// SPDX-License-Identifier: GPL-2.0
/*
 * Copyright (C) 2021 Broadcom. All Rights Reserved. The term
 * “Broadcom” refers to Broadcom Inc. and/or its subsidiaries.
 */

#include "efct_driver.h"
#include "efct_unsol.h"

#define frame_printf(efct, hdr, fmt, ...) \
	do { \
		char s_id_text[16]; \
		efc_node_fcid_display(ntoh24((hdr)->fh_s_id), \
			s_id_text, sizeof(s_id_text)); \
		efc_log_debug(efct, "[%06x.%s] %02x/%04x/%04x: " fmt, \
			ntoh24((hdr)->fh_d_id), s_id_text, \
			(hdr)->fh_r_ctl, be16_to_cpu((hdr)->fh_ox_id), \
			be16_to_cpu((hdr)->fh_rx_id), ##__VA_ARGS__); \
	} while (0)

static struct efct_node *
efct_node_find(struct efct *efct, u32 port_id, u32 node_id)
{
	struct efct_node *node;
	u64 id = (u64)port_id << 32 | node_id;

	/*
	 * During node shutdown, Lookup will be removed first,
	 * before announcing to backend. So, no new IOs will be allowed
	 */
	/* Find a target node, given s_id and d_id */
	node = xa_load(&efct->lookup, id);
	if (node)
		kref_get(&node->ref);

	return node;
}

static int
efct_dispatch_frame(struct efct *efct, struct efc_hw_sequence *seq)
{
	struct efct_node *node;
	struct fc_frame_header *hdr;
	u32 s_id, d_id;

	hdr = seq->header->dma.virt;

	/* extract the s_id and d_id */
	s_id = ntoh24(hdr->fh_s_id);
	d_id = ntoh24(hdr->fh_d_id);

	if (!(hdr->fh_type == FC_TYPE_FCP || hdr->fh_type == FC_TYPE_BLS))
		return -EIO;

	if (hdr->fh_type == FC_TYPE_FCP) {
		node = efct_node_find(efct, d_id, s_id);
		if (!node) {
			efc_log_err(efct,
				    "Node not found, drop cmd d_id:%x s_id:%x\n",
				    d_id, s_id);
			efct_hw_sequence_free(&efct->hw, seq);
			return 0;
		}

		efct_dispatch_fcp_cmd(node, seq);
	} else {
		node = efct_node_find(efct, d_id, s_id);
		if (!node) {
			efc_log_err(efct, "ABTS: Node not found, d_id:%x s_id:%x\n",
				    d_id, s_id);
			return -EIO;
		}

		efc_log_err(efct, "Received ABTS for Node:%p\n", node);
		efct_node_recv_abts_frame(node, seq);
	}

	kref_put(&node->ref, node->release);
	efct_hw_sequence_free(&efct->hw, seq);
	return 0;
}

int
efct_unsolicited_cb(void *arg, struct efc_hw_sequence *seq)
{
	struct efct *efct = arg;

	/* Process FCP command */
	if (!efct_dispatch_frame(efct, seq))
		return 0;

	/* Forward frame to discovery lib */
	efc_dispatch_frame(efct->efcport, seq);
	return 0;
}

static int
efct_fc_tmf_rejected_cb(struct efct_io *io,
			enum efct_scsi_io_status scsi_status,
			u32 flags, void *arg)
{
	efct_scsi_io_free(io);
	return 0;
}

static void
efct_dispatch_unsol_tmf(struct efct_io *io, u8 tm_flags, u32 lun)
{
	u32 i;
	struct {
		u32 mask;
		enum efct_scsi_tmf_cmd cmd;
	} tmflist[] = {
	{FCP_TMF_ABT_TASK_SET, EFCT_SCSI_TMF_ABORT_TASK_SET},
	{FCP_TMF_CLR_TASK_SET, EFCT_SCSI_TMF_CLEAR_TASK_SET},
	{FCP_TMF_LUN_RESET, EFCT_SCSI_TMF_LOGICAL_UNIT_RESET},
	{FCP_TMF_TGT_RESET, EFCT_SCSI_TMF_TARGET_RESET},
	{FCP_TMF_CLR_ACA, EFCT_SCSI_TMF_CLEAR_ACA} };

	io->exp_xfer_len = 0;

