// SPDX-License-Identifier: GPL-2.0
/*
 * Linux for s390 qdio support, buffer handling, qdio API and module support.
 *
 * Copyright IBM Corp. 2000, 2008
 * Author(s): Utz Bacher <utz.bacher@de.ibm.com>
 *            Jan Glauber <jang@linux.vnet.ibm.com>
 * 2.6 cio integration by Cornelia Huck <cornelia.huck@de.ibm.com>
 */

#include <linux/export.h>
#include <linux/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/kmemleak.h>
#include <linux/delay.h>
#include <linux/gfp.h>
#include <linux/io.h>
#include <linux/atomic.h>
#include <asm/debug.h>
#include <asm/qdio.h>
#include <asm/asm.h>
#include <asm/ipl.h>

#include "cio.h"
#include "css.h"
#include "device.h"
#include "qdio.h"
#include "qdio_debug.h"

MODULE_AUTHOR("Utz Bacher <utz.bacher@de.ibm.com>,"\
        "Jan Glauber <jang@linux.vnet.ibm.com>");
MODULE_DESCRIPTION("QDIO base support");
MODULE_LICENSE("GPL");

static inline int do_siga_sync(unsigned long schid,
                               unsigned long out_mask, unsigned long in_mask,
                               unsigned int fc)
{
        int cc;

        asm volatile(
                "       lgr     0,%[fc]\n"
                "       lgr     1,%[schid]\n"
                "       lgr     2,%[out]\n"
                "       lgr     3,%[in]\n"
                "       siga    0\n"
                CC_IPM(cc)
                : CC_OUT(cc, cc)
                : [fc] "d" (fc), [schid] "d" (schid),
                  [out] "d" (out_mask), [in] "d" (in_mask)
                : CC_CLOBBER_LIST("0", "1", "2", "3"));
        return CC_TRANSFORM(cc);
}

static inline int do_siga_input(unsigned long schid, unsigned long mask,
                                unsigned long fc)
{
        int cc;

        asm volatile(
                "       lgr     0,%[fc]\n"
                "       lgr     1,%[schid]\n"
                "       lgr     2,%[mask]\n"
                "       siga    0\n"
                CC_IPM(cc)
                : CC_OUT(cc, cc)
                : [fc] "d" (fc), [schid] "d" (schid), [mask] "d" (mask)
                : CC_CLOBBER_LIST("0", "1", "2"));
        return CC_TRANSFORM(cc);
}

/**
 * do_siga_output - perform SIGA-w/wt function
 * @schid: subchannel id or in case of QEBSM the subchannel token
 * @mask: which output queues to process
 * @bb: busy bit indicator, set only if SIGA-w/wt could not access a buffer
 * @fc: function code to perform
 * @aob: asynchronous operation block
 *
 * Returns condition code.
 * Note: For IQDC unicast queues only the highest priority queue is processed.
 */
static inline int do_siga_output(unsigned long schid, unsigned long mask,
                                 unsigned int *bb, unsigned long fc,
                                 dma64_t aob)
{
        int cc;

        asm volatile(
                "       lgr     0,%[fc]\n"
                "       lgr     1,%[schid]\n"
                "       lgr     2,%[mask]\n"
                "       lgr     3,%[aob]\n"
                "       siga    0\n"
                "       lgr     %[fc],0\n"
                CC_IPM(cc)
                : CC_OUT(cc, cc), [fc] "+&d" (fc)
                : [schid] "d" (schid), [mask] "d" (mask), [aob] "d" (aob)
                : CC_CLOBBER_LIST("0", "1", "2", "3"));
        *bb = fc >> 31;
        return CC_TRANSFORM(cc);
}

/**
 * qdio_do_eqbs - extract buffer states for QEBSM
 * @q: queue to manipulate
 * @state: state of the extracted buffers
 * @start: buffer number to start at
 * @count: count of buffers to examine
 * @auto_ack: automatically acknowledge buffers
 *
 * Returns the number of successfully extracted equal buffer states.
 * Stops processing if a state is different from the last buffers state.
 */
static int qdio_do_eqbs(struct qdio_q *q, unsigned char *state,
                        int start, int count, int auto_ack)
{
        int tmp_count = count, tmp_start = start, nr = q->nr;
        unsigned int ccq = 0;

        qperf_inc(q, eqbs);

        if (!q->is_input_q)
                nr += q->irq_ptr->nr_input_qs;
again:
        ccq = do_eqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count,
                      auto_ack);

        switch (ccq) {
        case 0:
        case 32:
                /* all done, or next buffer state different */
                return count - tmp_count;
        case 96:
                /* not all buffers processed */
                qperf_inc(q, eqbs_partial);
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "EQBS part:%02x",
                        tmp_count);
                return count - tmp_count;
        case 97:
                /* no buffer processed */
                DBF_DEV_EVENT(DBF_WARN, q->irq_ptr, "EQBS again:%2d", ccq);
                goto again;
        default:
                DBF_ERROR("%4x ccq:%3d", SCH_NO(q), ccq);
                DBF_ERROR("%4x EQBS ERROR", SCH_NO(q));
                DBF_ERROR("%3d%3d%2d", count, tmp_count, nr);
                q->handler(q->irq_ptr->cdev, QDIO_ERROR_GET_BUF_STATE, q->nr,
                           q->first_to_check, count, q->irq_ptr->int_parm);
                return 0;
        }
}

