/* * drivers/s390/char/sclp.c * core function to access sclp interface * * S390 version * Copyright (C) 1999 IBM Deutschland Entwicklung GmbH, IBM Corporation * Author(s): Martin Peschke * Martin Schwidefsky */ #include #include #include #include #include #include #include #include #include #include "sclp.h" #define SCLP_HEADER "sclp: " /* Structure for register_early_external_interrupt. */ static ext_int_info_t ext_int_info_hwc; /* Lock to protect internal data consistency. */ static DEFINE_SPINLOCK(sclp_lock); /* Mask of events that we can receive from the sclp interface. */ static sccb_mask_t sclp_receive_mask; /* Mask of events that we can send to the sclp interface. */ static sccb_mask_t sclp_send_mask; /* List of registered event listeners and senders. */ static struct list_head sclp_reg_list; /* List of queued requests. */ static struct list_head sclp_req_queue; /* Data for read and and init requests. */ static struct sclp_req sclp_read_req; static struct sclp_req sclp_init_req; static char sclp_read_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); static char sclp_init_sccb[PAGE_SIZE] __attribute__((__aligned__(PAGE_SIZE))); /* Timer for request retries. */ static struct timer_list sclp_request_timer; /* Internal state: is the driver initialized? */ static volatile enum sclp_init_state_t { sclp_init_state_uninitialized, sclp_init_state_initializing, sclp_init_state_initialized } sclp_init_state = sclp_init_state_uninitialized; /* Internal state: is a request active at the sclp? */ static volatile enum sclp_running_state_t { sclp_running_state_idle, sclp_running_state_running } sclp_running_state = sclp_running_state_idle; /* Internal state: is a read request pending? */ static volatile enum sclp_reading_state_t { sclp_reading_state_idle, sclp_reading_state_reading } sclp_reading_state = sclp_reading_state_idle; /* Internal state: is the driver currently serving requests? */ static volatile enum sclp_activation_state_t { sclp_activation_state_active, sclp_activation_state_deactivating, sclp_activation_state_inactive, sclp_activation_state_activating } sclp_activation_state = sclp_activation_state_active; /* Internal state: is an init mask request pending? */ static volatile enum sclp_mask_state_t { sclp_mask_state_idle, sclp_mask_state_initializing } sclp_mask_state = sclp_mask_state_idle; /* Maximum retry counts */ #define SCLP_INIT_RETRY 3 #define SCLP_MASK_RETRY 3 #define SCLP_REQUEST_RETRY 3 /* Timeout intervals in seconds.*/ #define SCLP_BUSY_INTERVAL 2 #define SCLP_RETRY_INTERVAL 5 static void sclp_process_queue(void); static int sclp_init_mask(int calculate); static int sclp_init(void); /* Perform service call. Return 0 on success, non-zero otherwise. */ static int service_call(sclp_cmdw_t command, void *sccb) { int cc; __asm__ __volatile__( " .insn rre,0xb2200000,%1,%2\n" /* servc %1,%2 */ " ipm %0\n" " srl %0,28" : "=&d" (cc) : "d" (command), "a" (__pa(sccb)) : "cc", "memory" ); if (cc == 3) return -EIO; if (cc == 2) return -EBUSY; return 0; } /* Request timeout handler. Restart the request queue. If DATA is non-zero, * force restart of running request. */ static void sclp_request_timeout(unsigned long data) { unsigned long flags; if (data) { spin_lock_irqsave(&sclp_lock, flags); sclp_running_state = sclp_running_state_idle; spin_unlock_irqrestore(&sclp_lock, flags); } sclp_process_queue(); } /* Set up request retry timer. Called while sclp_lock is locked. */ static inline void __sclp_set_request_timer(unsigned long time, void (*function)(unsigned long), unsigned long data) { del_timer(&sclp_request_timer); sclp_request_timer.function = function; sclp_request_timer.data = data; sclp_request_timer.expires = jiffies + time; add_timer(&sclp_request_timer); } /* Try to start a request. Return zero if the request was successfully * started or if it will be started at a later time. Return non-zero otherwise. * Called while sclp_lock is locked. */ static int __sclp_start_request(struct sclp_req *req) { int rc; if (sclp_running_state != sclp_running_state_idle) return 