sclp.c

linux-2.6.15.6

}

struct sclp_statechangebuf {
	struct evbuf_header	header;
	u8		validity_sclp_active_facility_mask : 1;
	u8		validity_sclp_receive_mask : 1;
	u8		validity_sclp_send_mask : 1;
	u8		validity_read_data_function_mask : 1;
	u16		_zeros : 12;
	u16		mask_length;
	u64		sclp_active_facility_mask;
	sccb_mask_t	sclp_receive_mask;
	sccb_mask_t	sclp_send_mask;
	u32		read_data_function_mask;
} __attribute__((packed));


/* State change event callback. Inform listeners of changes. */
static void
sclp_state_change_cb(struct evbuf_header *evbuf)
{
	unsigned long flags;
	struct sclp_statechangebuf *scbuf;

	scbuf = (struct sclp_statechangebuf *) evbuf;
	if (scbuf->mask_length != sizeof(sccb_mask_t))
		return;
	spin_lock_irqsave(&sclp_lock, flags);
	if (scbuf->validity_sclp_receive_mask)
		sclp_receive_mask = scbuf->sclp_receive_mask;
	if (scbuf->validity_sclp_send_mask)
		sclp_send_mask = scbuf->sclp_send_mask;
	spin_unlock_irqrestore(&sclp_lock, flags);
	sclp_dispatch_state_change();
}

static struct sclp_register sclp_state_change_event = {
	.receive_mask = EvTyp_StateChange_Mask,
	.receiver_fn = sclp_state_change_cb
};

/* Calculate receive and send mask of currently registered listeners.
 * Called while sclp_lock is locked. */
static inline void
__sclp_get_mask(sccb_mask_t *receive_mask, sccb_mask_t *send_mask)
{
	struct list_head *l;
	struct sclp_register *t;

	*receive_mask = 0;
	*send_mask = 0;
	list_for_each(l, &sclp_reg_list) {
		t = list_entry(l, struct sclp_register, list);
		*receive_mask |= t->receive_mask;
		*send_mask |= t->send_mask;
	}
}

/* Register event listener. Return 0 on success, non-zero otherwise. */
int
sclp_register(struct sclp_register *reg)
{
	unsigned long flags;
	sccb_mask_t receive_mask;
	sccb_mask_t send_mask;
	int rc;

	rc = sclp_init();
	if (rc)
		return rc;
	spin_lock_irqsave(&sclp_lock, flags);
	/* Check event mask for collisions */
	__sclp_get_mask(&receive_mask, &send_mask);
	if (reg->receive_mask & receive_mask || reg->send_mask & send_mask) {
		spin_unlock_irqrestore(&sclp_lock, flags);
		return -EBUSY;
	}
	/* Trigger initial state change callback */
	reg->sclp_receive_mask = 0;
	reg->sclp_send_mask = 0;
	list_add(&reg->list, &sclp_reg_list);
	spin_unlock_irqrestore(&sclp_lock, flags);
	rc = sclp_init_mask(1);
	if (rc) {
		spin_lock_irqsave(&sclp_lock, flags);
		list_del(&reg->list);
		spin_unlock_irqrestore(&sclp_lock, flags);
	}
	return rc;
}

EXPORT_SYMBOL(sclp_register);

/* Unregister event listener. */
void
sclp_unregister(struct sclp_register *reg)
{
	unsigned long flags;

	spin_lock_irqsave(&sclp_lock, flags);
	list_del(&reg->list);
	spin_unlock_irqrestore(&sclp_lock, flags);
	sclp_init_mask(1);
}

EXPORT_SYMBOL(sclp_unregister);

/* Remove event buffers which are marked processed. Return the number of
 * remaining event buffers. */
int
sclp_remove_processed(struct sccb_header *sccb)
{
	struct evbuf_header *evbuf;
	int unprocessed;
	u16 remaining;

	evbuf = (struct evbuf_header *) (sccb + 1);
	unprocessed = 0;
	remaining = sccb->length - sizeof(struct sccb_header);
	while (remaining > 0) {
		remaining -= evbuf->length;
		if (evbuf->flags & 0x80) {
			sccb->length -= evbuf->length;
			memcpy(evbuf, (void *) ((addr_t) evbuf + evbuf->length),
			       remaining);
		} else {
			unprocessed++;
			evbuf = (struct evbuf_header *)
					((addr_t) evbuf + evbuf->length);
		}
	}
	return unprocessed;
}

