x86/xen: resume timer irqs early

[linux/fpc-iii.git] / drivers / misc / hpilo.c

/*
 * Driver for the HP iLO 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 <linux/slab.h>
#include "hpilo.h"

static struct class *ilo_class;
static unsigned int ilo_major;
static unsigned int max_ccb = 16;
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 (ret) {
                pkt_id = get_entry_id(entry);
                if (id)
                        *id = pkt_id;
                if (len)
                        *len = get_entry_len(entry);
                if (pkt)
                        *pkt = (void *)(desc + desc_mem_sz(pkt_id));
        }

        return ret;
}

static int ilo_pkt_recv(struct ilo_hwinfo *hw, struct ccb *ccb)
{
        char *fifobar = ccb->ccb_u3.recv_fifobar;

        return fifo_check_recv(hw, fifobar);
}

static inline void doorbell_set(struct ccb *ccb)
{
        iowrite8(1, ccb->ccb_u5.db_base);
}

static inline void doorbell_clr(struct ccb *ccb)
{
        iowrite8(2, ccb->ccb_u5.db_base);
}

static inline int ctrl_set(int l2sz, int idxmask, int desclim)
{
        int active = 0, go = 1;
        return l2sz << CTRL_BITPOS_L2SZ |
               idxmask << CTRL_BITPOS_FIFOINDEXMASK |
               desclim << CTRL_BITPOS_DESCLIMIT |
               active << CTRL_BITPOS_A |
               go << CTRL_BITPOS_G;
}

static void ctrl_setup(struct ccb *ccb, int nr_desc, int l2desc_sz)
{
        /* for simplicity, use the same parameters for send and recv ctrls */
        ccb->send_ctrl = ctrl_set(l2desc_sz, nr_desc-1, nr_desc-1);
        ccb->recv_ctrl = ctrl_set(l2desc_sz, nr_desc-1, nr_desc-1);
}

static inline int fifo_sz(int nr_entry)
{
        /* size of a fifo is determined by the number of entries it contains */
        return (nr_entry * sizeof(u64)) + FIFOHANDLESIZE;
}

static void fifo_setup(void *base_addr, int nr_entry)
{
        struct fifo *fifo_q = base_addr;
        int i;

        /* set up an empty fifo */
        fifo_q->head = 0;
        fifo_q->tail = 0;
        fifo_q->reset = 0;
        fifo_q->nrents = nr_entry;
        fifo_q->imask = nr_entry - 1;
        fifo_q->merge = ENTRY_MASK_O;

        for (i = 0; i < nr_entry; i++)
                fifo_q->fifobar[i] = 0;
}

static void ilo_ccb_close(struct pci_dev *pdev, struct ccb_data *data)
{
        struct ccb *driver_ccb = &data->driver_ccb;
        struct ccb __iomem *device_ccb = data->mapped_ccb;
        int retries;

        /* complicated dance to tell the hw we are stopping */
        doorbell_clr(driver_ccb);
        iowrite32(ioread32(&device_ccb->send_ctrl) & ~(1 << CTRL_BITPOS_G),
                  &device_ccb->send_ctrl);
        iowrite32(ioread32(&device_ccb->recv_ctrl) & ~(1 << CTRL_BITPOS_G),
                  &device_ccb->recv_ctrl);

        /* give iLO some time to process stop request */
        for (retries = MAX_WAIT; retries > 0; retries--) {
                doorbell_set(driver_ccb);
                udelay(WAIT_TIME);
                if (!(ioread32(&device_ccb->send_ctrl) & (1 << CTRL_BITPOS_A))
                    &&
                    !(ioread32(&device_ccb->recv_ctrl) & (1 << CTRL_BITPOS_A)))
                        break;
        }
        if (retries == 0)
                dev_err(&pdev->dev, "Closing, but controller still active\n");

        /* clear the hw ccb */
        memset_io(device_ccb, 0, sizeof(struct ccb));

