dasd.c

优龙2410linux2.6.8内核源代码

/*
 * File...........: linux/drivers/s390/block/dasd.c
 * Author(s)......: Holger Smolinski <[e-mail]>
 *		    Horst Hummel <[e-mail]>
 *		    Carsten Otte <[e-mail]>
 *		    Martin Schwidefsky <[e-mail]>
 * Bugreports.to..: <[e-mail]>
 * (C) IBM Corporation, IBM Deutschland Entwicklung GmbH, 1999-2001
 *
 * $Revision: 1.147 $
 */

#include <linux/config.h>
#include <linux/kmod.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <linux/ctype.h>
#include <linux/major.h>
#include <linux/slab.h>
#include <linux/buffer_head.h>

#include <asm/ccwdev.h>
#include <asm/ebcdic.h>
#include <asm/idals.h>
#include <asm/todclk.h>

/* This is ugly... */
#define PRINTK_HEADER "dasd:"

#include "dasd_int.h"
/*
 * SECTION: Constant definitions to be used within this file
 */
#define DASD_CHANQ_MAX_SIZE 4

/*
 * SECTION: exported variables of dasd.c
 */
debug_info_t *dasd_debug_area;
struct dasd_discipline *dasd_diag_discipline_pointer;

MODULE_AUTHOR("Holger Smolinski <[e-mail]>");
MODULE_DESCRIPTION("Linux on S/390 DASD device driver,"
		   " Copyright 2000 IBM Corporation");
MODULE_SUPPORTED_DEVICE("dasd");
MODULE_PARM(dasd, "1-" __MODULE_STRING(256) "s");
MODULE_LICENSE("GPL");

/*
 * SECTION: prototypes for static functions of dasd.c
 */
static int  dasd_alloc_queue(struct dasd_device * device);
static void dasd_setup_queue(struct dasd_device * device);
static void dasd_free_queue(struct dasd_device * device);
static void dasd_flush_request_queue(struct dasd_device *);
static void dasd_int_handler(struct ccw_device *, unsigned long, struct irb *);
static void dasd_flush_ccw_queue(struct dasd_device *, int);
static void dasd_tasklet(struct dasd_device *);
static void do_kick_device(void *data);

/*
 * SECTION: Operations on the device structure.
 */
static wait_queue_head_t dasd_init_waitq;

/*
 * Allocate memory for a new device structure.
 */
struct dasd_device *
dasd_alloc_device(void)
{
	struct dasd_device *device;

	device = kmalloc(sizeof (struct dasd_device), GFP_ATOMIC);
	if (device == NULL)
		return ERR_PTR(-ENOMEM);
	memset(device, 0, sizeof (struct dasd_device));
	/* open_count = 0 means device online but not in use */
	atomic_set(&device->open_count, -1);

	/* Get two pages for normal block device operations. */
	device->ccw_mem = (void *) __get_free_pages(GFP_ATOMIC | GFP_DMA, 1);
	if (device->ccw_mem == NULL) {
		kfree(device);
		return ERR_PTR(-ENOMEM);
	}
	/* Get one page for error recovery. */
	device->erp_mem = (void *) get_zeroed_page(GFP_ATOMIC | GFP_DMA);
	if (device->erp_mem == NULL) {
		free_pages((unsigned long) device->ccw_mem, 1);
		kfree(device);
		return ERR_PTR(-ENOMEM);
	}

	dasd_init_chunklist(&device->ccw_chunks, device->ccw_mem, PAGE_SIZE*2);
	dasd_init_chunklist(&device->erp_chunks, device->erp_mem, PAGE_SIZE);
	spin_lock_init(&device->mem_lock);
	spin_lock_init(&device->request_queue_lock);
	atomic_set (&device->tasklet_scheduled, 0);
	tasklet_init(&device->tasklet, 
		     (void (*)(unsigned long)) dasd_tasklet,
		     (unsigned long) device);
	INIT_LIST_HEAD(&device->ccw_queue);
	init_timer(&device->timer);
	INIT_WORK(&device->kick_work, do_kick_device, device);
	device->state = DASD_STATE_NEW;
	device->target = DASD_STATE_NEW;

	return device;
}

/*
 * Free memory of a device structure.
 */
void
dasd_free_device(struct dasd_device *device)
{
	if (device->private)
		kfree(device->private);
	free_page((unsigned long) device->erp_mem);
	free_pages((unsigned long) device->ccw_mem, 1);
	kfree(device);
}

