zfcp_qdio.c

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/*
 * This file is part of the zfcp device driver for
 * FCP adapters for IBM System z9 and zSeries.
 *
 * (C) Copyright IBM Corp. 2002, 2006
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License as published by
 * the Free Software Foundation; either version 2, or (at your option)
 * any later version.
 *
 * This program is distributed in the hope that it will be useful,
 * but WITHOUT ANY WARRANTY; without even the implied warranty of
 * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 * GNU General Public License for more details.
 *
 * You should have received a copy of the GNU General Public License
 * along with this program; if not, write to the Free Software
 * Foundation, Inc., 675 Mass Ave, Cambridge, MA 02139, USA.
 */

#include "zfcp_ext.h"

static void zfcp_qdio_sbal_limit(struct zfcp_fsf_req *, int);
static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_get
	(struct zfcp_qdio_queue *, int, int);
static inline volatile struct qdio_buffer_element *zfcp_qdio_sbale_resp
	(struct zfcp_fsf_req *, int, int);
static volatile struct qdio_buffer_element *zfcp_qdio_sbal_chain
	(struct zfcp_fsf_req *, unsigned long);
static volatile struct qdio_buffer_element *zfcp_qdio_sbale_next
	(struct zfcp_fsf_req *, unsigned long);
static int zfcp_qdio_sbals_zero(struct zfcp_qdio_queue *, int, int);
static inline int zfcp_qdio_sbals_wipe(struct zfcp_fsf_req *);
static void zfcp_qdio_sbale_fill
	(struct zfcp_fsf_req *, unsigned long, void *, int);
static int zfcp_qdio_sbals_from_segment
	(struct zfcp_fsf_req *, unsigned long, void *, unsigned long);

static qdio_handler_t zfcp_qdio_request_handler;
static qdio_handler_t zfcp_qdio_response_handler;
static int zfcp_qdio_handler_error_check(struct zfcp_adapter *,
	unsigned int, unsigned int, unsigned int, int, int);

#define ZFCP_LOG_AREA                   ZFCP_LOG_AREA_QDIO

/*
 * Frees BUFFER memory for each of the pointers of the struct qdio_buffer array
 * in the adapter struct sbuf is the pointer array.
 *
 * locks:       must only be called with zfcp_data.config_sema taken
 */
static void
zfcp_qdio_buffers_dequeue(struct qdio_buffer **sbuf)
{
	int pos;

	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE)
		free_page((unsigned long) sbuf[pos]);
}

/*
 * Allocates BUFFER memory to each of the pointers of the qdio_buffer_t
 * array in the adapter struct.
 * Cur_buf is the pointer array
 *
 * returns:	zero on success else -ENOMEM
 * locks:       must only be called with zfcp_data.config_sema taken
 */
static int
zfcp_qdio_buffers_enqueue(struct qdio_buffer **sbuf)
{
	int pos;

	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos += QBUFF_PER_PAGE) {
		sbuf[pos] = (struct qdio_buffer *) get_zeroed_page(GFP_KERNEL);
		if (!sbuf[pos]) {
			zfcp_qdio_buffers_dequeue(sbuf);
			return -ENOMEM;
		}
	}
	for (pos = 0; pos < QDIO_MAX_BUFFERS_PER_Q; pos++)
		if (pos % QBUFF_PER_PAGE)
			sbuf[pos] = sbuf[pos - 1] + 1;
	return 0;
}

/* locks:       must only be called with zfcp_data.config_sema taken */
int
zfcp_qdio_allocate_queues(struct zfcp_adapter *adapter)
{
	int ret;

	ret = zfcp_qdio_buffers_enqueue(adapter->request_queue.buffer);
	if (ret)
		return ret;
	return zfcp_qdio_buffers_enqueue(adapter->response_queue.buffer);
}

/* locks:       must only be called with zfcp_data.config_sema taken */
void
zfcp_qdio_free_queues(struct zfcp_adapter *adapter)
{
	ZFCP_LOG_TRACE("freeing request_queue buffers\n");
	zfcp_qdio_buffers_dequeue(adapter->request_queue.buffer);