        /* free resources used to back send/recv queues */
        pci_free_consistent(pdev, data->dma_size, data->dma_va, data->dma_pa);
}

static int ilo_ccb_setup(struct ilo_hwinfo *hw, struct ccb_data *data, int slot)
{
        char *dma_va;
        dma_addr_t dma_pa;
        struct ccb *driver_ccb, *ilo_ccb;

        driver_ccb = &data->driver_ccb;
        ilo_ccb = &data->ilo_ccb;

        data->dma_size = 2 * fifo_sz(NR_QENTRY) +
                         2 * desc_mem_sz(NR_QENTRY) +
                         ILO_START_ALIGN + ILO_CACHE_SZ;

        data->dma_va = pci_alloc_consistent(hw->ilo_dev, data->dma_size,
                                            &data->dma_pa);
        if (!data->dma_va)
                return -ENOMEM;

        dma_va = (char *)data->dma_va;
        dma_pa = data->dma_pa;

        memset(dma_va, 0, data->dma_size);

        dma_va = (char *)roundup((unsigned long)dma_va, ILO_START_ALIGN);
        dma_pa = roundup(dma_pa, ILO_START_ALIGN);

        /*
         * Create two ccb's, one with virt addrs, one with phys addrs.
         * Copy the phys addr ccb to device shared mem.
         */
        ctrl_setup(driver_ccb, NR_QENTRY, L2_QENTRY_SZ);
        ctrl_setup(ilo_ccb, NR_QENTRY, L2_QENTRY_SZ);

        fifo_setup(dma_va, NR_QENTRY);
        driver_ccb->ccb_u1.send_fifobar = dma_va + FIFOHANDLESIZE;
        ilo_ccb->ccb_u1.send_fifobar_pa = dma_pa + FIFOHANDLESIZE;
        dma_va += fifo_sz(NR_QENTRY);
        dma_pa += fifo_sz(NR_QENTRY);

        dma_va = (char *)roundup((unsigned long)dma_va, ILO_CACHE_SZ);
        dma_pa = roundup(dma_pa, ILO_CACHE_SZ);

        fifo_setup(dma_va, NR_QENTRY);
        driver_ccb->ccb_u3.recv_fifobar = dma_va + FIFOHANDLESIZE;
        ilo_ccb->ccb_u3.recv_fifobar_pa = dma_pa + FIFOHANDLESIZE;
        dma_va += fifo_sz(NR_QENTRY);
        dma_pa += fifo_sz(NR_QENTRY);

        driver_ccb->ccb_u2.send_desc = dma_va;
        ilo_ccb->ccb_u2.send_desc_pa = dma_pa;
        dma_pa += desc_mem_sz(NR_QENTRY);
        dma_va += desc_mem_sz(NR_QENTRY);

        driver_ccb->ccb_u4.recv_desc = dma_va;
        ilo_ccb->ccb_u4.recv_desc_pa = dma_pa;

        driver_ccb->channel = slot;
        ilo_ccb->channel = slot;

        driver_ccb->ccb_u5.db_base = hw->db_vaddr + (slot << L2_DB_SIZE);
        ilo_ccb->ccb_u5.db_base = NULL; /* hw ccb's doorbell is not used */

        return 0;
}

static void ilo_ccb_open(struct ilo_hwinfo *hw, struct ccb_data *data, int slot)
{
        int pkt_id, pkt_sz;
        struct ccb *driver_ccb = &data->driver_ccb;

        /* copy the ccb with physical addrs to device memory */
        data->mapped_ccb = (struct ccb __iomem *)
                                (hw->ram_vaddr + (slot * ILOHW_CCB_SZ));
        memcpy_toio(data->mapped_ccb, &data->ilo_ccb, sizeof(struct ccb));

        /* put packets on the send and receive queues */
        pkt_sz = 0;
        for (pkt_id = 0; pkt_id < NR_QENTRY; pkt_id++) {
                ilo_pkt_enqueue(hw, driver_ccb, SENDQ, pkt_id, pkt_sz);
                doorbell_set(driver_ccb);
        }

        pkt_sz = desc_mem_sz(1);
        for (pkt_id = 0; pkt_id < NR_QENTRY; pkt_id++)
                ilo_pkt_enqueue(hw, driver_ccb, RECVQ, pkt_id, pkt_sz);

        /* the ccb is ready to use */
        doorbell_clr(driver_ccb);
}

static int ilo_ccb_verify(struct ilo_hwinfo *hw, struct ccb_data *data)
{
        int pkt_id, i;
        struct ccb *driver_ccb = &data->driver_ccb;

