chsc.c

底层驱动开发

			if (chpid < 0)
				CIO_CRW_EVENT(4, "%s: Invalid LIR, skipping\n",
					      __FUNCTION__);
			else
				s390_set_chpid_offline(chpid);
			break;
			
		case 2: /* i/o resource accessibiliy */
			CIO_CRW_EVENT(4, "chsc_process_crw: "
				      "channel subsystem reports some I/O "
				      "devices may have become accessible\n");
			pr_debug("Data received after sei: \n");
			pr_debug("Validity flags: %x\n", sei_area->vf);
			
			/* allocate a new channel path structure, if needed */
			status = get_chp_status(sei_area->rsid);
			if (status < 0)
				new_channel_path(sei_area->rsid);
			else if (!status)
				return 0;
			if ((sei_area->vf & 0x80) == 0) {
				pr_debug("chpid: %x\n", sei_area->rsid);
				ret = s390_process_res_acc(sei_area->rsid,
							   0, 0);
			} else if ((sei_area->vf & 0xc0) == 0x80) {
				pr_debug("chpid: %x link addr: %x\n",
					 sei_area->rsid, sei_area->fla);
				ret = s390_process_res_acc(sei_area->rsid,
							   sei_area->fla,
							   0xff00);
			} else if ((sei_area->vf & 0xc0) == 0xc0) {
				pr_debug("chpid: %x full link addr: %x\n",
					 sei_area->rsid, sei_area->fla);
				ret = s390_process_res_acc(sei_area->rsid,
							   sei_area->fla,
							   0xffff);
			}
			pr_debug("\n");
			
			break;
			
		default: /* other stuff */
			CIO_CRW_EVENT(4, "chsc_process_crw: event %d\n",
				      sei_area->cc);
			break;
		}
	} while (sei_area->flags & 0x80);
	return ret;
}

static int
chp_add(int chpid)
{
	struct subchannel *sch;
	int irq, ret, rc;
	char dbf_txt[15];

	if (!get_chp_status(chpid))
		return 0; /* no need to do the rest */
	
	sprintf(dbf_txt, "cadd%x", chpid);
	CIO_TRACE_EVENT(2, dbf_txt);

	rc = 0;
	for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
		int i;

		sch = get_subchannel_by_schid(irq);
		if (!sch) {
			struct schib schib;

			if (stsch(irq, &schib)) {
				/* We're through */
				if (need_rescan)
					rc = -EAGAIN;
				break;
			}
			if (need_rescan) {
				rc = -EAGAIN;
				continue;
			}
			/* Put it on the slow path. */
			ret = css_enqueue_subchannel_slow(irq);
			if (ret) {
				css_clear_subchannel_slow_list();
				need_rescan = 1;
			}
			rc = -EAGAIN;
			continue;
		}
	
		spin_lock(&sch->lock);
		for (i=0; i<8; i++)
			if (sch->schib.pmcw.chpid[i] == chpid) {
				if (stsch(sch->irq, &sch->schib) != 0) {
					/* Endgame. */
					spin_unlock(&sch->lock);
					return rc;
				}
				break;
			}
		if (i==8) {
			spin_unlock(&sch->lock);
			return rc;
		}
		sch->lpm = ((sch->schib.pmcw.pim &
			     sch->schib.pmcw.pam &
			     sch->schib.pmcw.pom)
			    | 0x80 >> i) & sch->opm;

		if (sch->driver && sch->driver->verify)
			sch->driver->verify(&sch->dev);

		spin_unlock(&sch->lock);
		put_device(&sch->dev);
	}
	return rc;
}

/* 
 * Handling of crw machine checks with channel path source.
 */
int
chp_process_crw(int chpid, int on)
{
	if (on == 0) {
		/* Path has gone. We use the link incident routine.*/
		s390_set_chpid_offline(chpid);
		return 0; /* De-register is async anyway. */
	}
	/*
	 * Path has come. Allocate a new channel path structure,
	 * if needed.
	 */
	if (get_chp_status(chpid) < 0)
		new_channel_path(chpid);
	/* Avoid the extra overhead in process_rec_acc. */
	return chp_add(chpid);
}