/**
 * qdio_do_sqbs - set buffer states for QEBSM
 * @q: queue to manipulate
 * @state: new state of the buffers
 * @start: first buffer number to change
 * @count: how many buffers to change
 *
 * Returns the number of successfully changed buffers.
 * Does retrying until the specified count of buffer states is set or an
 * error occurs.
 */
static int qdio_do_sqbs(struct qdio_q *q, unsigned char state, int start,
                        int count)
{
        unsigned int ccq = 0;
        int tmp_count = count, tmp_start = start;
        int nr = q->nr;

        qperf_inc(q, sqbs);

        if (!q->is_input_q)
                nr += q->irq_ptr->nr_input_qs;
again:
        ccq = do_sqbs(q->irq_ptr->sch_token, state, nr, &tmp_start, &tmp_count);

        switch (ccq) {
        case 0:
        case 32:
                /* all done, or active buffer adapter-owned */
                WARN_ON_ONCE(tmp_count);
                return count - tmp_count;
        case 96:
                /* not all buffers processed */
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "SQBS again:%2d", ccq);
                qperf_inc(q, sqbs_partial);
                goto again;
        default:
                DBF_ERROR("%4x ccq:%3d", SCH_NO(q), ccq);
                DBF_ERROR("%4x SQBS ERROR", SCH_NO(q));
                DBF_ERROR("%3d%3d%2d", count, tmp_count, nr);
                q->handler(q->irq_ptr->cdev, QDIO_ERROR_SET_BUF_STATE, q->nr,
                           q->first_to_check, count, q->irq_ptr->int_parm);
                return 0;
        }
}

/*
 * Returns number of examined buffers and their common state in *state.
 * Requested number of buffers-to-examine must be > 0.
 */
static inline int get_buf_states(struct qdio_q *q, unsigned int bufnr,
                                 unsigned char *state, unsigned int count,
                                 int auto_ack)
{
        unsigned char __state = 0;
        int i = 1;

        if (is_qebsm(q))
                return qdio_do_eqbs(q, state, bufnr, count, auto_ack);

        /* get initial state: */
        __state = q->slsb.val[bufnr];

        /* Bail out early if there is no work on the queue: */
        if (__state & SLSB_OWNER_CU)
                goto out;

        for (; i < count; i++) {
                bufnr = next_buf(bufnr);

                /* stop if next state differs from initial state: */
                if (q->slsb.val[bufnr] != __state)
                        break;
        }

out:
        *state = __state;
        return i;
}

static inline int get_buf_state(struct qdio_q *q, unsigned int bufnr,
                                unsigned char *state, int auto_ack)
{
        return get_buf_states(q, bufnr, state, 1, auto_ack);
}

/* wrap-around safe setting of slsb states, returns number of changed buffers */
static inline int set_buf_states(struct qdio_q *q, int bufnr,
                                 unsigned char state, int count)
{
        int i;

        if (is_qebsm(q))
                return qdio_do_sqbs(q, state, bufnr, count);

        /* Ensure that all preceding changes to the SBALs are visible: */
        mb();

        for (i = 0; i < count; i++) {
                WRITE_ONCE(q->slsb.val[bufnr], state);
                bufnr = next_buf(bufnr);
        }

        /* Make our SLSB changes visible: */
        mb();

        return count;
}

static inline int set_buf_state(struct qdio_q *q, int bufnr,
                                unsigned char state)
{
        return set_buf_states(q, bufnr, state, 1);
}

/* set slsb states to initial state */
static void qdio_init_buf_states(struct qdio_irq *irq_ptr)
{
        struct qdio_q *q;
        int i;

        for_each_input_queue(irq_ptr, q, i)
                set_buf_states(q, 0, SLSB_P_INPUT_NOT_INIT,
                               QDIO_MAX_BUFFERS_PER_Q);
        for_each_output_queue(irq_ptr, q, i)
                set_buf_states(q, 0, SLSB_P_OUTPUT_NOT_INIT,
                               QDIO_MAX_BUFFERS_PER_Q);
}

static inline int qdio_siga_sync(struct qdio_q *q, unsigned int output,
                          unsigned int input)
{
        unsigned long schid = *((u32 *) &q->irq_ptr->schid);
        unsigned int fc = QDIO_SIGA_SYNC;
        int cc;

        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-s:%1d", q->nr);
        qperf_inc(q, siga_sync);

        if (is_qebsm(q)) {
                schid = q->irq_ptr->sch_token;
                fc |= QDIO_SIGA_QEBSM_FLAG;
        }

        cc = do_siga_sync(schid, output, input, fc);
        if (unlikely(cc))
                DBF_ERROR("%4x SIGA-S:%2d", SCH_NO(q), cc);
        return (cc) ? -EIO : 0;
}

static inline int qdio_sync_input_queue(struct qdio_q *q)
{
        return qdio_siga_sync(q, 0, q->mask);
}

static inline int qdio_sync_output_queue(struct qdio_q *q)
{
        return qdio_siga_sync(q, q->mask, 0);
}

static inline int qdio_siga_sync_q(struct qdio_q *q)
{
        if (q->is_input_q)
                return qdio_sync_input_queue(q);
        else
                return qdio_sync_output_queue(q);
}

static int qdio_siga_output(struct qdio_q *q, unsigned int count,
                            unsigned int *busy_bit, dma64_t aob)
{
        unsigned long schid = *((u32 *) &q->irq_ptr->schid);
        unsigned int fc = QDIO_SIGA_WRITE;
        u64 start_time = 0;
        int retries = 0, cc;

        if (queue_type(q) == QDIO_IQDIO_QFMT && !multicast_outbound(q)) {
                if (count > 1)
                        fc = QDIO_SIGA_WRITEM;
                else if (aob)
                        fc = QDIO_SIGA_WRITEQ;
        }

        if (is_qebsm(q)) {
                schid = q->irq_ptr->sch_token;
                fc |= QDIO_SIGA_QEBSM_FLAG;
        }
again:
        cc = do_siga_output(schid, q->mask, busy_bit, fc, aob);

        /* hipersocket busy condition */
        if (unlikely(*busy_bit)) {
                retries++;

                if (!start_time) {
                        start_time = get_tod_clock_fast();
                        goto again;
                }
                if (get_tod_clock_fast() - start_time < QDIO_BUSY_BIT_PATIENCE)
                        goto again;
        }
        if (retries) {
                DBF_DEV_EVENT(DBF_WARN, q->irq_ptr,
                              "%4x cc2 BB1:%1d", SCH_NO(q), q->nr);
                DBF_DEV_EVENT(DBF_WARN, q->irq_ptr, "count:%u", retries);
        }
        return cc;
}

static inline int qdio_siga_input(struct qdio_q *q)
{
        unsigned long schid = *((u32 *) &q->irq_ptr->schid);
        unsigned int fc = QDIO_SIGA_READ;
        int cc;