        /* make sure iLO is really handling requests */
        for (i = MAX_WAIT; i > 0; i--) {
                if (ilo_pkt_dequeue(hw, driver_ccb, SENDQ, &pkt_id, NULL, NULL))
                        break;
                udelay(WAIT_TIME);
        }

        if (i == 0) {
                dev_err(&hw->ilo_dev->dev, "Open could not dequeue a packet\n");
                return -EBUSY;
        }

        ilo_pkt_enqueue(hw, driver_ccb, SENDQ, pkt_id, 0);
        doorbell_set(driver_ccb);
        return 0;
}

static inline int is_channel_reset(struct ccb *ccb)
{
        /* check for this particular channel needing a reset */
        return FIFOBARTOHANDLE(ccb->ccb_u1.send_fifobar)->reset;
}

static inline void set_channel_reset(struct ccb *ccb)
{
        /* set a flag indicating this channel needs a reset */
        FIFOBARTOHANDLE(ccb->ccb_u1.send_fifobar)->reset = 1;
}

static inline int get_device_outbound(struct ilo_hwinfo *hw)
{
        return ioread32(&hw->mmio_vaddr[DB_OUT]);
}

static inline int is_db_reset(int db_out)
{
        return db_out & (1 << DB_RESET);
}

static inline int is_device_reset(struct ilo_hwinfo *hw)
{
        /* check for global reset condition */
        return is_db_reset(get_device_outbound(hw));
}

static inline void clear_pending_db(struct ilo_hwinfo *hw, int clr)
{
        iowrite32(clr, &hw->mmio_vaddr[DB_OUT]);
}

static inline void clear_device(struct ilo_hwinfo *hw)
{
        /* clear the device (reset bits, pending channel entries) */
        clear_pending_db(hw, -1);
}

static inline void ilo_enable_interrupts(struct ilo_hwinfo *hw)
{
        iowrite8(ioread8(&hw->mmio_vaddr[DB_IRQ]) | 1, &hw->mmio_vaddr[DB_IRQ]);
}

static inline void ilo_disable_interrupts(struct ilo_hwinfo *hw)
{
        iowrite8(ioread8(&hw->mmio_vaddr[DB_IRQ]) & ~1,
                 &hw->mmio_vaddr[DB_IRQ]);
}

static void ilo_set_reset(struct ilo_hwinfo *hw)
{
        int slot;

        /*
         * Mapped memory is zeroed on ilo reset, so set a per ccb flag
         * to indicate that this ccb needs to be closed and reopened.
         */
        for (slot = 0; slot < max_ccb; slot++) {
                if (!hw->ccb_alloc[slot])
                        continue;
                set_channel_reset(&hw->ccb_alloc[slot]->driver_ccb);
        }
}

static ssize_t ilo_read(struct file *fp, char __user *buf,
                        size_t len, loff_t *off)
{
        int err, found, cnt, pkt_id, pkt_len;
        struct ccb_data *data = fp->private_data;
        struct ccb *driver_ccb = &data->driver_ccb;
        struct ilo_hwinfo *hw = data->ilo_hw;
        void *pkt;

        if (is_channel_reset(driver_ccb)) {
                /*
                 * If the device has been reset, applications
                 * need to close and reopen all ccbs.
                 */
                return -ENODEV;
        }

        /*
         * This function is to be called when data is expected
         * in the channel, and will return an error if no packet is found
         * during the loop below.  The sleep/retry logic is to allow
         * applications to call read() immediately post write(),
         * and give iLO some time to process the sent packet.
         */
        cnt = 20;
        do {
                /* look for a received packet */
                found = ilo_pkt_dequeue(hw, driver_ccb, RECVQ, &pkt_id,
                                        &pkt_len, &pkt);
                if (found)
                        break;
                cnt--;
                msleep(100);
        } while (!found && cnt);

        if (!found)
                return -EAGAIN;

        /* only copy the length of the received packet */
        if (pkt_len < len)
                len = pkt_len;

        err = copy_to_user(buf, pkt, len);

        /* return the received packet to the queue */
        ilo_pkt_enqueue(hw, driver_ccb, RECVQ, pkt_id, desc_mem_sz(1));

        return err ? -EFAULT : len;
}

static ssize_t ilo_write(struct file *fp, const char __user *buf,
                         size_t len, loff_t *off)
{
        int err, pkt_id, pkt_len;
        struct ccb_data *data = fp->private_data;
        struct ccb *driver_ccb = &data->driver_ccb;
        struct ilo_hwinfo *hw = data->ilo_hw;
        void *pkt;

        if (is_channel_reset(driver_ccb))
                return -ENODEV;