static inline int
__check_for_io_and_kill(struct subchannel *sch, int index)
{
	int cc;

	if (!device_is_online(sch))
		/* cio could be doing I/O. */
		return 0;
	cc = stsch(sch->irq, &sch->schib);
	if (cc)
		return 0;
	if (sch->schib.scsw.actl && sch->schib.pmcw.lpum == (0x80 >> index)) {
		device_set_waiting(sch);
		return 1;
	}
	return 0;
}

static inline void
__s390_subchannel_vary_chpid(struct subchannel *sch, __u8 chpid, int on)
{
	int chp, old_lpm;
	unsigned long flags;

	if (!sch->ssd_info.valid)
		return;
	
	spin_lock_irqsave(&sch->lock, flags);
	old_lpm = sch->lpm;
	for (chp = 0; chp < 8; chp++) {
		if (sch->ssd_info.chpid[chp] != chpid)
			continue;

		if (on) {
			sch->opm |= (0x80 >> chp);
			sch->lpm |= (0x80 >> chp);
			if (!old_lpm)
				device_trigger_reprobe(sch);
			else if (sch->driver && sch->driver->verify)
				sch->driver->verify(&sch->dev);
		} else {
			sch->opm &= ~(0x80 >> chp);
			sch->lpm &= ~(0x80 >> chp);
			/*
			 * Give running I/O a grace period in which it
			 * can successfully terminate, even using the
			 * just varied off path. Then kill it.
			 */
			if (!__check_for_io_and_kill(sch, chp) && !sch->lpm) {
				if (css_enqueue_subchannel_slow(sch->irq)) {
					css_clear_subchannel_slow_list();
					need_rescan = 1;
				}
			} else if (sch->driver && sch->driver->verify)
				sch->driver->verify(&sch->dev);
		}
		break;
	}
	spin_unlock_irqrestore(&sch->lock, flags);
}

static int
s390_subchannel_vary_chpid_off(struct device *dev, void *data)
{
	struct subchannel *sch;
	__u8 *chpid;

	sch = to_subchannel(dev);
	chpid = data;

	__s390_subchannel_vary_chpid(sch, *chpid, 0);
	return 0;
}

static int
s390_subchannel_vary_chpid_on(struct device *dev, void *data)
{
	struct subchannel *sch;
	__u8 *chpid;

	sch = to_subchannel(dev);
	chpid = data;

	__s390_subchannel_vary_chpid(sch, *chpid, 1);
	return 0;
}

/*
 * Function: s390_vary_chpid
 * Varies the specified chpid online or offline
 */
static int
s390_vary_chpid( __u8 chpid, int on)
{
	char dbf_text[15];
	int status, irq, ret;
	struct subchannel *sch;

	sprintf(dbf_text, on?"varyon%x":"varyoff%x", chpid);
	CIO_TRACE_EVENT( 2, dbf_text);

	status = get_chp_status(chpid);
	if (status < 0) {
		printk(KERN_ERR "Can't vary unknown chpid %02X\n", chpid);
		return -EINVAL;
	}

	if (!on && !status) {
		printk(KERN_ERR "chpid %x is already offline\n", chpid);
		return -EINVAL;
	}

	set_chp_logically_online(chpid, on);