	ZFCP_LOG_TRACE("freeing response_queue buffers\n");
	zfcp_qdio_buffers_dequeue(adapter->response_queue.buffer);
}

int
zfcp_qdio_allocate(struct zfcp_adapter *adapter)
{
	struct qdio_initialize *init_data;

	init_data = &adapter->qdio_init_data;

	init_data->cdev = adapter->ccw_device;
	init_data->q_format = QDIO_SCSI_QFMT;
	memcpy(init_data->adapter_name, zfcp_get_busid_by_adapter(adapter), 8);
	ASCEBC(init_data->adapter_name, 8);
	init_data->qib_param_field_format = 0;
	init_data->qib_param_field = NULL;
	init_data->input_slib_elements = NULL;
	init_data->output_slib_elements = NULL;
	init_data->min_input_threshold = ZFCP_MIN_INPUT_THRESHOLD;
	init_data->max_input_threshold = ZFCP_MAX_INPUT_THRESHOLD;
	init_data->min_output_threshold = ZFCP_MIN_OUTPUT_THRESHOLD;
	init_data->max_output_threshold = ZFCP_MAX_OUTPUT_THRESHOLD;
	init_data->no_input_qs = 1;
	init_data->no_output_qs = 1;
	init_data->input_handler = zfcp_qdio_response_handler;
	init_data->output_handler = zfcp_qdio_request_handler;
	init_data->int_parm = (unsigned long) adapter;
	init_data->flags = QDIO_INBOUND_0COPY_SBALS |
	    QDIO_OUTBOUND_0COPY_SBALS | QDIO_USE_OUTBOUND_PCIS;
	init_data->input_sbal_addr_array =
	    (void **) (adapter->response_queue.buffer);
	init_data->output_sbal_addr_array =
	    (void **) (adapter->request_queue.buffer);

	return qdio_allocate(init_data);
}

/*
 * function:   	zfcp_qdio_handler_error_check
 *
 * purpose:     called by the response handler to determine error condition
 *
 * returns:	error flag
 *
 */
static int
zfcp_qdio_handler_error_check(struct zfcp_adapter *adapter, unsigned int status,
			      unsigned int qdio_error, unsigned int siga_error,
			      int first_element, int elements_processed)
{
	int retval = 0;

	if (unlikely(status & QDIO_STATUS_LOOK_FOR_ERROR)) {
		retval = -EIO;

		ZFCP_LOG_INFO("QDIO problem occurred (status=0x%x, "
			      "qdio_error=0x%x, siga_error=0x%x)\n",
			      status, qdio_error, siga_error);

		zfcp_hba_dbf_event_qdio(adapter, status, qdio_error, siga_error,
				first_element, elements_processed);
               /*
               	* Restarting IO on the failed adapter from scratch.
                * Since we have been using this adapter, it is save to assume
                * that it is not failed but recoverable. The card seems to
                * report link-up events by self-initiated queue shutdown.
                * That is why we need to clear the link-down flag
                * which is set again in case we have missed by a mile.
                */
		zfcp_erp_adapter_reopen(adapter,
				       ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
				       ZFCP_STATUS_COMMON_ERP_FAILED);
	}
	return retval;
}

/*
 * function:    zfcp_qdio_request_handler
 *
 * purpose:	is called by QDIO layer for completed SBALs in request queue
 *
 * returns:	(void)
 */
static void
zfcp_qdio_request_handler(struct ccw_device *ccw_device,
			  unsigned int status,
			  unsigned int qdio_error,
			  unsigned int siga_error,
			  unsigned int queue_number,
			  int first_element,
			  int elements_processed,
			  unsigned long int_parm)
{
	struct zfcp_adapter *adapter;
	struct zfcp_qdio_queue *queue;

	adapter = (struct zfcp_adapter *) int_parm;
	queue = &adapter->request_queue;

	ZFCP_LOG_DEBUG("adapter %s, first=%d, elements_processed=%d\n",
		       zfcp_get_busid_by_adapter(adapter),
		       first_element, elements_processed);

	if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
						   siga_error, first_element,
						   elements_processed)))
		goto out;
	/*
	 * we stored address of struct zfcp_adapter  data structure
	 * associated with irq in int_parm
	 */

	/* cleanup all SBALs being program-owned now */
	zfcp_qdio_zero_sbals(queue->buffer, first_element, elements_processed);