        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-r:%1d", q->nr);
        qperf_inc(q, siga_read);

        if (is_qebsm(q)) {
                schid = q->irq_ptr->sch_token;
                fc |= QDIO_SIGA_QEBSM_FLAG;
        }

        cc = do_siga_input(schid, q->mask, fc);
        if (unlikely(cc))
                DBF_ERROR("%4x SIGA-R:%2d", SCH_NO(q), cc);
        return (cc) ? -EIO : 0;
}

int debug_get_buf_state(struct qdio_q *q, unsigned int bufnr,
                        unsigned char *state)
{
        if (qdio_need_siga_sync(q->irq_ptr))
                qdio_siga_sync_q(q);
        return get_buf_state(q, bufnr, state, 0);
}

static inline void qdio_stop_polling(struct qdio_q *q)
{
        if (!q->u.in.batch_count)
                return;

        qperf_inc(q, stop_polling);

        /* show the card that we are not polling anymore */
        set_buf_states(q, q->u.in.batch_start, SLSB_P_INPUT_NOT_INIT,
                       q->u.in.batch_count);
        q->u.in.batch_count = 0;
}

static inline void account_sbals(struct qdio_q *q, unsigned int count)
{
        q->q_stats.nr_sbal_total += count;
        q->q_stats.nr_sbals[ilog2(count)]++;
}

static void process_buffer_error(struct qdio_q *q, unsigned int start,
                                 int count)
{
        /* special handling for no target buffer empty */
        if (queue_type(q) == QDIO_IQDIO_QFMT && !q->is_input_q &&
            q->sbal[start]->element[15].sflags == 0x10) {
                qperf_inc(q, target_full);
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "OUTFULL FTC:%02x", start);
                return;
        }

        DBF_ERROR("%4x BUF ERROR", SCH_NO(q));
        DBF_ERROR((q->is_input_q) ? "IN:%2d" : "OUT:%2d", q->nr);
        DBF_ERROR("FTC:%3d C:%3d", start, count);
        DBF_ERROR("F14:%2x F15:%2x",
                  q->sbal[start]->element[14].sflags,
                  q->sbal[start]->element[15].sflags);
}

static inline void inbound_handle_work(struct qdio_q *q, unsigned int start,
                                       int count, bool auto_ack)
{
        /* ACK the newest SBAL: */
        if (!auto_ack)
                set_buf_state(q, add_buf(start, count - 1), SLSB_P_INPUT_ACK);

        if (!q->u.in.batch_count)
                q->u.in.batch_start = start;
        q->u.in.batch_count += count;
}

static int get_inbound_buffer_frontier(struct qdio_q *q, unsigned int start,
                                       unsigned int *error)
{
        unsigned char state = 0;
        int count;

        q->timestamp = get_tod_clock_fast();

        count = atomic_read(&q->nr_buf_used);
        if (!count)
                return 0;

        if (qdio_need_siga_sync(q->irq_ptr))
                qdio_sync_input_queue(q);

        count = get_buf_states(q, start, &state, count, 1);
        if (!count)
                return 0;

        switch (state) {
        case SLSB_P_INPUT_PRIMED:
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in prim:%1d %02x", q->nr,
                              count);

                inbound_handle_work(q, start, count, is_qebsm(q));
                if (atomic_sub_return(count, &q->nr_buf_used) == 0)
                        qperf_inc(q, inbound_queue_full);
                if (q->irq_ptr->perf_stat_enabled)
                        account_sbals(q, count);
                return count;
        case SLSB_P_INPUT_ERROR:
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in err:%1d %02x", q->nr,
                              count);

                *error = QDIO_ERROR_SLSB_STATE;
                process_buffer_error(q, start, count);
                inbound_handle_work(q, start, count, false);
                if (atomic_sub_return(count, &q->nr_buf_used) == 0)
                        qperf_inc(q, inbound_queue_full);
                if (q->irq_ptr->perf_stat_enabled)
                        account_sbals_error(q, count);
                return count;
        case SLSB_CU_INPUT_EMPTY:
                if (q->irq_ptr->perf_stat_enabled)
                        q->q_stats.nr_sbal_nop++;
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in nop:%1d %#02x",
                              q->nr, start);
                return 0;
        case SLSB_P_INPUT_NOT_INIT:
        case SLSB_P_INPUT_ACK:
                /* We should never see this state, throw a WARN: */
        default:
                dev_WARN_ONCE(&q->irq_ptr->cdev->dev, 1,
                              "found state %#x at index %u on queue %u\n",
                              state, start, q->nr);
                return 0;
        }
}

int qdio_inspect_input_queue(struct ccw_device *cdev, unsigned int nr,
                             unsigned int *bufnr, unsigned int *error)
{
        struct qdio_irq *irq = cdev->private->qdio_data;
        unsigned int start;
        struct qdio_q *q;
        int count;

        if (!irq)
                return -ENODEV;

        q = irq->input_qs[nr];
        start = q->first_to_check;
        *error = 0;

        count = get_inbound_buffer_frontier(q, start, error);
        if (count == 0)
                return 0;

