/* * hosts.h Copyright (C) 1992 Drew Eckhardt * Copyright (C) 1993, 1994, 1995, 1998, 1999 Eric Youngdale * * mid to low-level SCSI driver interface header * Initial versions: Drew Eckhardt * Subsequent revisions: Eric Youngdale * * <drew@colorado.edu> * * Modified by Eric Youngdale eric@andante.org to * add scatter-gather, multiple outstanding request, and other * enhancements. * * Further modified by Eric Youngdale to support multiple host adapters * of the same type. * * Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli * * Restructured scsi_host lists and associated functions. * September 04, 2002 Mike Anderson (andmike@us.ibm.com) */ #ifndef _HOSTS_H #define _HOSTS_H #include <linux/config.h> #include <linux/proc_fs.h> #include <linux/types.h> struct scsi_host_cmd_pool; /* It is senseless to set SG_ALL any higher than this - the performance * does not get any better, and it wastes memory */ #define SG_NONE 0 #define SG_ALL 0xff #define DISABLE_CLUSTERING 0 #define ENABLE_CLUSTERING 1 /* The various choices mean: * NONE: Self evident. Host adapter is not capable of scatter-gather. * ALL: Means that the host adapter module can do scatter-gather, * and that there is no limit to the size of the table to which * we scatter/gather data. * Anything else: Indicates the maximum number of chains that can be * used in one scatter-gather request. */ /* * The Scsi_Host_Template type has all that is needed to interface with a SCSI * host in a device independent matter. There is one entry for each different * type of host adapter that is supported on the system. */ typedef struct SHT { /* Used with loadable modules so that we know when it is safe to unload */ struct module * module; /* The pointer to the /proc/scsi directory entry */ struct proc_dir_entry *proc_dir; /* proc-fs info function. * Can be used to export driver statistics and other infos to the world * outside the kernel ie. userspace and it also provides an interface * to feed the driver with information. Check eata_dma_proc.c for reference */ int (*proc_info)(char *, char **, off_t, int, int, int); /* * The name pointer is a pointer to the name of the SCSI * device detected. */ const char *name; /* * The detect function shall return non zero on detection, * indicating the number of host adapters of this particular * type were found. It should also * initialize all data necessary for this particular * SCSI driver. It is passed the host number, so this host * knows where the first entry is in the scsi_hosts[] array. * * Note that the detect routine MUST not call any of the mid level * functions to queue commands because things are not guaranteed * to be set up yet. The detect routine can send commands to * the host adapter as long as the program control will not be * passed to scsi.c in the processing of the command. Note * especially that scsi_malloc/scsi_free must not be called. */ int (* detect)(struct SHT *); /* Used with loadable modules to unload the host structures. Note: * there is a default action built into the modules code which may * be sufficient for most host adapters. Thus you may not have to supply * this at all. */ int (*release)(struct Scsi_Host *); /* * The info function will return whatever useful * information the developer sees fit. If not provided, then * the name field will be used instead. */ const char *(* info)(struct Scsi_Host *); /* * ioctl interface */ int (*ioctl)(Scsi_Device *dev, int cmd, void *arg); /* * The command function takes a target, a command (this is a SCSI * command formatted as per the SCSI spec, nothing strange), a * data buffer pointer, and data buffer length pointer. The return * is a status int, bit fielded as follows : * Byte What * 0 SCSI status code * 1 SCSI 1 byte message * 2 host error return. * 3 mid level error return */ int (* command)(Scsi_Cmnd *); /* * The QueueCommand function works in a similar manner * to the command function. It takes an additional parameter, * void (* done)(int host, int code) which is passed the host * # and exit result when the command is complete. * Host number is the POSITION IN THE hosts array of THIS * host adapter. * * if queuecommand returns 0, then the HBA has accepted the * command. The done() function must be called on the command * when the driver has finished with it. (you may call done on the * command before queuecommand returns, but in this case you * *must* return 0 from queuecommand). * * queuecommand may also reject the command, in which case it may * not touch the command and must not call done() for it. * * There are two possible rejection returns: * * SCSI_MLQUEUE_DEVICE_BUSY: Block this device temporarily, but * allow commands to other devices serviced by this host. * * SCSI_MLQUEUE_HOST_BUSY: Block all devices served by this * host temporarily. * * for compatibility, any other non-zero return is treated the * same as SCSI_MLQUEUE_HOST_BUSY. * * NOTE: "temporarily" means either until the next command for * this device/host completes, or a period of time