	for (i = 0; i < ARRAY_SIZE(tmflist); i++) {
		if (tmflist[i].mask & tm_flags) {
			io->tmf_cmd = tmflist[i].cmd;
			efct_scsi_recv_tmf(io, lun, tmflist[i].cmd, NULL, 0);
			break;
		}
	}
	if (i == ARRAY_SIZE(tmflist)) {
		/* Not handled */
		efc_log_err(io->node->efct, "TMF x%x rejected\n", tm_flags);
		efct_scsi_send_tmf_resp(io, EFCT_SCSI_TMF_FUNCTION_REJECTED,
					NULL, efct_fc_tmf_rejected_cb, NULL);
	}
}

static int
efct_validate_fcp_cmd(struct efct *efct, struct efc_hw_sequence *seq)
{
	/*
	 * If we received less than FCP_CMND_IU bytes, assume that the frame is
	 * corrupted in some way and drop it.
	 * This was seen when jamming the FCTL
	 * fill bytes field.
	 */
	if (seq->payload->dma.len < sizeof(struct fcp_cmnd)) {
		struct fc_frame_header	*fchdr = seq->header->dma.virt;

		efc_log_debug(efct,
			      "drop ox_id %04x payload (%zd) less than (%zd)\n",
			      be16_to_cpu(fchdr->fh_ox_id),
			      seq->payload->dma.len, sizeof(struct fcp_cmnd));
		return -EIO;
	}
	return 0;
}

static void
efct_populate_io_fcp_cmd(struct efct_io *io, struct fcp_cmnd *cmnd,
			 struct fc_frame_header *fchdr, bool sit)
{
	io->init_task_tag = be16_to_cpu(fchdr->fh_ox_id);
	/* note, tgt_task_tag, hw_tag  set when HW io is allocated */
	io->exp_xfer_len = be32_to_cpu(cmnd->fc_dl);
	io->transferred = 0;

	/* The upper 7 bits of CS_CTL is the frame priority thru the SAN.
	 * Our assertion here is, the priority given to a frame containing
	 * the FCP cmd should be the priority given to ALL frames contained
	 * in that IO. Thus we need to save the incoming CS_CTL here.
	 */
	if (ntoh24(fchdr->fh_f_ctl) & FC_FC_RES_B17)
		io->cs_ctl = fchdr->fh_cs_ctl;
	else
		io->cs_ctl = 0;

	io->seq_init = sit;
}

static u32
efct_get_flags_fcp_cmd(struct fcp_cmnd *cmnd)
{
	u32 flags = 0;

	switch (cmnd->fc_pri_ta & FCP_PTA_MASK) {
	case FCP_PTA_SIMPLE:
		flags |= EFCT_SCSI_CMD_SIMPLE;
		break;
	case FCP_PTA_HEADQ:
		flags |= EFCT_SCSI_CMD_HEAD_OF_QUEUE;
		break;
	case FCP_PTA_ORDERED:
		flags |= EFCT_SCSI_CMD_ORDERED;
		break;
	case FCP_PTA_ACA:
		flags |= EFCT_SCSI_CMD_ACA;
		break;
	}
	if (cmnd->fc_flags & FCP_CFL_WRDATA)
		flags |= EFCT_SCSI_CMD_DIR_IN;
	if (cmnd->fc_flags & FCP_CFL_RDDATA)
		flags |= EFCT_SCSI_CMD_DIR_OUT;

	return flags;
}

static void
efct_sframe_common_send_cb(void *arg, u8 *cqe, int status)
{
	struct efct_hw_send_frame_context *ctx = arg;
	struct efct_hw *hw = ctx->hw;

	/* Free WQ completion callback */
	efct_hw_reqtag_free(hw, ctx->wqcb);

	/* Free sequence */
	efct_hw_sequence_free(hw, ctx->seq);
}

static int
efct_sframe_common_send(struct efct_node *node,
			struct efc_hw_sequence *seq,
			enum fc_rctl r_ctl, u32 f_ctl,
			u8 type, void *payload, u32 payload_len)
{
	struct efct *efct = node->efct;
	struct efct_hw *hw = &efct->hw;
	int rc = 0;
	struct fc_frame_header *req_hdr = seq->header->dma.virt;
	struct fc_frame_header hdr;
	struct efct_hw_send_frame_context *ctx;

	u32 heap_size = seq->payload->dma.size;
	uintptr_t heap_phys_base = seq->payload->dma.phys;
	u8 *heap_virt_base = seq->payload->dma.virt;
	u32 heap_offset = 0;