        /* get a packet to send the user command */
        if (!ilo_pkt_dequeue(hw, driver_ccb, SENDQ, &pkt_id, &pkt_len, &pkt))
                return -EBUSY;

        /* limit the length to the length of the packet */
        if (pkt_len < len)
                len = pkt_len;

        /* on failure, set the len to 0 to return empty packet to the device */
        err = copy_from_user(pkt, buf, len);
        if (err)
                len = 0;

        /* send the packet */
        ilo_pkt_enqueue(hw, driver_ccb, SENDQ, pkt_id, len);
        doorbell_set(driver_ccb);

        return err ? -EFAULT : len;
}

static unsigned int ilo_poll(struct file *fp, poll_table *wait)
{
        struct ccb_data *data = fp->private_data;
        struct ccb *driver_ccb = &data->driver_ccb;

        poll_wait(fp, &data->ccb_waitq, wait);

        if (is_channel_reset(driver_ccb))
                return POLLERR;
        else if (ilo_pkt_recv(data->ilo_hw, driver_ccb))
                return POLLIN | POLLRDNORM;

        return 0;
}

static int ilo_close(struct inode *ip, struct file *fp)
{
        int slot;
        struct ccb_data *data;
        struct ilo_hwinfo *hw;
        unsigned long flags;

        slot = iminor(ip) % max_ccb;
        hw = container_of(ip->i_cdev, struct ilo_hwinfo, cdev);

        spin_lock(&hw->open_lock);

        if (hw->ccb_alloc[slot]->ccb_cnt == 1) {

                data = fp->private_data;

                spin_lock_irqsave(&hw->alloc_lock, flags);
                hw->ccb_alloc[slot] = NULL;
                spin_unlock_irqrestore(&hw->alloc_lock, flags);

                ilo_ccb_close(hw->ilo_dev, data);

                kfree(data);
        } else
                hw->ccb_alloc[slot]->ccb_cnt--;

        spin_unlock(&hw->open_lock);

        return 0;
}

static int ilo_open(struct inode *ip, struct file *fp)
{
        int slot, error;
        struct ccb_data *data;
        struct ilo_hwinfo *hw;
        unsigned long flags;

        slot = iminor(ip) % max_ccb;
        hw = container_of(ip->i_cdev, struct ilo_hwinfo, cdev);

        /* new ccb allocation */
        data = kzalloc(sizeof(*data), GFP_KERNEL);
        if (!data)
                return -ENOMEM;

        spin_lock(&hw->open_lock);

        /* each fd private_data holds sw/hw view of ccb */
        if (hw->ccb_alloc[slot] == NULL) {
                /* create a channel control block for this minor */
                error = ilo_ccb_setup(hw, data, slot);
                if (error) {
                        kfree(data);
                        goto out;
                }

                data->ccb_cnt = 1;
                data->ccb_excl = fp->f_flags & O_EXCL;
                data->ilo_hw = hw;
                init_waitqueue_head(&data->ccb_waitq);

                /* write the ccb to hw */
                spin_lock_irqsave(&hw->alloc_lock, flags);
                ilo_ccb_open(hw, data, slot);
                hw->ccb_alloc[slot] = data;
                spin_unlock_irqrestore(&hw->alloc_lock, flags);

                /* make sure the channel is functional */
                error = ilo_ccb_verify(hw, data);
                if (error) {

                        spin_lock_irqsave(&hw->alloc_lock, flags);
                        hw->ccb_alloc[slot] = NULL;
                        spin_unlock_irqrestore(&hw->alloc_lock, flags);

                        ilo_ccb_close(hw->ilo_dev, data);

                        kfree(data);
                        goto out;
                }

        } else {
                kfree(data);
                if (fp->f_flags & O_EXCL || hw->ccb_alloc[slot]->ccb_excl) {
                        /*
                         * The channel exists, and either this open
                         * or a previous open of this channel wants
                         * exclusive access.
                         */
                        error = -EBUSY;
                } else {
                        hw->ccb_alloc[slot]->ccb_cnt++;
                        error = 0;
                }
        }
out:
        spin_unlock(&hw->open_lock);

        if (!error)
                fp->private_data = hw->ccb_alloc[slot];

        return error;
}

static const struct file_operations ilo_fops = {
        .owner          = THIS_MODULE,
        .read           = ilo_read,
        .write          = ilo_write,
        .poll           = ilo_poll,
        .open           = ilo_open,
        .release        = ilo_close,
        .llseek         = noop_llseek,
};

static irqreturn_t ilo_isr(int irq, void *data)
{
        struct ilo_hwinfo *hw = data;
        int pending, i;

        spin_lock(&hw->alloc_lock);

