[mirror_ubuntu-artful-kernel.git] / drivers / s390 / cio / qdio_thinint.c

/*
 * Copyright IBM Corp. 2000, 2009
 * Author(s): Utz Bacher <utz.bacher@de.ibm.com>
 *	      Cornelia Huck <cornelia.huck@de.ibm.com>
 *	      Jan Glauber <jang@linux.vnet.ibm.com>
 */
#include <linux/io.h>
#include <linux/slab.h>
#include <linux/kernel_stat.h>
#include <linux/atomic.h>
#include <asm/debug.h>
#include <asm/qdio.h>
#include <asm/airq.h>
#include <asm/isc.h>

#include "cio.h"
#include "ioasm.h"
#include "qdio.h"
#include "qdio_debug.h"

/*
 * Restriction: only 63 iqdio subchannels would have its own indicator,
 * after that, subsequent subchannels share one indicator
 */
#define TIQDIO_NR_NONSHARED_IND		63
#define TIQDIO_NR_INDICATORS		(TIQDIO_NR_NONSHARED_IND + 1)
#define TIQDIO_SHARED_IND		63

/* device state change indicators */
struct indicator_t {
	u32 ind;	/* u32 because of compare-and-swap performance */
	atomic_t count; /* use count, 0 or 1 for non-shared indicators */
};

/* list of thin interrupt input queues */
static LIST_HEAD(tiq_list);
static DEFINE_MUTEX(tiq_list_lock);

/* adapter local summary indicator */
static u8 *tiqdio_alsi;

static struct indicator_t *q_indicators;

u64 last_ai_time;

/* returns addr for the device state change indicator */
static u32 *get_indicator(void)
{
	int i;

	for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
		if (!atomic_read(&q_indicators[i].count)) {
			atomic_set(&q_indicators[i].count, 1);
			return &q_indicators[i].ind;
		}

	/* use the shared indicator */
	atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
	return &q_indicators[TIQDIO_SHARED_IND].ind;
}

static void put_indicator(u32 *addr)
{
	int i;

	if (!addr)
		return;
	i = ((unsigned long)addr - (unsigned long)q_indicators) /
		sizeof(struct indicator_t);
	atomic_dec(&q_indicators[i].count);
}

void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
{
	mutex_lock(&tiq_list_lock);
	BUG_ON(irq_ptr->nr_input_qs < 1);
	list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
	mutex_unlock(&tiq_list_lock);
	xchg(irq_ptr->dsci, 1 << 7);
}

void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
{
	struct qdio_q *q;

	BUG_ON(irq_ptr->nr_input_qs < 1);
	q = irq_ptr->input_qs[0];
	/* if establish triggered an error */
	if (!q || !q->entry.prev || !q->entry.next)
		return;

	mutex_lock(&tiq_list_lock);
	list_del_rcu(&q->entry);
	mutex_unlock(&tiq_list_lock);
	synchronize_rcu();
}

static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
{
	return irq_ptr->nr_input_qs > 1;
}

static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
{
	return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
}

static inline int shared_ind(struct qdio_irq *irq_ptr)
{
	return references_shared_dsci(irq_ptr) ||
		has_multiple_inq_on_dsci(irq_ptr);
}

void clear_nonshared_ind(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return;
	if (shared_ind(irq_ptr))
		return;
	xchg(irq_ptr->dsci, 0);
}

int test_nonshared_ind(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return 0;
	if (shared_ind(irq_ptr))
		return 0;
	if (*irq_ptr->dsci)
		return 1;
	else
		return 0;
}

static inline u32 clear_shared_ind(void)
{
	if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
		return 0;
	return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
}

static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
{
	struct qdio_q *q;
	int i;

	for_each_input_queue(irq, q, i) {
		if (!references_shared_dsci(irq) &&
		    has_multiple_inq_on_dsci(irq))
			xchg(q->irq_ptr->dsci, 0);

		if (q->u.in.queue_start_poll) {
			/* skip if polling is enabled or already in work */
			if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
					     &q->u.in.queue_irq_state)) {
				qperf_inc(q, int_discarded);
				continue;
			}

			/* avoid dsci clear here, done after processing */
			q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
						 q->irq_ptr->int_parm);
		} else {
			if (!shared_ind(q->irq_ptr))
				xchg(q->irq_ptr->dsci, 0);