	/* Build the FC header reusing the RQ header DMA buffer */
	memset(&hdr, 0, sizeof(hdr));
	hdr.fh_r_ctl = r_ctl;
	/* send it back to whomever sent it to us */
	memcpy(hdr.fh_d_id, req_hdr->fh_s_id, sizeof(hdr.fh_d_id));
	memcpy(hdr.fh_s_id, req_hdr->fh_d_id, sizeof(hdr.fh_s_id));
	hdr.fh_type = type;
	hton24(hdr.fh_f_ctl, f_ctl);
	hdr.fh_ox_id = req_hdr->fh_ox_id;
	hdr.fh_rx_id = req_hdr->fh_rx_id;
	hdr.fh_cs_ctl = 0;
	hdr.fh_df_ctl = 0;
	hdr.fh_seq_cnt = 0;
	hdr.fh_parm_offset = 0;

	/*
	 * send_frame_seq_id is an atomic, we just let it increment,
	 * while storing only the low 8 bits to hdr->seq_id
	 */
	hdr.fh_seq_id = (u8)atomic_add_return(1, &hw->send_frame_seq_id);
	hdr.fh_seq_id--;

	/* Allocate and fill in the send frame request context */
	ctx = (void *)(heap_virt_base + heap_offset);
	heap_offset += sizeof(*ctx);
	if (heap_offset > heap_size) {
		efc_log_err(efct, "Fill send frame failed offset %d size %d\n",
			    heap_offset, heap_size);
		return -EIO;
	}

	memset(ctx, 0, sizeof(*ctx));

	/* Save sequence */
	ctx->seq = seq;

	/* Allocate a response payload DMA buffer from the heap */
	ctx->payload.phys = heap_phys_base + heap_offset;
	ctx->payload.virt = heap_virt_base + heap_offset;
	ctx->payload.size = payload_len;
	ctx->payload.len = payload_len;
	heap_offset += payload_len;
	if (heap_offset > heap_size) {
		efc_log_err(efct, "Fill send frame failed offset %d size %d\n",
			    heap_offset, heap_size);
		return -EIO;
	}

	/* Copy the payload in */
	memcpy(ctx->payload.virt, payload, payload_len);

	/* Send */
	rc = efct_hw_send_frame(&efct->hw, (void *)&hdr, FC_SOF_N3,
				FC_EOF_T, &ctx->payload, ctx,
				efct_sframe_common_send_cb, ctx);
	if (rc)
		efc_log_debug(efct, "efct_hw_send_frame failed: %d\n", rc);

	return rc;
}

static int
efct_sframe_send_fcp_rsp(struct efct_node *node, struct efc_hw_sequence *seq,
			 void *rsp, u32 rsp_len)
{
	return efct_sframe_common_send(node, seq, FC_RCTL_DD_CMD_STATUS,
				      FC_FC_EX_CTX |
				      FC_FC_LAST_SEQ |
				      FC_FC_END_SEQ |
				      FC_FC_SEQ_INIT,
				      FC_TYPE_FCP,
				      rsp, rsp_len);
}

static int
efct_sframe_send_task_set_full_or_busy(struct efct_node *node,
				       struct efc_hw_sequence *seq)
{
	struct fcp_resp_with_ext fcprsp;
	struct fcp_cmnd *fcpcmd = seq->payload->dma.virt;
	int rc = 0;
	unsigned long flags = 0;
	struct efct *efct = node->efct;

	/* construct task set full or busy response */
	memset(&fcprsp, 0, sizeof(fcprsp));
	spin_lock_irqsave(&node->active_ios_lock, flags);
	fcprsp.resp.fr_status = list_empty(&node->active_ios) ?
				SAM_STAT_BUSY : SAM_STAT_TASK_SET_FULL;
	spin_unlock_irqrestore(&node->active_ios_lock, flags);
	*((u32 *)&fcprsp.ext.fr_resid) = be32_to_cpu(fcpcmd->fc_dl);

	/* send it using send_frame */
	rc = efct_sframe_send_fcp_rsp(node, seq, &fcprsp, sizeof(fcprsp));
	if (rc)
		efc_log_debug(efct, "efct_sframe_send_fcp_rsp failed %d\n", rc);

	return rc;
}

int
efct_dispatch_fcp_cmd(struct efct_node *node, struct efc_hw_sequence *seq)
{
	struct efct *efct = node->efct;
	struct fc_frame_header *fchdr = seq->header->dma.virt;
	struct fcp_cmnd	*cmnd = NULL;
	struct efct_io *io = NULL;
	u32 lun;

	if (!seq->payload) {
		efc_log_err(efct, "Sequence payload is NULL.\n");
		return -EIO;
	}

	cmnd = seq->payload->dma.virt;

