/*
 * IEEE 1394 for Linux
 *
 * Transaction support.
 *
 * Copyright (C) 1999 Andreas E. Bombe
 *
 * This code is licensed under the GPL.  See the file COPYING in the root
 * directory of the kernel sources for details.
 */

#include <linux/bitops.h>
#include <linux/compiler.h>
#include <linux/hardirq.h>
#include <linux/spinlock.h>
#include <linux/string.h>
#include <linux/sched.h>  /* because linux/wait.h is broken if CONFIG_SMP=n */
#include <linux/wait.h>

#include <asm/bug.h>
#include <asm/errno.h>
#include <asm/system.h>

#include "ieee1394.h"
#include "ieee1394_types.h"
#include "hosts.h"
#include "ieee1394_core.h"
#include "ieee1394_transactions.h"

#define PREP_ASYNC_HEAD_ADDRESS(tc) \
        packet->tcode = tc; \
        packet->header[0] = (packet->node_id << 16) | (packet->tlabel << 10) \
                | (1 << 8) | (tc << 4); \
        packet->header[1] = (packet->host->node_id << 16) | (addr >> 32); \
        packet->header[2] = addr & 0xffffffff

#ifndef HPSB_DEBUG_TLABELS
static
#endif
DEFINE_SPINLOCK(hpsb_tlabel_lock);

static DECLARE_WAIT_QUEUE_HEAD(tlabel_wq);

static void fill_async_readquad(struct hpsb_packet *packet, u64 addr)
{
        PREP_ASYNC_HEAD_ADDRESS(TCODE_READQ);
        packet->header_size = 12;
        packet->data_size = 0;
        packet->expect_response = 1;
}

static void fill_async_readblock(struct hpsb_packet *packet, u64 addr,
                                 int length)
{
        PREP_ASYNC_HEAD_ADDRESS(TCODE_READB);
        packet->header[3] = length << 16;
        packet->header_size = 16;
        packet->data_size = 0;
        packet->expect_response = 1;
}

static void fill_async_writequad(struct hpsb_packet *packet, u64 addr,
                                 quadlet_t data)
{
        PREP_ASYNC_HEAD_ADDRESS(TCODE_WRITEQ);
        packet->header[3] = data;
        packet->header_size = 16;
        packet->data_size = 0;
        packet->expect_response = 1;
}

static void fill_async_writeblock(struct hpsb_packet *packet, u64 addr,
                                  int length)
{
        PREP_ASYNC_HEAD_ADDRESS(TCODE_WRITEB);
        packet->header[3] = length << 16;
        packet->header_size = 16;
        packet->expect_response = 1;
        packet->data_size = length + (length % 4 ? 4 - (length % 4) : 0);
}

static void fill_async_lock(struct hpsb_packet *packet, u64 addr, int extcode,
                            int length)
{
        PREP_ASYNC_HEAD_ADDRESS(TCODE_LOCK_REQUEST);
        packet->header[3] = (length << 16) | extcode;
        packet->header_size = 16;
        packet->data_size = length;
        packet->expect_response = 1;
}

static void fill_phy_packet(struct hpsb_packet *packet, quadlet_t data)
{
        packet->header[0] = data;
        packet->header[1] = ~data;
        packet->header_size = 8;
        packet->data_size = 0;
        packet->expect_response = 0;
        packet->type = hpsb_raw;        /* No CRC added */
        packet->speed_code = IEEE1394_SPEED_100;        /* Force speed to be 100Mbps */
}

static void fill_async_stream_packet(struct hpsb_packet *packet, int length,
                                     int channel, int tag, int sync)
{
        packet->header[0] = (length << 16) | (tag << 14) | (channel << 8)
            | (TCODE_STREAM_DATA << 4) | sync;

        packet->header_size = 4;
        packet->data_size = length;
        packet->type = hpsb_async;
        packet->tcode = TCODE_ISO_DATA;
}

/* same as hpsb_get_tlabel, except that it returns immediately */
static int hpsb_get_tlabel_atomic(struct hpsb_packet *packet)
{
        unsigned long flags, *tp;
        u8 *next;
        int tlabel, n = NODEID_TO_NODE(packet->node_id);

