// 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/module.h>
#include <linux/init.h>
#include <linux/kernel.h>
#include <linux/timer.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/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 int out_mask, unsigned int in_mask,
                               unsigned int fc)
{
        register unsigned long __fc asm ("0") = fc;
        register unsigned long __schid asm ("1") = schid;
        register unsigned long out asm ("2") = out_mask;
        register unsigned long in asm ("3") = in_mask;
        int cc;

        asm volatile(
                "       siga    0\n"
                "       ipm     %0\n"
                "       srl     %0,28\n"
                : "=d" (cc)
                : "d" (__fc), "d" (__schid), "d" (out), "d" (in) : "cc");
        return cc;
}

static inline int do_siga_input(unsigned long schid, unsigned int mask,
                                unsigned int fc)
{
        register unsigned long __fc asm ("0") = fc;
        register unsigned long __schid asm ("1") = schid;
        register unsigned long __mask asm ("2") = mask;
        int cc;

        asm volatile(
                "       siga    0\n"
                "       ipm     %0\n"
                "       srl     %0,28\n"
                : "=d" (cc)
                : "d" (__fc), "d" (__schid), "d" (__mask) : "cc");
        return 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 int fc,
                                 unsigned long aob)
{
        register unsigned long __fc asm("0") = fc;
        register unsigned long __schid asm("1") = schid;
        register unsigned long __mask asm("2") = mask;
        register unsigned long __aob asm("3") = aob;
        int cc;

        asm volatile(
                "       siga    0\n"
                "       ipm     %0\n"
                "       srl     %0,28\n"
                : "=d" (cc), "+d" (__fc), "+d" (__aob)
                : "d" (__schid), "d" (__mask)
                : "cc");
        *bb = __fc >> 31;
        return 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_WARN, 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_kick, 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;

        if (!count)
                return 0;
        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_kick, 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, int merge_pending)
{
        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;

        if (merge_pending && __state == SLSB_P_OUTPUT_PENDING)
                __state = SLSB_P_OUTPUT_EMPTY;

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

                /* merge PENDING into EMPTY: */
                if (merge_pending &&
                    q->slsb.val[bufnr] == SLSB_P_OUTPUT_PENDING &&
                    __state == SLSB_P_OUTPUT_EMPTY)
                        continue;

                /* 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, 0);
}

/* 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);

        for (i = 0; i < count; i++) {
                xchg(&q->slsb.val[bufnr], state);
                bufnr = next_buf(bufnr);
        }
        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_siga_sync_q(struct qdio_q *q)
{
        if (q->is_input_q)
                return qdio_siga_sync(q, 0, q->mask);
        else
                return qdio_siga_sync(q, q->mask, 0);
}

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

        if (aob) {
                fc = QDIO_SIGA_WRITEQ;
                laob = aob;
        }

        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, laob);

        /* 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;
}

#define qdio_siga_sync_out(q) qdio_siga_sync(q, ~0U, 0)
#define qdio_siga_sync_all(q) qdio_siga_sync(q, ~0U, ~0U)

static inline void qdio_sync_queues(struct qdio_q *q)
{
        /* PCI capable outbound queues will also be scanned so sync them too */
        if (pci_out_supported(q->irq_ptr))
                qdio_siga_sync_all(q);
        else
                qdio_siga_sync_q(q);
}

int debug_get_buf_state(struct qdio_q *q, unsigned int bufnr,
                        unsigned char *state)
{
        if (need_siga_sync(q))
                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.polling)
                return;

        q->u.in.polling = 0;
        qperf_inc(q, stop_polling);

        /* show the card that we are not polling anymore */
        if (is_qebsm(q)) {
                set_buf_states(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT,
                               q->u.in.ack_count);
                q->u.in.ack_count = 0;
        } else
                set_buf_state(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT);
}

static inline void account_sbals(struct qdio_q *q, unsigned int count)
{
        int pos;

        q->q_stats.nr_sbal_total += count;
        if (count == QDIO_MAX_BUFFERS_MASK) {
                q->q_stats.nr_sbals[7]++;
                return;
        }
        pos = ilog2(count);
        q->q_stats.nr_sbals[pos]++;
}

static void process_buffer_error(struct qdio_q *q, unsigned int start,
                                 int count)
{
        unsigned char state = (q->is_input_q) ? SLSB_P_INPUT_NOT_INIT :
                                        SLSB_P_OUTPUT_NOT_INIT;

        q->qdio_error = QDIO_ERROR_SLSB_STATE;

