/*
* hosts.c Copyright (C) 1992 Drew Eckhardt
* Copyright (C) 1993, 1994, 1995 Eric Youngdale
* Copyright (C) 2002-2003 Christoph Hellwig
*
* mid to lowlevel SCSI driver interface
* Initial versions: Drew Eckhardt
* Subsequent revisions: Eric Youngdale
*
* <drew@colorado.edu>
*
* Jiffies wrap fixes (host->resetting), 3 Dec 1998 Andrea Arcangeli
* Added QLOGIC QLA1280 SCSI controller kernel host support.
* August 4, 1999 Fred Lewis, Intel DuPont
*
* Updated to reflect the new initialization scheme for the higher
* level of scsi drivers (sd/sr/st)
* September 17, 2000 Torben Mathiasen <tmm@image.dk>
*
* Restructured scsi_host lists and associated functions.
* September 04, 2002 Mike Anderson (andmike@us.ibm.com)
*/
#include <linux/module.h>
#include <linux/blkdev.h>
#include <linux/kernel.h>
#include <linux/string.h>
#include <linux/mm.h>
#include <linux/init.h>
#include <linux/completion.h>
#include <linux/transport_class.h>
#include <scsi/scsi_device.h>
#include <scsi/scsi_host.h>
#include <scsi/scsi_transport.h>
#include "scsi_priv.h"
#include "scsi_logging.h"
static int scsi_host_next_hn; /* host_no for next new host */
static void scsi_host_cls_release(struct class_device *class_dev)
{
put_device(&class_to_shost(class_dev)->shost_gendev);
}
static struct class shost_class = {
.name = "scsi_host",
.release = scsi_host_cls_release,
};
/**
* scsi_host_set_state - Take the given host through the host
* state model.
* @shost: scsi host to change the state of.
* @state: state to change to.
*
* Returns zero if unsuccessful or an error if the requested
* transition is illegal.
**/
int scsi_host_set_state(struct Scsi_Host *shost, enum scsi_host_state state)
{
enum scsi_host_state oldstate = shost->shost_state;
if (state == oldstate)
return 0;
switch (state) {
case SHOST_CREATED:
/* There are no legal states that come back to
* created. This is the manually initialised start
* state */
goto illegal;
case SHOST_RUNNING:
switch (oldstate) {
case SHOST_CREATED:
case SHOST_RECOVERY:
break;
default:
goto illegal;
}
break;
case SHOST_RECOVERY:
switch (oldstate) {
case SHOST_RUNNING:
break;
default:
goto illegal;
}
break;
case SHOST_CANCEL:
switch (oldstate) {
case SHOST_CREATED:
case SHOST_RUNNING:
break;
default:
goto illegal;
}
break;
case SHOST_DEL:
switch (oldstate) {
case SHOST_CANCEL:
break;
default:
goto illegal;
}
break;
}
shost->shost_state = state;
return 0;
illegal:
SCSI_LOG_ERROR_RECOVERY(1,
dev_printk(KERN_ERR, &shost->shost_gendev,
"Illegal host state transition"
"%s->%s\n",
scsi_host_state_name(oldstate),
scsi_host_state_name(state)));
return -EINVAL;
}
EXPORT_SYMBOL(scsi_host_set_state);
/**
* scsi_remove_host - remove a scsi host
* @shost: a pointer to a scsi host to remove
**/
void scsi_remove_host(struct Scsi_Host *shost)
{
down(&shost->scan_mutex);
scsi_host_set_state(shost, SHOST_CANCEL);
up(&shost->scan_mutex);
scsi_forget_host(shost);
scsi_proc_host_rm(shost);
scsi_host_set_state(shost, SHOST_DEL);
transport_unregister_device(&shost->shost_gendev);
class_device_unregister(&shost->shost_classdev);
device_del(&shost->shost_gendev);
}
EXPORT_SYMBOL(scsi_remove_host);
/**
* scsi_add_host - add a scsi host
* @shost: scsi host pointer to add
* @dev: a struct device of type scsi class
*
* Return value:
* 0 on success / != 0 for error
**/
int scsi_add_host(struct Scsi_Host *shost, struct device *dev)
{
struct scsi_host_template *sht = shost->hostt;
int error = -EINVAL;
printk(KERN_INFO "scsi%d : %s\n", shost->host_no,
sht->info ? sht->info(shost) : sht->name);
if (!shost->can_queue) {
printk(KERN_ERR "%s: can_queue = 0 no longer supported\n",
sht->name);
goto out;
}
if (!shost->shost_gendev.parent)
shost->shost_gendev.parent = dev ? dev : &platform_bus;
error = device_add(&shost->shost_gendev);
if (error)
goto out;
scsi_host_set_state(shost, SHOST_RUNNING);
get_device(shost->shost_gendev.parent);
error = class_device_add(&shost->shost_classdev);
if (error)
goto out_del_gendev;
get_device(&shost->shost_gendev);
if (shost->transportt->host_size &&
(shost->shost_data = kmalloc(shost->transportt->host_size,