/*
 * Make a new device known to the system.
 */
static inline int
dasd_state_new_to_known(struct dasd_device *device)
{
	int rc;

	/*
	 * As long as the device is not in state DASD_STATE_NEW we want to 
	 * keep the reference count > 0.
	 */
	dasd_get_device(device);

	rc = dasd_alloc_queue(device);
	if (rc) {
		dasd_put_device(device);
		return rc;
	}

	device->state = DASD_STATE_KNOWN;
	return 0;
}

/*
 * Let the system forget about a device.
 */
static inline void
dasd_state_known_to_new(struct dasd_device * device)
{
	/* Forget the discipline information. */
	device->discipline = NULL;
	device->state = DASD_STATE_NEW;

	dasd_free_queue(device);

	/* Give up reference we took in dasd_state_new_to_known. */
	dasd_put_device(device);
}

/*
 * Request the irq line for the device.
 */
static inline int
dasd_state_known_to_basic(struct dasd_device * device)
{
	int rc;

	/* Allocate and register gendisk structure. */
	rc = dasd_gendisk_alloc(device);
	if (rc)
		return rc;

	/* register 'device' debug area, used for all DBF_DEV_XXX calls */
	device->debug_area = debug_register(device->cdev->dev.bus_id, 0, 2,
					    8 * sizeof (long));
	debug_register_view(device->debug_area, &debug_sprintf_view);
	debug_set_level(device->debug_area, DBF_ERR);
	DBF_DEV_EVENT(DBF_EMERG, device, "%s", "debug area created");

	device->state = DASD_STATE_BASIC;
	return 0;
}

/*
 * Release the irq line for the device. Terminate any running i/o.
 */
static inline void
dasd_state_basic_to_known(struct dasd_device * device)
{
	dasd_gendisk_free(device);
	dasd_flush_ccw_queue(device, 1);
	DBF_DEV_EVENT(DBF_EMERG, device, "%p debug area deleted", device);
	if (device->debug_area != NULL) {
		debug_unregister(device->debug_area);
		device->debug_area = NULL;
	}
	device->state = DASD_STATE_KNOWN;
}

/*
 * Do the initial analysis. The do_analysis function may return
 * -EAGAIN in which case the device keeps the state DASD_STATE_BASIC
 * until the discipline decides to continue the startup sequence
 * by calling the function dasd_change_state. The eckd disciplines
 * uses this to start a ccw that detects the format. The completion
 * interrupt for this detection ccw uses the kernel event daemon to
 * trigger the call to dasd_change_state. All this is done in the
 * discipline code, see dasd_eckd.c.
 * After the analysis ccw is done (do_analysis returned 0 or error)
 * the block device is setup. Either a fake disk is added to allow
 * formatting or a proper device request queue is created.
 */
static inline int
dasd_state_basic_to_ready(struct dasd_device * device)
{
	int rc;

	rc = 0;
	if (device->discipline->do_analysis != NULL)
		rc = device->discipline->do_analysis(device);
	if (rc)
		return rc;
	dasd_setup_queue(device);
	device->state = DASD_STATE_READY;
	if (dasd_scan_partitions(device) != 0)
		device->state = DASD_STATE_BASIC;
	return 0;
}

/*
 * Remove device from block device layer. Destroy dirty buffers.
 * Forget format information. Check if the target level is basic
 * and if it is create fake disk for formatting.
 */
static inline void
dasd_state_ready_to_basic(struct dasd_device * device)
{
	dasd_flush_ccw_queue(device, 0);
	dasd_destroy_partitions(device);
	dasd_flush_request_queue(device);
	device->blocks = 0;
	device->bp_block = 0;
	device->s2b_shift = 0;
	device->state = DASD_STATE_BASIC;
}