        /* 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);
                goto set;
        }

        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);

set:
        /*
         * Interrupts may be avoided as long as the error is present
         * so change the buffer state immediately to avoid starvation.
         */
        set_buf_states(q, start, state, count);
}

static inline void inbound_primed(struct qdio_q *q, unsigned int start,
                                  int count)
{
        int new;

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

        /* for QEBSM the ACK was already set by EQBS */
        if (is_qebsm(q)) {
                if (!q->u.in.polling) {
                        q->u.in.polling = 1;
                        q->u.in.ack_count = count;
                        q->u.in.ack_start = start;
                        return;
                }

                /* delete the previous ACK's */
                set_buf_states(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT,
                               q->u.in.ack_count);
                q->u.in.ack_count = count;
                q->u.in.ack_start = start;
                return;
        }

        /*
         * ACK the newest buffer. The ACK will be removed in qdio_stop_polling
         * or by the next inbound run.
         */
        new = add_buf(start, count - 1);
        if (q->u.in.polling) {
                /* reset the previous ACK but first set the new one */
                set_buf_state(q, new, SLSB_P_INPUT_ACK);
                set_buf_state(q, q->u.in.ack_start, SLSB_P_INPUT_NOT_INIT);
        } else {
                q->u.in.polling = 1;
                set_buf_state(q, new, SLSB_P_INPUT_ACK);
        }

        q->u.in.ack_start = new;
        count--;
        if (!count)
                return;
        /* need to change ALL buffers to get more interrupts */
        set_buf_states(q, start, SLSB_P_INPUT_NOT_INIT, count);
}

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

        q->timestamp = get_tod_clock_fast();

        /*
         * Don't check 128 buffers, as otherwise qdio_inbound_q_moved
         * would return 0.
         */
        count = min(atomic_read(&q->nr_buf_used), QDIO_MAX_BUFFERS_MASK);
        if (!count)
                return 0;

        /*
         * No siga sync here, as a PCI or we after a thin interrupt
         * already sync'ed the queues.
         */
        count = get_buf_states(q, start, &state, count, 1, 0);
        if (!count)
                return 0;

        switch (state) {
        case SLSB_P_INPUT_PRIMED:
                inbound_primed(q, start, count);
                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:
                process_buffer_error(q, start, count);
                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:
        case SLSB_P_INPUT_NOT_INIT:
        case SLSB_P_INPUT_ACK:
                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;
        default:
                WARN_ON_ONCE(1);
                return 0;
        }
}

static int qdio_inbound_q_moved(struct qdio_q *q, unsigned int start)
{
        int count;

        count = get_inbound_buffer_frontier(q, start);

        if (count && !is_thinint_irq(q->irq_ptr) && MACHINE_IS_LPAR)
                q->u.in.timestamp = get_tod_clock();

        return count;
}

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 (need_siga_sync(q))
                qdio_siga_sync_q(q);
        get_buf_state(q, start, &state, 0);

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

        if (is_thinint_irq(q->irq_ptr))
                return 1;

        /* don't poll under z/VM */
        if (MACHINE_IS_VM)
                return 1;

        /*
         * At this point we know, that inbound first_to_check
         * has (probably) not moved (see qdio_inbound_processing).
         */
        if (get_tod_clock_fast() > q->u.in.timestamp + QDIO_INPUT_THRESHOLD) {
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "in done:%02x", start);
                return 1;
        } else
                return 0;
}

static inline void qdio_handle_aobs(struct qdio_q *q, int start, int count)
{
        unsigned char state = 0;
        int j, b = start;

        for (j = 0; j < count; ++j) {
                get_buf_state(q, b, &state, 0);
                if (state == SLSB_P_OUTPUT_PENDING) {
                        struct qaob *aob = q->u.out.aobs[b];
                        if (aob == NULL)
                                continue;