        *bufnr = start;
        q->first_to_check = add_buf(start, count);
        return count;
}
EXPORT_SYMBOL_GPL(qdio_inspect_input_queue);

static inline int qdio_inbound_q_done(struct qdio_q *q, unsigned int start)
{
        unsigned char state = 0;

        if (!atomic_read(&q->nr_buf_used))
                return 1;

        if (qdio_need_siga_sync(q->irq_ptr))
                qdio_sync_input_queue(q);
        get_buf_state(q, start, &state, 0);

        if (state == SLSB_P_INPUT_PRIMED || state == SLSB_P_INPUT_ERROR)
                /* more work coming */
                return 0;

        return 1;
}

static int get_outbound_buffer_frontier(struct qdio_q *q, unsigned int start,
                                        unsigned int *error)
{
        unsigned char state = 0;
        int count;

        q->timestamp = get_tod_clock_fast();

        count = atomic_read(&q->nr_buf_used);
        if (!count)
                return 0;

        if (qdio_need_siga_sync(q->irq_ptr))
                qdio_sync_output_queue(q);

        count = get_buf_states(q, start, &state, count, 0);
        if (!count)
                return 0;

        switch (state) {
        case SLSB_P_OUTPUT_PENDING:
                *error = QDIO_ERROR_SLSB_PENDING;
                fallthrough;
        case SLSB_P_OUTPUT_EMPTY:
                /* the adapter got it */
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr,
                        "out empty:%1d %02x", q->nr, count);

                atomic_sub(count, &q->nr_buf_used);
                if (q->irq_ptr->perf_stat_enabled)
                        account_sbals(q, count);
                return count;
        case SLSB_P_OUTPUT_ERROR:
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "out error:%1d %02x",
                              q->nr, count);

                *error = QDIO_ERROR_SLSB_STATE;
                process_buffer_error(q, start, count);
                atomic_sub(count, &q->nr_buf_used);
                if (q->irq_ptr->perf_stat_enabled)
                        account_sbals_error(q, count);
                return count;
        case SLSB_CU_OUTPUT_PRIMED:
                /* the adapter has not fetched the output yet */
                if (q->irq_ptr->perf_stat_enabled)
                        q->q_stats.nr_sbal_nop++;
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "out primed:%1d",
                              q->nr);
                return 0;
        case SLSB_P_OUTPUT_HALTED:
                return 0;
        case SLSB_P_OUTPUT_NOT_INIT:
                /* We should never see this state, throw a WARN: */
        default:
                dev_WARN_ONCE(&q->irq_ptr->cdev->dev, 1,
                              "found state %#x at index %u on queue %u\n",
                              state, start, q->nr);
                return 0;
        }
}

int qdio_inspect_output_queue(struct ccw_device *cdev, unsigned int nr,
                              unsigned int *bufnr, unsigned int *error)
{
        struct qdio_irq *irq = cdev->private->qdio_data;
        unsigned int start;
        struct qdio_q *q;
        int count;

        if (!irq)
                return -ENODEV;

        q = irq->output_qs[nr];
        start = q->first_to_check;
        *error = 0;

        count = get_outbound_buffer_frontier(q, start, error);
        if (count == 0)
                return 0;

        *bufnr = start;
        q->first_to_check = add_buf(start, count);
        return count;
}
EXPORT_SYMBOL_GPL(qdio_inspect_output_queue);

static int qdio_kick_outbound_q(struct qdio_q *q, unsigned int count,
                                dma64_t aob)
{
        int retries = 0, cc;
        unsigned int busy_bit;

        if (!qdio_need_siga_out(q->irq_ptr))
                return 0;

        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w:%1d", q->nr);
retry:
        qperf_inc(q, siga_write);

        cc = qdio_siga_output(q, count, &busy_bit, aob);
        switch (cc) {
        case 0:
                break;
        case 2:
                if (busy_bit) {
                        while (++retries < QDIO_BUSY_BIT_RETRIES) {
                                mdelay(QDIO_BUSY_BIT_RETRY_DELAY);
                                goto retry;
                        }
                        DBF_ERROR("%4x cc2 BBC:%1d", SCH_NO(q), q->nr);
                        cc = -EBUSY;
                } else {
                        DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "siga-w cc2:%1d", q->nr);
                        cc = -ENOBUFS;
                }
                break;
        case 1:
        case 3:
                DBF_ERROR("%4x SIGA-W:%1d", SCH_NO(q), cc);
                cc = -EIO;
                break;
        }
        if (retries) {
                DBF_ERROR("%4x cc2 BB2:%1d", SCH_NO(q), q->nr);
                DBF_ERROR("count:%u", retries);
        }
        return cc;
}

static inline void qdio_set_state(struct qdio_irq *irq_ptr,
                                  enum qdio_irq_states state)
{
        DBF_DEV_EVENT(DBF_INFO, irq_ptr, "newstate: %1d", state);

        irq_ptr->state = state;
        mb();
}

static void qdio_irq_check_sense(struct qdio_irq *irq_ptr, struct irb *irb)
{
        if (irb->esw.esw0.erw.cons) {
                DBF_ERROR("%4x sense:", irq_ptr->schid.sch_no);
                DBF_ERROR_HEX(irb, 64);
                DBF_ERROR_HEX(irb->ecw, 64);
        }
}

/* PCI interrupt handler */
static void qdio_int_handler_pci(struct qdio_irq *irq_ptr)
{
        if (unlikely(irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))
                return;

        qdio_deliver_irq(irq_ptr);
        irq_ptr->last_data_irq_time = get_lowcore()->int_clock;
}

static void qdio_handle_activate_check(struct qdio_irq *irq_ptr,
                                       unsigned long intparm, int cstat,
                                       int dstat)
{
        unsigned int first_to_check = 0;

        DBF_ERROR("%4x ACT CHECK", irq_ptr->schid.sch_no);
        DBF_ERROR("intp :%lx", intparm);
        DBF_ERROR("ds: %2x cs:%2x", dstat, cstat);

        /* zfcp wants this: */
        if (irq_ptr->nr_input_qs)
                first_to_check = irq_ptr->input_qs[0]->first_to_check;

        irq_ptr->error_handler(irq_ptr->cdev, QDIO_ERROR_ACTIVATE, 0,
                               first_to_check, 0, irq_ptr->int_parm);
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_STOPPED);
        /*
         * In case of z/VM LGR (Live Guest Migration) QDIO recovery will happen.
         * Therefore we call the LGR detection function here.
         */
        lgr_info_log();
}

static int qdio_establish_handle_irq(struct qdio_irq *irq_ptr, int cstat,
                                     int dstat, int dcc)
{
        DBF_DEV_EVENT(DBF_INFO, irq_ptr, "qest irq");

        if (cstat)
                goto error;
        if (dstat & ~(DEV_STAT_DEV_END | DEV_STAT_CHN_END))
                goto error;
        if (dcc == 1)
                return -EAGAIN;
        if (!(dstat & DEV_STAT_DEV_END))
                goto error;
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ESTABLISHED);
        return 0;

error:
        DBF_ERROR("%4x EQ:error", irq_ptr->schid.sch_no);
        DBF_ERROR("ds: %2x cs:%2x", dstat, cstat);
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ERR);
        return -EIO;
}