determined by * I/O pressure in the system if there are no other outstanding * commands. * */ int (* queuecommand)(Scsi_Cmnd *, void (*done)(Scsi_Cmnd *)); /* * This is an error handling strategy routine. You don't need to * define one of these if you don't want to - there is a default * routine that is present that should work in most cases. For those * driver authors that have the inclination and ability to write their * own strategy routine, this is where it is specified. Note - the * strategy routine is *ALWAYS* run in the context of the kernel eh * thread. Thus you are guaranteed to *NOT* be in an interrupt handler * when you execute this, and you are also guaranteed to *NOT* have any * other commands being queued while you are in the strategy routine. * When you return from this function, operations return to normal. * * See scsi_error.c scsi_unjam_host for additional comments about what * this function should and should not be attempting to do. */ int (*eh_strategy_handler)(struct Scsi_Host *); int (*eh_abort_handler)(Scsi_Cmnd *); int (*eh_device_reset_handler)(Scsi_Cmnd *); int (*eh_bus_reset_handler)(Scsi_Cmnd *); int (*eh_host_reset_handler)(Scsi_Cmnd *); /* * Old EH handlers, no longer used. Make them warn the user of old * drivers by using a wrong type */ int (*abort)(int); int (*reset)(int,int); /* * slave_alloc() - Optional * * Before the mid layer attempts to scan for a new device where none * currently exists, it will call this entry in your driver. Should * your driver need to allocate any structs or perform any other init * items in order to send commands to a currently unused target/lun * combo, then this is where you can perform those allocations. This * is specifically so that drivers won't have to perform any kind of * "is this a new device" checks in their queuecommand routine, * thereby making the hot path a bit quicker. * * Return values: 0 on success, non-0 on failure * * Deallocation: If we didn't find any devices at this ID, you will * get an immediate call to slave_destroy(). If we find something here * then you will get a call to slave_configure(), then the device will be * used for however long it is kept around, then when the device is * removed from the system (or * possibly at reboot time), you will * then get a call to slave_detach(). This is assuming you implement * slave_configure and slave_destroy. However, if you allocate memory * and hang it off the device struct, then you must implement the * slave_destroy() routine at a minimum in order to avoid leaking memory * each time a device is tore down. */ int (* slave_alloc)(Scsi_Device *); /* * slave_configure() - Optional * * Once the device has responded to an INQUIRY and we know the device * is online, we call into the low level driver with the Scsi_Device * * If the low level device driver implements this function, it *must* * perform the task of setting the queue depth on the device. All other * tasks are optional and depend on what the driver supports and various * implementation details. * * Things currently recommended to be handled at this time include: * * 1. Setting the device queue depth. Proper setting of this is * described in the comments for scsi_adjust_queue_depth. * 2. Determining if the device supports the various synchronous * negotiation protocols. The device struct will already have * responded to INQUIRY and the results of the standard items * will have been shoved into the various device flag bits, eg. * device->sdtr will be true if the device supports SDTR messages. * 3. Allocating command structs that the device will need. * 4. Setting the default timeout on this device (if needed). * 5. Anything else the low level driver might want to do on a device * specific setup basis... * 6. Return 0 on success, non-0 on error. The device will be marked * as offline on error so that no access will occur. If you return * non-0, your slave_detach routine will never get called for this * device, so don't leave any loose memory hanging around, clean * up after yourself before returning non-0 */ int (* slave_configure)(Scsi_Device *); /* * slave_destroy() - Optional * * Immediately prior to deallocating the device and after all activity * has ceased the mid layer calls this point so that the low level driver * may completely detach itself from the scsi device and vice versa. * The low level driver is responsible for freeing any memory it allocated * in the slave_alloc or slave_configure calls. */ void (* slave_destroy)(Scsi_Device *); /* * This function determines the bios parameters for a given * harddisk. These tend to be numbers that are made up by * the host adapter. Parameters: * size, device, list (heads, sectors, cylinders) */ int (* bios_param)(struct scsi_device *, struct block_device *, sector_t, int []); /* * This determines if we will use a non-interrupt driven * or an interrupt driven scheme, It is set to the maximum number * of simultaneous commands a given host adapter will accept. */ int can_queue; /* * In