                        q->u.out.sbal_state[b].flags |=
                                QDIO_OUTBUF_STATE_FLAG_PENDING;
                        q->u.out.aobs[b] = NULL;
                }
                b = next_buf(b);
        }
}

static inline unsigned long qdio_aob_for_buffer(struct qdio_output_q *q,
                                        int bufnr)
{
        unsigned long phys_aob = 0;

        if (!q->aobs[bufnr]) {
                struct qaob *aob = qdio_allocate_aob();
                q->aobs[bufnr] = aob;
        }
        if (q->aobs[bufnr]) {
                q->aobs[bufnr]->user1 = (u64) q->sbal_state[bufnr].user;
                phys_aob = virt_to_phys(q->aobs[bufnr]);
                WARN_ON_ONCE(phys_aob & 0xFF);
        }

        q->sbal_state[bufnr].flags = 0;
        return phys_aob;
}

static void qdio_kick_handler(struct qdio_q *q, unsigned int count)
{
        int start = q->first_to_kick;

        if (unlikely(q->irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))
                return;

        if (q->is_input_q) {
                qperf_inc(q, inbound_handler);
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "kih s:%02x c:%02x", start, count);
        } else {
                qperf_inc(q, outbound_handler);
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "koh: s:%02x c:%02x",
                              start, count);
                if (q->u.out.use_cq)
                        qdio_handle_aobs(q, start, count);
        }

        q->handler(q->irq_ptr->cdev, q->qdio_error, q->nr, start, count,
                   q->irq_ptr->int_parm);

        /* for the next time */
        q->first_to_kick = add_buf(start, count);
        q->qdio_error = 0;
}

static inline int qdio_tasklet_schedule(struct qdio_q *q)
{
        if (likely(q->irq_ptr->state == QDIO_IRQ_STATE_ACTIVE)) {
                tasklet_schedule(&q->tasklet);
                return 0;
        }
        return -EPERM;
}

static void __qdio_inbound_processing(struct qdio_q *q)
{
        unsigned int start = q->first_to_check;
        int count;

        qperf_inc(q, tasklet_inbound);

        count = qdio_inbound_q_moved(q, start);
        if (count == 0)
                return;

        start = add_buf(start, count);
        q->first_to_check = start;
        qdio_kick_handler(q, count);

        if (!qdio_inbound_q_done(q, start)) {
                /* means poll time is not yet over */
                qperf_inc(q, tasklet_inbound_resched);
                if (!qdio_tasklet_schedule(q))
                        return;
        }

        qdio_stop_polling(q);
        /*
         * We need to check again to not lose initiative after
         * resetting the ACK state.
         */
        if (!qdio_inbound_q_done(q, start)) {
                qperf_inc(q, tasklet_inbound_resched2);
                qdio_tasklet_schedule(q);
        }
}

void qdio_inbound_processing(unsigned long data)
{
        struct qdio_q *q = (struct qdio_q *)data;
        __qdio_inbound_processing(q);
}

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

        q->timestamp = get_tod_clock_fast();

        if (need_siga_sync(q))
                if (((queue_type(q) != QDIO_IQDIO_QFMT) &&
                    !pci_out_supported(q->irq_ptr)) ||
                    (queue_type(q) == QDIO_IQDIO_QFMT &&
                    multicast_outbound(q)))
                        qdio_siga_sync_q(q);

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

        count = get_buf_states(q, start, &state, count, 0, q->u.out.use_cq);
        if (!count)
                return 0;

        switch (state) {
        case SLSB_P_OUTPUT_EMPTY:
        case SLSB_P_OUTPUT_PENDING:
                /* 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:
                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_NOT_INIT:
        case SLSB_P_OUTPUT_HALTED:
                return 0;
        default:
                WARN_ON_ONCE(1);
                return 0;
        }
}

/* all buffers processed? */
static inline int qdio_outbound_q_done(struct qdio_q *q)
{
        return atomic_read(&q->nr_buf_used) == 0;
}

static inline int qdio_outbound_q_moved(struct qdio_q *q, unsigned int start)
{
        int count;

        count = get_outbound_buffer_frontier(q, start);

        if (count)
                DBF_DEV_EVENT(DBF_INFO, q->irq_ptr, "out moved:%1d", q->nr);

        return count;
}

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

        if (!need_siga_out(q))
                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, &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 void __qdio_outbound_processing(struct qdio_q *q)
{
        unsigned int start = q->first_to_check;
        int count;

        qperf_inc(q, tasklet_outbound);
        WARN_ON_ONCE(atomic_read(&q->nr_buf_used) < 0);

        count = qdio_outbound_q_moved(q, start);
        if (count) {
                q->first_to_check = add_buf(start, count);
                qdio_kick_handler(q, count);
        }

        if (queue_type(q) == QDIO_ZFCP_QFMT && !pci_out_supported(q->irq_ptr) &&
            !qdio_outbound_q_done(q))
                goto sched;

        if (q->u.out.pci_out_enabled)
                return;

