path: root/drivers/s390/scsi/zfcp_qdio.c

// SPDX-License-Identifier: GPL-2.0
/*
 * zfcp device driver
 *
 * Setup and helper functions to access QDIO.
 *
 * Copyright IBM Corp. 2002, 2020
 */

#define KMSG_COMPONENT "zfcp"
#define pr_fmt(fmt) KMSG_COMPONENT ": " fmt

#include <linux/lockdep.h>
#include <linux/slab.h>
#include <linux/module.h>
#include "zfcp_ext.h"
#include "zfcp_qdio.h"

static bool enable_multibuffer = true;
module_param_named(datarouter, enable_multibuffer, bool, 0400);
MODULE_PARM_DESC(datarouter, "Enable hardware data router support (default on)");

static void zfcp_qdio_handler_error(struct zfcp_qdio *qdio, char *dbftag,
				    unsigned int qdio_err)
{
	struct zfcp_adapter *adapter = qdio->adapter;

	dev_warn(&adapter->ccw_device->dev, "A QDIO problem occurred\n");

	if (qdio_err & QDIO_ERROR_SLSB_STATE) {
		zfcp_qdio_siosl(adapter);
		zfcp_erp_adapter_shutdown(adapter, 0, dbftag);
		return;
	}
	zfcp_erp_adapter_reopen(adapter,
				ZFCP_STATUS_ADAPTER_LINK_UNPLUGGED |
				ZFCP_STATUS_COMMON_ERP_FAILED, dbftag);
}

static void zfcp_qdio_zero_sbals(struct qdio_buffer *sbal[], int first, int cnt)
{
	int i, sbal_idx;

	for (i = first; i < first + cnt; i++) {
		sbal_idx = i % QDIO_MAX_BUFFERS_PER_Q;
		memset(sbal[sbal_idx], 0, sizeof(struct qdio_buffer));
	}
}

/* this needs to be called prior to updating the queue fill level */
static inline void zfcp_qdio_account(struct zfcp_qdio *qdio)
{
	unsigned long long now, span;
	int used;

	now = get_tod_clock_monotonic();
	span = (now - qdio->req_q_time) >> 12;
	used = QDIO_MAX_BUFFERS_PER_Q - atomic_read(&qdio->req_q_free);
	qdio->req_q_util += used * span;
	qdio->req_q_time = now;
}

static void zfcp_qdio_int_req(struct ccw_device *cdev, unsigned int qdio_err,
			      int queue_no, int idx, int count,
			      unsigned long parm)
{
	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;

	if (unlikely(qdio_err)) {
		zfcp_qdio_handler_error(qdio, "qdireq1", qdio_err);
		return;
	}

	/* cleanup all SBALs being program-owned now */
	zfcp_qdio_zero_sbals(qdio->req_q, idx, count);

	spin_lock_irq(&qdio->stat_lock);
	zfcp_qdio_account(qdio);
	spin_unlock_irq(&qdio->stat_lock);
	atomic_add(count, &qdio->req_q_free);
	wake_up(&qdio->req_q_wq);
}

static void zfcp_qdio_int_resp(struct ccw_device *cdev, unsigned int qdio_err,
			       int queue_no, int idx, int count,
			       unsigned long parm)
{
	struct zfcp_qdio *qdio = (struct zfcp_qdio *) parm;
	struct zfcp_adapter *adapter = qdio->adapter;
	int sbal_no, sbal_idx;

	if (unlikely(qdio_err)) {
		if (zfcp_adapter_multi_buffer_active(adapter)) {
			void *pl[ZFCP_QDIO_MAX_SBALS_PER_REQ + 1];
			struct qdio_buffer_element *sbale;
			u64 req_id;
			u8 scount;

			memset(pl, 0,
			       ZFCP_QDIO_MAX_SBALS_PER_REQ * sizeof(void *));
			sbale = qdio->res_q[idx]->element;
			req_id = sbale->addr;
			scount = min(sbale->scount + 1,
				     ZFCP_QDIO_MAX_SBALS_PER_REQ + 1);
				     /* incl. signaling SBAL */

			for (sbal_no = 0; sbal_no < scount; sbal_no++) {
				sbal_idx = (idx + sbal_no) %
					QDIO_MAX_BUFFERS_PER_Q;
				pl[sbal_no] = qdio->res_q[sbal_idx];
			}
			zfcp_dbf_hba_def_err(adapter, req_id, scount, pl);
		}
		zfcp_qdio_handler_error(qdio, "qdires1", qdio_err);
		return;
	}