/* qdio interrupt handler */
void qdio_int_handler(struct ccw_device *cdev, unsigned long intparm,
                      struct irb *irb)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        struct subchannel_id schid;
        int cstat, dstat, rc, dcc;

        if (!intparm || !irq_ptr) {
                ccw_device_get_schid(cdev, &schid);
                DBF_ERROR("qint:%4x", schid.sch_no);
                return;
        }

        if (irq_ptr->perf_stat_enabled)
                irq_ptr->perf_stat.qdio_int++;

        if (IS_ERR(irb)) {
                DBF_ERROR("%4x IO error", irq_ptr->schid.sch_no);
                qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ERR);
                wake_up(&cdev->private->wait_q);
                return;
        }
        qdio_irq_check_sense(irq_ptr, irb);
        cstat = irb->scsw.cmd.cstat;
        dstat = irb->scsw.cmd.dstat;
        dcc   = scsw_cmd_is_valid_cc(&irb->scsw) ? irb->scsw.cmd.cc : 0;
        rc    = 0;

        switch (irq_ptr->state) {
        case QDIO_IRQ_STATE_INACTIVE:
                rc = qdio_establish_handle_irq(irq_ptr, cstat, dstat, dcc);
                break;
        case QDIO_IRQ_STATE_CLEANUP:
                qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);
                break;
        case QDIO_IRQ_STATE_ESTABLISHED:
        case QDIO_IRQ_STATE_ACTIVE:
                if (cstat & SCHN_STAT_PCI) {
                        qdio_int_handler_pci(irq_ptr);
                        return;
                }
                if (cstat || dstat)
                        qdio_handle_activate_check(irq_ptr, intparm, cstat,
                                                   dstat);
                else if (dcc == 1)
                        rc = -EAGAIN;
                break;
        case QDIO_IRQ_STATE_STOPPED:
                break;
        default:
                WARN_ON_ONCE(1);
        }

        if (rc == -EAGAIN) {
                DBF_DEV_EVENT(DBF_INFO, irq_ptr, "qint retry");
                rc = ccw_device_start(cdev, irq_ptr->ccw, intparm, 0, 0);
                if (!rc)
                        return;
                DBF_ERROR("%4x RETRY ERR", irq_ptr->schid.sch_no);
                DBF_ERROR("rc:%4x", rc);
                qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ERR);
        }

        wake_up(&cdev->private->wait_q);
}

/**
 * qdio_get_ssqd_desc - get qdio subchannel description
 * @cdev: ccw device to get description for
 * @data: where to store the ssqd
 *
 * Returns 0 or an error code. The results of the chsc are stored in the
 * specified structure.
 */
int qdio_get_ssqd_desc(struct ccw_device *cdev,
                       struct qdio_ssqd_desc *data)
{
        struct subchannel_id schid;

        if (!cdev || !cdev->private)
                return -EINVAL;

        ccw_device_get_schid(cdev, &schid);
        DBF_EVENT("get ssqd:%4x", schid.sch_no);
        return qdio_setup_get_ssqd(NULL, &schid, data);
}
EXPORT_SYMBOL_GPL(qdio_get_ssqd_desc);

static int qdio_cancel_ccw(struct qdio_irq *irq, int how)
{
        struct ccw_device *cdev = irq->cdev;
        long timeout;
        int rc;

        spin_lock_irq(get_ccwdev_lock(cdev));
        qdio_set_state(irq, QDIO_IRQ_STATE_CLEANUP);
        if (how & QDIO_FLAG_CLEANUP_USING_CLEAR)
                rc = ccw_device_clear(cdev, QDIO_DOING_CLEANUP);
        else
                /* default behaviour is halt */
                rc = ccw_device_halt(cdev, QDIO_DOING_CLEANUP);
        spin_unlock_irq(get_ccwdev_lock(cdev));
        if (rc) {
                DBF_ERROR("%4x SHUTD ERR", irq->schid.sch_no);
                DBF_ERROR("rc:%4d", rc);
                return rc;
        }

        timeout = wait_event_interruptible_timeout(cdev->private->wait_q,
                                                   irq->state == QDIO_IRQ_STATE_INACTIVE ||
                                                   irq->state == QDIO_IRQ_STATE_ERR,
                                                   10 * HZ);
        if (timeout <= 0)
                rc = (timeout == -ERESTARTSYS) ? -EINTR : -ETIME;

        return rc;
}

/**
 * qdio_shutdown - shut down a qdio subchannel
 * @cdev: associated ccw device
 * @how: use halt or clear to shutdown
 */
int qdio_shutdown(struct ccw_device *cdev, int how)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        struct subchannel_id schid;
        int rc;

        if (!irq_ptr)
                return -ENODEV;

        WARN_ON_ONCE(irqs_disabled());
        ccw_device_get_schid(cdev, &schid);
        DBF_EVENT("qshutdown:%4x", schid.sch_no);

        mutex_lock(&irq_ptr->setup_mutex);
        /*
         * Subchannel was already shot down. We cannot prevent being called
         * twice since cio may trigger a shutdown asynchronously.
         */
        if (irq_ptr->state == QDIO_IRQ_STATE_INACTIVE) {
                mutex_unlock(&irq_ptr->setup_mutex);
                return 0;
        }

        /*
         * Indicate that the device is going down.
         */
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_STOPPED);

        qdio_shutdown_debug_entries(irq_ptr);

        rc = qdio_cancel_ccw(irq_ptr, how);
        qdio_shutdown_thinint(irq_ptr);
        qdio_shutdown_irq(irq_ptr);