/*
 * Make the device online and schedule the bottom half to start
 * the requeueing of requests from the linux request queue to the
 * ccw queue.
 */
static inline int
dasd_state_ready_to_online(struct dasd_device * device)
{
	device->state = DASD_STATE_ONLINE;
	dasd_schedule_bh(device);
	return 0;
}

/*
 * Stop the requeueing of requests again.
 */
static inline void
dasd_state_online_to_ready(struct dasd_device * device)
{
	device->state = DASD_STATE_READY;
}

/*
 * Device startup state changes.
 */
static inline int
dasd_increase_state(struct dasd_device *device)
{
	int rc;

	rc = 0;
	if (device->state == DASD_STATE_NEW &&
	    device->target >= DASD_STATE_KNOWN)
		rc = dasd_state_new_to_known(device);

	if (!rc &&
	    device->state == DASD_STATE_KNOWN &&
	    device->target >= DASD_STATE_BASIC)
		rc = dasd_state_known_to_basic(device);

	if (!rc &&
	    device->state == DASD_STATE_BASIC &&
	    device->target >= DASD_STATE_READY)
		rc = dasd_state_basic_to_ready(device);

	if (!rc &&
	    device->state == DASD_STATE_READY &&
	    device->target >= DASD_STATE_ONLINE)
		rc = dasd_state_ready_to_online(device);

	return rc;
}

/*
 * Device shutdown state changes.
 */
static inline int
dasd_decrease_state(struct dasd_device *device)
{
	if (device->state == DASD_STATE_ONLINE &&
	    device->target <= DASD_STATE_READY)
		dasd_state_online_to_ready(device);
	
	if (device->state == DASD_STATE_READY &&
	    device->target <= DASD_STATE_BASIC)
		dasd_state_ready_to_basic(device);
	
	if (device->state == DASD_STATE_BASIC && 
	    device->target <= DASD_STATE_KNOWN)
		dasd_state_basic_to_known(device);
	
	if (device->state == DASD_STATE_KNOWN &&
	    device->target <= DASD_STATE_NEW)
		dasd_state_known_to_new(device);

	return 0;
}

/*
 * This is the main startup/shutdown routine.
 */
static void
dasd_change_state(struct dasd_device *device)
{
        int rc;

	if (device->state == device->target)
		/* Already where we want to go today... */
		return;
	if (device->state < device->target)
		rc = dasd_increase_state(device);
	else
		rc = dasd_decrease_state(device);
        if (rc && rc != -EAGAIN)
                device->target = device->state;

	if (device->state == device->target)
		wake_up(&dasd_init_waitq);
}

/*
 * Kick starter for devices that did not complete the startup/shutdown
 * procedure or were sleeping because of a pending state.
 * dasd_kick_device will schedule a call do do_kick_device to the kernel
 * event daemon.
 */
static void
do_kick_device(void *data)
{
	struct dasd_device *device;

	device = (struct dasd_device *) data;
	dasd_change_state(device);
	dasd_schedule_bh(device);
	dasd_put_device(device);
}

void
dasd_kick_device(struct dasd_device *device)
{
	dasd_get_device(device);
	/* queue call to dasd_kick_device to the kernel event daemon. */
	schedule_work(&device->kick_work);
}

/*
 * Set the target state for a device and starts the state change.
 */
void
dasd_set_target_state(struct dasd_device *device, int target)
{
	/* If we are in probeonly mode stop at DASD_STATE_READY. */
	if (dasd_probeonly && target > DASD_STATE_READY)
		target = DASD_STATE_READY;
	if (device->target != target) {
                if (device->state == target)
			wake_up(&dasd_init_waitq);
		device->target = target;
	}
	if (device->state != device->target)
		dasd_change_state(device);
}

