diff options
Diffstat (limited to 'drivers/misc/ibmasm/event.c')
| -rw-r--r-- | drivers/misc/ibmasm/event.c | 169 |
1 files changed, 169 insertions, 0 deletions
diff --git a/drivers/misc/ibmasm/event.c b/drivers/misc/ibmasm/event.c new file mode 100644 index 000000000000..e100f34f1587 --- /dev/null +++ b/drivers/misc/ibmasm/event.c @@ -0,0 +1,169 @@ + +/* + * IBM ASM Service Processor Device Driver + * + * This program is free software; you can redistribute it and/or modify + * it under the terms of the GNU General Public License as published by + * the Free Software Foundation; either version 2 of the License, or + * (at your option) any later version. + * + * This program is distributed in the hope that it will be useful, + * but WITHOUT ANY WARRANTY; without even the implied warranty of + * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE. See the + * GNU General Public License for more details. + * + * You should have received a copy of the GNU General Public License + * along with this program; if not, write to the Free Software + * Foundation, Inc., 59 Temple Place - Suite 330, Boston, MA 02111-1307, USA. + * + * Copyright (C) IBM Corporation, 2004 + * + * Author: Max Asböck <amax@us.ibm.com> + * + */ + +#include "ibmasm.h" + +/* + * ASM service processor event handling routines. + * + * Events are signalled to the device drivers through interrupts. + * They have the format of dot commands, with the type field set to + * sp_event. + * The driver does not interpret the events, it simply stores them in a + * circular buffer. + */ + + +static void wake_up_event_readers(struct service_processor *sp) +{ + struct event_reader *reader; + + list_for_each_entry(reader, &sp->event_buffer->readers, node) + wake_up_interruptible(&reader->wait); +} + +/** + * receive_event + * Called by the interrupt handler when a dot command of type sp_event is + * received. + * Store the event in the circular event buffer, wake up any sleeping + * event readers. + * There is no reader marker in the buffer, therefore readers are + * responsible for keeping up with the writer, or they will loose events. + */ +void ibmasm_receive_event(struct service_processor *sp, void *data, unsigned int data_size) +{ + struct event_buffer *buffer = sp->event_buffer; + struct ibmasm_event *event; + unsigned long flags; + + data_size = min(data_size, IBMASM_EVENT_MAX_SIZE); + + spin_lock_irqsave(&sp->lock, flags); + /* copy the event into the next slot in the circular buffer */ + event = &buffer->events[buffer->next_index]; + memcpy(event->data, data, data_size); + event->data_size = data_size; + event->serial_number = buffer->next_serial_number; + + /* advance indices in the buffer */ + buffer->next_index = (buffer->next_index + 1) % IBMASM_NUM_EVENTS; + buffer->next_serial_number++; + spin_unlock_irqrestore(&sp->lock, flags); + + wake_up_event_readers(sp); +} + +static inline int event_available(struct event_buffer *b, struct event_reader *r) +{ + return (r->next_serial_number < b->next_serial_number); +} + +/** + * get_next_event + * Called by event readers (initiated from user space through the file + * system). + * Sleeps until a new event is available. + */ +int ibmasm_get_next_event(struct service_processor *sp, struct event_reader *reader) +{ + struct event_buffer *buffer = sp->event_buffer; + struct ibmasm_event *event; + unsigned int index; + unsigned long flags; + + if (wait_event_interruptible(reader->wait, event_available(buffer, reader))) + return -ERESTARTSYS; + + if (!event_available(buffer, reader)) + return 0; + + spin_lock_irqsave(&sp->lock, flags); + + index = buffer->next_index; + event = &buffer->events[index]; + while (event->serial_number < reader->next_serial_number) { + index = (index + 1) % IBMASM_NUM_EVENTS; + event = &buffer->events[index]; + } + memcpy(reader->data, event->data, event->data_size); + reader->data_size = event->data_size; + reader->next_serial_number = event->serial_number + 1; + + spin_unlock_irqrestore(&sp->lock, flags); + + return event->data_size; +} + +void ibmasm_event_reader_register(struct service_processor *sp, struct event_reader *reader) +{ + unsigned long flags; + + reader->next_serial_number = sp->event_buffer->next_serial_number; + init_waitqueue_head(&reader->wait); + spin_lock_irqsave(&sp->lock, flags); + list_add(&reader->node, &sp->event_buffer->readers); + spin_unlock_irqrestore(&sp->lock, flags); +} + +void ibmasm_event_reader_unregister(struct service_processor *sp, struct event_reader *reader) +{ + unsigned long flags; + + wake_up_interruptible(&reader->wait); + + spin_lock_irqsave(&sp->lock, flags); + list_del(&reader->node); + spin_unlock_irqrestore(&sp->lock, flags); +} + +int ibmasm_event_buffer_init(struct service_processor *sp) +{ + struct event_buffer *buffer; + struct ibmasm_event *event; + int i; + + buffer = kmalloc(sizeof(struct event_buffer), GFP_KERNEL); + if (!buffer) + return 1; + + buffer->next_index = 0; + buffer->next_serial_number = 1; + + event = buffer->events; + for (i=0; i<IBMASM_NUM_EVENTS; i++, event++) + event->serial_number = 0; + + INIT_LIST_HEAD(&buffer->readers); + + sp->event_buffer = buffer; + + return 0; +} + +void ibmasm_event_buffer_exit(struct service_processor *sp) +{ + wake_up_event_readers(sp); + kfree(sp->event_buffer); +} |