        /*
         * Now we know that queue type is either qeth without pci enabled
         * or HiperSockets. Make sure buffer switch from PRIMED to EMPTY
         * is noticed and outbound_handler is called after some time.
         */
        if (qdio_outbound_q_done(q))
                del_timer_sync(&q->u.out.timer);
        else
                if (!timer_pending(&q->u.out.timer) &&
                    likely(q->irq_ptr->state == QDIO_IRQ_STATE_ACTIVE))
                        mod_timer(&q->u.out.timer, jiffies + 10 * HZ);
        return;

sched:
        qdio_tasklet_schedule(q);
}

/* outbound tasklet */
void qdio_outbound_processing(unsigned long data)
{
        struct qdio_q *q = (struct qdio_q *)data;
        __qdio_outbound_processing(q);
}

void qdio_outbound_timer(struct timer_list *t)
{
        struct qdio_q *q = from_timer(q, t, u.out.timer);

        qdio_tasklet_schedule(q);
}

static inline void qdio_check_outbound_pci_queues(struct qdio_irq *irq)
{
        struct qdio_q *out;
        int i;

        if (!pci_out_supported(irq))
                return;

        for_each_output_queue(irq, out, i)
                if (!qdio_outbound_q_done(out))
                        qdio_tasklet_schedule(out);
}

static void __tiqdio_inbound_processing(struct qdio_q *q)
{
        unsigned int start = q->first_to_check;
        int count;

        qperf_inc(q, tasklet_inbound);
        if (need_siga_sync(q) && need_siga_sync_after_ai(q))
                qdio_sync_queues(q);

        /* The interrupt could be caused by a PCI request: */
        qdio_check_outbound_pci_queues(q->irq_ptr);

        count = qdio_inbound_q_moved(q, start);
        if (count == 0)
                return;

        start = add_buf(start, count);
        q->first_to_check = start;
        qdio_kick_handler(q, count);

        if (!qdio_inbound_q_done(q, start)) {
                qperf_inc(q, tasklet_inbound_resched);
                if (!qdio_tasklet_schedule(q))
                        return;
        }

        qdio_stop_polling(q);
        /*
         * We need to check again to not lose initiative after
         * resetting the ACK state.
         */
        if (!qdio_inbound_q_done(q, start)) {
                qperf_inc(q, tasklet_inbound_resched2);
                qdio_tasklet_schedule(q);
        }
}

void tiqdio_inbound_processing(unsigned long data)
{
        struct qdio_q *q = (struct qdio_q *)data;
        __tiqdio_inbound_processing(q);
}

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)
{
        int i;
        struct qdio_q *q;

        if (unlikely(irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))
                return;

        for_each_input_queue(irq_ptr, q, i) {
                if (q->u.in.queue_start_poll) {
                        /* skip if polling is enabled or already in work */
                        if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
                                     &q->u.in.queue_irq_state)) {
                                qperf_inc(q, int_discarded);
                                continue;
                        }
                        q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
                                                 q->irq_ptr->int_parm);
                } else {
                        tasklet_schedule(&q->tasklet);
                }
        }

        if (!pci_out_supported(irq_ptr))
                return;

        for_each_output_queue(irq_ptr, q, i) {
                if (qdio_outbound_q_done(q))
                        continue;
                if (need_siga_sync(q) && need_siga_sync_out_after_pci(q))
                        qdio_siga_sync_q(q);
                qdio_tasklet_schedule(q);
        }
}

static void qdio_handle_activate_check(struct ccw_device *cdev,
                                unsigned long intparm, int cstat, int dstat)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        struct qdio_q *q;
        int count;

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

        if (irq_ptr->nr_input_qs) {
                q = irq_ptr->input_qs[0];
        } else if (irq_ptr->nr_output_qs) {

                q = irq_ptr->output_qs[0];
        } else {
                dump_stack();
                goto no_handler;
        }

        count = sub_buf(q->first_to_check, q->first_to_kick);
        q->handler(q->irq_ptr->cdev, QDIO_ERROR_ACTIVATE,
                   q->nr, q->first_to_kick, count, irq_ptr->int_parm);
no_handler:
        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 void qdio_establish_handle_irq(struct ccw_device *cdev, int cstat,
                                      int dstat)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;