        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);
        mutex_unlock(&irq_ptr->setup_mutex);
        if (rc)
                return rc;
        return 0;
}
EXPORT_SYMBOL_GPL(qdio_shutdown);

/**
 * qdio_free - free data structures for a qdio subchannel
 * @cdev: associated ccw device
 */
int qdio_free(struct ccw_device *cdev)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        struct subchannel_id schid;

        if (!irq_ptr)
                return -ENODEV;

        ccw_device_get_schid(cdev, &schid);
        DBF_EVENT("qfree:%4x", schid.sch_no);
        DBF_DEV_EVENT(DBF_ERR, irq_ptr, "dbf abandoned");
        mutex_lock(&irq_ptr->setup_mutex);

        irq_ptr->debug_area = NULL;
        cdev->private->qdio_data = NULL;
        mutex_unlock(&irq_ptr->setup_mutex);

        qdio_free_queues(irq_ptr);
        free_page((unsigned long) irq_ptr->qdr);
        free_page(irq_ptr->chsc_page);
        kfree(irq_ptr->ccw);
        free_page((unsigned long) irq_ptr);
        return 0;
}
EXPORT_SYMBOL_GPL(qdio_free);

/**
 * qdio_allocate - allocate qdio queues and associated data
 * @cdev: associated ccw device
 * @no_input_qs: allocate this number of Input Queues
 * @no_output_qs: allocate this number of Output Queues
 */
int qdio_allocate(struct ccw_device *cdev, unsigned int no_input_qs,
                  unsigned int no_output_qs)
{
        struct subchannel_id schid;
        struct qdio_irq *irq_ptr;
        int rc = -ENOMEM;

        ccw_device_get_schid(cdev, &schid);
        DBF_EVENT("qallocate:%4x", schid.sch_no);

        if (no_input_qs > QDIO_MAX_QUEUES_PER_IRQ ||
            no_output_qs > QDIO_MAX_QUEUES_PER_IRQ)
                return -EINVAL;

        irq_ptr = (void *) get_zeroed_page(GFP_KERNEL);
        if (!irq_ptr)
                return -ENOMEM;

        irq_ptr->ccw = kmalloc_obj(*irq_ptr->ccw, GFP_KERNEL | GFP_DMA);
        if (!irq_ptr->ccw)
                goto err_ccw;

        /* kmemleak doesn't scan the page-allocated irq_ptr: */
        kmemleak_not_leak(irq_ptr->ccw);

        irq_ptr->cdev = cdev;
        mutex_init(&irq_ptr->setup_mutex);
        if (qdio_allocate_dbf(irq_ptr))
                goto err_dbf;

        DBF_DEV_EVENT(DBF_ERR, irq_ptr, "alloc niq:%1u noq:%1u", no_input_qs,
                      no_output_qs);

        /*
         * Allocate a page for the chsc calls in qdio_establish.
         * Must be pre-allocated since a zfcp recovery will call
         * qdio_establish. In case of low memory and swap on a zfcp disk
         * we may not be able to allocate memory otherwise.
         */
        irq_ptr->chsc_page = get_zeroed_page(GFP_KERNEL);
        if (!irq_ptr->chsc_page)
                goto err_chsc;

        /* qdr is used in ccw1.cda which is u32 */
        irq_ptr->qdr = (struct qdr *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!irq_ptr->qdr)
                goto err_qdr;

        rc = qdio_allocate_qs(irq_ptr, no_input_qs, no_output_qs);
        if (rc)
                goto err_queues;

        cdev->private->qdio_data = irq_ptr;
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);
        return 0;

err_queues:
        free_page((unsigned long) irq_ptr->qdr);
err_qdr:
        free_page(irq_ptr->chsc_page);
err_chsc:
err_dbf:
        kfree(irq_ptr->ccw);
err_ccw:
        free_page((unsigned long) irq_ptr);
        return rc;
}
EXPORT_SYMBOL_GPL(qdio_allocate);

static void qdio_trace_init_data(struct qdio_irq *irq,
                                 struct qdio_initialize *data)
{
        DBF_DEV_EVENT(DBF_ERR, irq, "qfmt:%1u", data->q_format);
        DBF_DEV_EVENT(DBF_ERR, irq, "qpff%4x", data->qib_param_field_format);
        DBF_DEV_HEX(irq, &data->qib_param_field, sizeof(void *), DBF_ERR);
        DBF_DEV_EVENT(DBF_ERR, irq, "niq:%1u noq:%1u", data->no_input_qs,
                      data->no_output_qs);
        DBF_DEV_HEX(irq, &data->input_handler, sizeof(void *), DBF_ERR);
        DBF_DEV_HEX(irq, &data->output_handler, sizeof(void *), DBF_ERR);
        DBF_DEV_HEX(irq, &data->int_parm, sizeof(long), DBF_ERR);
        DBF_DEV_HEX(irq, &data->input_sbal_addr_array, sizeof(void *), DBF_ERR);
        DBF_DEV_HEX(irq, &data->output_sbal_addr_array, sizeof(void *),
                    DBF_ERR);
}

/**
 * qdio_establish - establish queues on a qdio subchannel
 * @cdev: associated ccw device
 * @init_data: initialization data
 */
int qdio_establish(struct ccw_device *cdev,
                   struct qdio_initialize *init_data)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        struct subchannel_id schid;
        struct ciw *ciw;
        long timeout;
        int rc;

        ccw_device_get_schid(cdev, &schid);
        DBF_EVENT("qestablish:%4x", schid.sch_no);

        if (!irq_ptr)
                return -ENODEV;

        if (init_data->no_input_qs > irq_ptr->max_input_qs ||
            init_data->no_output_qs > irq_ptr->max_output_qs)
                return -EINVAL;

