/*
   * SCLP "store data in absolute storage"
   *
   * Copyright IBM Corp. 2003, 2013
   * Author(s): Michael Holzheu
   */
  
  #define KMSG_COMPONENT "sclp_sdias"
  #define pr_fmt(fmt) KMSG_COMPONENT ": " fmt
  
  #include <linux/completion.h>
  #include <linux/sched.h>
  #include <asm/sclp.h>
  #include <asm/debug.h>
  #include <asm/ipl.h>
  
  #include "sclp_sdias.h"
  #include "sclp.h"
  #include "sclp_rw.h"
  
  #define TRACE(x...) debug_sprintf_event(sdias_dbf, 1, x)
  
  #define SDIAS_RETRIES 300
  
  static struct debug_info *sdias_dbf;
  
  static struct sclp_register sclp_sdias_register = {
  	.send_mask = EVTYP_SDIAS_MASK,
  };
  
  static struct sdias_sccb sccb __attribute__((aligned(4096)));
  static struct sdias_evbuf sdias_evbuf;
  
  static DECLARE_COMPLETION(evbuf_accepted);
  static DECLARE_COMPLETION(evbuf_done);
  static DEFINE_MUTEX(sdias_mutex);
  
  /*
   * Called by SCLP base when read event data has been completed (async mode only)
   */
  static void sclp_sdias_receiver_fn(struct evbuf_header *evbuf)
  {
  	memcpy(&sdias_evbuf, evbuf,
  	       min_t(unsigned long, sizeof(sdias_evbuf), evbuf->length));
  	complete(&evbuf_done);
  	TRACE("sclp_sdias_receiver_fn done
  ");
  }
  
  /*
   * Called by SCLP base when sdias event has been accepted
   */
  static void sdias_callback(struct sclp_req *request, void *data)
  {
  	complete(&evbuf_accepted);
  	TRACE("callback done
  ");
  }
  
  static int sdias_sclp_send(struct sclp_req *req)
  {
  	int retries;
  	int rc;
  
  	for (retries = SDIAS_RETRIES; retries; retries--) {
  		TRACE("add request
  ");
  		rc = sclp_add_request(req);
  		if (rc) {
  			/* not initiated, wait some time and retry */
  			set_current_state(TASK_INTERRUPTIBLE);
  			TRACE("add request failed: rc = %i
  ",rc);
  			schedule_timeout(msecs_to_jiffies(500));
  			continue;
  		}
  		/* initiated, wait for completion of service call */
  		wait_for_completion(&evbuf_accepted);
  		if (req->status == SCLP_REQ_FAILED) {
  			TRACE("sclp request failed
  ");
  			continue;
  		}
  		/* if not accepted, retry */
  		if (!(sccb.evbuf.hdr.flags & 0x80)) {
  			TRACE("sclp request failed: flags=%x
  ",
  			      sccb.evbuf.hdr.flags);
  			continue;
  		}
  		/*
  		 * for the sync interface the response is in the initial sccb
  		 */
  		if (!sclp_sdias_register.receiver_fn) {
  			memcpy(&sdias_evbuf, &sccb.evbuf, sizeof(sdias_evbuf));
  			TRACE("sync request done
  ");
  			return 0;
  		}
  		/* otherwise we wait for completion */
  		wait_for_completion(&evbuf_done);
  		TRACE("request done
  ");
  		return 0;
  	}
  	return -EIO;
  }
  
  /*
   * Get number of blocks (4K) available in the HSA
   */
  int sclp_sdias_blk_count(void)
  {
  	struct sclp_req request;
  	int rc;
  
  	mutex_lock(&sdias_mutex);
  
  	memset(&sccb, 0, sizeof(sccb));
  	memset(&request, 0, sizeof(request));
  
  	sccb.hdr.length = sizeof(sccb);
  	sccb.evbuf.hdr.length = sizeof(struct sdias_evbuf);
  	sccb.evbuf.hdr.type = EVTYP_SDIAS;
  	sccb.evbuf.event_qual = SDIAS_EQ_SIZE;
  	sccb.evbuf.data_id = SDIAS_DI_FCP_DUMP;
  	sccb.evbuf.event_id = 4712;
  	sccb.evbuf.dbs = 1;
  
  	request.sccb = &sccb;
  	request.command = SCLP_CMDW_WRITE_EVENT_DATA;
  	request.status = SCLP_REQ_FILLED;
  	request.callback = sdias_callback;
  
  	rc = sdias_sclp_send(&request);
  	if (rc) {
  		pr_err("sclp_send failed for get_nr_blocks
  ");
  		goto out;
  	}
  	if (sccb.hdr.response_code != 0x0020) {
  		TRACE("send failed: %x
  ", sccb.hdr.response_code);
  		rc = -EIO;
  		goto out;
  	}
  
  	switch (sdias_evbuf.event_status) {
  		case 0:
  			rc = sdias_evbuf.blk_cnt;
  			break;
  		default:
  			pr_err("SCLP error: %x
  ", sdias_evbuf.event_status);
  			rc = -EIO;
  			goto out;
  	}
  	TRACE("%i blocks
  ", rc);
  out:
  	mutex_unlock(&sdias_mutex);
  	return rc;
  }
  
