246 lines
7.3 KiB
C
246 lines
7.3 KiB
C
/*
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* hosts.h Copyright (C) 1992 Drew Eckhardt
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* mid to low-level SCSI driver interface header by
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* Drew Eckhardt
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*
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* <drew@colorado.edu>
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*
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* Modified by Eric Youngdale eric@tantalus.nrl.navy.mil to
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* add scatter-gather, multiple outstanding request, and other
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* enhancements.
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*
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* Further modified by Eric Youngdale to support multiple host adapters
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* of the same type.
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*/
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#ifndef _HOSTS_H
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#define _HOSTS_H
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/*
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$Header: /usr/src/linux/kernel/blk_drv/scsi/RCS/hosts.h,v 1.3 1993/09/24 12:21:00 drew Exp drew $
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*/
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/* A jumpstart is often required when the reset() function is called -
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many host adapters cannot do this cleanly, so they do nothing at all.
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To get the command going again, these routines set this bit in the flags
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so that a scsi_request_sense() is executed, and the command starts running
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again */
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#define NEEDS_JUMPSTART 0x20
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#define SG_NONE 0
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#define SG_ALL 0xff
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/* The various choices mean:
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NONE: Self evident. Host adapter is not capable of scatter-gather.
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ALL: Means that the host adapter module can do scatter-gather,
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and that there is no limit to the size of the table to which
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we scatter/gather data.
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Anything else: Indicates the maximum number of chains that can be
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used in one scatter-gather request.
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*/
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/*
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The Scsi_Host_Template type has all that is needed to interface with a SCSI
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host in a device independant matter. There is one entry for each different
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type of host adapter that is supported on the system.
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*/
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typedef struct
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{
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/*
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The name pointer is a pointer to the name of the SCSI
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device detected.
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*/
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char *name;
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/*
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The detect function shall return non zero on detection,
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indicating the number of host adapters of this particular
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type were found. It should also
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initialize all data necessary for this particular
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SCSI driver. It is passed the host number, so this host
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knows where the first entry is in the scsi_hosts[] array.
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Note that the detect routine MUST not call any of the mid level
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functions to queue commands because things are not guaranteed
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to be set up yet. The detect routine can send commands to
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the host adapter as long as the program control will not be
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passed to scsi.c in the processesing of the command. Note
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especially that scsi_malloc/scsi_free must not be called.
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*/
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int (* detect)(int);
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/*
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The info function will return whatever useful
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information the developer sees fit.
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*/
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const char *(* info)(void);
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/*
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The command function takes a target, a command (this is a SCSI
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command formatted as per the SCSI spec, nothing strange), a
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data buffer pointer, and data buffer length pointer. The return
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is a status int, bit fielded as follows :
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Byte What
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0 SCSI status code
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1 SCSI 1 byte message
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2 host error return.
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3 mid level error return
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*/
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int (* command)(Scsi_Cmnd *);
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/*
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The QueueCommand function works in a similar manner
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to the command function. It takes an additional parameter,
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void (* done)(int host, int code) which is passed the host
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# and exit result when the command is complete.
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Host number is the POSITION IN THE hosts array of THIS
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host adapter.
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*/
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int (* queuecommand)(Scsi_Cmnd *, void (*done)(Scsi_Cmnd *));
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/*
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Since the mid level driver handles time outs, etc, we want to
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be able to abort the current command. Abort returns 0 if the
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abortion was successful. If non-zero, the code passed to it
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will be used as the return code, otherwise
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DID_ABORT should be returned.
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Note that the scsi driver should "clean up" after itself,
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resetting the bus, etc. if necessary.
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*/
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int (* abort)(Scsi_Cmnd *, int);
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/*
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The reset function will reset the SCSI bus. Any executing
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commands should fail with a DID_RESET in the host byte.
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The Scsi_Cmnd is passed so that the reset routine can figure
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out which host adapter should be reset, and also which command
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within the command block was responsible for the reset in
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the first place. Some hosts do not implement a reset function,
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and these hosts must call scsi_request_sense(SCpnt) to keep
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the command alive.
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*/
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int (* reset)(Scsi_Cmnd *);
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/*
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This function is used to select synchronous communications,
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which will result in a higher data throughput. Not implemented
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yet.
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*/
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int (* slave_attach)(int, int);
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/*
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This function determines the bios parameters for a given
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harddisk. These tend to be numbers that are made up by
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the host adapter. Parameters:
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size, device number, list (heads, sectors, cylinders)
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*/
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int (* bios_param)(int, int, int []);
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/*
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This determines if we will use a non-interrupt driven
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or an interrupt driven scheme, It is set to the maximum number
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of simulataneous commands a given host adapter will accept.
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*/
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int can_queue;
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/*
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In many instances, especially where disconnect / reconnect are
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supported, our host also has an ID on the SCSI bus. If this is
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the case, then it must be reserved. Please set this_id to -1 if
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your settup is in single initiator mode, and the host lacks an
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ID.
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*/
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int this_id;
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/*
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This determines the degree to which the host adapter is capable
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of scatter-gather.
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*/
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short unsigned int sg_tablesize;
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/*
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True if this host adapter can make good use of linked commands.
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This will allow more than one command to be queued to a given
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unit on a given host. Set this to the maximum number of command
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blocks to be provided for each device. Set this to 1 for one
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command block per lun, 2 for two, etc. Do not set this to 0.
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You should make sure that the host adapter will do the right thing
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before you try setting this above 1.
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*/
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short cmd_per_lun;
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/*
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present contains counter indicating how many boards of this
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type were found when we did the scan.
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*/
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unsigned char present;
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/*
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true if this host adapter uses unchecked DMA onto an ISA bus.
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*/
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unsigned unchecked_isa_dma:1;
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} Scsi_Host_Template;
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/*
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The scsi_hosts array is the array containing the data for all
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possible <supported> scsi hosts. This is similar to the
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Scsi_Host_Template, except that we have one entry for each
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actual physical host adapter on the system, stored as a linked
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list. Note that if there are 2 aha1542 boards, then there will
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be two Scsi_Host entries, but only 1 Scsi_Host_Template entries.
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*/
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struct Scsi_Host
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{
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struct Scsi_Host * next;
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volatile unsigned char host_busy;
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char host_no; /* Used for IOCTL_GET_IDLUN */
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int last_reset;
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struct wait_queue *host_wait;
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Scsi_Cmnd *host_queue;
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Scsi_Host_Template * hostt;
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/* These parameters should be set by the detect routine */
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unsigned char *base;
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short unsigned int io_port;
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unsigned char irq;
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unsigned char dma_channel;
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/*
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The rest can be copied from the template, or specifically
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initialized, as required.
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*/
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int this_id;
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short unsigned int sg_tablesize;
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unsigned unchecked_isa_dma:1;
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int hostdata[0]; /* Used for storage of host specific stuff */
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};
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extern struct Scsi_Host * scsi_hostlist;
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extern Scsi_Host_Template scsi_hosts[];
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/*
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scsi_init initializes the scsi hosts.
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*/
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unsigned int scsi_init(unsigned long memory_start,unsigned long memory_end);
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extern struct Scsi_Host * scsi_register(int i, int j);
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extern void scsi_unregister(struct Scsi_Host * i, int j);
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#define BLANK_HOST {"", 0, 0, 0, 0, 0, 0, 0, 0, 0, 0, 0}
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#endif
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