        /* Needed as error_handler: */
        if (!init_data->input_handler)
                return -EINVAL;

        if (init_data->no_output_qs && !init_data->output_handler)
                return -EINVAL;

        if (!init_data->input_sbal_addr_array ||
            !init_data->output_sbal_addr_array)
                return -EINVAL;

        if (!init_data->irq_poll)
                return -EINVAL;

        ciw = ccw_device_get_ciw(cdev, CIW_TYPE_EQUEUE);
        if (!ciw) {
                DBF_ERROR("%4x NO EQ", schid.sch_no);
                return -EIO;
        }

        mutex_lock(&irq_ptr->setup_mutex);
        qdio_trace_init_data(irq_ptr, init_data);
        qdio_setup_irq(irq_ptr, init_data);

        rc = qdio_establish_thinint(irq_ptr);
        if (rc)
                goto err_thinint;

        /* establish q */
        irq_ptr->ccw->cmd_code = ciw->cmd;
        irq_ptr->ccw->flags = CCW_FLAG_SLI;
        irq_ptr->ccw->count = ciw->count;
        irq_ptr->ccw->cda = virt_to_dma32(irq_ptr->qdr);

        spin_lock_irq(get_ccwdev_lock(cdev));
        ccw_device_set_options_mask(cdev, 0);

        rc = ccw_device_start(cdev, irq_ptr->ccw, QDIO_DOING_ESTABLISH, 0, 0);
        spin_unlock_irq(get_ccwdev_lock(cdev));
        if (rc) {
                DBF_ERROR("%4x est IO ERR", irq_ptr->schid.sch_no);
                DBF_ERROR("rc:%4x", rc);
                goto err_ccw_start;
        }

        timeout = wait_event_interruptible_timeout(cdev->private->wait_q,
                                                   irq_ptr->state == QDIO_IRQ_STATE_ESTABLISHED ||
                                                   irq_ptr->state == QDIO_IRQ_STATE_ERR, HZ);
        if (timeout <= 0) {
                rc = (timeout == -ERESTARTSYS) ? -EINTR : -ETIME;
                goto err_ccw_timeout;
        }

        if (irq_ptr->state != QDIO_IRQ_STATE_ESTABLISHED) {
                rc = -EIO;
                goto err_ccw_error;
        }

        qdio_setup_ssqd_info(irq_ptr);

        /* qebsm is now setup if available, initialize buffer states */
        qdio_init_buf_states(irq_ptr);

        mutex_unlock(&irq_ptr->setup_mutex);
        qdio_print_subchannel_info(irq_ptr);
        qdio_setup_debug_entries(irq_ptr);
        return 0;

err_ccw_timeout:
        qdio_cancel_ccw(irq_ptr, QDIO_FLAG_CLEANUP_USING_CLEAR);
err_ccw_error:
err_ccw_start:
        qdio_shutdown_thinint(irq_ptr);
err_thinint:
        qdio_shutdown_irq(irq_ptr);
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);
        mutex_unlock(&irq_ptr->setup_mutex);
        return rc;
}
EXPORT_SYMBOL_GPL(qdio_establish);

/**
 * qdio_activate - activate queues on a qdio subchannel
 * @cdev: associated cdev
 */
int qdio_activate(struct ccw_device *cdev)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        struct subchannel_id schid;
        struct ciw *ciw;
        int rc;

        ccw_device_get_schid(cdev, &schid);
        DBF_EVENT("qactivate:%4x", schid.sch_no);

        if (!irq_ptr)
                return -ENODEV;

        ciw = ccw_device_get_ciw(cdev, CIW_TYPE_AQUEUE);
        if (!ciw) {
                DBF_ERROR("%4x NO AQ", schid.sch_no);
                return -EIO;
        }

        mutex_lock(&irq_ptr->setup_mutex);
        if (irq_ptr->state == QDIO_IRQ_STATE_INACTIVE) {
                rc = -EBUSY;
                goto out;
        }

        irq_ptr->ccw->cmd_code = ciw->cmd;
        irq_ptr->ccw->flags = CCW_FLAG_SLI;
        irq_ptr->ccw->count = ciw->count;
        irq_ptr->ccw->cda = 0;

        spin_lock_irq(get_ccwdev_lock(cdev));
        ccw_device_set_options(cdev, CCWDEV_REPORT_ALL);

        rc = ccw_device_start(cdev, irq_ptr->ccw, QDIO_DOING_ACTIVATE,
                              0, DOIO_DENY_PREFETCH);
        spin_unlock_irq(get_ccwdev_lock(cdev));
        if (rc) {
                DBF_ERROR("%4x act IO ERR", irq_ptr->schid.sch_no);
                DBF_ERROR("rc:%4x", rc);
                goto out;
        }

        /* wait for subchannel to become active */
        msleep(5);

        switch (irq_ptr->state) {
        case QDIO_IRQ_STATE_STOPPED:
        case QDIO_IRQ_STATE_ERR:
                rc = -EIO;
                break;
        default:
                qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ACTIVE);
                rc = 0;
        }
out:
        mutex_unlock(&irq_ptr->setup_mutex);
        return rc;
}
EXPORT_SYMBOL_GPL(qdio_activate);

/**
 * handle_inbound - reset processed input buffers
 * @q: queue containing the buffers
 * @bufnr: first buffer to process
 * @count: how many buffers are emptied
 */
static int handle_inbound(struct qdio_q *q, int bufnr, int count)
{
        int overlap;

        qperf_inc(q, inbound_call);

        /* If any processed SBALs are returned to HW, adjust our tracking: */
        overlap = min_t(int, count - sub_buf(q->u.in.batch_start, bufnr),
                             q->u.in.batch_count);
        if (overlap > 0) {
                q->u.in.batch_start = add_buf(q->u.in.batch_start, overlap);
                q->u.in.batch_count -= overlap;
        }

        count = set_buf_states(q, bufnr, SLSB_CU_INPUT_EMPTY, count);
        atomic_add(count, &q->nr_buf_used);

        if (qdio_need_siga_in(q->irq_ptr))
                return qdio_siga_input(q);

        return 0;
}

/**
 * qdio_add_bufs_to_input_queue - process buffers on an Input Queue
 * @cdev: associated ccw_device for the qdio subchannel
 * @q_nr: queue number
 * @bufnr: buffer number
 * @count: how many buffers to process
 */
int qdio_add_bufs_to_input_queue(struct ccw_device *cdev, unsigned int q_nr,
                                 unsigned int bufnr, unsigned int count)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;

        if (bufnr >= QDIO_MAX_BUFFERS_PER_Q || count > QDIO_MAX_BUFFERS_PER_Q)
                return -EINVAL;

        if (!irq_ptr)
                return -ENODEV;

