400 lines
9.3 KiB
C
400 lines
9.3 KiB
C
/*
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* Copyright (C) 1995 Advanced RISC Machines Limited. All rights reserved.
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*
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* This software may be freely used, copied, modified, and distributed
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* provided that the above copyright notice is preserved in all copies of the
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* software.
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*/
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/* -*-C-*-
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*
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* $Revision$
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* $Date$
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*
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*/
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#include <stdio.h>
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#include <stdlib.h>
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#include "adp.h"
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#include "hsys.h"
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#include "rxtx.h"
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#include "drivers.h"
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#include "buffers.h"
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#include "devclnt.h"
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#include "adperr.h"
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#include "devsw.h"
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#include "hostchan.h"
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#include "logging.h"
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/*
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* TODO: this should be adjustable - it could be done by defining
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* a reason code for DevSW_Ioctl. It could even be a
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* per-devicechannel parameter.
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*/
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static const unsigned int allocsize = ADP_BUFFER_MIN_SIZE;
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#define illegalDevChanID(type) ((type) >= DC_NUM_CHANNELS)
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/**********************************************************************/
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/*
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* Function: initialise_read
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* Purpose: Set up a read request for another packet
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*
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* Params:
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* In/Out: ds State structure to be initialised
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*
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* Returns:
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* OK: 0
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* Error: -1
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*/
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static int initialise_read(DevSWState *ds)
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{
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struct data_packet *dp;
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/*
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* try to claim the structure that will
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* eventually hold the new packet.
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*/
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if ((ds->ds_nextreadpacket = DevSW_AllocatePacket(allocsize)) == NULL)
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return -1;
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/*
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* Calls into the device driver use the DriverCall structure: use
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* the buffer we have just allocated, and declare its size. We
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* are also obliged to clear the driver's context pointer.
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*/
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dp = &ds->ds_activeread.dc_packet;
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dp->buf_len = allocsize;
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dp->data = ds->ds_nextreadpacket->pk_buffer;
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ds->ds_activeread.dc_context = NULL;
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return 0;
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}
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/*
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* Function: initialise_write
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* Purpose: Set up a write request for another packet
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*
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* Params:
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* Input: packet The packet to be written
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*
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* type The type of the packet
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*
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* In/Out: dc The structure to be intialised
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*
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* Returns: Nothing
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*/
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static void initialise_write(DriverCall *dc, Packet *packet, DevChanID type)
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{
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struct data_packet *dp = &dc->dc_packet;
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dp->len = packet->pk_length;
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dp->data = packet->pk_buffer;
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dp->type = type;
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/*
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* we are required to clear the state structure for the driver
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*/
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dc->dc_context = NULL;
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}
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/*
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* Function: enqueue_packet
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* Purpose: move a newly read packet onto the appropriate queue
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* of read packets
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*
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* Params:
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* In/Out: ds State structure with new packet
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*
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* Returns: Nothing
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*/
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static void enqueue_packet(DevSWState *ds)
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{
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struct data_packet *dp = &ds->ds_activeread.dc_packet;
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Packet *packet = ds->ds_nextreadpacket;
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/*
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* transfer the length
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*/
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packet->pk_length = dp->len;
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/*
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* take this packet out of the incoming slot
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*/
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ds->ds_nextreadpacket = NULL;
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/*
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* try to put it on the correct input queue
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*/
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if (illegalDevChanID(dp->type))
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{
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/* this shouldn't happen */
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WARN("Illegal type for Rx packet");
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DevSW_FreePacket(packet);
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}
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else
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Adp_addToQueue(&ds->ds_readqueue[dp->type], packet);
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}
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/*
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* Function: flush_packet
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* Purpose: Send a packet to the device driver
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*
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* Params:
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* Input: device The device to be written to
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*
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* In/Out: dc Describes the packet to be sent
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*
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* Returns: Nothing
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*
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* Post-conditions: If the whole packet was accepted by the device
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* driver, then dc->dc_packet.data will be
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* set to NULL.
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*/
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static void flush_packet(const DeviceDescr *device, DriverCall *dc)
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{
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if (device->DeviceWrite(dc) > 0)
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/*
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* the whole packet was swallowed
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*/
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dc->dc_packet.data = NULL;
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}
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/**********************************************************************/
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/*
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* These are the externally visible functions. They are documented in
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* devsw.h
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*/
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Packet *DevSW_AllocatePacket(const unsigned int length)
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{
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Packet *pk;
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if ((pk = malloc(sizeof(*pk))) == NULL)
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{
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WARN("malloc failure");
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return NULL;
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}
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if ((pk->pk_buffer = malloc(length+CHAN_HEADER_SIZE)) == NULL)
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{
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WARN("malloc failure");
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free(pk);
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return NULL;
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}
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return pk;
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}
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void DevSW_FreePacket(Packet *pk)
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{
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free(pk->pk_buffer);
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free(pk);
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}
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AdpErrs DevSW_Open(DeviceDescr *device, const char *name, const char *arg,
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const DevChanID type)
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{
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DevSWState *ds;
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/*
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* is this the very first open call for this driver?
