path: root/drivers/misc/hpilo.c

/*
 * Driver for HP iLO/iLO2 management processor.
 *
 * Copyright (C) 2008 Hewlett-Packard Development Company, L.P.
 *	David Altobelli <david.altobelli@hp.com>
 *
 * This program is free software; you can redistribute it and/or modify
 * it under the terms of the GNU General Public License version 2 as
 * published by the Free Software Foundation.
 */
#include <linux/kernel.h>
#include <linux/types.h>
#include <linux/module.h>
#include <linux/fs.h>
#include <linux/pci.h>
#include <linux/interrupt.h>
#include <linux/ioport.h>
#include <linux/device.h>
#include <linux/file.h>
#include <linux/cdev.h>
#include <linux/sched.h>
#include <linux/spinlock.h>
#include <linux/delay.h>
#include <linux/uaccess.h>
#include <linux/io.h>
#include <linux/wait.h>
#include <linux/poll.h>
#include "hpilo.h"

static struct class *ilo_class;
static unsigned int ilo_major;
static char ilo_hwdev[MAX_ILO_DEV];

static inline int get_entry_id(int entry)
{
	return (entry & ENTRY_MASK_DESCRIPTOR) >> ENTRY_BITPOS_DESCRIPTOR;
}

static inline int get_entry_len(int entry)
{
	return ((entry & ENTRY_MASK_QWORDS) >> ENTRY_BITPOS_QWORDS) << 3;
}

static inline int mk_entry(int id, int len)
{
	int qlen = len & 7 ? (len >> 3) + 1 : len >> 3;
	return id << ENTRY_BITPOS_DESCRIPTOR | qlen << ENTRY_BITPOS_QWORDS;
}

static inline int desc_mem_sz(int nr_entry)
{
	return nr_entry << L2_QENTRY_SZ;
}

/*
 * FIFO queues, shared with hardware.
 *
 * If a queue has empty slots, an entry is added to the queue tail,
 * and that entry is marked as occupied.
 * Entries can be dequeued from the head of the list, when the device
 * has marked the entry as consumed.
 *
 * Returns true on successful queue/dequeue, false on failure.
 */
static int fifo_enqueue(struct ilo_hwinfo *hw, char *fifobar, int entry)
{
	struct fifo *fifo_q = FIFOBARTOHANDLE(fifobar);
	unsigned long flags;
	int ret = 0;

	spin_lock_irqsave(&hw->fifo_lock, flags);
	if (!(fifo_q->fifobar[(fifo_q->tail + 1) & fifo_q->imask]
	      & ENTRY_MASK_O)) {
		fifo_q->fifobar[fifo_q->tail & fifo_q->imask] |=
				(entry & ENTRY_MASK_NOSTATE) | fifo_q->merge;
		fifo_q->tail += 1;
		ret = 1;
	}
	spin_unlock_irqrestore(&hw->fifo_lock, flags);

	return ret;
}

static int fifo_dequeue(struct ilo_hwinfo *hw, char *fifobar, int *entry)
{
	struct fifo *fifo_q = FIFOBARTOHANDLE(fifobar);
	unsigned long flags;
	int ret = 0;
	u64 c;

	spin_lock_irqsave(&hw->fifo_lock, flags);
	c = fifo_q->fifobar[fifo_q->head & fifo_q->imask];
	if (c & ENTRY_MASK_C) {
		if (entry)
			*entry = c & ENTRY_MASK_NOSTATE;

		fifo_q->fifobar[fifo_q->head & fifo_q->imask] =
							(c | ENTRY_MASK) + 1;
		fifo_q->head += 1;
		ret = 1;
	}
	spin_unlock_irqrestore(&hw->fifo_lock, flags);

	return ret;
}

static int fifo_check_recv(struct ilo_hwinfo *hw, char *fifobar)
{
	struct fifo *fifo_q = FIFOBARTOHANDLE(fifobar);
	unsigned long flags;
	int ret = 0;
	u64 c;

	spin_lock_irqsave(&hw->fifo_lock, flags);
	c = fifo_q->fifobar[fifo_q->head & fifo_q->imask];
	if (c & ENTRY_MASK_C)
		ret = 1;
	spin_unlock_irqrestore(&hw->fifo_lock, flags);

	return ret;
}

static int ilo_pkt_enqueue(struct ilo_hwinfo *hw, struct ccb *ccb,
			   int dir, int id, int len)
{
	char *fifobar;
	int entry;

	if (dir == SENDQ)
		fifobar = ccb->ccb_u1.send_fifobar;
	else
		fifobar = ccb->ccb_u3.recv_fifobar;

	entry = mk_entry(id, len);
	return fifo_enqueue(hw, fifobar, entry);
}

static int ilo_pkt_dequeue(struct ilo_hwinfo *hw, struct ccb *ccb,
			   int dir, int *id, int *len, void **pkt)
{
	char *fifobar, *desc;
	int entry = 0, pkt_id = 0;
	int ret;

	if (dir == SENDQ) {
		fifobar = ccb->ccb_u1.send_fifobar;
		desc = ccb->ccb_u2.send_desc;
	} else {
		fifobar = ccb->ccb_u3.recv_fifobar;
		desc = ccb->ccb_u4.recv_desc;
	}

	ret = fifo_dequeue(hw, fifobar, &entry);
	if