  /*
   * Copy from HSA to absolute storage (not reentrant):
   *
   * @dest     : Address of buffer where data should be copied
   * @start_blk: Start Block (beginning with 1)
   * @nr_blks  : Number of 4K blocks to copy
   *
   * Return Value: 0 : Requested 'number' of blocks of data copied
   *		 <0: ERROR - negative event status
   */
  int sclp_sdias_copy(void *dest, int start_blk, int nr_blks)
  {
  	struct sclp_req request;
  	int rc;
  
  	mutex_lock(&sdias_mutex);
  
  	memset(&sccb, 0, sizeof(sccb));
  	memset(&request, 0, sizeof(request));
  
  	sccb.hdr.length = sizeof(sccb);
  	sccb.evbuf.hdr.length = sizeof(struct sdias_evbuf);
  	sccb.evbuf.hdr.type = EVTYP_SDIAS;
  	sccb.evbuf.hdr.flags = 0;
  	sccb.evbuf.event_qual = SDIAS_EQ_STORE_DATA;
  	sccb.evbuf.data_id = SDIAS_DI_FCP_DUMP;
  	sccb.evbuf.event_id = 4712;
  	sccb.evbuf.asa_size = SDIAS_ASA_SIZE_64;
  	sccb.evbuf.event_status = 0;
  	sccb.evbuf.blk_cnt = nr_blks;
  	sccb.evbuf.asa = (unsigned long)dest;
  	sccb.evbuf.fbn = start_blk;
  	sccb.evbuf.lbn = 0;
  	sccb.evbuf.dbs = 1;
  
  	request.sccb	 = &sccb;
  	request.command  = SCLP_CMDW_WRITE_EVENT_DATA;
  	request.status	 = SCLP_REQ_FILLED;
  	request.callback = sdias_callback;
  
  	rc = sdias_sclp_send(&request);
  	if (rc) {
  		pr_err("sclp_send failed: %x
  ", rc);
  		goto out;
  	}
  	if (sccb.hdr.response_code != 0x0020) {
  		TRACE("copy failed: %x
  ", sccb.hdr.response_code);
  		rc = -EIO;
  		goto out;
  	}
  
  	switch (sdias_evbuf.event_status) {
  	case SDIAS_EVSTATE_ALL_STORED:
  		TRACE("all stored
  ");
  		break;
  	case SDIAS_EVSTATE_PART_STORED:
  		TRACE("part stored: %i
  ", sdias_evbuf.blk_cnt);
  		break;
  	case SDIAS_EVSTATE_NO_DATA:
  		TRACE("no data
  ");
  		/* fall through */
  	default:
  		pr_err("Error from SCLP while copying hsa. Event status = %x
  ",
  		       sdias_evbuf.event_status);
  		rc = -EIO;
  	}
  out:
  	mutex_unlock(&sdias_mutex);
  	return rc;
  }
  
  static int __init sclp_sdias_register_check(void)
  {
  	int rc;
  
  	rc = sclp_register(&sclp_sdias_register);
  	if (rc)
  		return rc;
  	if (sclp_sdias_blk_count() == 0) {
  		sclp_unregister(&sclp_sdias_register);
  		return -ENODEV;
  	}
  	return 0;
  }
  
  static int __init sclp_sdias_init_sync(void)
  {
  	TRACE("Try synchronous mode
  ");
  	sclp_sdias_register.receive_mask = 0;
  	sclp_sdias_register.receiver_fn = NULL;
  	return sclp_sdias_register_check();
  }
  
  static int __init sclp_sdias_init_async(void)
  {
  	TRACE("Try asynchronous mode
  ");
  	sclp_sdias_register.receive_mask = EVTYP_SDIAS_MASK;
  	sclp_sdias_register.receiver_fn = sclp_sdias_receiver_fn;
  	return sclp_sdias_register_check();
  }
  
  int __init sclp_sdias_init(void)
  {
  	if (ipl_info.type != IPL_TYPE_FCP_DUMP)
  		return 0;
  	sdias_dbf = debug_register("dump_sdias", 4, 1, 4 * sizeof(long));
  	debug_register_view(sdias_dbf, &debug_sprintf_view);
  	debug_set_level(sdias_dbf, 6);
  	if (sclp_sdias_init_sync() == 0)
  		goto out;
  	if (sclp_sdias_init_async() == 0)
  		goto out;
  	TRACE("init failed
  ");
  	return -ENODEV;
  out:
  	TRACE("init done
  ");
  	return 0;
  }
  
  void __exit sclp_sdias_exit(void)
  {
  	debug_unregister(sdias_dbf);
  	sclp_unregister(&sclp_sdias_register);
  }