many instances, especially where disconnect / reconnect are * supported, our host also has an ID on the SCSI bus. If this is * the case, then it must be reserved. Please set this_id to -1 if * your setup is in single initiator mode, and the host lacks an * ID. */ int this_id; /* * This determines the degree to which the host adapter is capable * of scatter-gather. */ short unsigned int sg_tablesize; /* * if the host adapter has limitations beside segment count */ short unsigned int max_sectors; /* * True if this host adapter can make good use of linked commands. * This will allow more than one command to be queued to a given * unit on a given host. Set this to the maximum number of command * blocks to be provided for each device. Set this to 1 for one * command block per lun, 2 for two, etc. Do not set this to 0. * You should make sure that the host adapter will do the right thing * before you try setting this above 1. */ short cmd_per_lun; /* * present contains counter indicating how many boards of this * type were found when we did the scan. */ unsigned char present; /* * true if this host adapter uses unchecked DMA onto an ISA bus. */ unsigned unchecked_isa_dma:1; /* * true if this host adapter can make good use of clustering. * I originally thought that if the tablesize was large that it * was a waste of CPU cycles to prepare a cluster list, but * it works out that the Buslogic is faster if you use a smaller * number of segments (i.e. use clustering). I guess it is * inefficient. */ unsigned use_clustering:1; /* * True for emulated SCSI host adapters (e.g. ATAPI) */ unsigned emulated:1; unsigned highmem_io:1; /* * True if the driver wishes to use the generic block layer * tag queueing functions */ unsigned use_blk_tcq:1; /* * Name of proc directory */ char *proc_name; /* * countdown for host blocking with no commands outstanding */ unsigned int max_host_blocked; /* * Default value for the blocking. If the queue is empty, host_blocked * counts down in the request_fn until it restarts host operations as * zero is reached. * * FIXME: This should probably be a value in the template */ #define SCSI_DEFAULT_HOST_BLOCKED 7 } Scsi_Host_Template; /* * The scsi_hosts array is the array containing the data for all * possible <supported> scsi hosts. This is similar to the * Scsi_Host_Template, except that we have one entry for each * actual physical host adapter on the system, stored as a linked * list. Note that if there are 2 aha1542 boards, then there will * be two Scsi_Host entries, but only 1 Scsi_Host_Template entry. */ struct Scsi_Host { /* private: */ /* * This information is private to the scsi mid-layer. Wrapping it in a * struct private is a way of marking it in a sort of C++ type of way. */ struct list_head sh_list; struct list_head my_devices; struct scsi_host_cmd_pool *cmd_pool; spinlock_t free_list_lock; struct list_head free_list; /* backup store of cmd structs */ struct list_head starved_list; spinlock_t default_lock; spinlock_t *host_lock; struct list_head eh_cmd_q; struct task_struct * ehandler; /* Error recovery thread. */ struct semaphore * eh_wait; /* The error recovery thread waits on this. */ struct completion * eh_notify; /* wait for eh to begin or end */ struct semaphore * eh_action; /* Wait for specific actions on the host. */ unsigned int eh_active:1; /* Indicates the eh thread is awake and active if this is true. */ unsigned int eh_kill:1; /* set when killing the eh thread */ wait_queue_head_t host_wait; Scsi_Host_Template * hostt; volatile unsigned short host_busy; /* commands actually active on low-level */ volatile unsigned short host_failed; /* commands that failed. */ /* public: */ unsigned short host_no; /* Used for IOCTL_GET_IDLUN, /proc/scsi et al. */ int resetting; /* if set, it means that last_reset is a valid value */ unsigned long last_reset; /* * These three parameters can be used to allow for wide scsi, * and for host adapters that support multiple busses * The first two should be set to 1 more than the actual max id * or lun (i.e. 8 for normal systems). */ unsigned int max_id; unsigned int max_lun; unsigned int max_channel; /* These parameters should be set by the detect routine */ unsigned long base; unsigned long io_port; unsigned char n_io_port; unsigned char dma_channel; unsigned int irq; /* * This is a unique identifier that must be assigned so that we * have some way of identifying each detected host adapter properly * and uniquely. For hosts that do not support more than one card * in the system at one time, this does not need to be set. It is * initialized to 0 in scsi_register. */ unsigned int unique_id; /* * The rest can be copied from the template, or specifically * initialized, as required. */ /* * The maximum length of SCSI commands that this host can accept. * Probably 12 for most host adapters, but could be 16 for others. * For drivers that don't set this field, a value of 12 is * assumed. I am leaving this as a number rather than a bit * because you never know what