	/*
	 * go through all SBALs from input queue currently
	 * returned by QDIO layer
	 */
	for (sbal_no = 0; sbal_no < count; sbal_no++) {
		sbal_idx = (idx + sbal_no) % QDIO_MAX_BUFFERS_PER_Q;
		/* go through all SBALEs of SBAL */
		zfcp_fsf_reqid_check(qdio, sbal_idx);
	}

	/*
	 * put SBALs back to response queue
	 */
	if (do_QDIO(cdev, QDIO_FLAG_SYNC_INPUT, 0, idx, count))
		zfcp_erp_adapter_reopen(qdio->adapter, 0, "qdires2");
}

static void zfcp_qdio_irq_tasklet(struct tasklet_struct *tasklet)
{
	struct zfcp_qdio *qdio = from_tasklet(qdio, tasklet, irq_tasklet);
	struct ccw_device *cdev = qdio->adapter->ccw_device;
	unsigned int start, error;
	int completed;

	/* Check the Response Queue, and kick off the Request Queue tasklet: */
	completed = qdio_get_next_buffers(cdev, 0, &start, &error);
	if (completed < 0)
		return;
	if (completed > 0)
		zfcp_qdio_int_resp(cdev, error, 0, start, completed,
				   (unsigned long) qdio);

	if (qdio_start_irq(cdev))
		/* More work pending: */
		tasklet_schedule(&qdio->irq_tasklet);
}

static void zfcp_qdio_poll(struct ccw_device *cdev, unsigned long data)
{
	struct zfcp_qdio *qdio = (struct zfcp_qdio *) data;

	tasklet_schedule(&qdio->irq_tasklet);
}

static struct qdio_buffer_element *
zfcp_qdio_sbal_chain(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
{
	struct qdio_buffer_element *sbale;

	/* set last entry flag in current SBALE of current SBAL */
	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
	sbale->eflags |= SBAL_EFLAGS_LAST_ENTRY;

	/* don't exceed last allowed SBAL */
	if (q_req->sbal_last == q_req->sbal_limit)
		return NULL;

	/* set chaining flag in first SBALE of current SBAL */
	sbale = zfcp_qdio_sbale_req(qdio, q_req);
	sbale->sflags |= SBAL_SFLAGS0_MORE_SBALS;

	/* calculate index of next SBAL */
	q_req->sbal_last++;
	q_req->sbal_last %= QDIO_MAX_BUFFERS_PER_Q;

	/* keep this requests number of SBALs up-to-date */
	q_req->sbal_number++;
	BUG_ON(q_req->sbal_number > ZFCP_QDIO_MAX_SBALS_PER_REQ);

	/* start at first SBALE of new SBAL */
	q_req->sbale_curr = 0;

	/* set storage-block type for new SBAL */
	sbale = zfcp_qdio_sbale_curr(qdio, q_req);
	sbale->sflags |= q_req->sbtype;

	return sbale;
}

static struct qdio_buffer_element *
zfcp_qdio_sbale_next(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req)
{
	if (q_req->sbale_curr == qdio->max_sbale_per_sbal - 1)
		return zfcp_qdio_sbal_chain(qdio, q_req);
	q_req->sbale_curr++;
	return zfcp_qdio_sbale_curr(qdio, q_req);
}

/**
 * zfcp_qdio_sbals_from_sg - fill SBALs from scatter-gather list
 * @qdio: pointer to struct zfcp_qdio
 * @q_req: pointer to struct zfcp_qdio_req
 * @sg: scatter-gather list
 * Returns: zero or -EINVAL on error
 */
int zfcp_qdio_sbals_from_sg(struct zfcp_qdio *qdio, struct zfcp_qdio_req *q_req,
			    struct scatterlist *sg)
{
	struct qdio_buffer_element *sbale;

	/* set