	/*
	 * Redo PathVerification on the devices the chpid connects to
	 */

	bus_for_each_dev(&css_bus_type, NULL, &chpid, on ?
			 s390_subchannel_vary_chpid_on :
			 s390_subchannel_vary_chpid_off);
	if (!on)
		goto out;
	/* Scan for new devices on varied on path. */
	for (irq = 0; irq < __MAX_SUBCHANNELS; irq++) {
		struct schib schib;

		if (need_rescan)
			break;
		sch = get_subchannel_by_schid(irq);
		if (sch) {
			put_device(&sch->dev);
			continue;
		}
		if (stsch(irq, &schib))
			/* We're through */
			break;
		/* Put it on the slow path. */
		ret = css_enqueue_subchannel_slow(irq);
		if (ret) {
			css_clear_subchannel_slow_list();
			need_rescan = 1;
		}
	}
out:
	if (need_rescan || css_slow_subchannels_exist())
		queue_work(slow_path_wq, &slow_path_work);
	return 0;
}

/*
 * Files for the channel path entries.
 */
static ssize_t
chp_status_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct channel_path *chp = container_of(dev, struct channel_path, dev);

	if (!chp)
		return 0;
	return (get_chp_status(chp->id) ? sprintf(buf, "online\n") :
		sprintf(buf, "offline\n"));
}

static ssize_t
chp_status_write(struct device *dev, struct device_attribute *attr, const char *buf, size_t count)
{
	struct channel_path *cp = container_of(dev, struct channel_path, dev);
	char cmd[10];
	int num_args;
	int error;

	num_args = sscanf(buf, "%5s", cmd);
	if (!num_args)
		return count;

	if (!strnicmp(cmd, "on", 2))
		error = s390_vary_chpid(cp->id, 1);
	else if (!strnicmp(cmd, "off", 3))
		error = s390_vary_chpid(cp->id, 0);
	else
		error = -EINVAL;

	return error < 0 ? error : count;

}

static DEVICE_ATTR(status, 0644, chp_status_show, chp_status_write);

static ssize_t
chp_type_show(struct device *dev, struct device_attribute *attr, char *buf)
{
	struct channel_path *chp = container_of(dev, struct channel_path, dev);

	if (!chp)
		return 0;
	return sprintf(buf, "%x\n", chp->desc.desc);
}

static DEVICE_ATTR(type, 0444, chp_type_show, NULL);

static struct attribute * chp_attrs[] = {
	&dev_attr_status.attr,
	&dev_attr_type.attr,
	NULL,
};

static struct attribute_group chp_attr_group = {
	.attrs = chp_attrs,
};

static void
chp_release(struct device *dev)
{
	struct channel_path *cp;
	
	cp = container_of(dev, struct channel_path, dev);
	kfree(cp);
}

static int
chsc_determine_channel_path_description(int chpid,
					struct channel_path_desc *desc)
{
	int ccode, ret;

	struct {
		struct chsc_header request;
		u32 : 24;
		u32 first_chpid : 8;
		u32 : 24;
		u32 last_chpid : 8;
		u32 zeroes1;
		struct chsc_header response;
		u32 zeroes2;
		struct channel_path_desc desc;
	} *scpd_area;

	scpd_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
	if (!scpd_area)
		return -ENOMEM;

	scpd_area->request = (struct chsc_header) {
		.length = 0x0010,
		.code   = 0x0002,
	};

	scpd_area->first_chpid = chpid;
	scpd_area->last_chpid = chpid;

	ccode = chsc(scpd_area);
	if (ccode > 0) {
		ret = (ccode == 3) ? -ENODEV : -EBUSY;
		goto out;
	}

	switch (scpd_area->response.code) {
	case 0x0001: /* Success. */
		memcpy(desc, &scpd_area->desc,
		       sizeof(struct channel_path_desc));
		ret = 0;
		break;
	case 0x0003: /* Invalid block. */
	case 0x0007: /* Invalid format. */
	case 0x0008: /* Other invalid block. */
		CIO_CRW_EVENT(2, "Error in chsc request block!\n");
		ret = -EINVAL;
		break;
	case 0x0004: /* Command not provided in model. */
		CIO_CRW_EVENT(2, "Model does not provide scpd\n");
		ret = -EOPNOTSUPP;
		break;
	default:
		CIO_CRW_EVENT(2, "Unknown CHSC response %d\n",
			      scpd_area->response.code);
		ret = -EIO;
	}
out:
	free_page((unsigned long)scpd_area);
	return ret;
}

