/*
   * Copyright 2014 Cisco Systems, Inc.  All rights reserved.
   *
   * This program is free software; you may redistribute it and/or modify
   * it under the terms of the GNU General Public License as published by
   * the Free Software Foundation; version 2 of the License.
   *
   * THE SOFTWARE IS PROVIDED "AS IS", WITHOUT WARRANTY OF ANY KIND,
   * EXPRESS OR IMPLIED, INCLUDING BUT NOT LIMITED TO THE WARRANTIES OF
   * MERCHANTABILITY, FITNESS FOR A PARTICULAR PURPOSE AND
   * NONINFRINGEMENT. IN NO EVENT SHALL THE AUTHORS OR COPYRIGHT HOLDERS
   * BE LIABLE FOR ANY CLAIM, DAMAGES OR OTHER LIABILITY, WHETHER IN AN
   * ACTION OF CONTRACT, TORT OR OTHERWISE, ARISING FROM, OUT OF OR IN
   * CONNECTION WITH THE SOFTWARE OR THE USE OR OTHER DEALINGS IN THE
   * SOFTWARE.
   */
  
  #include <linux/errno.h>
  #include <linux/pci.h>
  #include <linux/slab.h>
  
  #include <linux/interrupt.h>
  #include <linux/workqueue.h>
  #include <linux/spinlock.h>
  #include <linux/mempool.h>
  #include <scsi/scsi_tcq.h>
  #include <linux/ctype.h>
  
  #include "snic_io.h"
  #include "snic.h"
  #include "cq_enet_desc.h"
  #include "snic_fwint.h"
  
  /*
   * snic_handle_link : Handles link flaps.
   */
  void
  snic_handle_link(struct work_struct *work)
  {
  	struct snic *snic = container_of(work, struct snic, link_work);
  
  	if (snic->config.xpt_type != SNIC_DAS) {
  		SNIC_HOST_INFO(snic->shost, "Link Event Received.
  ");
  		SNIC_ASSERT_NOT_IMPL(1);
  
  		return;
  	}
  
  	snic->link_status = svnic_dev_link_status(snic->vdev);
  	snic->link_down_cnt = svnic_dev_link_down_cnt(snic->vdev);
  	SNIC_HOST_INFO(snic->shost, "Link Event: Link %s.
  ",
  		       ((snic->link_status) ? "Up" : "Down"));
  }
  
  
  /*
   * snic_ver_enc : Encodes version str to int
   * version string is similar to netmask string
   */
  static int
  snic_ver_enc(const char *s)
  {
  	int v[4] = {0};
  	int  i = 0, x = 0;
  	char c;
  	const char *p = s;
  
  	/* validate version string */
  	if ((strlen(s) > 15) || (strlen(s) < 7))
  		goto end;
  
  	while ((c = *p++)) {
  		if (c == '.') {
  			i++;
  			continue;
  		}
  
  		if (i > 4 || !isdigit(c))
  			goto end;
  
  		v[i] = v[i] * 10 + (c - '0');
  	}
  
  	/* validate sub version numbers */
  	for (i = 3; i >= 0; i--)
  		if (v[i] > 0xff)
  			goto end;
  
  	x |= (v[0] << 24) | v[1] << 16 | v[2] << 8 | v[3];
  
  end:
  	if (x == 0) {
  		SNIC_ERR("Invalid version string [%s].
  ", s);
  
  		return -1;
  	}
  
  	return x;
  } /* end of snic_ver_enc */
  
  /*
   * snic_qeueue_exch_ver_req :
   *
   * Queues Exchange Version Request, to communicate host information
   * in return, it gets firmware version details
   */
  int
  snic_queue_exch_ver_req(struct snic *snic)
  {
  	struct snic_req_info *rqi = NULL;
  	struct snic_host_req *req = NULL;
  	u32 ver = 0;
  	int ret = 0;
  
  	SNIC_HOST_INFO(snic->shost, "Exch Ver Req Preparing...
  ");
  
  	rqi = snic_req_init(snic, 0);
  	if (!rqi) {
  		SNIC_HOST_ERR(snic->shost,
  			      "Queuing Exch Ver Req failed, err = %d
  ",
  			      ret);
  
  		ret = -ENOMEM;
  		goto error;
  	}
  
  	req = rqi_to_req(rqi);
  
  	/* Initialize snic_host_req */
  	snic_io_hdr_enc(&req->hdr, SNIC_REQ_EXCH_VER, 0, SCSI_NO_TAG,
  			snic->config.hid, 0, (ulong)rqi);
  	ver = snic_ver_enc(SNIC_DRV_VERSION);
  	req->u.exch_ver.drvr_ver = cpu_to_le32(ver);
  	req->u.exch_ver.os_type = cpu_to_le32(SNIC_OS_LINUX);
  
  	snic_handle_untagged_req(snic, rqi);
  
  	ret = snic_queue_wq_desc(snic, req, sizeof(*req));
  	if (ret) {
  		snic_release_untagged_req(snic, rqi);
  		SNIC_HOST_ERR(snic->shost,
  			      "Queuing Exch Ver Req failed, err = %d
  ",
  			      ret);
  		goto error;
  	}
  
  	SNIC_HOST_INFO(snic->shost, "Exch Ver Req is issued. ret = %d
  ", ret);
  
  error:
  	return ret;
  } /* end of snic_queue_exch_ver_req */
  
  /*
   * snic_io_exch_ver_cmpl_handler
   */
  int
  snic_io_exch_ver_cmpl_handler(struct snic *snic, struct snic_fw_req *fwreq)
  {
  	struct snic_req_info *rqi = NULL;
  	struct snic_exch_ver_rsp *exv_cmpl = &fwreq->u.exch_ver_cmpl;
  	u8 typ, hdr_stat;
  	u32 cmnd_id, hid, max_sgs;
  	ulong ctx = 0;
  	unsigned long flags;
  	int ret = 0;
  