subsequent SCSI standards might do * (i.e. could there be a 20 byte or a 24-byte command a few years * down the road?). */ unsigned char max_cmd_len; int this_id; int can_queue; short cmd_per_lun; short unsigned int sg_tablesize; short unsigned int max_sectors; unsigned in_recovery:1; unsigned unchecked_isa_dma:1; unsigned use_clustering:1; unsigned highmem_io:1; unsigned use_blk_tcq:1; /* * Host has requested that no further requests come through for the * time being. */ unsigned host_self_blocked:1; /* * Host uses correct SCSI ordering not PC ordering. The bit is * set for the minority of drivers whose authors actually read the spec ;) */ unsigned reverse_ordering:1; /* * Host has rejected a command because it was busy. */ unsigned int host_blocked; /* * Value host_blocked counts down from */ unsigned int max_host_blocked; /* * Support for driverfs filesystem */ struct device *host_gendev; /* * We should ensure that this is aligned, both for better performance * and also because some compilers (m68k) don't automatically force * alignment to a long boundary. */ unsigned long hostdata[0] /* Used for storage of host specific stuff */ __attribute__ ((aligned (sizeof(unsigned long)))); }; #define to_scsi_host(d) d->class_data /* * These two functions are used to allocate and free a pseudo device * which will connect to the host adapter itself rather than any * physical device. You must deallocate when you are done with the * thing. This physical pseudo-device isn't real and won't be available * from any high-level drivers. */ extern void scsi_free_host_dev(Scsi_Device *); extern Scsi_Device * scsi_get_host_dev(struct Scsi_Host *); extern void scsi_unblock_requests(struct Scsi_Host *); extern void scsi_block_requests(struct Scsi_Host *); extern void scsi_report_bus_reset(struct Scsi_Host *, int); static inline void scsi_assign_lock(struct Scsi_Host *shost, spinlock_t *lock) { shost->host_lock = lock; } static inline void scsi_set_device(struct Scsi_Host *shost, struct device *dev) { shost->host_gendev = dev; } static inline struct device *scsi_get_device(struct Scsi_Host *shost) { return shost->host_gendev; } /* * Prototypes for functions/data in scsi_scan.c */ extern void scsi_scan_host(struct Scsi_Host *); extern void scsi_forget_host(struct Scsi_Host *); struct Scsi_Device_Template { struct list_head list; const char * name; struct module * module; /* Used for loadable modules */ unsigned char scsi_type; int (*attach)(Scsi_Device *); /* Attach devices to arrays */ void (*detach)(Scsi_Device *); int (*init_command)(Scsi_Cmnd *); /* Used by new queueing code. Selects command for blkdevs */ void (*rescan)(Scsi_Device *); struct device_driver scsi_driverfs_driver; }; /* * Highlevel driver registration/unregistration. */ extern int scsi_register_device(struct Scsi_Device_Template *); extern int scsi_unregister_device(struct Scsi_Device_Template *); /* * HBA allocation/freeing. */ extern struct Scsi_Host * scsi_register(Scsi_Host_Template *, int); extern void scsi_unregister(struct Scsi_Host *); /* * HBA registration/unregistration. */ extern int scsi_add_host(struct Scsi_Host *, struct device *); extern int scsi_remove_host(struct Scsi_Host *); /* * Legacy HBA template registration/unregistration. */ extern int scsi_register_host(Scsi_Host_Template *); extern int scsi_unregister_host(Scsi_Host_Template *); extern struct Scsi_Host *scsi_host_get_next(struct Scsi_Host *); extern struct Scsi_Host *scsi_host_hn_get(unsigned short); extern void scsi_host_put(struct Scsi_Host *); extern void scsi_host_init(void); /* * host_busy inc/dec/test functions */ extern void scsi_host_busy_inc(struct Scsi_Host *, Scsi_Device *); extern void scsi_host_busy_dec_and_test(struct Scsi_Host *, Scsi_Device *); /** * scsi_find_device - find a device given the host * @shost: SCSI host pointer * @channel: SCSI channel (zero if only one channel) * @pun: SCSI target number (physical unit number) * @lun: SCSI Logical Unit Number **/ static inline Scsi_Device *scsi_find_device(struct Scsi_Host *shost, int channel, int pun, int lun) { Scsi_Device *sdev; list_for_each_entry (sdev, &shost->my_devices, siblings) if (sdev->channel == channel && sdev->id == pun && sdev->lun ==lun) return sdev; return NULL; } /* * sysfs support */ extern int scsi_upper_driver_register(struct Scsi_Device_Template *); extern void scsi_upper_driver_unregister(struct Scsi_Device_Template *); extern struct device_class shost_devclass; #endif /* * Overrides for Emacs so that we follow Linus's tabbing style. * Emacs will notice this stuff at the end of the file and automatically * adjust the settings for this buffer only. This must remain at the end * of the file. * --------------------------------------------------------------------------- * Local variables: * c-indent-level: 4 * c-brace-imaginary-offset: 0 * c-brace-offset: -4 * c-argdecl-indent: 4 * c-label-offset: -4 * c-continued-statement-offset: 4 * c-continued-brace-offset: 0 * indent-tabs-mode: nil * tab-width: 8 * End: */