/* 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
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