        DBF_DEV_EVENT(DBF_INFO, irq_ptr, "addi b:%02x c:%02x", bufnr, count);

        if (irq_ptr->state != QDIO_IRQ_STATE_ACTIVE)
                return -EIO;
        if (!count)
                return 0;

        return handle_inbound(irq_ptr->input_qs[q_nr], bufnr, count);
}
EXPORT_SYMBOL_GPL(qdio_add_bufs_to_input_queue);

/**
 * handle_outbound - process filled outbound buffers
 * @q: queue containing the buffers
 * @bufnr: first buffer to process
 * @count: how many buffers are filled
 * @aob: asynchronous operation block
 */
static int handle_outbound(struct qdio_q *q, unsigned int bufnr, unsigned int count,
                           struct qaob *aob)
{
        unsigned char state = 0;
        int used, rc = 0;

        qperf_inc(q, outbound_call);

        count = set_buf_states(q, bufnr, SLSB_CU_OUTPUT_PRIMED, count);
        used = atomic_add_return(count, &q->nr_buf_used);

        if (used == QDIO_MAX_BUFFERS_PER_Q)
                qperf_inc(q, outbound_queue_full);

        if (queue_type(q) == QDIO_IQDIO_QFMT) {
                dma64_t phys_aob = aob ? virt_to_dma64(aob) : 0;

                WARN_ON_ONCE(!IS_ALIGNED(dma64_to_u64(phys_aob), 256));
                rc = qdio_kick_outbound_q(q, count, phys_aob);
        } else if (qdio_need_siga_sync(q->irq_ptr)) {
                rc = qdio_sync_output_queue(q);
        } else if (count < QDIO_MAX_BUFFERS_PER_Q &&
                   get_buf_state(q, prev_buf(bufnr), &state, 0) > 0 &&
                   state == SLSB_CU_OUTPUT_PRIMED) {
                /* The previous buffer is not processed yet, tack on. */
                qperf_inc(q, fast_requeue);
        } else {
                rc = qdio_kick_outbound_q(q, count, 0);
        }

        return rc;
}

/**
 * qdio_add_bufs_to_output_queue - process buffers on an Output Queue
 * @cdev: associated ccw_device for the qdio subchannel
 * @q_nr: queue number
 * @bufnr: buffer number
 * @count: how many buffers to process
 * @aob: asynchronous operation block
 */
int qdio_add_bufs_to_output_queue(struct ccw_device *cdev, unsigned int q_nr,
                                  unsigned int bufnr, unsigned int count,
                                  struct qaob *aob)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;

        if (bufnr >= QDIO_MAX_BUFFERS_PER_Q || count > QDIO_MAX_BUFFERS_PER_Q)
                return -EINVAL;

        if (!irq_ptr)
                return -ENODEV;

        DBF_DEV_EVENT(DBF_INFO, irq_ptr, "addo b:%02x c:%02x", bufnr, count);

        if (irq_ptr->state != QDIO_IRQ_STATE_ACTIVE)
                return -EIO;
        if (!count)
                return 0;

        return handle_outbound(irq_ptr->output_qs[q_nr], bufnr, count, aob);
}
EXPORT_SYMBOL_GPL(qdio_add_bufs_to_output_queue);

/**
 * qdio_start_irq - enable interrupt processing for the device
 * @cdev: associated ccw_device for the qdio subchannel
 *
 * Return codes
 *   0 - success
 *   1 - irqs not started since new data is available
 */
int qdio_start_irq(struct ccw_device *cdev)
{
        struct qdio_q *q;
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        unsigned int i;

        if (!irq_ptr)
                return -ENODEV;

        for_each_input_queue(irq_ptr, q, i)
                qdio_stop_polling(q);

        clear_bit(QDIO_IRQ_DISABLED, &irq_ptr->poll_state);

        /*
         * We need to check again to not lose initiative after
         * resetting the ACK state.
         */
        if (test_nonshared_ind(irq_ptr))
                goto rescan;

        for_each_input_queue(irq_ptr, q, i) {
                if (!qdio_inbound_q_done(q, q->first_to_check))
                        goto rescan;
        }

        return 0;

rescan:
        if (test_and_set_bit(QDIO_IRQ_DISABLED, &irq_ptr->poll_state))
                return 0;
        else
                return 1;

}
EXPORT_SYMBOL(qdio_start_irq);

/**
 * qdio_stop_irq - disable interrupt processing for the device
 * @cdev: associated ccw_device for the qdio subchannel
 *
 * Return codes
 *   0 - interrupts were already disabled
 *   1 - interrupts successfully disabled
 */
int qdio_stop_irq(struct ccw_device *cdev)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;

        if (!irq_ptr)
                return -ENODEV;

        if (test_and_set_bit(QDIO_IRQ_DISABLED, &irq_ptr->poll_state))
                return 0;
        else
                return 1;
}
EXPORT_SYMBOL(qdio_stop_irq);

static int __init init_QDIO(void)
{
        int rc;

        rc = qdio_debug_init();
        if (rc)
                return rc;
        rc = qdio_setup_init();
        if (rc)
                goto out_debug;
        rc = qdio_thinint_init();
        if (rc)
                goto out_cache;
        return 0;

out_cache:
        qdio_setup_exit();
out_debug:
        qdio_debug_exit();
        return rc;
}

static void __exit exit_QDIO(void)
{
        qdio_thinint_exit();
        qdio_setup_exit();
        qdio_debug_exit();
}

module_init(init_QDIO);
module_exit(exit_QDIO);