GFP_KERNEL)) == NULL)
goto out_del_classdev;
if (shost->transportt->create_work_queue) {
snprintf(shost->work_q_name, KOBJ_NAME_LEN, "scsi_wq_%d",
shost->host_no);
shost->work_q = create_singlethread_workqueue(
shost->work_q_name);
if (!shost->work_q)
goto out_free_shost_data;
}
error = scsi_sysfs_add_host(shost);
if (error)
goto out_destroy_host;
scsi_proc_host_add(shost);
return error;
out_destroy_host:
if (shost->work_q)
destroy_workqueue(shost->work_q);
out_free_shost_data:
kfree(shost->shost_data);
out_del_classdev:
class_device_del(&shost->shost_classdev);
out_del_gendev:
device_del(&shost->shost_gendev);
out:
return error;
}
EXPORT_SYMBOL(scsi_add_host);
static void scsi_host_dev_release(struct device *dev)
{
struct Scsi_Host *shost = dev_to_shost(dev);
struct device *parent = dev->parent;
if (shost->ehandler) {
DECLARE_COMPLETION(sem);
shost->eh_notify = &sem;
shost->eh_kill = 1;
up(shost->eh_wait);
wait_for_completion(&sem);
shost->eh_notify = NULL;
}
if (shost->work_q)
destroy_workqueue(shost->work_q);
scsi_proc_hostdir_rm(shost->hostt);
scsi_destroy_command_freelist(shost);
kfree(shost->shost_data);
if (parent)
put_device(parent);
kfree(shost);
}
/**
* scsi_host_alloc - register a scsi host adapter instance.
* @sht: pointer to scsi host template
* @privsize: extra bytes to allocate for driver
*
* Note:
* Allocate a new Scsi_Host and perform basic initialization.
* The host is not published to the scsi midlayer until scsi_add_host
* is called.
*
* Return value:
* Pointer to a new Scsi_Host
**/
struct Scsi_Host *scsi_host_alloc(struct scsi_host_template *sht, int privsize)
{
struct Scsi_Host *shost;
int gfp_mask = GFP_KERNEL, rval;
DECLARE_COMPLETION(complete);
if (sht->unchecked_isa_dma && privsize)
gfp_mask |= __GFP_DMA;
/* Check to see if this host has any error handling facilities */
if (!sht->eh_strategy_handler && !sht->eh_abort_handler &&
!sht->eh_device_reset_handler && !sht->eh_bus_reset_handler &&
!sht->eh_host_reset_handler) {
printk(KERN_ERR "ERROR: SCSI host `%s' has no error handling\n"
"ERROR: This is not a safe way to run your "
"SCSI host\n"
"ERROR: The error handling must be added to "
"this driver\n", sht->proc_name);
dump_stack();
}
shost = kmalloc(sizeof(struct Scsi_Host) + privsize, gfp_mask);
if (!shost)
return NULL;
memset(shost, 0, sizeof(struct Scsi_Host) + privsize);
spin_lock_init(&shost->default_lock);
scsi_assign_lock(shost, &shost->default_lock);
shost->shost_state = SHOST_CREATED;
INIT_LIST_HEAD(&shost->__devices);
INIT_LIST_HEAD(&shost->__targets);
INIT_LIST_HEAD(&shost->eh_cmd_q);
INIT_LIST_HEAD(&shost->starved_list);
init_waitqueue_head(&shost->host_wait);
init_MUTEX(&shost->scan_mutex);
shost->host_no = scsi_host_next_hn++; /* XXX(hch): still racy */
shost->dma_channel = 0xff;
/* These three are default values which can be overridden */
shost->max_channel = 0;
shost->max_id = 8;
shost->max_lun = 8;
/* Give each shost a default transportt */
shost->transportt = &blank_transport_template;
/*
* All drivers right now should be able to handle 12 byte
* commands. Every so often there are requests for 16 byte
* commands, but individual low-level drivers need to certify that
* they actually do something sensible with such commands.
*/
shost->max_cmd_len = 12;
shost->hostt = sht;
shost->this_id = sht->this_id;
shost->can_queue = sht->can_queue;
shost->sg_tablesize = sht->sg_tablesize;
shost->cmd_per_lun = sht->cmd_per_lun;
shost->unchecked_isa_dma = sht->unchecked_isa_dma;
shost->use_clustering = sht->use_clustering;
shost->ordered_flush = sht->ordered_flush;
shost->ordered_tag = sht->ordered_tag;
/*
* hosts/devices that do queueing must support ordered tags
*/
if (shost->can_queue > 1 && shost->ordered_flush) {
printk(KERN_ERR "scsi: ordered flushes don't support queueing\n");
shost->ordered_flush = 0;
}
if (sht->max_host_blocked)
shost->max_host_blocked = sht->max_host_blocked;
else
shost->max_host_blocked = SCSI_DEFAULT_HOST_BLOCKED;
/*
* If the driver imposes no hard sector transfer limit, start at
* machine infinity initially.
