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