EXPORT_SYMBOL(sclp_remove_processed);

struct init_sccb {
	struct sccb_header header;
	u16 _reserved;
	u16 mask_length;
	sccb_mask_t receive_mask;
	sccb_mask_t send_mask;
	sccb_mask_t sclp_send_mask;
	sccb_mask_t sclp_receive_mask;
} __attribute__((packed));

/* Prepare init mask request. Called while sclp_lock is locked. */
static inline void
__sclp_make_init_req(u32 receive_mask, u32 send_mask)
{
	struct init_sccb *sccb;

	sccb = (struct init_sccb *) sclp_init_sccb;
	clear_page(sccb);
	memset(&sclp_init_req, 0, sizeof(struct sclp_req));
	sclp_init_req.command = SCLP_CMDW_WRITEMASK;
	sclp_init_req.status = SCLP_REQ_FILLED;
	sclp_init_req.start_count = 0;
	sclp_init_req.callback = NULL;
	sclp_init_req.callback_data = NULL;
	sclp_init_req.sccb = sccb;
	sccb->header.length = sizeof(struct init_sccb);
	sccb->mask_length = sizeof(sccb_mask_t);
	sccb->receive_mask = receive_mask;
	sccb->send_mask = send_mask;
	sccb->sclp_receive_mask = 0;
	sccb->sclp_send_mask = 0;
}

/* Start init mask request. If calculate is non-zero, calculate the mask as
 * requested by registered listeners. Use zero mask otherwise. Return 0 on
 * success, non-zero otherwise. */
static int
sclp_init_mask(int calculate)
{
	unsigned long flags;
	struct init_sccb *sccb = (struct init_sccb *) sclp_init_sccb;
	sccb_mask_t receive_mask;
	sccb_mask_t send_mask;
	int retry;
	int rc;
	unsigned long wait;

	spin_lock_irqsave(&sclp_lock, flags);
	/* Check if interface is in appropriate state */
	if (sclp_mask_state != sclp_mask_state_idle) {
		spin_unlock_irqrestore(&sclp_lock, flags);
		return -EBUSY;
	}
	if (sclp_activation_state == sclp_activation_state_inactive) {
		spin_unlock_irqrestore(&sclp_lock, flags);
		return -EINVAL;
	}
	sclp_mask_state = sclp_mask_state_initializing;
	/* Determine mask */
	if (calculate)
		__sclp_get_mask(&receive_mask, &send_mask);
	else {
		receive_mask = 0;
		send_mask = 0;
	}
	rc = -EIO;
	for (retry = 0; retry <= SCLP_MASK_RETRY; retry++) {
		/* Prepare request */
		__sclp_make_init_req(receive_mask, send_mask);
		spin_unlock_irqrestore(&sclp_lock, flags);
		if (sclp_add_request(&sclp_init_req)) {
			/* Try again later */
			wait = jiffies + SCLP_BUSY_INTERVAL * HZ;
			while (time_before(jiffies, wait))
				sclp_sync_wait();
			spin_lock_irqsave(&sclp_lock, flags);
			continue;
		}
		while (sclp_init_req.status != SCLP_REQ_DONE &&
		       sclp_init_req.status != SCLP_REQ_FAILED)
			sclp_sync_wait();
		spin_lock_irqsave(&sclp_lock, flags);
		if (sclp_init_req.status == SCLP_REQ_DONE &&
		    sccb->header.response_code == 0x20) {
			/* Successful request */
			if (calculate) {
				sclp_receive_mask = sccb->sclp_receive_mask;
				sclp_send_mask = sccb->sclp_send_mask;
			} else {
				sclp_receive_mask = 0;
				sclp_send_mask = 0;
			}
			spin_unlock_irqrestore(&sclp_lock, flags);
			sclp_dispatch_state_change();
			spin_lock_irqsave(&sclp_lock, flags);
			rc = 0;
			break;
		}
	}
	sclp_mask_state = sclp_mask_state_idle;
	spin_unlock_irqrestore(&sclp_lock, flags);
	return rc;
}