/*
 * Entries for chpids on the system bus.
 * This replaces /proc/chpids.
 */
static int
new_channel_path(int chpid)
{
	struct channel_path *chp;
	int ret;

	chp = kmalloc(sizeof(struct channel_path), GFP_KERNEL);
	if (!chp)
		return -ENOMEM;
	memset(chp, 0, sizeof(struct channel_path));

	/* fill in status, etc. */
	chp->id = chpid;
	chp->state = 1;
	chp->dev = (struct device) {
		.parent  = &css_bus_device,
		.release = chp_release,
	};
	snprintf(chp->dev.bus_id, BUS_ID_SIZE, "chp0.%x", chpid);

	/* Obtain channel path description and fill it in. */
	ret = chsc_determine_channel_path_description(chpid, &chp->desc);
	if (ret)
		goto out_free;

	/* make it known to the system */
	ret = device_register(&chp->dev);
	if (ret) {
		printk(KERN_WARNING "%s: could not register %02x\n",
		       __func__, chpid);
		goto out_free;
	}
	ret = sysfs_create_group(&chp->dev.kobj, &chp_attr_group);
	if (ret) {
		device_unregister(&chp->dev);
		goto out_free;
	} else
		chps[chpid] = chp;
	return ret;
out_free:
	kfree(chp);
	return ret;
}

void *
chsc_get_chp_desc(struct subchannel *sch, int chp_no)
{
	struct channel_path *chp;
	struct channel_path_desc *desc;

	chp = chps[sch->schib.pmcw.chpid[chp_no]];
	if (!chp)
		return NULL;
	desc = kmalloc(sizeof(struct channel_path_desc), GFP_KERNEL);
	if (!desc)
		return NULL;
	memcpy(desc, &chp->desc, sizeof(struct channel_path_desc));
	return desc;
}


static int __init
chsc_alloc_sei_area(void)
{
	sei_page = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
	if (!sei_page)
		printk(KERN_WARNING"Can't allocate page for processing of " \
		       "chsc machine checks!\n");
	return (sei_page ? 0 : -ENOMEM);
}

subsys_initcall(chsc_alloc_sei_area);

struct css_general_char css_general_characteristics;
struct css_chsc_char css_chsc_characteristics;

int __init
chsc_determine_css_characteristics(void)
{
	int result;
	struct {
		struct chsc_header request;
		u32 reserved1;
		u32 reserved2;
		u32 reserved3;
		struct chsc_header response;
		u32 reserved4;
		u32 general_char[510];
		u32 chsc_char[518];
	} *scsc_area;

	scsc_area = (void *)get_zeroed_page(GFP_KERNEL | GFP_DMA);
	if (!scsc_area) {
	        printk(KERN_WARNING"cio: Was not able to determine available" \
		       "CHSCs due to no memory.\n");
		return -ENOMEM;
	}

	scsc_area->request = (struct chsc_header) {
		.length = 0x0010,
		.code   = 0x0010,
	};

	result = chsc(scsc_area);
	if (result) {
		printk(KERN_WARNING"cio: Was not able to determine " \
		       "available CHSCs, cc=%i.\n", result);
		result = -EIO;
		goto exit;
	}

	if (scsc_area->response.code != 1) {
		printk(KERN_WARNING"cio: Was not able to determine " \
		       "available CHSCs.\n");
		result = -EIO;
		goto exit;
	}
	memcpy(&css_general_characteristics, scsc_area->general_char,
	       sizeof(css_general_characteristics));
	memcpy(&css_chsc_characteristics, scsc_area->chsc_char,
	       sizeof(css_chsc_characteristics));
exit:
	free_page ((unsigned long) scsc_area);
	return result;
}

EXPORT_SYMBOL_GPL(css_general_characteristics);
EXPORT_SYMBOL_GPL(css_chsc_characteristics);