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*/
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if ((ds = (DevSWState *)(device->SwitcherState)) == NULL)
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{
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/*
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* yes, it is: initialise state
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*/
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if ((ds = malloc(sizeof(*ds))) == NULL)
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/* give up */
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return adp_malloc_failure;
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(void)memset(ds, 0, sizeof(*ds));
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device->SwitcherState = (void *)ds;
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}
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/*
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* check that we haven't already been opened for this type
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*/
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if ((ds->ds_opendevchans & (1 << type)) != 0)
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return adp_device_already_open;
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/*
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* if no opens have been done for this device, then do it now
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*/
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if (ds->ds_opendevchans == 0)
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if (device->DeviceOpen(name, arg) < 0)
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return adp_device_open_failed;
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/*
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* open has finished
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*/
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ds->ds_opendevchans |= (1 << type);
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return adp_ok;
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}
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AdpErrs DevSW_Match(const DeviceDescr *device, const char *name,
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const char *arg)
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{
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return (device->DeviceMatch(name, arg) == -1) ? adp_failed : adp_ok;
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}
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AdpErrs DevSW_Close(const DeviceDescr *device, const DevChanID type)
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{
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DevSWState *ds = (DevSWState *)(device->SwitcherState);
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Packet *pk;
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if ((ds->ds_opendevchans & (1 << type)) == 0)
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return adp_device_not_open;
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ds->ds_opendevchans &= ~(1 << type);
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/*
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* if this is the last close for this channel, then inform the driver
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*/
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if (ds->ds_opendevchans == 0)
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device->DeviceClose();
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/*
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* release all packets of the appropriate type
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*/
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for (pk = Adp_removeFromQueue(&(ds->ds_readqueue[type]));
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pk != NULL;
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pk = Adp_removeFromQueue(&(ds->ds_readqueue[type])))
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DevSW_FreePacket(pk);
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/* that's all */
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return adp_ok;
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}
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AdpErrs DevSW_Read(const DeviceDescr *device, const DevChanID type,
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Packet **packet, bool block)
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{
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int read_err;
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DevSWState *ds = device->SwitcherState;
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/*
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* To try to get information out of the device driver as
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* quickly as possible, we try and read more packets, even
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* if a completed packet is already available.
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*/
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/*
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* have we got a packet currently pending?
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*/
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if (ds->ds_nextreadpacket == NULL)
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/*
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* no - set things up
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*/
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if (initialise_read(ds) < 0) {
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/*
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* we failed to initialise the next packet, but can
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* still return a packet that has already arrived.
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*/
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*packet = Adp_removeFromQueue(&ds->ds_readqueue[type]);
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return adp_ok;
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}
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read_err = device->DeviceRead(&ds->ds_activeread, block);
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switch (read_err) {
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case 1:
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/*
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* driver has pulled in a complete packet, queue it up
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*/
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#ifdef RET_DEBUG
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printf("got a complete packet\n");
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#endif
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enqueue_packet(ds);
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*packet = Adp_removeFromQueue(&ds->ds_readqueue[type]);
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return adp_ok;
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case 0:
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/*
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* OK, return the head of the read queue for the given type
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*/
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/* enqueue_packet(ds); */
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*packet = Adp_removeFromQueue(&ds->ds_readqueue[type]);
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return adp_ok;
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case -1:
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#ifdef RET_DEBUG
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printf("got a bad packet\n");
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#endif
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/* bad packet */
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*packet = NULL;
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return adp_bad_packet;
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default:
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panic("DevSW_Read: bad read status %d", read_err);
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}
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return 0; /* get rid of a potential compiler warning */
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}
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AdpErrs DevSW_FlushPendingWrite(const DeviceDescr *device)
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{
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struct DriverCall *dc;
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struct data_packet *dp;
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dc = &((DevSWState *)(device->SwitcherState))->ds_activewrite;
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dp = &dc->dc_packet;
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/*
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* try to flush any packet that is still being written
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*/
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if (dp->data != NULL)
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{
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flush_packet(device, dc);
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/* see if it has gone */
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if (dp->data != NULL)
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return adp_write_busy;
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else
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return adp_ok;
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}
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else
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return adp_ok;
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}
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AdpErrs DevSW_Write(const DeviceDescr *device, Packet *packet, DevChanID type)
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{
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struct DriverCall *dc;
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struct data_packet *dp;
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dc = &((DevSWState *)(device->SwitcherState))->ds_activewrite;
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dp = &dc->dc_packet;
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if (illegalDevChanID(type))
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return adp_illegal_args;
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/*
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* try to flush any packet that is still being written
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*/
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if (DevSW_FlushPendingWrite(device) != adp_ok)
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return adp_write_busy;
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/*
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* we can take this packet - set things up, then try to get rid of it
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*/
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initialise_write(dc, packet, type);
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flush_packet(device, dc);
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return adp_ok;
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}
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AdpErrs DevSW_Ioctl(const DeviceDescr *device, const int opcode, void *args)
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{
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return (device->DeviceIoctl(opcode, args) < 0) ? adp_failed : adp_ok;
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}
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bool DevSW_WriteFinished(const DeviceDescr *device)
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{
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struct DriverCall *dc;
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struct data_packet *dp;
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dc = &((DevSWState *)(device->SwitcherState))->ds_activewrite;
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dp = &dc->dc_packet;
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return (dp == NULL || dp->data == NULL);
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}
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/* EOF devsw.c */
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