[S390] qdio: new qdio driver.

List of major changes:
- split qdio driver into several files
- seperation of thin interrupt code
- improved handling for multiple thin interrupt devices
- inbound and outbound processing now always runs in tasklet context
- significant less tasklet schedules per interrupt needed
- merged qebsm with non-qebsm handling
- cleanup qdio interface and added kerneldoc
- coding style

Reviewed-by: Cornelia Huck <cornelia.huck@de.ibm.com>
Reviewed-by: Utz Bacher <utz.bacher@de.ibm.com>
Reviewed-by: Ursula Braun <braunu@de.ibm.com>
Signed-off-by: Jan Glauber <jang@linux.vnet.ibm.com>
Signed-off-by: Martin Schwidefsky <schwidefsky@de.ibm.com>
Signed-off-by: Heiko Carstens <heiko.carstens@de.ibm.com>

1 files changed, 380 insertions, 0 deletions

diff --git a/drivers/s390/cio/qdio_thinint.c b/drivers/s390/cio/qdio_thinint.c
new file mode 100644
index 000000000000..9291a771d812
--- /dev/null
+++ b/drivers/s390/cio/qdio_thinint.c
@@ -0,0 +1,380 @@
+/*
+ * linux/drivers/s390/cio/thinint_qdio.c
+ *
+ * thin interrupt support for qdio
+ *
+ * Copyright 2000-2008 IBM Corp.
+ * 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 <asm/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"
+#include "qdio_perf.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
+
+/* list of thin interrupt input queues */
+static LIST_HEAD(tiq_list);
+
+/* adapter local summary indicator */
+static unsigned char *tiqdio_alsi;
+
+/* 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 */
+};
+static struct indicator_t *q_indicators;
+
+static void tiqdio_tasklet_fn(unsigned long data);
+static DECLARE_TASKLET(tiqdio_tasklet, tiqdio_tasklet_fn, 0);
+
+static int css_qdio_omit_svs;
+
+static inline unsigned long do_clear_global_summary(void)
+{
+        register unsigned long __fn asm("1") = 3;
+        register unsigned long __tmp asm("2");
+        register unsigned long __time asm("3");
+
+        asm volatile(
+                "       .insn   rre,0xb2650000,2,0"
+                : "+d" (__fn), "=d" (__tmp), "=d" (__time));
+        return __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)
+{
+        struct qdio_q *q;
+        int i;
+
+        /* No TDD facility? If we must use SIGA-s we can also omit SVS. */
+        if (!css_qdio_omit_svs && irq_ptr->siga_flag.sync)
+                css_qdio_omit_svs = 1;
+
+        for_each_input_queue(irq_ptr, q, i) {
+                list_add_rcu(&q->entry, &tiq_list);
+                synchronize_rcu();
+        }
+        xchg(irq_ptr->dsci, 1);
+        tasklet_schedule(&tiqdio_tasklet);
+}
+
+/*
+ * we cannot stop the tiqdio tasklet here since it is for all
+ * thinint qdio devices and it must run as long as there is a
+ * thinint device left
+ */
+void tiqdio_remove_input_queues(struct qdio_irq *irq_ptr)
+{
+        struct qdio_q *q;
+        int i;
+
+        for_each_input_queue(irq_ptr, q, i) {
+                list_del_rcu(&q->entry);
+                synchronize_rcu();
+        }
+}
+
+static inline int tiqdio_inbound_q_done(struct qdio_q *q)
+{
+        unsigned char state;
+
+        if (!atomic_read(&q->nr_buf_used))
+                return 1;
+
+        qdio_siga_sync_q(q);
+        get_buf_state(q, q->first_to_check, &state);
+
+        if (state == SLSB_P_INPUT_PRIMED)
+                /* more work coming */
+                return 0;
+        return 1;
+}
+
+static inline int shared_ind(struct qdio_irq *irq_ptr)
+{
+        return irq_ptr->dsci == &q_indicators[TIQDIO_SHARED_IND].ind;
+}
+
+static void __tiqdio_inbound_processing(struct qdio_q *q)
+{
+        qdio_perf_stat_inc(&perf_stats.thinint_inbound);
+        qdio_sync_after_thinint(q);
+
+        /*
+         * Maybe we have work on our outbound queues... at least
+         * we have to check the PCI capable queues.
+         */
+        qdio_check_outbound_after_thinint(q);
+
+again:
+        if (!qdio_inbound_q_moved(q))
+                return;
+
+        qdio_kick_inbound_handler(q);
+
+        if (!tiqdio_inbound_q_done(q)) {
+                qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop);
+                goto again;
+        }
+
+        qdio_stop_polling(q);
+        /*
+         * We need to check again to not lose initiative after
+         * resetting the ACK state.
+         */
+        if (!tiqdio_inbound_q_done(q)) {
+                qdio_perf_stat_inc(&perf_stats.thinint_inbound_loop2);
+                goto again;
+        }
+}
+
+void tiqdio_inbound_processing(unsigned long data)
+{
