/*
 * Copyright (c) 2016 Chelsio Communications, Inc.
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */

#include "cxgbit.h"

static void
cxgbit_set_one_ppod(struct cxgbi_pagepod *ppod,
		    struct cxgbi_task_tag_info *ttinfo,
		    struct scatterlist **sg_pp, unsigned int *sg_off)
{
	struct scatterlist *sg = sg_pp ? *sg_pp : NULL;
	unsigned int offset = sg_off ? *sg_off : 0;
	dma_addr_t addr = 0UL;
	unsigned int len = 0;
	int i;

	memcpy(ppod, &ttinfo->hdr, sizeof(struct cxgbi_pagepod_hdr));

	if (sg) {
		addr = sg_dma_address(sg);
		len = sg_dma_len(sg);
	}

	for (i = 0; i < PPOD_PAGES_MAX; i++) {
		if (sg) {
			ppod->addr[i] = cpu_to_be64(addr + offset);
			offset += PAGE_SIZE;
			if (offset == (len + sg->offset)) {
				offset = 0;
				sg = sg_next(sg);
				if (sg) {
					addr = sg_dma_address(sg);
					len = sg_dma_len(sg);
				}
			}
		} else {
			ppod->addr[i] = 0ULL;
		}
	}

	/*
	 * the fifth address needs to be repeated in the next ppod, so do
	 * not move sg
	 */
	if (sg_pp) {
		*sg_pp = sg;
		*sg_off = offset;
	}

	if (offset == len) {
		offset = 0;
		if (sg) {
			sg = sg_next(sg);
			if (sg)
				addr = sg_dma_address(sg);
		}
	}
	ppod->addr[i] = sg ? cpu_to_be64(addr + offset) : 0ULL;
}

static struct sk_buff *
cxgbit_ppod_init_idata(struct cxgbit_device *cdev, struct cxgbi_ppm *ppm,
		       unsigned int idx, unsigned int npods, unsigned int tid)
{
	struct ulp_mem_io *req;
	struct ulptx_idata *idata;
	unsigned int pm_addr = (idx << PPOD_SIZE_SHIFT) + ppm->llimit;
	unsigned int dlen = npods << PPOD_SIZE_SHIFT;
	unsigned int wr_len = roundup(sizeof(struct ulp_mem_io) +
				sizeof(struct ulptx_idata) + dlen, 16);
	struct sk_buff *skb;

	skb  = alloc_skb(wr_len, GFP_KERNEL);
	if (!skb)
		return NULL;

	req = __skb_put(skb, wr_len);
	INIT_ULPTX_WR(req, wr_len, 0, tid);
	req->wr.wr_hi = htonl(FW_WR_OP_V(FW_ULPTX_WR) |
		FW_WR_ATOMIC_V(0));
	req->cmd = htonl(ULPTX_CMD_V(ULP_TX_MEM_WRITE) |
		ULP_MEMIO_ORDER_V(0) |
		T5_ULP_MEMIO_IMM_V(1));
	req->dlen = htonl(ULP_MEMIO_DATA_LEN_V(dlen >> 5));
	req->lock_addr = htonl(ULP_MEMIO_ADDR_V(pm_addr >> 5));
	req->len16 = htonl(DIV_ROUND_UP(wr_len - sizeof(req->wr), 16));

	idata = (struct ulptx_idata *)(req + 1);
	idata->cmd_more = htonl(ULPTX_CMD_V(ULP_TX_SC_IMM));
	idata->len = htonl(dlen);

	return skb;
}

static int
cxgbit_ppod_write_idata(struct cxgbi_ppm *ppm, struct cxgbit_sock *csk,
			struct cxgbi_task_tag_info *ttinfo, unsigned int idx,
			unsigned int npods, struct scatterlist **sg_pp,
			unsigned int *sg_off)
{
	struct cxgbit_device *cdev = csk->com.cdev;
	struct sk_buff *skb;
	struct ulp_mem_io *req;
	struct ulptx_idata *idata;
	struct cxgbi_pagepod *ppod;
	unsigned int i;

	skb = cxgbit_ppod_init_idata(cdev, ppm, idx, npods, csk->tid);
	if (!skb)
		return -ENOMEM;

	req = (struct ulp_mem_io *)skb->data;
	idata = (struct ulptx_idata *)(req + 1);
	ppod = (struct cxgbi_pagepod *)(idata + 1);

	for (i = 0; i < npods; i++, ppod++)
		cxgbit_set_one_ppod(ppod, ttinfo, sg_pp, sg_off);

