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ieee1394_transactions.c

/*
 * 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;

      BUG_ON(in_interrupt()); // We can't be called in an interrupt, yet

      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;

      BUG_ON(in_interrupt()); // We can't be called in an interrupt, yet

      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;
}

#if 0

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;

      BUG_ON(in_interrupt()); // We can't be called in an interrupt, yet

      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;
}

int hpsb_send_gasp(struct hpsb_host *host, int channel, unsigned int generation,
               quadlet_t * buffer, size_t length, u32 specifier_id,
               unsigned int version)
{
      struct hpsb_packet *packet;
      int retval = 0;
      u16 specifier_id_hi = (specifier_id & 0x00ffff00) >> 8;
      u8 specifier_id_lo = specifier_id & 0xff;

      HPSB_VERBOSE("Send GASP: channel = %d, length = %Zd", channel, length);

      length += 8;

      packet = hpsb_make_streampacket(host, NULL, length, channel, 3, 0);
      if (!packet)
            return -ENOMEM;

      packet->data[0] = cpu_to_be32((host->node_id << 16) | specifier_id_hi);
      packet->data[1] =
          cpu_to_be32((specifier_id_lo << 24) | (version & 0x00ffffff));

      memcpy(&(packet->data[2]), buffer, length - 8);

      packet->generation = generation;

      packet->no_waiter = 1;

      retval = hpsb_send_packet(packet);
      if (retval < 0)
            hpsb_free_packet(packet);

      return retval;
}

#endif                        /*  0  */

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