        /* Broadcast transactions are complete once the request has been sent.
         * Use the same transaction label for all broadcast transactions. */
        if (unlikely(n == ALL_NODES)) {
                packet->tlabel = 0;
                return 0;
        }
        tp = packet->host->tl_pool[n].map;
        next = &packet->host->next_tl[n];

        spin_lock_irqsave(&hpsb_tlabel_lock, flags);
        tlabel = find_next_zero_bit(tp, 64, *next);
        if (tlabel > 63)
                tlabel = find_first_zero_bit(tp, 64);
        if (tlabel > 63) {
                spin_unlock_irqrestore(&hpsb_tlabel_lock, flags);
                return -EAGAIN;
        }
        __set_bit(tlabel, tp);
        *next = (tlabel + 1) & 63;
        spin_unlock_irqrestore(&hpsb_tlabel_lock, flags);

        packet->tlabel = tlabel;
        return 0;
}

/**
 * hpsb_get_tlabel - allocate a transaction label
 * @packet: the packet whose tlabel and tl_pool we set
 *
 * Every asynchronous transaction on the 1394 bus needs a transaction
 * label to match the response to the request.  This label has to be
 * different from any other transaction label in an outstanding request to
 * the same node to make matching possible without ambiguity.
 *
 * There are 64 different tlabels, so an allocated tlabel has to be freed
 * with hpsb_free_tlabel() after the transaction is complete (unless it's
 * reused again for the same target node).
 *
 * Return value: Zero on success, otherwise non-zero. A non-zero return
 * generally means there are no available tlabels. If this is called out
 * of interrupt or atomic context, then it will sleep until can return a
 * tlabel or a signal is received.
 */
int hpsb_get_tlabel(struct hpsb_packet *packet)
{
        if (irqs_disabled() || in_atomic())
                return hpsb_get_tlabel_atomic(packet);

        /* NB: The macro wait_event_interruptible() is called with a condition
         * argument with side effect.  This is only possible because the side
         * effect does not occur until the condition became true, and
         * wait_event_interruptible() won't evaluate the condition again after
         * that. */
        return wait_event_interruptible(tlabel_wq,
                                        !hpsb_get_tlabel_atomic(packet));
}

/**
 * hpsb_free_tlabel - free an allocated transaction label
 * @packet: packet whose tlabel and tl_pool needs to be cleared
 *
 * Frees the transaction label allocated with hpsb_get_tlabel().  The
 * tlabel has to be freed after the transaction is complete (i.e. response
 * was received for a split transaction or packet was sent for a unified
 * transaction).
 *
 * A tlabel must not be freed twice.
 */
void hpsb_free_tlabel(struct hpsb_packet *packet)
{
        unsigned long flags, *tp;
        int tlabel, n = NODEID_TO_NODE(packet->node_id);

        if (unlikely(n == ALL_NODES))
                return;
        tp = packet->host->tl_pool[n].map;
        tlabel = packet->tlabel;
        BUG_ON(tlabel > 63 || tlabel < 0);

        spin_lock_irqsave(&hpsb_tlabel_lock, flags);
        BUG_ON(!__test_and_clear_bit(tlabel, tp));
        spin_unlock_irqrestore(&hpsb_tlabel_lock, flags);

        wake_up_interruptible(&tlabel_wq);
}

/**
 * hpsb_packet_success - Make sense of the ack and reply codes
 *
 * Make sense of the ack and reply codes and return more convenient error codes:
 * 0 = success.  -%EBUSY = node is busy, try again.  -%EAGAIN = error which can
 * probably resolved by retry.  -%EREMOTEIO = node suffers from an internal
 * error.  -%EACCES = this transaction is not allowed on requested address.
 * -%EINVAL = invalid address at node.
 */
int hpsb_packet_success(struct hpsb_packet *packet)
{
        switch (packet->ack_code) {
        case ACK_PENDING:
                switch ((packet->header[1] >> 12) & 0xf) {
                case RCODE_COMPLETE:
                        return 0;
                case RCODE_CONFLICT_ERROR:
                        return -EAGAIN;
                case RCODE_DATA_ERROR:
                        return -EREMOTEIO;
                case RCODE_TYPE_ERROR:
                        return -EACCES;
                case RCODE_ADDRESS_ERROR:
                        return -EINVAL;
                default:
                        HPSB_ERR("received reserved rcode %d from node %d",
                                 (packet->header[1] >> 12) & 0xf,
                                 packet->node_id);
                        return -EAGAIN;
                }

        case ACK_BUSY_X:
        case ACK_BUSY_A:
        case ACK_BUSY_B:
                return -EBUSY;

        case ACK_TYPE_ERROR:
                return -EACCES;

        case ACK_COMPLETE:
                if (packet->tcode == TCODE_WRITEQ
                    || packet->tcode == TCODE_WRITEB) {
                        return 0;
                } else {
                        HPSB_ERR("impossible ack_complete from node %d "
                                 "(tcode %d)", packet->node_id, packet->tcode);
                        return -EAGAIN;
                }