        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 (!(dstat & DEV_STAT_DEV_END))
                goto error;
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_ESTABLISHED);
        return;

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);
}

/* 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;

        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;

        switch (irq_ptr->state) {
        case QDIO_IRQ_STATE_INACTIVE:
                qdio_establish_handle_irq(cdev, cstat, dstat);
                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(cdev, intparm, cstat,
                                                   dstat);
                break;
        case QDIO_IRQ_STATE_STOPPED:
                break;
        default:
                WARN_ON_ONCE(1);
        }
        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 void qdio_shutdown_queues(struct ccw_device *cdev)
{
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        struct qdio_q *q;
        int i;

        for_each_input_queue(irq_ptr, q, i)
                tasklet_kill(&q->tasklet);

        for_each_output_queue(irq_ptr, q, i) {
                del_timer_sync(&q->u.out.timer);
                tasklet_kill(&q->tasklet);
        }
}

/**
 * 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. Scheduling the queue
         * tasklets is forbidden from here on.
         */
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_STOPPED);

        tiqdio_remove_input_queues(irq_ptr);
        qdio_shutdown_queues(cdev);
        qdio_shutdown_debug_entries(irq_ptr);

        /* cleanup subchannel */
        spin_lock_irq(get_ccwdev_lock(cdev));

        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);
        if (rc) {
                DBF_ERROR("%4x SHUTD ERR", irq_ptr->schid.sch_no);
                DBF_ERROR("rc:%4d", rc);
                goto no_cleanup;
        }

        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_CLEANUP);
        spin_unlock_irq(get_ccwdev_lock(cdev));
        wait_event_interruptible_timeout(cdev->private->wait_q,
                irq_ptr->state == QDIO_IRQ_STATE_INACTIVE ||
                irq_ptr->state == QDIO_IRQ_STATE_ERR,
                10 * HZ);
        spin_lock_irq(get_ccwdev_lock(cdev));

no_cleanup:
        qdio_shutdown_thinint(irq_ptr);

        /* restore interrupt handler */
        if ((void *)cdev->handler == (void *)qdio_int_handler) {
                cdev->handler = irq_ptr->orig_handler;
                cdev->private->intparm = 0;
        }
        spin_unlock_irq(get_ccwdev_lock(cdev));

        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_release_memory(irq_ptr);
        return 0;
}
EXPORT_SYMBOL_GPL(qdio_free);

/**
 * qdio_allocate - allocate qdio queues and associated data
 * @init_data: initialization data
 */
int qdio_allocate(struct qdio_initialize *init_data)
{
        struct subchannel_id schid;
        struct qdio_irq *irq_ptr;

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

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

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

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

        /* irq_ptr must be in GFP_DMA since it contains ccw1.cda */
        irq_ptr = (void *) get_zeroed_page(GFP_KERNEL | GFP_DMA);
        if (!irq_ptr)
                goto out_err;

        mutex_init(&irq_ptr->setup_mutex);
        if (qdio_allocate_dbf(init_data, irq_ptr))
                goto out_rel;

        /*
         * 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 out_rel;

        /* 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 out_rel;

        if (qdio_allocate_qs(irq_ptr, init_data->no_input_qs,
                             init_data->no_output_qs))
                goto out_rel;

        init_data->cdev->private->qdio_data = irq_ptr;
        qdio_set_state(irq_ptr, QDIO_IRQ_STATE_INACTIVE);
        return 0;
out_rel:
        qdio_release_memory(irq_ptr);
out_err:
        return -ENOMEM;
}
EXPORT_SYMBOL_GPL(qdio_allocate);

static void qdio_detect_hsicq(struct qdio_irq *irq_ptr)
{
        struct qdio_q *q = irq_ptr->input_qs[0];
        int i, use_cq = 0;

        if (irq_ptr->nr_input_qs > 1 && queue_type(q) == QDIO_IQDIO_QFMT)
                use_cq = 1;

        for_each_output_queue(irq_ptr, q, i) {
                if (use_cq) {
                        if (multicast_outbound(q))
                                continue;
                        if (qdio_enable_async_operation(&q->u.out) < 0) {
                                use_cq = 0;
                                continue;
                        }
                } else
                        qdio_disable_async_operation(&q->u.out);
        }
        DBF_EVENT("use_cq:%d", use_cq);
}