	/* increase free space in outbound queue */
	atomic_add(elements_processed, &queue->free_count);
	ZFCP_LOG_DEBUG("free_count=%d\n", atomic_read(&queue->free_count));
	wake_up(&adapter->request_wq);
	ZFCP_LOG_DEBUG("elements_processed=%d, free count=%d\n",
		       elements_processed, atomic_read(&queue->free_count));
 out:
	return;
}

/**
 * zfcp_qdio_reqid_check - checks for valid reqids.
 */
static void zfcp_qdio_reqid_check(struct zfcp_adapter *adapter,
				  unsigned long req_id)
{
	struct zfcp_fsf_req *fsf_req;
	unsigned long flags;

	debug_long_event(adapter->erp_dbf, 4, req_id);

	spin_lock_irqsave(&adapter->req_list_lock, flags);
	fsf_req = zfcp_reqlist_find(adapter, req_id);

	if (!fsf_req)
		/*
		 * Unknown request means that we have potentially memory
		 * corruption and must stop the machine immediatly.
		 */
		panic("error: unknown request id (%ld) on adapter %s.\n",
		      req_id, zfcp_get_busid_by_adapter(adapter));

	zfcp_reqlist_remove(adapter, fsf_req);
	atomic_dec(&adapter->reqs_active);
	spin_unlock_irqrestore(&adapter->req_list_lock, flags);

	/* finish the FSF request */
	zfcp_fsf_req_complete(fsf_req);
}

/*
 * function:   	zfcp_qdio_response_handler
 *
 * purpose:	is called by QDIO layer for completed SBALs in response queue
 *
 * returns:	(void)
 */
static void
zfcp_qdio_response_handler(struct ccw_device *ccw_device,
			   unsigned int status,
			   unsigned int qdio_error,
			   unsigned int siga_error,
			   unsigned int queue_number,
			   int first_element,
			   int elements_processed,
			   unsigned long int_parm)
{
	struct zfcp_adapter *adapter;
	struct zfcp_qdio_queue *queue;
	int buffer_index;
	int i;
	struct qdio_buffer *buffer;
	int retval = 0;
	u8 count;
	u8 start;
	volatile struct qdio_buffer_element *buffere = NULL;
	int buffere_index;

	adapter = (struct zfcp_adapter *) int_parm;
	queue = &adapter->response_queue;

	if (unlikely(zfcp_qdio_handler_error_check(adapter, status, qdio_error,
						   siga_error, first_element,
						   elements_processed)))
		goto out;

	/*
	 * we stored address of struct zfcp_adapter  data structure
	 * associated with irq in int_parm
	 */

	buffere = &(queue->buffer[first_element]->element[0]);
	ZFCP_LOG_DEBUG("first BUFFERE flags=0x%x\n", buffere->flags);
	/*
	 * go through all SBALs from input queue currently
	 * returned by QDIO layer
	 */

	for (i = 0; i < elements_processed; i++) {

		buffer_index = first_element + i;
		buffer_index %= QDIO_MAX_BUFFERS_PER_Q;
		buffer = queue->buffer[buffer_index];

		/* go through all SBALEs of SBAL */
		for (buffere_index = 0;
		     buffere_index < QDIO_MAX_ELEMENTS_PER_BUFFER;
		     buffere_index++) {

			/* look for QDIO request identifiers in SB */
			buffere = &buffer->element[buffere_index];
			zfcp_qdio_reqid_check(adapter,
					      (unsigned long) buffere->addr);

			/*
			 * A single used SBALE per inbound SBALE has been
			 * implemented by QDIO so far. Hope they will
			 * do some optimisation. Will need to change to
			 * unlikely() then.
			 */
			if (likely(buffere->flags & SBAL_FLAGS_LAST_ENTRY))
				break;
		};

		if (unlikely(!(buffere->flags & SBAL_FLAGS_LAST_ENTRY))) {
			ZFCP_LOG_NORMAL("bug: End of inbound data "
					"not marked!\n");
		}
	}

	/*
	 * put range of SBALs back to response queue
	 * (including SBALs which have already been free before)
	 */
	count = atomic_read(&queue->free_count) + elements_processed;