// SPDX-License-Identifier: (GPL-2.0 OR BSD-3-Clause)
/*
 * Copyright(c) 2018 Intel Corporation.
 *
 */

#include "hfi.h"
#include "verbs.h"
#include "tid_rdma.h"

/*
 * J_KEY for kernel contexts when TID RDMA is used.
 * See generate_jkey() in hfi.h for more information.
 */
#define TID_RDMA_JKEY                   32
#define HFI1_KERNEL_MIN_JKEY HFI1_ADMIN_JKEY_RANGE
#define HFI1_KERNEL_MAX_JKEY (2 * HFI1_ADMIN_JKEY_RANGE - 1)

#define TID_RDMA_MAX_READ_SEGS_PER_REQ  6
#define TID_RDMA_MAX_WRITE_SEGS_PER_REQ 4

#define TID_OPFN_QP_CTXT_MASK 0xff
#define TID_OPFN_QP_CTXT_SHIFT 56
#define TID_OPFN_QP_KDETH_MASK 0xff
#define TID_OPFN_QP_KDETH_SHIFT 48
#define TID_OPFN_MAX_LEN_MASK 0x7ff
#define TID_OPFN_MAX_LEN_SHIFT 37
#define TID_OPFN_TIMEOUT_MASK 0x1f
#define TID_OPFN_TIMEOUT_SHIFT 32
#define TID_OPFN_RESERVED_MASK 0x3f
#define TID_OPFN_RESERVED_SHIFT 26
#define TID_OPFN_URG_MASK 0x1
#define TID_OPFN_URG_SHIFT 25
#define TID_OPFN_VER_MASK 0x7
#define TID_OPFN_VER_SHIFT 22
#define TID_OPFN_JKEY_MASK 0x3f
#define TID_OPFN_JKEY_SHIFT 16
#define TID_OPFN_MAX_READ_MASK 0x3f
#define TID_OPFN_MAX_READ_SHIFT 10
#define TID_OPFN_MAX_WRITE_MASK 0x3f
#define TID_OPFN_MAX_WRITE_SHIFT 4

/*
 * OPFN TID layout
 *
 * 63               47               31               15
 * NNNNNNNNKKKKKKKK MMMMMMMMMMMTTTTT DDDDDDUVVVJJJJJJ RRRRRRWWWWWWCCCC
 * 3210987654321098 7654321098765432 1098765432109876 5432109876543210
 * N - the context Number
 * K - the Kdeth_qp
 * M - Max_len
 * T - Timeout
 * D - reserveD
 * V - version
 * U - Urg capable
 * J - Jkey
 * R - max_Read
 * W - max_Write
 * C - Capcode
 */

static u64 tid_rdma_opfn_encode(struct tid_rdma_params *p)
{
	return
		(((u64)p->qp & TID_OPFN_QP_CTXT_MASK) <<
			TID_OPFN_QP_CTXT_SHIFT) |
		((((u64)p->qp >> 16) & TID_OPFN_QP_KDETH_MASK) <<
			TID_OPFN_QP_KDETH_SHIFT) |
		(((u64)((p->max_len >> PAGE_SHIFT) - 1) &
			TID_OPFN_MAX_LEN_MASK) << TID_OPFN_MAX_LEN_SHIFT) |
		(((u64)p->timeout & TID_OPFN_TIMEOUT_MASK) <<
			TID_OPFN_TIMEOUT_SHIFT) |
		(((u64)p->urg & TID_OPFN_URG_MASK) << TID_OPFN_URG_SHIFT) |
		(((u64)p->jkey & TID_OPFN_JKEY_MASK) << TID_OPFN_JKEY_SHIFT) |
		(((u64)p->max_read & TID_OPFN_MAX_READ_MASK) <<
			TID_OPFN_MAX_READ_SHIFT) |
		(((u64)p->max_write & TID_OPFN_MAX_WRITE_MASK) <<
			TID_OPFN_MAX_WRITE_SHIFT);
}

static void tid_rdma_opfn_decode(struct tid_rdma_params *p, u64 data)
{
	p->max_len = (((data >> TID_OPFN_MAX_LEN_SHIFT) &
		TID_OPFN_MAX_LEN_MASK) + 1) << PAGE_SHIFT;
	p->jkey = (data >> TID_OPFN_JKEY_SHIFT) & TID_OPFN_JKEY_MASK;
	p->max_write = (data >> TID_OPFN_MAX_WRITE_SHIFT) &
		TID_OPFN_MAX_WRITE_MASK;
	p->max_read = (data >> TID_OPFN_MAX_READ_SHIFT) &
		TID_OPFN_MAX_READ_MASK;
	p->qp =
		((((data >> TID_OPFN_QP_KDETH_SHIFT) & TID_OPFN_QP_KDETH_MASK)
			<< 16) |
		((data >> TID_OPFN_QP_CTXT_SHIFT) & TID_OPFN_QP_CTXT_MASK));
	p->urg = (data >> TID_OPFN_URG_SHIFT) & TID_OPFN_URG_MASK;
	p->timeout = (data >> TID_OPFN_TIMEOUT_SHIFT) & TID_OPFN_TIMEOUT_MASK;
}

void tid_rdma_opfn_init(struct rvt_qp *qp, struct tid_rdma_params *p)
{
	struct hfi1_qp_priv *priv = qp->priv;

	p->qp = (kdeth_qp << 16) | priv->rcd->ctxt;
	p->max_len = TID_RDMA_MAX_SEGMENT_SIZE;
	p->jkey = priv->rcd->jkey;
	p->max_read = TID_RDMA_MAX_READ_SEGS_PER_REQ;
	p->max_write = TID_RDMA_MAX_WRITE_SEGS_PER_REQ;
	p->timeout = qp->timeout;
	p->urg = is_urg_masked(priv->rcd);
}

bool tid_rdma_conn_req(struct rvt_qp *qp, u64 *data)
{
	struct hfi1_qp_priv *priv = qp->priv;