*/
if (sht->max_sectors)
shost->max_sectors = sht->max_sectors;
else
shost->max_sectors = SCSI_DEFAULT_MAX_SECTORS;
/*
* assume a 4GB boundary, if not set
*/
if (sht->dma_boundary)
shost->dma_boundary = sht->dma_boundary;
else
shost->dma_boundary = 0xffffffff;
rval = scsi_setup_command_freelist(shost);
if (rval)
goto fail_kfree;
device_initialize(&shost->shost_gendev);
snprintf(shost->shost_gendev.bus_id, BUS_ID_SIZE, "host%d",
shost->host_no);
shost->shost_gendev.release = scsi_host_dev_release;
class_device_initialize(&shost->shost_classdev);
shost->shost_classdev.dev = &shost->shost_gendev;
shost->shost_classdev.class = &shost_class;
snprintf(shost->shost_classdev.class_id, BUS_ID_SIZE, "host%d",
shost->host_no);
shost->eh_notify = &complete;
rval = kernel_thread(scsi_error_handler, shost, 0);
if (rval < 0)
goto fail_destroy_freelist;
wait_for_completion(&complete);
shost->eh_notify = NULL;
scsi_proc_hostdir_add(shost->hostt);
return shost;
fail_destroy_freelist:
scsi_destroy_command_freelist(shost);
fail_kfree:
kfree(shost);
return NULL;
}
EXPORT_SYMBOL(scsi_host_alloc);
struct Scsi_Host *scsi_register(struct scsi_host_template *sht, int privsize)
{
struct Scsi_Host *shost = scsi_host_alloc(sht, privsize);
if (!sht->detect) {
printk(KERN_WARNING "scsi_register() called on new-style "
"template for driver %s\n", sht->name);
dump_stack();
}
if (shost)
list_add_tail(&shost->sht_legacy_list, &sht->legacy_hosts);
return shost;
}
EXPORT_SYMBOL(scsi_register);
void scsi_unregister(struct Scsi_Host *shost)
{
list_del(&shost->sht_legacy_list);
scsi_host_put(shost);
}
EXPORT_SYMBOL(scsi_unregister);
/**
* scsi_host_lookup - get a reference to a Scsi_Host by host no
*
* @hostnum: host number to locate
*
* Return value:
* A pointer to located Scsi_Host or NULL.
**/
struct Scsi_Host *scsi_host_lookup(unsigned short hostnum)
{
struct class *class = &shost_class;
struct class_device *cdev;
struct Scsi_Host *shost = ERR_PTR(-ENXIO), *p;
down_read(&class->subsys.rwsem);
list_for_each_entry(cdev, &class->children, node) {
p = class_to_shost(cdev);
if (p->host_no == hostnum) {
shost = scsi_host_get(p);
break;
}
}
up_read(&class->subsys.rwsem);
return shost;
}
EXPORT_SYMBOL(scsi_host_lookup);
/**
* scsi_host_get - inc a Scsi_Host ref count
* @shost: Pointer to Scsi_Host to inc.
**/
struct Scsi_Host *scsi_host_get(struct Scsi_Host *shost)
{
if ((shost->shost_state == SHOST_DEL) ||
!get_device(&shost->shost_gendev))
return NULL;
return shost;
}
EXPORT_SYMBOL(scsi_host_get);
/**
* scsi_host_put - dec a Scsi_Host ref count
* @shost: Pointer to Scsi_Host to dec.
**/
void scsi_host_put(struct Scsi_Host *shost)
{
put_device(&shost->shost_gendev);
}
EXPORT_SYMBOL(scsi_host_put);
int scsi_init_hosts(void)
{
return class_register(&shost_class);
}
void scsi_exit_hosts(void)
{
class_unregister(&shost_class);
}
int scsi_is_host_device(const struct device *dev)
{
return dev->release == scsi_host_dev_release;
}
EXPORT_SYMBOL(scsi_is_host_device);
/**
* scsi_queue_work - Queue work to the Scsi_Host workqueue.
* @shost: Pointer to Scsi_Host.
* @work: Work to queue for execution.
*
* Return value:
* 0 on success / != 0 for error
**/
int scsi_queue_work(struct Scsi_Host *shost, struct work_struct *work)
{
if (unlikely(!shost->work_q)) {
printk(KERN_ERR
"ERROR: Scsi host '%s' attempted to queue scsi-work, "
"when no workqueue created.\n", shost->hostt->name);
dump_stack();
return -EINVAL;
}
return queue_work(shost->work_q, work);
}
EXPORT_SYMBOL_GPL(scsi_queue_work);
/**
* scsi_flush_work - Flush a Scsi_Host's workqueue.
* @shost: Pointer to Scsi_Host.
**/
void scsi_flush_work(struct Scsi_Host *shost)
{
if (!shost->work_q) {
printk(KERN_ERR
"ERROR: Scsi host '%s' attempted to flush scsi-work, "
"when no workqueue created.\n", shost->hostt->name);
dump_stack();
return;
}
flush_workqueue(shost->work_q);
}
EXPORT_SYMBOL_GPL(scsi_flush_work);