        case ACK_DATA_ERROR:
                if (packet->tcode == TCODE_WRITEB
                    || packet->tcode == TCODE_LOCK_REQUEST) {
                        return -EAGAIN;
                } else {
                        HPSB_ERR("impossible ack_data_error from node %d "
                                 "(tcode %d)", packet->node_id, packet->tcode);
                        return -EAGAIN;
                }

        case ACK_ADDRESS_ERROR:
                return -EINVAL;

        case ACK_TARDY:
        case ACK_CONFLICT_ERROR:
        case ACKX_NONE:
        case ACKX_SEND_ERROR:
        case ACKX_ABORTED:
        case ACKX_TIMEOUT:
                /* error while sending */
                return -EAGAIN;

        default:
                HPSB_ERR("got invalid ack %d from node %d (tcode %d)",
                         packet->ack_code, packet->node_id, packet->tcode);
                return -EAGAIN;
        }
}

struct hpsb_packet *hpsb_make_readpacket(struct hpsb_host *host, nodeid_t node,
                                         u64 addr, size_t length)
{
        struct hpsb_packet *packet;

        if (length == 0)
                return NULL;

        packet = hpsb_alloc_packet(length);
        if (!packet)
                return NULL;

        packet->host = host;
        packet->node_id = node;

        if (hpsb_get_tlabel(packet)) {
                hpsb_free_packet(packet);
                return NULL;
        }

        if (length == 4)
                fill_async_readquad(packet, addr);
        else
                fill_async_readblock(packet, addr, length);

        return packet;
}

struct hpsb_packet *hpsb_make_writepacket(struct hpsb_host *host, nodeid_t node,
                                          u64 addr, quadlet_t * buffer,
                                          size_t length)
{
        struct hpsb_packet *packet;

        if (length == 0)
                return NULL;

        packet = hpsb_alloc_packet(length);
        if (!packet)
                return NULL;

        if (length % 4) {       /* zero padding bytes */
                packet->data[length >> 2] = 0;
        }
        packet->host = host;
        packet->node_id = node;

        if (hpsb_get_tlabel(packet)) {
                hpsb_free_packet(packet);
                return NULL;
        }

        if (length == 4) {
                fill_async_writequad(packet, addr, buffer ? *buffer : 0);
        } else {
                fill_async_writeblock(packet, addr, length);
                if (buffer)
                        memcpy(packet->data, buffer, length);
        }

        return packet;
}

struct hpsb_packet *hpsb_make_streampacket(struct hpsb_host *host, u8 * buffer,
                                           int length, int channel, int tag,
                                           int sync)
{
        struct hpsb_packet *packet;

        if (length == 0)
                return NULL;

        packet = hpsb_alloc_packet(length);
        if (!packet)
                return NULL;

        if (length % 4) {       /* zero padding bytes */
                packet->data[length >> 2] = 0;
        }
        packet->host = host;

        /* Because it is too difficult to determine all PHY speeds and link
         * speeds here, we use S100... */
        packet->speed_code = IEEE1394_SPEED_100;

        /* ...and prevent hpsb_send_packet() from overriding it. */
        packet->node_id = LOCAL_BUS | ALL_NODES;

        if (hpsb_get_tlabel(packet)) {
                hpsb_free_packet(packet);
                return NULL;
        }

        fill_async_stream_packet(packet, length, channel, tag, sync);
        if (buffer)
                memcpy(packet->data, buffer, length);

        return packet;
}

struct hpsb_packet *hpsb_make_lockpacket(struct hpsb_host *host, nodeid_t node,
                                         u64 addr, int extcode,
                                         quadlet_t * data, quadlet_t arg)
{
        struct hpsb_packet *p;
        u32 length;

        p = hpsb_alloc_packet(8);
        if (!p)
                return NULL;

        p->host = host;
        p->node_id = node;
        if (hpsb_get_tlabel(p)) {
                hpsb_free_packet(p);
                return NULL;
        }

        switch (extcode) {
        case EXTCODE_FETCH_ADD:
        case EXTCODE_LITTLE_ADD:
                length = 4;
                if (data)
                        p->data[0] = *data;
                break;
        default:
                length = 8;
                if (data) {
                        p->data[0] = arg;
                        p->data[1] = *data;
                }
                break;
        }
        fill_async_lock(p, addr, extcode, length);

