linux/drivers/misc/ibmasm/event.c
Thomas Gleixner 1a59d1b8e0 treewide: Replace GPLv2 boilerplate/reference with SPDX - rule 156
Based on 1 normalized pattern(s):

  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

extracted by the scancode license scanner the SPDX license identifier

  GPL-2.0-or-later

has been chosen to replace the boilerplate/reference in 1334 file(s).

Signed-off-by: Thomas Gleixner <tglx@linutronix.de>
Reviewed-by: Allison Randal <allison@lohutok.net>
Reviewed-by: Richard Fontana <rfontana@redhat.com>
Cc: linux-spdx@vger.kernel.org
Link: https://lkml.kernel.org/r/20190527070033.113240726@linutronix.de
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-05-30 11:26:35 -07:00

164 lines
4.2 KiB
C

// SPDX-License-Identifier: GPL-2.0-or-later
/*
* IBM ASM Service Processor Device Driver
*
* Copyright (C) IBM Corporation, 2004
*
* Author: Max Asböck <amax@us.ibm.com>
*/
#include <linux/sched.h>
#include <linux/slab.h>
#include "ibmasm.h"
#include "lowlevel.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 lose 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_fromio(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;
reader->cancelled = 0;
if (wait_event_interruptible(reader->wait,
event_available(buffer, reader) || reader->cancelled))
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_cancel_next_event(struct event_reader *reader)
{
reader->cancelled = 1;
wake_up_interruptible(&reader->wait);
}
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;
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 -ENOMEM;
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)
{
kfree(sp->event_buffer);
}