	__skb_queue_tail(&csk->ppodq, skb);

	return 0;
}

static int
cxgbit_ddp_set_map(struct cxgbi_ppm *ppm, struct cxgbit_sock *csk,
		   struct cxgbi_task_tag_info *ttinfo)
{
	unsigned int pidx = ttinfo->idx;
	unsigned int npods = ttinfo->npods;
	unsigned int i, cnt;
	struct scatterlist *sg = ttinfo->sgl;
	unsigned int offset = 0;
	int ret = 0;

	for (i = 0; i < npods; i += cnt, pidx += cnt) {
		cnt = npods - i;

		if (cnt > ULPMEM_IDATA_MAX_NPPODS)
			cnt = ULPMEM_IDATA_MAX_NPPODS;

		ret = cxgbit_ppod_write_idata(ppm, csk, ttinfo, pidx, cnt,
					      &sg, &offset);
		if (ret < 0)
			break;
	}

	return ret;
}

static int cxgbit_ddp_sgl_check(struct scatterlist *sg,
				unsigned int nents)
{
	unsigned int last_sgidx = nents - 1;
	unsigned int i;

	for (i = 0; i < nents; i++, sg = sg_next(sg)) {
		unsigned int len = sg->length + sg->offset;

		if ((sg->offset & 0x3) || (i && sg->offset) ||
		    ((i != last_sgidx) && (len != PAGE_SIZE))) {
			return -EINVAL;
		}
	}

	return 0;
}

static int
cxgbit_ddp_reserve(struct cxgbit_sock *csk, struct cxgbi_task_tag_info *ttinfo,
		   unsigned int xferlen)
{
	struct cxgbit_device *cdev = csk->com.cdev;
	struct cxgbi_ppm *ppm = cdev2ppm(cdev);
	struct scatterlist *sgl = ttinfo->sgl;
	unsigned int sgcnt = ttinfo->nents;
	unsigned int sg_offset = sgl->offset;
	int ret;

	if ((xferlen < DDP_THRESHOLD) || (!sgcnt)) {
		pr_debug("ppm 0x%p, pgidx %u, xfer %u, sgcnt %u, NO ddp.\n",
			 ppm, ppm->tformat.pgsz_idx_dflt,
			 xferlen, ttinfo->nents);
		return -EINVAL;
	}

	if (cxgbit_ddp_sgl_check(sgl, sgcnt) < 0)
		return -EINVAL;

	ttinfo->nr_pages = (xferlen + sgl->offset +
			    (1 << PAGE_SHIFT) - 1) >> PAGE_SHIFT;

	/*
	 * the ddp tag will be used for the ttt in the outgoing r2t pdu
	 */
	ret = cxgbi_ppm_ppods_reserve(ppm, ttinfo->nr_pages, 0, &ttinfo->idx,
				      &ttinfo->tag, 0);
	if (ret < 0)
		return ret;
	ttinfo->npods = ret;

	sgl->offset = 0;
	ret = dma_map_sg(&ppm->pdev->dev, sgl, sgcnt, DMA_FROM_DEVICE);
	sgl->offset = sg_offset;
	if (!ret) {
		pr_debug("%s: 0x%x, xfer %u, sgl %u dma mapping err.\n",
			 __func__, 0, xferlen, sgcnt);
		goto rel_ppods;
	}

	cxgbi_ppm_make_ppod_hdr(ppm, ttinfo->tag, csk->tid, sgl->offset,
				xferlen, &ttinfo->hdr);

	ret = cxgbit_ddp_set_map(ppm, csk, ttinfo);
	if (ret < 0) {
		__skb_queue_purge(&csk->ppodq);
		dma_unmap_sg(&ppm->pdev->dev, sgl, sgcnt, DMA_FROM_DEVICE);
		goto rel_ppods;
	}

	return 0;