        return p;
}

struct hpsb_packet *hpsb_make_lock64packet(struct hpsb_host *host,
                                           nodeid_t node, u64 addr, int extcode,
                                           octlet_t * data, octlet_t arg)
{
        struct hpsb_packet *p;
        u32 length;

        p = hpsb_alloc_packet(16);
        if (!p)
                return NULL;

        p->host = host;
        p->node_id = node;
        if (hpsb_get_tlabel(p)) {
                hpsb_free_packet(p);
                return NULL;
        }

        switch (extcode) {
        case EXTCODE_FETCH_ADD:
        case EXTCODE_LITTLE_ADD:
                length = 8;
                if (data) {
                        p->data[0] = *data >> 32;
                        p->data[1] = *data & 0xffffffff;
                }
                break;
        default:
                length = 16;
                if (data) {
                        p->data[0] = arg >> 32;
                        p->data[1] = arg & 0xffffffff;
                        p->data[2] = *data >> 32;
                        p->data[3] = *data & 0xffffffff;
                }
                break;
        }
        fill_async_lock(p, addr, extcode, length);

        return p;
}

struct hpsb_packet *hpsb_make_phypacket(struct hpsb_host *host, quadlet_t data)
{
        struct hpsb_packet *p;

        p = hpsb_alloc_packet(0);
        if (!p)
                return NULL;

        p->host = host;
        fill_phy_packet(p, data);

        return p;
}

/*
 * FIXME - these functions should probably read from / write to user space to
 * avoid in kernel buffers for user space callers
 */

/**
 * hpsb_read - generic read function
 *
 * Recognizes the local node ID and act accordingly.  Automatically uses a
 * quadlet read request if @length == 4 and and a block read request otherwise.
 * It does not yet support lengths that are not a multiple of 4.
 *
 * You must explicitly specifiy the @generation for which the node ID is valid,
 * to avoid sending packets to the wrong nodes when we race with a bus reset.
 */
int hpsb_read(struct hpsb_host *host, nodeid_t node, unsigned int generation,
              u64 addr, quadlet_t * buffer, size_t length)
{
        struct hpsb_packet *packet;
        int retval = 0;

        if (length == 0)
                return -EINVAL;

        packet = hpsb_make_readpacket(host, node, addr, length);

        if (!packet) {
                return -ENOMEM;
        }

        packet->generation = generation;
        retval = hpsb_send_packet_and_wait(packet);
        if (retval < 0)
                goto hpsb_read_fail;

        retval = hpsb_packet_success(packet);

        if (retval == 0) {
                if (length == 4) {
                        *buffer = packet->header[3];
                } else {
                        memcpy(buffer, packet->data, length);
                }
        }

      hpsb_read_fail:
        hpsb_free_tlabel(packet);
        hpsb_free_packet(packet);

        return retval;
}

/**
 * hpsb_write - generic write function
 *
 * Recognizes the local node ID and act accordingly.  Automatically uses a
 * quadlet write request if @length == 4 and and a block write request
 * otherwise.  It does not yet support lengths that are not a multiple of 4.
 *
 * You must explicitly specifiy the @generation for which the node ID is valid,
 * to avoid sending packets to the wrong nodes when we race with a bus reset.
 */
int hpsb_write(struct hpsb_host *host, nodeid_t node, unsigned int generation,
               u64 addr, quadlet_t * buffer, size_t length)
{
        struct hpsb_packet *packet;
        int retval;

        if (length == 0)
                return -EINVAL;

        packet = hpsb_make_writepacket(host, node, addr, buffer, length);

        if (!packet)
                return -ENOMEM;

        packet->generation = generation;
        retval = hpsb_send_packet_and_wait(packet);
        if (retval < 0)
                goto hpsb_write_fail;

        retval = hpsb_packet_success(packet);

      hpsb_write_fail:
        hpsb_free_tlabel(packet);
        hpsb_free_packet(packet);

        return retval;
}

int hpsb_lock(struct hpsb_host *host, nodeid_t node, unsigned int generation,
              u64 addr, int extcode, quadlet_t *data, quadlet_t arg)
{
        struct hpsb_packet *packet;
        int retval = 0;

        packet = hpsb_make_lockpacket(host, node, addr, extcode, data, arg);
        if (!packet)
                return -ENOMEM;

        packet->generation = generation;
        retval = hpsb_send_packet_and_wait(packet);
        if (retval < 0)
                goto hpsb_lock_fail;

        retval = hpsb_packet_success(packet);

        if (retval == 0)
                *data = packet->data[0];

hpsb_lock_fail:
        hpsb_free_tlabel(packet);
        hpsb_free_packet(packet);

        return retval;
}