	*data = tid_rdma_opfn_encode(&priv->tid_rdma.local);
	return true;
}

bool tid_rdma_conn_reply(struct rvt_qp *qp, u64 data)
{
	struct hfi1_qp_priv *priv = qp->priv;
	struct tid_rdma_params *remote, *old;
	bool ret = true;

	old = rcu_dereference_protected(priv->tid_rdma.remote,
					lockdep_is_held(&priv->opfn.lock));
	data &= ~0xfULL;
	/*
	 * If data passed in is zero, return true so as not to continue the
	 * negotiation process
	 */
	if (!data || !HFI1_CAP_IS_KSET(TID_RDMA))
		goto null;
	/*
	 * If kzalloc fails, return false. This will result in:
	 * * at the requester a new OPFN request being generated to retry
	 *   the negotiation
	 * * at the responder, 0 being returned to the requester so as to
	 *   disable TID RDMA at both the requester and the responder
	 */
	remote = kzalloc(sizeof(*remote), GFP_ATOMIC);
	if (!remote) {
		ret = false;
		goto null;
	}

	tid_rdma_opfn_decode(remote, data);
	priv->tid_timer_timeout_jiffies =
		usecs_to_jiffies((((4096UL * (1UL << remote->timeout)) /
				   1000UL) << 3) * 7);
	rcu_assign_pointer(priv->tid_rdma.remote, remote);
	/*
	 * A TID RDMA READ request's segment size is not equal to
	 * remote->max_len only when the request's data length is smaller
	 * than remote->max_len. In that case, there will be only one segment.
	 * Therefore, when priv->pkts_ps is used to calculate req->cur_seg
	 * during retry, it will lead to req->cur_seg = 0, which is exactly
	 * what is expected.
	 */
	priv->pkts_ps = (u16)rvt_div_mtu(qp, remote->max_len);
	priv->timeout_shift = ilog2(priv->pkts_ps - 1) + 1;
	goto free;
null:
	RCU_INIT_POINTER(priv->tid_rdma.remote, NULL);
	priv->timeout_shift = 0;
free:
	if (old)
		kfree_rcu(old, rcu_head);
	return ret;
}

bool tid_rdma_conn_resp(struct rvt_qp *qp, u64 *data)
{
	bool ret;

	ret = tid_rdma_conn_reply(qp, *data);
	*data = 0;
	/*
	 * If tid_rdma_conn_reply() returns error, set *data as 0 to indicate
	 * TID RDMA could not be enabled. This will result in TID RDMA being
	 * disabled at the requester too.
	 */
	if (ret)
		(void)tid_rdma_conn_req(qp, data);
	return ret;
}

void tid_rdma_conn_error(struct rvt_qp *qp)
{
	struct hfi1_qp_priv *priv = qp->priv;
	struct tid_rdma_params *old;

	old = rcu_dereference_protected(priv->tid_rdma.remote,
					lockdep_is_held(&priv->opfn.lock));
	RCU_INIT_POINTER(priv->tid_rdma.remote, NULL);
	if (old)
		kfree_rcu(old, rcu_head);
}

/* This is called at context initialization time */
int hfi1_kern_exp_rcv_init(struct hfi1_ctxtdata *rcd, int reinit)
{
	if (reinit)
		return 0;

	BUILD_BUG_ON(TID_RDMA_JKEY < HFI1_KERNEL_MIN_JKEY);
	BUILD_BUG_ON(TID_RDMA_JKEY > HFI1_KERNEL_MAX_JKEY);
	rcd->jkey = TID_RDMA_JKEY;
	hfi1_set_ctxt_jkey(rcd->dd, rcd, rcd->jkey);
	return 0;
}

/**
 * qp_to_rcd - determine the receive context used by a qp
 * @qp - the qp
 *
 * This routine returns the receive context associated
 * with a a qp's qpn.
 *
 * Returns the context.
 */
static struct hfi1_ctxtdata *qp_to_rcd(struct rvt_dev_info *rdi,
				       struct rvt_qp *qp)
{
	struct hfi1_ibdev *verbs_dev = container_of(rdi,
						    struct hfi1_ibdev,
						    rdi);
	struct hfi1_devdata *dd = container_of(verbs_dev,
					       struct hfi1_devdata,
					       verbs_dev);
	unsigned int ctxt;

	if (qp->ibqp.qp_num == 0)
		ctxt = 0;
	else
		ctxt = ((qp->ibqp.qp_num >> dd->qos_shift) %
			(dd->n_krcv_queues - 1)) + 1;

	return dd->rcd[ctxt];
}

int hfi1_qp_priv_init(struct rvt_dev_info *rdi, struct rvt_qp *qp,
		      struct ib_qp_init_attr *init_attr)
{
	struct hfi1_qp_priv *qpriv = qp->priv;

	qpriv->rcd = qp_to_rcd(rdi, qp);

	return 0;
}