/* Deactivate SCLP interface. On success, new requests will be rejected,
 * events will no longer be dispatched. Return 0 on success, non-zero
 * otherwise. */
int
sclp_deactivate(void)
{
	unsigned long flags;
	int rc;

	spin_lock_irqsave(&sclp_lock, flags);
	/* Deactivate can only be called when active */
	if (sclp_activation_state != sclp_activation_state_active) {
		spin_unlock_irqrestore(&sclp_lock, flags);
		return -EINVAL;
	}
	sclp_activation_state = sclp_activation_state_deactivating;
	spin_unlock_irqrestore(&sclp_lock, flags);
	rc = sclp_init_mask(0);
	spin_lock_irqsave(&sclp_lock, flags);
	if (rc == 0)
		sclp_activation_state = sclp_activation_state_inactive;
	else
		sclp_activation_state = sclp_activation_state_active;
	spin_unlock_irqrestore(&sclp_lock, flags);
	return rc;
}

EXPORT_SYMBOL(sclp_deactivate);

/* Reactivate SCLP interface after sclp_deactivate. On success, new
 * requests will be accepted, events will be dispatched again. Return 0 on
 * success, non-zero otherwise. */
int
sclp_reactivate(void)
{
	unsigned long flags;
	int rc;

	spin_lock_irqsave(&sclp_lock, flags);
	/* Reactivate can only be called when inactive */
	if (sclp_activation_state != sclp_activation_state_inactive) {
		spin_unlock_irqrestore(&sclp_lock, flags);
		return -EINVAL;
	}
	sclp_activation_state = sclp_activation_state_activating;
	spin_unlock_irqrestore(&sclp_lock, flags);
	rc = sclp_init_mask(1);
	spin_lock_irqsave(&sclp_lock, flags);
	if (rc == 0)
		sclp_activation_state = sclp_activation_state_active;
	else
		sclp_activation_state = sclp_activation_state_inactive;
	spin_unlock_irqrestore(&sclp_lock, flags);
	return rc;
}

EXPORT_SYMBOL(sclp_reactivate);

/* Handler for external interruption used during initialization. Modify
 * request state to done. */
static void
sclp_check_handler(struct pt_regs *regs, __u16 code)
{
	u32 finished_sccb;

	finished_sccb = S390_lowcore.ext_params & 0xfffffff8;
	/* Is this the interrupt we are waiting for? */
	if (finished_sccb == 0)
		return;
	if (finished_sccb != (u32) (addr_t) sclp_init_sccb) {
		printk(KERN_WARNING SCLP_HEADER "unsolicited interrupt "
		       "for buffer at 0x%x\n", finished_sccb);
		return;
	}
	spin_lock(&sclp_lock);
	if (sclp_running_state == sclp_running_state_running) {
		sclp_init_req.status = SCLP_REQ_DONE;
		sclp_running_state = sclp_running_state_idle;
	}
	spin_unlock(&sclp_lock);
}

/* Initial init mask request timed out. Modify request state to failed. */
static void
sclp_check_timeout(unsigned long data)
{
	unsigned long flags;

	spin_lock_irqsave(&sclp_lock, flags);
	if (sclp_running_state == sclp_running_state_running) {
		sclp_init_req.status = SCLP_REQ_FAILED;
		sclp_running_state = sclp_running_state_idle;
	}
	spin_unlock_irqrestore(&sclp_lock, flags);
}