	/* perform FCP_CMND validation check(s) */
	if (efct_validate_fcp_cmd(efct, seq))
		return -EIO;

	lun = scsilun_to_int(&cmnd->fc_lun);
	if (lun == U32_MAX)
		return -EIO;

	io = efct_scsi_io_alloc(node);
	if (!io) {
		int rc;

		/* Use SEND_FRAME to send task set full or busy */
		rc = efct_sframe_send_task_set_full_or_busy(node, seq);
		if (rc)
			efc_log_err(efct, "Failed to send busy task: %d\n", rc);

		return rc;
	}

	io->hw_priv = seq->hw_priv;

	io->app_id = 0;

	/* RQ pair, if we got here, SIT=1 */
	efct_populate_io_fcp_cmd(io, cmnd, fchdr, true);

	if (cmnd->fc_tm_flags) {
		efct_dispatch_unsol_tmf(io, cmnd->fc_tm_flags, lun);
	} else {
		u32 flags = efct_get_flags_fcp_cmd(cmnd);

		if (cmnd->fc_flags & FCP_CFL_LEN_MASK) {
			efc_log_err(efct, "Additional CDB not supported\n");
			return -EIO;
		}
		/*
		 * Can return failure for things like task set full and UAs,
		 * no need to treat as a dropped frame if rc != 0
		 */
		efct_scsi_recv_cmd(io, lun, cmnd->fc_cdb,
				   sizeof(cmnd->fc_cdb), flags);
	}

	return 0;
}

static int
efct_process_abts(struct efct_io *io, struct fc_frame_header *hdr)
{
	struct efct_node *node = io->node;
	struct efct *efct = io->efct;
	u16 ox_id = be16_to_cpu(hdr->fh_ox_id);
	u16 rx_id = be16_to_cpu(hdr->fh_rx_id);
	struct efct_io *abortio;

	/* Find IO and attempt to take a reference on it */
	abortio = efct_io_find_tgt_io(efct, node, ox_id, rx_id);

	if (abortio) {
		/* Got a reference on the IO. Hold it until backend
		 * is notified below
		 */
		efc_log_info(node->efct, "Abort ox_id [%04x] rx_id [%04x]\n",
			     ox_id, rx_id);

		/*
		 * Save the ox_id for the ABTS as the init_task_tag in our
		 * manufactured
		 * TMF IO object
		 */
		io->display_name = "abts";
		io->init_task_tag = ox_id;
		/* don't set tgt_task_tag, don't want to confuse with XRI */

		/*
		 * Save the rx_id from the ABTS as it is
		 * needed for the BLS response,
		 * regardless of the IO context's rx_id
		 */
		io->abort_rx_id = rx_id;

		/* Call target server command abort */
		io->tmf_cmd = EFCT_SCSI_TMF_ABORT_TASK;
		efct_scsi_recv_tmf(io, abortio->tgt_io.lun,
				   EFCT_SCSI_TMF_ABORT_TASK, abortio, 0);

		/*
		 * Backend will have taken an additional
		 * reference on the IO if needed;
		 * done with current reference.
		 */
		kref_put(&abortio->ref, abortio->release);
	} else {
		/*
		 * Either IO was not found or it has been
		 * freed between finding it
		 * and attempting to get the reference,
		 */
		efc_log_info(node->efct, "Abort: ox_id [%04x], IO not found\n",
			     ox_id);

		/* Send a BA_RJT */
		efct_bls_send_rjt(io, hdr);
	}
	return 0;
}

int
efct_node_recv_abts_frame(struct efct_node *node, struct efc_hw_sequence *seq)
{
	struct efct *efct = node->efct;
	struct fc_frame_header *hdr = seq->header->dma.virt;
	struct efct_io *io = NULL;

	node->abort_cnt++;
	io = efct_scsi_io_alloc(node);
	if (io) {
		io->hw_priv = seq->hw_priv;
		/* If we got this far, SIT=1 */
		io->seq_init = 1;

		/* fill out generic fields */
		io->efct = efct;
		io->node = node;
		io->cmd_tgt = true;

		efct_process_abts(io, seq->header->dma.virt);
	} else {
		efc_log_err(efct,
			    "SCSI IO allocation failed for ABTS received ");
		efc_log_err(efct, "s_id %06x d_id %06x ox_id %04x rx_id %04x\n",
			    ntoh24(hdr->fh_s_id), ntoh24(hdr->fh_d_id),
			    be16_to_cpu(hdr->fh_ox_id),
			    be16_to_cpu(hdr->fh_rx_id));
	}

	return 0;
}