			/*
			 * Call inbound processing but not directly
			 * since that could starve other thinint queues.
			 */
			tasklet_schedule(&q->tasklet);
		}
	}
}

/**
 * tiqdio_thinint_handler - thin interrupt handler for qdio
 * @alsi: pointer to adapter local summary indicator
 * @data: NULL
 */
static void tiqdio_thinint_handler(void *alsi, void *data)
{
	u32 si_used = clear_shared_ind();
	struct qdio_q *q;

	last_ai_time = S390_lowcore.int_clock;
	kstat_cpu(smp_processor_id()).irqs[IOINT_QAI]++;

	/* protect tiq_list entries, only changed in activate or shutdown */
	rcu_read_lock();

	/* check for work on all inbound thinint queues */
	list_for_each_entry_rcu(q, &tiq_list, entry) {
		struct qdio_irq *irq;

		/* only process queues from changed sets */
		irq = q->irq_ptr;
		if (unlikely(references_shared_dsci(irq))) {
			if (!si_used)
				continue;
		} else if (!*irq->dsci)
			continue;

		tiqdio_call_inq_handlers(irq);

		qperf_inc(q, adapter_int);
	}
	rcu_read_unlock();
}

static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
{
	struct scssc_area *scssc_area;
	int rc;

	scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
	memset(scssc_area, 0, PAGE_SIZE);

	if (reset) {
		scssc_area->summary_indicator_addr = 0;
		scssc_area->subchannel_indicator_addr = 0;
	} else {
		scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
		scssc_area->subchannel_indicator_addr =
			virt_to_phys(irq_ptr->dsci);
	}

	scssc_area->request = (struct chsc_header) {
		.length = 0x0fe0,
		.code	= 0x0021,
	};
	scssc_area->operation_code = 0;
	scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
	scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
	scssc_area->isc = QDIO_AIRQ_ISC;
	scssc_area->schid = irq_ptr->schid;

	/* enable the time delay disablement facility */
	if (css_general_characteristics.aif_tdd)
		scssc_area->word_with_d_bit = 0x10000000;

	rc = chsc(scssc_area);
	if (rc)
		return -EIO;

	rc = chsc_error_from_response(scssc_area->response.code);
	if (rc) {
		DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
			  scssc_area->response.code);
		DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
		return rc;
	}

	DBF_EVENT("setscind");
	DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
	DBF_HEX(&scssc_area->subchannel_indicator_addr,	sizeof(unsigned long));
	return 0;
}

/* allocate non-shared indicators and shared indicator */
int __init tiqdio_allocate_memory(void)
{
	q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
			     GFP_KERNEL);
	if (!q_indicators)
		return -ENOMEM;
	return 0;
}

void tiqdio_free_memory(void)
{
	kfree(q_indicators);
}

int __init tiqdio_register_thinints(void)
{
	isc_register(QDIO_AIRQ_ISC);
	tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
						      NULL, QDIO_AIRQ_ISC);
	if (IS_ERR(tiqdio_alsi)) {
		DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
		tiqdio_alsi = NULL;
		isc_unregister(QDIO_AIRQ_ISC);
		return -ENOMEM;
	}
	return 0;
}

int qdio_establish_thinint(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return 0;
	return set_subchannel_ind(irq_ptr, 0);
}

void qdio_setup_thinint(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return;
	irq_ptr->dsci = get_indicator();
	DBF_HEX(&irq_ptr->dsci, sizeof(void *));
}

void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
{
	if (!is_thinint_irq(irq_ptr))
		return;

	/* reset adapter interrupt indicators */
	set_subchannel_ind(irq_ptr, 1);
	put_indicator(irq_ptr->dsci);
}

void __exit tiqdio_unregister_thinints(void)
{
	WARN_ON(!list_empty(&tiq_list));

