drivers/ieee1394/ieee1394_transactions.c - kernel/msm - Gitiles

 /*
  * 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/sched.h>
 #include <linux/bitops.h>
 #include <linux/smp_lock.h>
 #include <linux/interrupt.h>

 #include <asm/errno.h>

 #include "ieee1394.h"
 #include "ieee1394_types.h"
 #include "hosts.h"
 #include "ieee1394_core.h"
 #include "highlevel.h"
 #include "nodemgr.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


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

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

 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;
 }

 /**
  * hpsb_get_tlabel - allocate a transaction label
  * @packet: the packet who's tlabel/tpool 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.
  */
 int hpsb_get_tlabel(struct hpsb_packet *packet)
 {
 	unsigned long flags;
 	struct hpsb_tlabel_pool *tp;

 	tp = &packet->host->tpool[packet->node_id & NODE_MASK];

 	if (irqs_disabled() || in_atomic()) {
 		if (down_trylock(&tp->count))
 			return 1;
 	} else {
 		down(&tp->count);
 	}

 	spin_lock_irqsave(&tp->lock, flags);

 	packet->tlabel = find_next_zero_bit(tp->pool, 64, tp->next);
 	if (packet->tlabel > 63)
 		packet->tlabel = find_first_zero_bit(tp->pool, 64);
 	tp->next = (packet->tlabel + 1) % 64;
 	/* Should _never_ happen */
 	BUG_ON(test_and_set_bit(packet->tlabel, tp->pool));
 	tp->allocations++;
 	spin_unlock_irqrestore(&tp->lock, flags);

 	return 0;
 }

 /**
  * hpsb_free_tlabel - free an allocated transaction label
  * @packet: packet whos tlabel/tpool 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;
 	struct hpsb_tlabel_pool *tp;

 	tp = &packet->host->tpool[packet->node_id & NODE_MASK];

 	BUG_ON(packet->tlabel > 63 || packet->tlabel < 0);

         spin_lock_irqsave(&tp->lock, flags);
 	BUG_ON(!test_and_clear_bit(packet->tlabel, tp->pool));
         spin_unlock_irqrestore(&tp->lock, flags);

 	up(&tp->count);
 }


 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;
                 }
                 HPSB_PANIC("reached unreachable code 1 in %s", __FUNCTION__);

         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;
         }

         HPSB_PANIC("reached unreachable code 2 in %s", __FUNCTION__);
 }

 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;

 	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;
 }

 struct hpsb_packet *hpsb_make_isopacket(struct hpsb_host *host,
 					int length, int channel,
 					int tag, int sync)
 {
 	struct hpsb_packet *p;

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

 	p->host = host;
 	fill_iso_packet(p, length, channel, tag, sync);

 	p->generation = get_hpsb_generation(host);

 	return p;
 }

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

 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;
 }


 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  */
	/*
	* 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/sched.h>
	#include <linux/bitops.h>
	#include <linux/smp_lock.h>
	#include <linux/interrupt.h>

	#include <asm/errno.h>

	#include "ieee1394.h"
	#include "ieee1394_types.h"
	#include "hosts.h"
	#include "ieee1394_core.h"
	#include "highlevel.h"
	#include "nodemgr.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


	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_iso_packet(struct hpsb_packet *packet, int length, int channel,
	int tag, int sync)
	{
	packet->header[0] = (length << 16) \| (tag << 14) \| (channel << 8)
	\| (TCODE_ISO_DATA << 4) \| sync;

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

	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;
	}

	/**
	* hpsb_get_tlabel - allocate a transaction label
	* @packet: the packet who's tlabel/tpool 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.
	*/
	int hpsb_get_tlabel(struct hpsb_packet *packet)
	{
	unsigned long flags;
	struct hpsb_tlabel_pool *tp;

	tp = &packet->host->tpool[packet->node_id & NODE_MASK];

	if (irqs_disabled() \|\| in_atomic()) {
	if (down_trylock(&tp->count))
	return 1;
	} else {
	down(&tp->count);
	}

	spin_lock_irqsave(&tp->lock, flags);

	packet->tlabel = find_next_zero_bit(tp->pool, 64, tp->next);
	if (packet->tlabel > 63)
	packet->tlabel = find_first_zero_bit(tp->pool, 64);
	tp->next = (packet->tlabel + 1) % 64;
	/* Should _never_ happen */
	BUG_ON(test_and_set_bit(packet->tlabel, tp->pool));
	tp->allocations++;
	spin_unlock_irqrestore(&tp->lock, flags);

	return 0;
	}

	/**
	* hpsb_free_tlabel - free an allocated transaction label
	* @packet: packet whos tlabel/tpool 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;
	struct hpsb_tlabel_pool *tp;

	tp = &packet->host->tpool[packet->node_id & NODE_MASK];

	BUG_ON(packet->tlabel > 63 \|\| packet->tlabel < 0);

	spin_lock_irqsave(&tp->lock, flags);
	BUG_ON(!test_and_clear_bit(packet->tlabel, tp->pool));
	spin_unlock_irqrestore(&tp->lock, flags);

	up(&tp->count);
	}



	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;
	}
	HPSB_PANIC("reached unreachable code 1 in %s", __FUNCTION__);

	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;
	}

	HPSB_PANIC("reached unreachable code 2 in %s", __FUNCTION__);
	}

	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;

	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;
	}

	struct hpsb_packet hpsb_make_isopacket(struct hpsb_host host,
	int length, int channel,
	int tag, int sync)
	{
	struct hpsb_packet *p;

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

	p->host = host;
	fill_iso_packet(p, length, channel, tag, sync);

	p->generation = get_hpsb_generation(host);

	return p;
	}

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

	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;
	}


	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 */