0; del_timer(&sclp_request_timer); if (req->start_count <= SCLP_REQUEST_RETRY) { rc = service_call(req->command, req->sccb); req->start_count++; } else rc = -EIO; if (rc == 0) { /* Sucessfully started request */ req->status = SCLP_REQ_RUNNING; sclp_running_state = sclp_running_state_running; __sclp_set_request_timer(SCLP_RETRY_INTERVAL * HZ, sclp_request_timeout, 1); return 0; } else if (rc == -EBUSY) { /* Try again later */ __sclp_set_request_timer(SCLP_BUSY_INTERVAL * HZ, sclp_request_timeout, 0); return 0; } /* Request failed */ req->status = SCLP_REQ_FAILED; return rc; } /* Try to start queued requests. */ static void sclp_process_queue(void) { struct sclp_req *req; int rc; unsigned long flags; spin_lock_irqsave(&sclp_lock, flags); if (sclp_running_state != sclp_running_state_idle) { spin_unlock_irqrestore(&sclp_lock, flags); return; } del_timer(&sclp_request_timer); while (!list_empty(&sclp_req_queue)) { req = list_entry(sclp_req_queue.next, struct sclp_req, list); rc = __sclp_start_request(req); if (rc == 0) break; /* Request failed. */ list_del(&req->list); if (req->callback) { spin_unlock_irqrestore(&sclp_lock, flags); req->callback(req, req->callback_data); spin_lock_irqsave(&sclp_lock, flags); } } spin_unlock_irqrestore(&sclp_lock, flags); } /* Queue a new request. Return zero on success, non-zero otherwise. */ int sclp_add_request(struct sclp_req *req) { unsigned long flags; int rc; spin_lock_irqsave(&sclp_lock, flags); if ((sclp_init_state != sclp_init_state_initialized || sclp_activation_state != sclp_activation_state_active) && req != &sclp_init_req) { spin_unlock_irqrestore(&sclp_lock, flags); return -EIO; } req->status = SCLP_REQ_QUEUED; req->start_count = 0; list_add_tail(&req->list, &sclp_req_queue); rc = 0; /* Start if request is first in list */ if (req->list.prev == &sclp_req_queue) { rc = __sclp_start_request(req); if (rc) list_del(&req->list); } spin_unlock_irqrestore(&sclp_lock, flags); return rc; } EXPORT_SYMBOL(sclp_add_request); /* Dispatch events found in request buffer to registered listeners. Return 0 * if all events were dispatched, non-zero otherwise. */ static int sclp_dispatch_evbufs(struct sccb_header *sccb) { unsigned long flags; struct evbuf_header *evbuf; struct list_head *l; struct sclp_register *reg; int offset; int rc; spin_lock_irqsave(&sclp_lock, flags); rc = 0; for (offset = sizeof(struct sccb_header); offset < sccb->length; offset += evbuf->length) { /* Search for event handler */ evbuf = (struct evbuf_header *) ((addr_t) sccb + offset); reg = NULL; list_for_each(l, &sclp_reg_list) { reg = list_entry(l, struct sclp_register, list); if (reg->receive_mask & (1 << (32 - evbuf->type))) break; else reg = NULL; } if (reg && reg->receiver_fn) { spin_unlock_irqrestore(&sclp_lock, flags); reg->receiver_fn(evbuf); spin_lock_irqsave(&sclp_lock, flags); } else if (reg == NULL) rc = -ENOSYS; } spin_unlock_irqrestore(&sclp_lock, flags); return rc; } /* Read event data request callback. */ static void sclp_read_cb(struct sclp_req *req, void *data) { unsigned long flags; struct sccb_header *sccb; sccb = (struct sccb_header *) req->sccb; if (req->status == SCLP_REQ_DONE && (sccb->response_code == 0x20 || sccb->response_code == 0x220)) sclp_dispatch_evbufs(sccb); spin_lock_irqsave(&sclp_lock, flags); sclp_reading_state = sclp_reading_state_idle; spin_unlock_irqrestore(&sclp_lock, flags); } /* Prepare read event data request. Called while sclp_lock is locked. */ static inline void __sclp_make_read_req(void) { struct sccb_header *sccb; sccb = (struct sccb_header *) sclp_read_sccb; clear_page(sccb); memset(&sclp_read_req, 0, sizeof(struct sclp_req)); sclp_read_req.command = SCLP_CMDW_READDATA; sclp_read_req.status = SCLP_REQ_QUEUED; sclp_read_req.start_count = 0; sclp_read_req.callback = sclp_read_cb; sclp_read_req.sccb = sccb; sccb->length = PAGE_SIZE; sccb->function_code = 0; sccb->control_mask[2] = 0x80; } /* Search request list for request with matching sccb. Return request if found, * NULL otherwise. Called while sclp_lock is