/**
 * qdio_establish - establish queues on a qdio subchannel
 * @init_data: initialization data
 */
int qdio_establish(struct qdio_initialize *init_data)
{
        struct ccw_device *cdev = init_data->cdev;
        struct subchannel_id schid;
        struct qdio_irq *irq_ptr;
        int rc;

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

        irq_ptr = cdev->private->qdio_data;
        if (!irq_ptr)
                return -ENODEV;

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

        rc = qdio_establish_thinint(irq_ptr);
        if (rc) {
                mutex_unlock(&irq_ptr->setup_mutex);
                qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
                return rc;
        }

        /* establish q */
        irq_ptr->ccw.cmd_code = irq_ptr->equeue.cmd;
        irq_ptr->ccw.flags = CCW_FLAG_SLI;
        irq_ptr->ccw.count = irq_ptr->equeue.count;
        irq_ptr->ccw.cda = (u32)((addr_t)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);
                mutex_unlock(&irq_ptr->setup_mutex);
                qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
                return rc;
        }

        wait_event_interruptible_timeout(cdev->private->wait_q,
                irq_ptr->state == QDIO_IRQ_STATE_ESTABLISHED ||
                irq_ptr->state == QDIO_IRQ_STATE_ERR, HZ);

        if (irq_ptr->state != QDIO_IRQ_STATE_ESTABLISHED) {
                mutex_unlock(&irq_ptr->setup_mutex);
                qdio_shutdown(cdev, QDIO_FLAG_CLEANUP_USING_CLEAR);
                return -EIO;
        }

        qdio_setup_ssqd_info(irq_ptr);

        qdio_detect_hsicq(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, cdev);
        qdio_setup_debug_entries(irq_ptr, cdev);
        return 0;
}
EXPORT_SYMBOL_GPL(qdio_establish);

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

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

        irq_ptr = cdev->private->qdio_data;
        if (!irq_ptr)
                return -ENODEV;

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

        irq_ptr->ccw.cmd_code = irq_ptr->aqueue.cmd;
        irq_ptr->ccw.flags = CCW_FLAG_SLI;
        irq_ptr->ccw.count = irq_ptr->aqueue.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;
        }

        if (is_thinint_irq(irq_ptr))
                tiqdio_add_input_queues(irq_ptr);

        /* 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);

static inline int buf_in_between(int bufnr, int start, int count)
{
        int end = add_buf(start, count);

        if (end > start) {
                if (bufnr >= start && bufnr < end)
                        return 1;
                else
                        return 0;
        }

        /* wrap-around case */
        if ((bufnr >= start && bufnr <= QDIO_MAX_BUFFERS_PER_Q) ||
            (bufnr < end))
                return 1;
        else
                return 0;
}

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

        qperf_inc(q, inbound_call);

        if (!q->u.in.polling)
                goto set;

        /* protect against stop polling setting an ACK for an emptied slsb */
        if (count == QDIO_MAX_BUFFERS_PER_Q) {
                /* overwriting everything, just delete polling status */
                q->u.in.polling = 0;
                q->u.in.ack_count = 0;
                goto set;
        } else if (buf_in_between(q->u.in.ack_start, bufnr, count)) {
                if (is_qebsm(q)) {
                        /* partial overwrite, just update ack_start */
                        diff = add_buf(bufnr, count);
                        diff = sub_buf(diff, q->u.in.ack_start);
                        q->u.in.ack_count -= diff;
                        if (q->u.in.ack_count <= 0) {
                                q->u.in.polling = 0;
                                q->u.in.ack_count = 0;
                                goto set;
                        }
                        q->u.in.ack_start = add_buf(q->u.in.ack_start, diff);
                }
                else
                        /* the only ACK will be deleted, so stop polling */
                        q->u.in.polling = 0;
        }

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

        if (need_siga_in(q))
                return qdio_siga_input(q);

        return 0;
}

/**
 * handle_outbound - process filled outbound buffers
 * @q: queue containing the buffers
 * @callflags: flags
 * @bufnr: first buffer to process
 * @count: how many buffers are filled
 */
static int handle_outbound(struct qdio_q *q, unsigned int callflags,
                           int bufnr, int count)
{
        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 (callflags & QDIO_FLAG_PCI_OUT) {
                q->u.out.pci_out_enabled = 1;
                qperf_inc(q, pci_request_int);
        } else
                q->u.out.pci_out_enabled = 0;

        if (queue_type(q) == QDIO_IQDIO_QFMT) {
                unsigned long phys_aob = 0;

