tx = NULL;
+
+	if (!list_empty(&w->tx_head)) {
+		tx = list_first_entry(&w->tx_head, struct sdma_txreq,
+				      list);
+		if (tx->flags & SDMA_TXREQ_F_VIP)
+			w->iow->priority++;
+	}
+}
+
+static inline void iowait_update_all_priority(struct iowait *w)
+{
+	iowait_update_priority(&w->wait[IOWAIT_IB_SE]);
+	iowait_update_priority(&w->wait[IOWAIT_TID_SE]);
+}
+
+static inline void iowait_init_priority(struct iowait *w)
+{
+	w->priority = 0;
+	if (w->init_priority)
+		w->init_priority(w);
+}
+
+static inline void iowait_get_priority(struct iowait *w)
+{
+	iowait_init_priority(w);
+	iowait_update_all_priority(w);
+}
+
+/**
+ * iowait_queue - Put the iowait on a wait queue
+ * @pkts_sent: have some packets been sent before queuing?
+ * @w: the iowait struct
+ * @wait_head: the wait queue
+ *
+ * This function is called to insert an iowait struct into a
+ * wait queue after a resource (eg, sdma descriptor or pio
+ * buffer) is run out.
+ */
+static inline void iowait_queue(bool pkts_sent, struct iowait *w,
+				struct list_head *wait_head)
+{
+	/*
+	 * To play fair, insert the iowait at the tail of the wait queue if it
+	 * has already sent some packets; Otherwise, put it at the head.
+	 * However, if it has priority packets to send, also put it at the
+	 * head.
+	 */
+	if (pkts_sent)
+		w->starved_cnt = 0;
+	else
+		w->starved_cnt++;
+
+	if (w->priority > 0 || !pkts_sent)
+		list_add(&w->list, wait_head);
+	else
+		list_add_tail(&w->list, wait_head);
+}
+
+/**
+ * iowait_starve_clear - clear the wait queue's starve count
+ * @pkts_sent: have some packets been sent?
+ * @w: the iowait struct
+ *
+ * This function is called to clear the starve count. If no
+ * packets have been sent, the starve count will not be cleared.
+ */
+static inline void iowait_starve_clear(bool pkts_sent, struct iowait *w)
+{
+	if (pkts_sent)
+		w->starved_cnt = 0;
+}
+
+/* Update the top priority index */
+uint iowait_priority_update_top(struct iowait *w,
+				struct iowait *top,
+				uint idx, uint top_idx);
+
+/**
+ * iowait_packet_queued() - determine if a packet is queued
+ * @wait: the iowait_work structure
+ */
+static inline bool iowait_packet_queued(struct iowait_work *wait)
+{
+	return !list_empty(&wait->tx_head);
+}
+
+/**
+ * inc_wait_count - increment wait counts
+ * @w: the log work struct
+ * @n: the count
+ */
+static inline void iowait_inc_wait_count(struct iowait_work *w, u16 n)
+{
+	if (!w)
+		return;
+	w->iow->tx_count++;
+	w->iow->count += n;
+}
+
+/**
+ * iowait_get_tid_work - return iowait_work for tid SE
+ * @w: the iowait struct
+ */
+static inline struct iowait_work *iowait_get_tid_work(struct iowait *w)
+{
+	return &w->wait[IOWAIT_TID_SE];
+}
+
+/**
+ * iowait_get_ib_work - return iowait_work for ib SE
+ * @w: the iowait struct
+ */
+static inline struct iowait_work *iowait_get_ib_work(struct iowait *w)
+{
+	return &w->wait[IOWAIT_IB_SE];
+}
+
+/**
+ * iowait_ioww_to_iow - return iowait given iowait_work
+ * @w: the iowait_work struct
+ */
+static inline struct iowait *iowait_ioww_to_iow(struct iowait_work *w)
+{
+	if (likely(w))
+		return w->iow;
+	return NULL;
+}
+
+void iowait_cancel_work(struct iowait *w);
+int iowait_set_work_flag(struct iowait_work *w);
+
+#endif