/*
 * Enable devices with device numbers in [from..to].
 */
static inline int
_wait_for_device(struct dasd_device *device)
{
	return (device->state == device->target);
}

void
dasd_enable_device(struct dasd_device *device)
{
	dasd_set_target_state(device, DASD_STATE_ONLINE);
	if (device->state <= DASD_STATE_KNOWN)
		/* No discipline for device found. */
		dasd_set_target_state(device, DASD_STATE_NEW);
	/* Now wait for the devices to come up. */
	wait_event(dasd_init_waitq, _wait_for_device(device));
}

/*
 * SECTION: device operation (interrupt handler, start i/o, term i/o ...)
 */
#ifdef CONFIG_DASD_PROFILE

struct dasd_profile_info_t dasd_global_profile;
unsigned int dasd_profile_level = DASD_PROFILE_OFF;

/*
 * Increments counter in global and local profiling structures.
 */
#define dasd_profile_counter(value, counter, device) \
{ \
	int index; \
	for (index = 0; index < 31 && value >> (2+index); index++); \
	dasd_global_profile.counter[index]++; \
	device->profile.counter[index]++; \
}

/*
 * Add profiling information for cqr before execution.
 */
static inline void
dasd_profile_start(struct dasd_device *device, struct dasd_ccw_req * cqr,
		   struct request *req)
{
	struct list_head *l;
	unsigned int counter;

	if (dasd_profile_level != DASD_PROFILE_ON)
		return;

	/* count the length of the chanq for statistics */
	counter = 0;
	list_for_each(l, &device->ccw_queue)
		if (++counter >= 31)
			break;
	dasd_global_profile.dasd_io_nr_req[counter]++;
	device->profile.dasd_io_nr_req[counter]++;
}

/*
 * Add profiling information for cqr after execution.
 */
static inline void
dasd_profile_end(struct dasd_device *device, struct dasd_ccw_req * cqr,
		 struct request *req)
{
	long strtime, irqtime, endtime, tottime;	/* in microseconds */
	long tottimeps, sectors;

	if (dasd_profile_level != DASD_PROFILE_ON)
		return;

	sectors = req->nr_sectors;
	if (!cqr->buildclk || !cqr->startclk ||
	    !cqr->stopclk || !cqr->endclk ||
	    !sectors)
		return;

	strtime = ((cqr->startclk - cqr->buildclk) >> 12);
	irqtime = ((cqr->stopclk - cqr->startclk) >> 12);
	endtime = ((cqr->endclk - cqr->stopclk) >> 12);
	tottime = ((cqr->endclk - cqr->buildclk) >> 12);
	tottimeps = tottime / sectors;

	if (!dasd_global_profile.dasd_io_reqs)
		memset(&dasd_global_profile, 0,
		       sizeof (struct dasd_profile_info_t));
	dasd_global_profile.dasd_io_reqs++;
	dasd_global_profile.dasd_io_sects += sectors;

	if (!device->profile.dasd_io_reqs)
		memset(&device->profile, 0,
		       sizeof (struct dasd_profile_info_t));
	device->profile.dasd_io_reqs++;
	device->profile.dasd_io_sects += sectors;

	dasd_profile_counter(sectors, dasd_io_secs, device);
	dasd_profile_counter(tottime, dasd_io_times, device);
	dasd_profile_counter(tottimeps, dasd_io_timps, device);
	dasd_profile_counter(strtime, dasd_io_time1, device);
	dasd_profile_counter(irqtime, dasd_io_time2, device);
	dasd_profile_counter(irqtime / sectors, dasd_io_time2ps, device);
	dasd_profile_counter(endtime, dasd_io_time3, device);
}
#else
#define dasd_profile_start(device, cqr, req) do {} while (0)
#define dasd_profile_end(device, cqr, req) do {} while (0)
#endif				/* CONFIG_DASD_PROFILE */

/*
 * Allocate memory for a channel program with 'cplength' channel
 * command words and 'datasize' additional space. There are two
 * variantes: 1) dasd_kmalloc_request uses kmalloc to get the needed
 * memory and 2) dasd_smalloc_request uses the static ccw memory
 * that gets allocated for each device.
 */
struct dasd_ccw_req *
dasd_kmalloc_request(char *magic, int cplength, int datasize,