rel_ppods:
	cxgbi_ppm_ppod_release(ppm, ttinfo->idx);
	return -EINVAL;
}

void
cxgbit_get_r2t_ttt(struct iscsi_conn *conn, struct iscsi_cmd *cmd,
		   struct iscsi_r2t *r2t)
{
	struct cxgbit_sock *csk = conn->context;
	struct cxgbit_device *cdev = csk->com.cdev;
	struct cxgbit_cmd *ccmd = iscsit_priv_cmd(cmd);
	struct cxgbi_task_tag_info *ttinfo = &ccmd->ttinfo;
	int ret = -EINVAL;

	if ((!ccmd->setup_ddp) ||
	    (!test_bit(CSK_DDP_ENABLE, &csk->com.flags)))
		goto out;

	ccmd->setup_ddp = false;

	ttinfo->sgl = cmd->se_cmd.t_data_sg;
	ttinfo->nents = cmd->se_cmd.t_data_nents;

	ret = cxgbit_ddp_reserve(csk, ttinfo, cmd->se_cmd.data_length);
	if (ret < 0) {
		pr_debug("csk 0x%p, cmd 0x%p, xfer len %u, sgcnt %u no ddp.\n",
			 csk, cmd, cmd->se_cmd.data_length, ttinfo->nents);

		ttinfo->sgl = NULL;
		ttinfo->nents = 0;
	} else {
		ccmd->release = true;
	}
out:
	pr_debug("cdev 0x%p, cmd 0x%p, tag 0x%x\n", cdev, cmd, ttinfo->tag);
	r2t->targ_xfer_tag = ttinfo->tag;
}

void cxgbit_release_cmd(struct iscsi_conn *conn, struct iscsi_cmd *cmd)
{
	struct cxgbit_cmd *ccmd = iscsit_priv_cmd(cmd);

	if (ccmd->release) {
		struct cxgbi_task_tag_info *ttinfo = &ccmd->ttinfo;

		if (ttinfo->sgl) {
			struct cxgbit_sock *csk = conn->context;
			struct cxgbit_device *cdev = csk->com.cdev;
			struct cxgbi_ppm *ppm = cdev2ppm(cdev);

			/* Abort the TCP conn if DDP is not complete to
			 * avoid any possibility of DDP after freeing
			 * the cmd.
			 */
			if (unlikely(cmd->write_data_done !=
				     cmd->se_cmd.data_length))
				cxgbit_abort_conn(csk);

			cxgbi_ppm_ppod_release(ppm, ttinfo->idx);

			dma_unmap_sg(&ppm->pdev->dev, ttinfo->sgl,
				     ttinfo->nents, DMA_FROM_DEVICE);
		} else {
			put_page(sg_page(&ccmd->sg));
		}

		ccmd->release = false;
	}
}

int cxgbit_ddp_init(struct cxgbit_device *cdev)
{
	struct cxgb4_lld_info *lldi = &cdev->lldi;
	struct net_device *ndev = cdev->lldi.ports[0];
	struct cxgbi_tag_format tformat;
	unsigned int ppmax;
	int ret, i;

	if (!lldi->vr->iscsi.size) {
		pr_warn("%s, iscsi NOT enabled, check config!\n", ndev->name);
		return -EACCES;
	}

	ppmax = lldi->vr->iscsi.size >> PPOD_SIZE_SHIFT;

	memset(&tformat, 0, sizeof(struct cxgbi_tag_format));
	for (i = 0; i < 4; i++)
		tformat.pgsz_order[i] = (lldi->iscsi_pgsz_order >> (i << 3))
					 & 0xF;
	cxgbi_tagmask_check(lldi->iscsi_tagmask, &tformat);

	ret = cxgbi_ppm_init(lldi->iscsi_ppm, cdev->lldi.ports[0],
			     cdev->lldi.pdev, &cdev->lldi, &tformat,
			     ppmax, lldi->iscsi_llimit,
			     lldi->vr->iscsi.start, 2);
	if (ret >= 0) {
		struct cxgbi_ppm *ppm = (struct cxgbi_ppm *)(*lldi->iscsi_ppm);

		if ((ppm->tformat.pgsz_idx_dflt < DDP_PGIDX_MAX) &&
		    (ppm->ppmax >= 1024))
			set_bit(CDEV_DDP_ENABLE, &cdev->flags);
		ret = 0;
	}

	return ret;
}