locked. */ static inline struct sclp_req * __sclp_find_req(u32 sccb) { struct list_head *l; struct sclp_req *req; list_for_each(l, &sclp_req_queue) { req = list_entry(l, struct sclp_req, list); if (sccb == (u32) (addr_t) req->sccb) return req; } return NULL; } /* Handler for external interruption. Perform request post-processing. * Prepare read event data request if necessary. Start processing of next * request on queue. */ static void sclp_interrupt_handler(struct pt_regs *regs, __u16 code) { struct sclp_req *req; u32 finished_sccb; u32 evbuf_pending; spin_lock(&sclp_lock); finished_sccb = S390_lowcore.ext_params & 0xfffffff8; evbuf_pending = S390_lowcore.ext_params & 0x3; if (finished_sccb) { req = __sclp_find_req(finished_sccb); if (req) { /* Request post-processing */ list_del(&req->list); req->status = SCLP_REQ_DONE; if (req->callback) { spin_unlock(&sclp_lock); req->callback(req, req->callback_data); spin_lock(&sclp_lock); } } sclp_running_state = sclp_running_state_idle; } if (evbuf_pending && sclp_receive_mask != 0 && sclp_reading_state == sclp_reading_state_idle && sclp_activation_state == sclp_activation_state_active ) { sclp_reading_state = sclp_reading_state_reading; __sclp_make_read_req(); /* Add request to head of queue */ list_add(&sclp_read_req.list, &sclp_req_queue); } spin_unlock(&sclp_lock); sclp_process_queue(); } /* Return current Time-Of-Day clock. */ static inline u64 sclp_get_clock(void) { u64 result; asm volatile ("STCK 0(%1)" : "=m" (result) : "a" (&(result)) : "cc"); return result; } /* Convert interval in jiffies to TOD ticks. */ static inline u64 sclp_tod_from_jiffies(unsigned long jiffies) { return (u64) (jiffies / HZ) << 32; } /* Wait until a currently running request finished. Note: while this function * is running, no timers are served on the calling CPU. */ void sclp_sync_wait(void) { unsigned long psw_mask; unsigned long cr0, cr0_sync; u64 timeout; /* We'll be disabling timer interrupts, so we need a custom timeout * mechanism */ timeout = 0; if (timer_pending(&sclp_request_timer)) { /* Get timeout TOD value */ timeout = sclp_get_clock() + sclp_tod_from_jiffies(sclp_request_timer.expires - jiffies); } /* Prevent bottom half from executing once we force interrupts open */ local_bh_disable(); /* Enable service-signal interruption, disable timer interrupts */ __ctl_store(cr0, 0, 0); cr0_sync = cr0; cr0_sync |= 0x00000200; cr0_sync &= 0xFFFFF3AC; __ctl_load(cr0_sync, 0, 0); asm volatile ("STOSM 0(%1),0x01" : "=m" (psw_mask) : "a" (&psw_mask) : "memory"); /* Loop until driver state indicates finished request */ while (sclp_running_state != sclp_running_state_idle) { /* Check for expired request timer */ if (timer_pending(&sclp_request_timer) && sclp_get_clock() > timeout && del_timer(&sclp_request_timer)) sclp_request_timer.function(sclp_request_timer.data); barrier(); cpu_relax(); } /* Restore interrupt settings */ asm volatile ("SSM 0(%0)" : : "a" (&psw_mask) : "memory"); __ctl_load(cr0, 0, 0); __local_bh_enable(); } EXPORT_SYMBOL(sclp_sync_wait); /* Dispatch changes in send and receive mask to registered listeners. */ static inline void sclp_dispatch_state_change(void) { struct list_head *l; struct sclp_register *reg; unsigned long flags; sccb_mask_t receive_mask; sccb_mask_t send_mask; do { spin_lock_irqsave(&sclp_lock, flags); reg = NULL; list_for_each(l, &sclp_reg_list) { reg = list_entry(l, struct sclp_register, list); receive_mask = reg->receive_mask & sclp_receive_mask; send_mask = reg->send_mask & sclp_send_mask; if (reg->sclp_receive_mask != receive_mask || reg->sclp_send_mask != send_mask) { reg->sclp_receive_mask = receive_mask; reg->sclp_send_mask = send_mask; break; } else reg = NULL; } spin_unlock_irqrestore(&sclp_lock, flags); if (reg && reg->state_change_fn) reg->state_change_fn(reg); } while (reg); } 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(®->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(®->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(®->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; }