  	SNIC_HOST_INFO(snic->shost, "Exch Ver Compl Received.
  ");
  	snic_io_hdr_dec(&fwreq->hdr, &typ, &hdr_stat, &cmnd_id, &hid, &ctx);
  	SNIC_BUG_ON(snic->config.hid != hid);
  	rqi = (struct snic_req_info *) ctx;
  
  	if (hdr_stat) {
  		SNIC_HOST_ERR(snic->shost,
  			      "Exch Ver Completed w/ err status %d
  ",
  			      hdr_stat);
  
  		goto exch_cmpl_end;
  	}
  
  	spin_lock_irqsave(&snic->snic_lock, flags);
  	snic->fwinfo.fw_ver = le32_to_cpu(exv_cmpl->version);
  	snic->fwinfo.hid = le32_to_cpu(exv_cmpl->hid);
  	snic->fwinfo.max_concur_ios = le32_to_cpu(exv_cmpl->max_concur_ios);
  	snic->fwinfo.max_sgs_per_cmd = le32_to_cpu(exv_cmpl->max_sgs_per_cmd);
  	snic->fwinfo.max_io_sz = le32_to_cpu(exv_cmpl->max_io_sz);
  	snic->fwinfo.max_tgts = le32_to_cpu(exv_cmpl->max_tgts);
  	snic->fwinfo.io_tmo = le16_to_cpu(exv_cmpl->io_timeout);
  
  	SNIC_HOST_INFO(snic->shost,
  		       "vers %u hid %u max_concur_ios %u max_sgs_per_cmd %u max_io_sz %u max_tgts %u fw tmo %u
  ",
  		       snic->fwinfo.fw_ver,
  		       snic->fwinfo.hid,
  		       snic->fwinfo.max_concur_ios,
  		       snic->fwinfo.max_sgs_per_cmd,
  		       snic->fwinfo.max_io_sz,
  		       snic->fwinfo.max_tgts,
  		       snic->fwinfo.io_tmo);
  
  	SNIC_HOST_INFO(snic->shost,
  		       "HBA Capabilities = 0x%x
  ",
  		       le32_to_cpu(exv_cmpl->hba_cap));
  
  	/* Updating SGList size */
  	max_sgs = snic->fwinfo.max_sgs_per_cmd;
  	if (max_sgs && max_sgs < SNIC_MAX_SG_DESC_CNT) {
  		snic->shost->sg_tablesize = max_sgs;
  		SNIC_HOST_INFO(snic->shost, "Max SGs set to %d
  ",
  			       snic->shost->sg_tablesize);
  	} else if (max_sgs > snic->shost->sg_tablesize) {
  		SNIC_HOST_INFO(snic->shost,
  			       "Target type %d Supports Larger Max SGList %d than driver's Max SG List %d.
  ",
  			       snic->config.xpt_type, max_sgs,
  			       snic->shost->sg_tablesize);
  	}
  
  	if (snic->shost->can_queue > snic->fwinfo.max_concur_ios)
  		snic->shost->can_queue = snic->fwinfo.max_concur_ios;
  
  	snic->shost->max_sectors = snic->fwinfo.max_io_sz >> 9;
  	if (snic->fwinfo.wait)
  		complete(snic->fwinfo.wait);
  
  	spin_unlock_irqrestore(&snic->snic_lock, flags);
  
  exch_cmpl_end:
  	snic_release_untagged_req(snic, rqi);
  
  	SNIC_HOST_INFO(snic->shost, "Exch_cmpl Done, hdr_stat %d.
  ", hdr_stat);
  
  	return ret;
  } /* end of snic_io_exch_ver_cmpl_handler */
  
  /*
   * snic_get_conf
   *
   * Synchronous call, and Retrieves snic params.
   */
  int
  snic_get_conf(struct snic *snic)
  {
  	DECLARE_COMPLETION_ONSTACK(wait);
  	unsigned long flags;
  	int ret;
  	int nr_retries = 3;
  
  	SNIC_HOST_INFO(snic->shost, "Retrieving snic params.
  ");
  	spin_lock_irqsave(&snic->snic_lock, flags);
  	memset(&snic->fwinfo, 0, sizeof(snic->fwinfo));
  	snic->fwinfo.wait = &wait;
  	spin_unlock_irqrestore(&snic->snic_lock, flags);
  
  	/* Additional delay to handle HW Resource initialization. */
  	msleep(50);
  
  	/*
  	 * Exch ver req can be ignored by FW, if HW Resource initialization
  	 * is in progress, Hence retry.
  	 */
  	do {
  		ret = snic_queue_exch_ver_req(snic);
  		if (ret)
  			return ret;
  
  		wait_for_completion_timeout(&wait, msecs_to_jiffies(2000));
  		spin_lock_irqsave(&snic->snic_lock, flags);
  		ret = (snic->fwinfo.fw_ver != 0) ? 0 : -ETIMEDOUT;
  		if (ret)
  			SNIC_HOST_ERR(snic->shost,
  				      "Failed to retrieve snic params,
  ");
  
  		/* Unset fwinfo.wait, on success or on last retry */
  		if (ret == 0 || nr_retries == 1)
  			snic->fwinfo.wait = NULL;
  
  		spin_unlock_irqrestore(&snic->snic_lock, flags);
  	} while (ret && --nr_retries);
  
  	return ret;
  } /* end of snic_get_info */