	if (tiqdio_alsi) {
		s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
		isc_unregister(QDIO_AIRQ_ISC);
	}
}
Commit	Line	Data
779e6e1c	1	/*
a53c8fab	2	* Copyright IBM Corp. 2000, 2009
779e6e1c JG	3	* Author(s): Utz Bacher <utz.bacher@de.ibm.com>
	4	* Cornelia Huck <cornelia.huck@de.ibm.com>
	5	* Jan Glauber <jang@linux.vnet.ibm.com>
	6	*/
	7	#include <linux/io.h>
5a0e3ad6	8	#include <linux/slab.h>
30d77c3e	9	#include <linux/kernel_stat.h>
60063497	10	#include <linux/atomic.h>
779e6e1c JG	11	#include <asm/debug.h>
	12	#include <asm/qdio.h>
	13	#include <asm/airq.h>
	14	#include <asm/isc.h>
	15
	16	#include "cio.h"
	17	#include "ioasm.h"
	18	#include "qdio.h"
	19	#include "qdio_debug.h"
779e6e1c JG	20
	21	/*
	22	* Restriction: only 63 iqdio subchannels would have its own indicator,
	23	* after that, subsequent subchannels share one indicator
	24	*/
	25	#define TIQDIO_NR_NONSHARED_IND 63
	26	#define TIQDIO_NR_INDICATORS (TIQDIO_NR_NONSHARED_IND + 1)
5f4026f8 JG	27	#define TIQDIO_SHARED_IND 63
	28
	29	/* device state change indicators */
	30	struct indicator_t {
	31	u32 ind; /* u32 because of compare-and-swap performance */
	32	atomic_t count; /* use count, 0 or 1 for non-shared indicators */
	33	};
779e6e1c JG	34
	35	/* list of thin interrupt input queues */
	36	static LIST_HEAD(tiq_list);
c4736d96	37	static DEFINE_MUTEX(tiq_list_lock);
779e6e1c JG	38
779e6e1c JG	39	/* adapter local summary indicator */
d36deae7	40	static u8 *tiqdio_alsi;
779e6e1c	41
5f4026f8	42	static struct indicator_t *q_indicators;
779e6e1c	43
a2b86019	44	u64 last_ai_time;
d36deae7	45
779e6e1c JG	46	/* returns addr for the device state change indicator */
	47	static u32 *get_indicator(void)
	48	{
	49	int i;
	50
	51	for (i = 0; i < TIQDIO_NR_NONSHARED_IND; i++)
	52	if (!atomic_read(&q_indicators[i].count)) {
	53	atomic_set(&q_indicators[i].count, 1);
	54	return &q_indicators[i].ind;
	55	}
	56
	57	/* use the shared indicator */
	58	atomic_inc(&q_indicators[TIQDIO_SHARED_IND].count);
	59	return &q_indicators[TIQDIO_SHARED_IND].ind;
	60	}
	61
	62	static void put_indicator(u32 *addr)
	63	{
	64	int i;
	65
	66	if (!addr)
	67	return;
	68	i = ((unsigned long)addr - (unsigned long)q_indicators) /
	69	sizeof(struct indicator_t);
	70	atomic_dec(&q_indicators[i].count);
	71	}
	72
	73	void tiqdio_add_input_queues(struct qdio_irq *irq_ptr)
	74	{
b4547402	75	mutex_lock(&tiq_list_lock);
104ea556	76	BUG_ON(irq_ptr->nr_input_qs < 1);
104ea556	77	list_add_rcu(&irq_ptr->input_qs[0]->entry, &tiq_list);
b4547402	78	mutex_unlock(&tiq_list_lock);
d0c9d4a8	79	xchg(irq_ptr->dsci, 1 << 7);
779e6e1c JG	80	}
779e6e1c JG	81
779e6e1c JG	82	void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
	83	{
	84	struct qdio_q *q;
779e6e1c	85
104ea556	86	BUG_ON(irq_ptr->nr_input_qs < 1);
	87	q = irq_ptr->input_qs[0];
	88	/* if establish triggered an error */
	89	if (!q \|\| !q->entry.prev \|\| !q->entry.next)
	90	return;
b4547402	91
104ea556	92	mutex_lock(&tiq_list_lock);
	93	list_del_rcu(&q->entry);
	94	mutex_unlock(&tiq_list_lock);
	95	synchronize_rcu();
779e6e1c JG	96	}
779e6e1c JG	97
5f4026f8 JG	98	static inline int has_multiple_inq_on_dsci(struct qdio_irq *irq_ptr)
	99	{
	100	return irq_ptr->nr_input_qs > 1;
	101	}
	102