/* Perform a check of the SCLP interface. Return zero if the interface is
 * available and there are no pending requests from a previous instance.
 * Return non-zero otherwise. */
static int
sclp_check_interface(void)
{
	struct init_sccb *sccb;
	unsigned long flags;
	int retry;
	int rc;

	spin_lock_irqsave(&sclp_lock, flags);
	/* Prepare init mask command */
	rc = register_early_external_interrupt(0x2401, sclp_check_handler,
					       &ext_int_info_hwc);
	if (rc) {
		spin_unlock_irqrestore(&sclp_lock, flags);
		return rc;
	}
	for (retry = 0; retry <= SCLP_INIT_RETRY; retry++) {
		__sclp_make_init_req(0, 0);
		sccb = (struct init_sccb *) sclp_init_req.sccb;
		rc = service_call(sclp_init_req.command, sccb);
		if (rc == -EIO)
			break;
		sclp_init_req.status = SCLP_REQ_RUNNING;
		sclp_running_state = sclp_running_state_running;
		__sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ,
					 sclp_check_timeout, 0);
		spin_unlock_irqrestore(&sclp_lock, flags);
		/* Enable service-signal interruption - needs to happen
		 * with IRQs enabled. */
		ctl_set_bit(0, 9);
		/* Wait for signal from interrupt or timeout */
		sclp_sync_wait();
		/* Disable service-signal interruption - needs to happen
		 * with IRQs enabled. */
		ctl_clear_bit(0,9);
		spin_lock_irqsave(&sclp_lock, flags);
		del_timer(&sclp_request_timer);
		if (sclp_init_req.status == SCLP_REQ_DONE &&
		    sccb->header.response_code == 0x20) {
			rc = 0;
			break;
		} else
			rc = -EBUSY;
	}
	unregister_early_external_interrupt(0x2401, sclp_check_handler,
					    &ext_int_info_hwc);
	spin_unlock_irqrestore(&sclp_lock, flags);
	return rc;
}

/* Reboot event handler. Reset send and receive mask to prevent pending SCLP
 * events from interfering with rebooted system. */
static int
sclp_reboot_event(struct notifier_block *this, unsigned long event, void *ptr)
{
	sclp_deactivate();
	return NOTIFY_DONE;
}

static struct notifier_block sclp_reboot_notifier = {
	.notifier_call = sclp_reboot_event
};

/* Initialize SCLP driver. Return zero if driver is operational, non-zero
 * otherwise. */
static int
sclp_init(void)
{
	unsigned long flags;
	int rc;

	if (!MACHINE_HAS_SCLP)
		return -ENODEV;
	spin_lock_irqsave(&sclp_lock, flags);
	/* Check for previous or running initialization */
	if (sclp_init_state != sclp_init_state_uninitialized) {
		spin_unlock_irqrestore(&sclp_lock, flags);
		return 0;
	}
	sclp_init_state = sclp_init_state_initializing;
	/* Set up variables */
	INIT_LIST_HEAD(&sclp_req_queue);
	INIT_LIST_HEAD(&sclp_reg_list);
	list_add(&sclp_state_change_event.list, &sclp_reg_list);
	init_timer(&sclp_request_timer);
	/* Check interface */
	spin_unlock_irqrestore(&sclp_lock, flags);
	rc = sclp_check_interface();
	spin_lock_irqsave(&sclp_lock, flags);
	if (rc) {
		sclp_init_state = sclp_init_state_uninitialized;
		spin_unlock_irqrestore(&sclp_lock, flags);
		return rc;
	}
	/* Register reboot handler */
	rc = register_reboot_notifier(&sclp_reboot_notifier);
	if (rc) {
		sclp_init_state = sclp_init_state_uninitialized;
		spin_unlock_irqrestore(&sclp_lock, flags);
		return rc;
	}
	/* Register interrupt handler */
	rc = register_early_external_interrupt(0x2401, sclp_interrupt_handler,
					       &ext_int_info_hwc);
	if (rc) {
		unregister_reboot_notifier(&sclp_reboot_notifier);
		sclp_init_state = sclp_init_state_uninitialized;
		spin_unlock_irqrestore(&sclp_lock, flags);
		return rc;
	}
	sclp_init_state = sclp_init_state_initialized;
	spin_unlock_irqrestore(&sclp_lock, flags);
	/* Enable service-signal external interruption - needs to happen with
	 * IRQs enabled. */
	ctl_set_bit(0, 9);
	sclp_init_mask(1);
	return 0;
}