                /* One SIGA-W per buffer required for unicast HSI */
                WARN_ON_ONCE(count > 1 && !multicast_outbound(q));

                if (q->u.out.use_cq)
                        phys_aob = qdio_aob_for_buffer(&q->u.out, bufnr);

                rc = qdio_kick_outbound_q(q, phys_aob);
        } else if (need_siga_sync(q)) {
                rc = qdio_siga_sync_q(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, 0);
        }

        /* in case of SIGA errors we must process the error immediately */
        if (used >= q->u.out.scan_threshold || rc)
                qdio_tasklet_schedule(q);
        else
                /* free the SBALs in case of no further traffic */
                if (!timer_pending(&q->u.out.timer) &&
                    likely(q->irq_ptr->state == QDIO_IRQ_STATE_ACTIVE))
                        mod_timer(&q->u.out.timer, jiffies + HZ);
        return rc;
}

/**
 * do_QDIO - process input or output buffers
 * @cdev: associated ccw_device for the qdio subchannel
 * @callflags: input or output and special flags from the program
 * @q_nr: queue number
 * @bufnr: buffer number
 * @count: how many buffers to process
 */
int do_QDIO(struct ccw_device *cdev, unsigned int callflags,
            int q_nr, unsigned int bufnr, unsigned int count)
{
        struct qdio_irq *irq_ptr;

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

        irq_ptr = cdev->private->qdio_data;
        if (!irq_ptr)
                return -ENODEV;

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

        if (irq_ptr->state != QDIO_IRQ_STATE_ACTIVE)
                return -EIO;
        if (!count)
                return 0;
        if (callflags & QDIO_FLAG_SYNC_INPUT)
                return handle_inbound(irq_ptr->input_qs[q_nr],
                                      callflags, bufnr, count);
        else if (callflags & QDIO_FLAG_SYNC_OUTPUT)
                return handle_outbound(irq_ptr->output_qs[q_nr],
                                       callflags, bufnr, count);
        return -EINVAL;
}
EXPORT_SYMBOL_GPL(do_QDIO);

/**
 * qdio_start_irq - process input buffers
 * @cdev: associated ccw_device for the qdio subchannel
 * @nr: input queue number
 *
 * Return codes
 *   0 - success
 *   1 - irqs not started since new data is available
 */
int qdio_start_irq(struct ccw_device *cdev, int nr)
{
        struct qdio_q *q;
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;

        if (!irq_ptr)
                return -ENODEV;
        q = irq_ptr->input_qs[nr];

        clear_nonshared_ind(irq_ptr);
        qdio_stop_polling(q);
        clear_bit(QDIO_QUEUE_IRQS_DISABLED, &q->u.in.queue_irq_state);

        /*
         * We need to check again to not lose initiative after
         * resetting the ACK state.
         */
        if (test_nonshared_ind(irq_ptr))
                goto rescan;
        if (!qdio_inbound_q_done(q, q->first_to_check))
                goto rescan;
        return 0;

rescan:
        if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
                             &q->u.in.queue_irq_state))
                return 0;
        else
                return 1;

}
EXPORT_SYMBOL(qdio_start_irq);

/**
 * qdio_get_next_buffers - process input buffers
 * @cdev: associated ccw_device for the qdio subchannel
 * @nr: input queue number
 * @bufnr: first filled buffer number
 * @error: buffers are in error state
 *
 * Return codes
 *   < 0 - error
 *   = 0 - no new buffers found
 *   > 0 - number of processed buffers
 */
int qdio_get_next_buffers(struct ccw_device *cdev, int nr, int *bufnr,
                          int *error)
{
        struct qdio_q *q;
        struct qdio_irq *irq_ptr = cdev->private->qdio_data;
        unsigned int start;
        int count;

        if (!irq_ptr)
                return -ENODEV;
        q = irq_ptr->input_qs[nr];
        start = q->first_to_check;

        /*
         * Cannot rely on automatic sync after interrupt since queues may
         * also be examined without interrupt.
         */
        if (need_siga_sync(q))
                qdio_sync_queues(q);

        qdio_check_outbound_pci_queues(irq_ptr);

        count = qdio_inbound_q_moved(q, start);
        if (count == 0)
                return 0;

        start = add_buf(start, count);
        q->first_to_check = start;