+        struct qdio_q *q = (struct qdio_q *)data;
+
+        __tiqdio_inbound_processing(q);
+}
+
+/* check for work on all inbound thinint queues */
+static void tiqdio_tasklet_fn(unsigned long data)
+{
+        struct qdio_q *q;
+
+        qdio_perf_stat_inc(&perf_stats.tasklet_thinint);
+again:
+
+        /* protect tiq_list entries, only changed in activate or shutdown */
+        rcu_read_lock();
+
+        list_for_each_entry_rcu(q, &tiq_list, entry)
+                /* only process queues from changed sets */
+                if (*q->irq_ptr->dsci) {
+
+                        /* only clear it if the indicator is non-shared */
+                        if (!shared_ind(q->irq_ptr))
+                                xchg(q->irq_ptr->dsci, 0);
+                        /*
+                         * don't call inbound processing directly since
+                         * that could starve other thinint queues
+                         */
+                        tasklet_schedule(&q->tasklet);
+                }
+
+        rcu_read_unlock();
+
+        /*
+         * if we used the shared indicator clear it now after all queues
+         * were processed
+         */
+        if (atomic_read(&q_indicators[TIQDIO_SHARED_IND].count)) {
+                xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 0);
+
+                /* prevent racing */
+                if (*tiqdio_alsi)
+                        xchg(&q_indicators[TIQDIO_SHARED_IND].ind, 1);
+        }
+
+        /* check for more work */
+        if (*tiqdio_alsi) {
+                xchg(tiqdio_alsi, 0);
+                qdio_perf_stat_inc(&perf_stats.tasklet_thinint_loop);
+                goto again;
+        }
+}
+
+/**
+ * tiqdio_thinint_handler - thin interrupt handler for qdio
+ * @ind: pointer to adapter local summary indicator
+ * @drv_data: NULL
+ */
+static void tiqdio_thinint_handler(void *ind, void *drv_data)
+{
+        qdio_perf_stat_inc(&perf_stats.thin_int);
+
+        /*
+         * SVS only when needed: issue SVS to benefit from iqdio interrupt
+         * avoidance (SVS clears adapter interrupt suppression overwrite)
+         */
+        if (!css_qdio_omit_svs)
+                do_clear_global_summary();
+
+        /*
+         * reset local summary indicator (tiqdio_alsi) to stop adapter
+         * interrupts for now, the tasklet will clean all dsci's
+         */
+        xchg((u8 *)ind, 0);
+        tasklet_hi_schedule(&tiqdio_tasklet);
+}
+
+static int set_subchannel_ind(struct qdio_irq *irq_ptr, int reset)
+{
+        struct scssc_area *scssc_area;
+        char dbf_text[15];
+        void *ptr;
+        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;
+        scssc_area->kc = PAGE_DEFAULT_KEY;
+        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) {
+                sprintf(dbf_text, "sidR%4x", scssc_area->response.code);
+                QDIO_DBF_TEXT1(0, trace, dbf_text);
+                QDIO_DBF_TEXT1(0, setup, dbf_text);
+                ptr = &scssc_area->response;
+                QDIO_DBF_HEX2(1, setup, &ptr, QDIO_DBF_SETUP_LEN);
+                return rc;
+        }
+
+        QDIO_DBF_TEXT2(0, setup, "setscind");
+        QDIO_DBF_HEX2(0, setup, &scssc_area->summary_indicator_addr,
+                      sizeof(unsigned long));
+        QDIO_DBF_HEX2(0, setup, &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)
+{
+        char dbf_text[20];
+
+        isc_register(QDIO_AIRQ_ISC);
+        tiqdio_alsi = s390_register_adapter_interrupt(&tiqdio_thinint_handler,
+                                                      NULL, QDIO_AIRQ_ISC);
+        if (IS_ERR(tiqdio_alsi)) {
+                sprintf(dbf_text, "regthn%lx", PTR_ERR(tiqdio_alsi));
+                QDIO_DBF_TEXT0(0, setup, dbf_text);
+                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;
+
+        /* Check for aif time delay disablement. If installed,
+         * omit SVS even under LPAR
+         */
+        if (css_general_characteristics.aif_tdd)
+                css_qdio_omit_svs = 1;
+        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();
+        QDIO_DBF_HEX1(0, setup, &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 */
+        put_indicator(irq_ptr->dsci);
+        set_subchannel_ind(irq_ptr, 1);
+}
+
+void __exit tiqdio_unregister_thinints(void)
+{
+        tasklet_disable(&tiqdio_tasklet);
+
+        if (tiqdio_alsi) {
+                s390_unregister_adapter_interrupt(tiqdio_alsi, QDIO_AIRQ_ISC);
+                isc_unregister(QDIO_AIRQ_ISC);
+        }
+}