	103	static inline int references_shared_dsci(struct qdio_irq *irq_ptr)
	104	{
	105	return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
	106	}
	107
	108	static inline int shared_ind(struct qdio_irq *irq_ptr)
	109	{
	110	return references_shared_dsci(irq_ptr) \|\|
	111	has_multiple_inq_on_dsci(irq_ptr);
	112	}
	113
	114	void clear_nonshared_ind(struct qdio_irq *irq_ptr)
	115	{
	116	if (!is_thinint_irq(irq_ptr))
	117	return;
	118	if (shared_ind(irq_ptr))
	119	return;
	120	xchg(irq_ptr->dsci, 0);
	121	}
	122
	123	int test_nonshared_ind(struct qdio_irq *irq_ptr)
	124	{
	125	if (!is_thinint_irq(irq_ptr))
	126	return 0;
	127	if (shared_ind(irq_ptr))
	128	return 0;
	129	if (*irq_ptr->dsci)
	130	return 1;
	131	else
	132	return 0;
	133	}
	134
b02f0c2e	135	static inline u32 clear_shared_ind(void)
779e6e1c	136	{
b02f0c2e JG	137	if (!atomic_read(&q_indicators[TIQDIO_SHARED_IND].count))
	138	return 0;
	139	return xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
779e6e1c JG	140	}
779e6e1c JG	141
104ea556	142	static inline void tiqdio_call_inq_handlers(struct qdio_irq *irq)
	143	{
	144	struct qdio_q *q;
	145	int i;
	146
	147	for_each_input_queue(irq, q, i) {
	148	if (!references_shared_dsci(irq) &&
	149	has_multiple_inq_on_dsci(irq))
	150	xchg(q->irq_ptr->dsci, 0);
	151
	152	if (q->u.in.queue_start_poll) {
	153	/* skip if polling is enabled or already in work */
	154	if (test_and_set_bit(QDIO_QUEUE_IRQS_DISABLED,
	155	&q->u.in.queue_irq_state)) {
	156	qperf_inc(q, int_discarded);
	157	continue;
	158	}
	159
	160	/* avoid dsci clear here, done after processing */
	161	q->u.in.queue_start_poll(q->irq_ptr->cdev, q->nr,
	162	q->irq_ptr->int_parm);
	163	} else {
5f4026f8	164	if (!shared_ind(q->irq_ptr))
104ea556	165	xchg(q->irq_ptr->dsci, 0);
	166
	167	/*
	168	* Call inbound processing but not directly
	169	* since that could starve other thinint queues.
	170	*/
	171	tasklet_schedule(&q->tasklet);
	172	}
	173	}
	174	}
	175
cf9a031c JG	176	/**
cf9a031c JG	177	* tiqdio_thinint_handler - thin interrupt handler for qdio
d36deae7 JG	178	* @alsi: pointer to adapter local summary indicator
d36deae7 JG	179	* @data: NULL
cf9a031c	180	*/
d36deae7	181	static void tiqdio_thinint_handler(void alsi, void data)
779e6e1c	182	{
b02f0c2e	183	u32 si_used = clear_shared_ind();
779e6e1c JG	184	struct qdio_q *q;
779e6e1c JG	185
d36deae7	186	last_ai_time = S390_lowcore.int_clock;
30d77c3e	187	kstat_cpu(smp_processor_id()).irqs[IOINT_QAI]++;
d36deae7	188
779e6e1c JG	189	/* protect tiq_list entries, only changed in activate or shutdown */
	190	rcu_read_lock();
	191
cf9a031c	192	/* check for work on all inbound thinint queues */
d36deae7	193	list_for_each_entry_rcu(q, &tiq_list, entry) {
104ea556	194	struct qdio_irq *irq;
d36deae7	195
779e6e1c	196	/* only process queues from changed sets */
104ea556	197	irq = q->irq_ptr;
104ea556	198	if (unlikely(references_shared_dsci(irq))) {
4f325184 JG	199	if (!si_used)
4f325184 JG	200	continue;
104ea556	201	} else if (!*irq->dsci)
d36deae7	202	continue;
779e6e1c	203
104ea556	204	tiqdio_call_inq_handlers(irq);
d36deae7	205
d36deae7 JG	206	qperf_inc(q, adapter_int);
d36deae7 JG	207	}
779e6e1c	208	rcu_read_unlock();
779e6e1c JG	209	}
	210
	211	static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