        /* Note: upper-layer MUST stop processing immediately here ... */
        if (unlikely(q->irq_ptr->state != QDIO_IRQ_STATE_ACTIVE))
                return -EIO;

        *bufnr = q->first_to_kick;
        *error = q->qdio_error;

        /* for the next time */
        q->first_to_kick = add_buf(q->first_to_kick, count);
        q->qdio_error = 0;

        return count;
}
EXPORT_SYMBOL(qdio_get_next_buffers);

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

        if (!irq_ptr)
                return -ENODEV;
        q = irq_ptr->input_qs[nr];

        if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
                             &q->u.in.queue_irq_state))
                return 0;
        else
                return 1;
}
EXPORT_SYMBOL(qdio_stop_irq);

/**
 * qdio_pnso_brinfo() - perform network subchannel op #0 - bridge info.
 * @schid:              Subchannel ID.
 * @cnc:                Boolean Change-Notification Control
 * @response:           Response code will be stored at this address
 * @cb:                 Callback function will be executed for each element
 *                      of the address list
 * @priv:               Pointer to pass to the callback function.
 *
 * Performs "Store-network-bridging-information list" operation and calls
 * the callback function for every entry in the list. If "change-
 * notification-control" is set, further changes in the address list
 * will be reported via the IPA command.
 */
int qdio_pnso_brinfo(struct subchannel_id schid,
                int cnc, u16 *response,
                void (*cb)(void *priv, enum qdio_brinfo_entry_type type,
                                void *entry),
                void *priv)
{
        struct chsc_pnso_area *rr;
        int rc;
        u32 prev_instance = 0;
        int isfirstblock = 1;
        int i, size, elems;

        rr = (struct chsc_pnso_area *)get_zeroed_page(GFP_KERNEL);
        if (rr == NULL)
                return -ENOMEM;
        do {
                /* on the first iteration, naihdr.resume_token will be zero */
                rc = chsc_pnso_brinfo(schid, rr, rr->naihdr.resume_token, cnc);
                if (rc != 0 && rc != -EBUSY)
                        goto out;
                if (rr->response.code != 1) {
                        rc = -EIO;
                        continue;
                } else
                        rc = 0;

                if (cb == NULL)
                        continue;

                size = rr->naihdr.naids;
                elems = (rr->response.length -
                                sizeof(struct chsc_header) -
                                sizeof(struct chsc_brinfo_naihdr)) /
                                size;

                if (!isfirstblock && (rr->naihdr.instance != prev_instance)) {
                        /* Inform the caller that they need to scrap */
                        /* the data that was already reported via cb */
                                rc = -EAGAIN;
                                break;
                }
                isfirstblock = 0;
                prev_instance = rr->naihdr.instance;
                for (i = 0; i < elems; i++)
                        switch (size) {
                        case sizeof(struct qdio_brinfo_entry_l3_ipv6):
                                (*cb)(priv, l3_ipv6_addr,
                                                &rr->entries.l3_ipv6[i]);
                                break;
                        case sizeof(struct qdio_brinfo_entry_l3_ipv4):
                                (*cb)(priv, l3_ipv4_addr,
                                                &rr->entries.l3_ipv4[i]);
                                break;
                        case sizeof(struct qdio_brinfo_entry_l2):
                                (*cb)(priv, l2_addr_lnid,
                                                &rr->entries.l2[i]);
                                break;
                        default:
                                WARN_ON_ONCE(1);
                                rc = -EIO;
                                goto out;
                        }
        } while (rr->response.code == 0x0107 ||  /* channel busy */
                  (rr->response.code == 1 && /* list stored */
                   /* resume token is non-zero => list incomplete */
                   (rr->naihdr.resume_token.t1 || rr->naihdr.resume_token.t2)));
        (*response) = rr->response.code;

out:
        free_page((unsigned long)rr);
        return rc;
}
EXPORT_SYMBOL_GPL(qdio_pnso_brinfo);

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 = tiqdio_allocate_memory();
        if (rc)
                goto out_cache;
        rc = tiqdio_register_thinints();
        if (rc)
                goto out_ti;
        return 0;

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

static void __exit exit_QDIO(void)
{
        tiqdio_unregister_thinints();
        tiqdio_free_memory();
        qdio_setup_exit();
        qdio_debug_exit();
}

module_init(init_QDIO);
module_exit(exit_QDIO);