	212	{
	213	struct scssc_area *scssc_area;
779e6e1c JG	214	int rc;
	215
	216	scssc_area = (struct scssc_area *)irq_ptr->chsc_page;
	217	memset(scssc_area, 0, PAGE_SIZE);
	218
	219	if (reset) {
	220	scssc_area->summary_indicator_addr = 0;
	221	scssc_area->subchannel_indicator_addr = 0;
	222	} else {
	223	scssc_area->summary_indicator_addr = virt_to_phys(tiqdio_alsi);
	224	scssc_area->subchannel_indicator_addr =
	225	virt_to_phys(irq_ptr->dsci);
	226	}
	227
	228	scssc_area->request = (struct chsc_header) {
	229	.length = 0x0fe0,
	230	.code = 0x0021,
	231	};
	232	scssc_area->operation_code = 0;
d1bf8590 HC	233	scssc_area->ks = PAGE_DEFAULT_KEY >> 4;
d1bf8590 HC	234	scssc_area->kc = PAGE_DEFAULT_KEY >> 4;
779e6e1c JG	235	scssc_area->isc = QDIO_AIRQ_ISC;
	236	scssc_area->schid = irq_ptr->schid;
	237
	238	/* enable the time delay disablement facility */
	239	if (css_general_characteristics.aif_tdd)
	240	scssc_area->word_with_d_bit = 0x10000000;
	241
	242	rc = chsc(scssc_area);
	243	if (rc)
	244	return -EIO;
	245
	246	rc = chsc_error_from_response(scssc_area->response.code);
	247	if (rc) {
22f99347 JG	248	DBF_ERROR("%4x SSI r:%4x", irq_ptr->schid.sch_no,
	249	scssc_area->response.code);
	250	DBF_ERROR_HEX(&scssc_area->response, sizeof(void *));
779e6e1c JG	251	return rc;
	252	}
	253
22f99347 JG	254	DBF_EVENT("setscind");
	255	DBF_HEX(&scssc_area->summary_indicator_addr, sizeof(unsigned long));
	256	DBF_HEX(&scssc_area->subchannel_indicator_addr, sizeof(unsigned long));
779e6e1c JG	257	return 0;
	258	}
	259
	260	/* allocate non-shared indicators and shared indicator */
	261	int __init tiqdio_allocate_memory(void)
	262	{
	263	q_indicators = kzalloc(sizeof(struct indicator_t) * TIQDIO_NR_INDICATORS,
	264	GFP_KERNEL);
	265	if (!q_indicators)
	266	return -ENOMEM;
	267	return 0;
	268	}
	269
	270	void tiqdio_free_memory(void)
	271	{
	272	kfree(q_indicators);
	273	}
	274
	275	int __init tiqdio_register_thinints(void)
	276	{
779e6e1c JG	277	isc_register(QDIO_AIRQ_ISC);
	278	tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
	279	NULL, QDIO_AIRQ_ISC);
	280	if (IS_ERR(tiqdio_alsi)) {
22f99347	281	DBF_EVENT("RTI:%lx", PTR_ERR(tiqdio_alsi));
779e6e1c JG	282	tiqdio_alsi = NULL;
	283	isc_unregister(QDIO_AIRQ_ISC);
	284	return -ENOMEM;
	285	}
	286	return 0;
	287	}
	288
	289	int qdio_establish_thinint(struct qdio_irq *irq_ptr)
	290	{
	291	if (!is_thinint_irq(irq_ptr))
	292	return 0;
779e6e1c JG	293	return set_subchannel_ind(irq_ptr, 0);
	294	}
	295
	296	void qdio_setup_thinint(struct qdio_irq *irq_ptr)
	297	{
	298	if (!is_thinint_irq(irq_ptr))
	299	return;
	300	irq_ptr->dsci = get_indicator();
22f99347	301	DBF_HEX(&irq_ptr->dsci, sizeof(void *));
779e6e1c JG	302	}
	303
	304	void qdio_shutdown_thinint(struct qdio_irq *irq_ptr)
	305	{
	306	if (!is_thinint_irq(irq_ptr))
	307	return;
	308
	309	/* reset adapter interrupt indicators */
779e6e1c	310	set_subchannel_ind(irq_ptr, 1);
4814a2b3	311	put_indicator(irq_ptr->dsci);
779e6e1c JG	312	}
	313
	314	void __exit tiqdio_unregister_thinints(void)
	315	{
9e890ad8	316	WARN_ON(!list_empty(&tiq_list));
779e6e1c JG	317
	318	if (tiqdio_alsi) {
	319	s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
	320	isc_unregister(QDIO_AIRQ_ISC);
	321	}
	322	}