        /* check for ccbs which have data */
        pending = get_device_outbound(hw);
        if (!pending) {
                spin_unlock(&hw->alloc_lock);
                return IRQ_NONE;
        }

        if (is_db_reset(pending)) {
                /* wake up all ccbs if the device was reset */
                pending = -1;
                ilo_set_reset(hw);
        }

        for (i = 0; i < max_ccb; i++) {
                if (!hw->ccb_alloc[i])
                        continue;
                if (pending & (1 << i))
                        wake_up_interruptible(&hw->ccb_alloc[i]->ccb_waitq);
        }

        /* clear the device of the channels that have been handled */
        clear_pending_db(hw, pending);

        spin_unlock(&hw->alloc_lock);

        return IRQ_HANDLED;
}

static void ilo_unmap_device(struct pci_dev *pdev, struct ilo_hwinfo *hw)
{
        pci_iounmap(pdev, hw->db_vaddr);
        pci_iounmap(pdev, hw->ram_vaddr);
        pci_iounmap(pdev, hw->mmio_vaddr);
}

static int ilo_map_device(struct pci_dev *pdev, struct ilo_hwinfo *hw)
{
        int error = -ENOMEM;

        /* map the memory mapped i/o registers */
        hw->mmio_vaddr = pci_iomap(pdev, 1, 0);
        if (hw->mmio_vaddr == NULL) {
                dev_err(&pdev->dev, "Error mapping mmio\n");
                goto out;
        }

        /* map the adapter shared memory region */
        hw->ram_vaddr = pci_iomap(pdev, 2, max_ccb * ILOHW_CCB_SZ);
        if (hw->ram_vaddr == NULL) {
                dev_err(&pdev->dev, "Error mapping shared mem\n");
                goto mmio_free;
        }

        /* map the doorbell aperture */
        hw->db_vaddr = pci_iomap(pdev, 3, max_ccb * ONE_DB_SIZE);
        if (hw->db_vaddr == NULL) {
                dev_err(&pdev->dev, "Error mapping doorbell\n");
                goto ram_free;
        }

        return 0;
ram_free:
        pci_iounmap(pdev, hw->ram_vaddr);
mmio_free:
        pci_iounmap(pdev, hw->mmio_vaddr);
out:
        return error;
}

static void ilo_remove(struct pci_dev *pdev)
{
        int i, minor;
        struct ilo_hwinfo *ilo_hw = pci_get_drvdata(pdev);

        if (!ilo_hw)
                return;

        clear_device(ilo_hw);

        minor = MINOR(ilo_hw->cdev.dev);
        for (i = minor; i < minor + max_ccb; i++)
                device_destroy(ilo_class, MKDEV(ilo_major, i));

        cdev_del(&ilo_hw->cdev);
        ilo_disable_interrupts(ilo_hw);
        free_irq(pdev->irq, ilo_hw);
        ilo_unmap_device(pdev, ilo_hw);
        pci_release_regions(pdev);
        /*
         * pci_disable_device(pdev) used to be here. But this PCI device has
         * two functions with interrupt lines connected to a single pin. The
         * other one is a USB host controller. So when we disable the PIN here
         * e.g. by rmmod hpilo, the controller stops working. It is because
         * the interrupt link is disabled in ACPI since it is not refcounted
         * yet. See acpi_pci_link_free_irq called from acpi_pci_irq_disable.
         */
        kfree(ilo_hw);
        ilo_hwdev[(minor / max_ccb)] = 0;
}

static int ilo_probe(struct pci_dev *pdev,
                               const struct pci_device_id *ent)
{
        int devnum, minor, start, error = 0;
        struct ilo_hwinfo *ilo_hw;

        /* Ignore subsystem_device = 0x1979 (set by BIOS)  */
        if (pdev->subsystem_device == 0x1979)
                return 0;

        if (max_ccb > MAX_CCB)
                max_ccb = MAX_CCB;
        else if (max_ccb < MIN_CCB)
                max_ccb = MIN_CCB;

        /* find a free range for device files */
        for (devnum = 0; devnum < MAX_ILO_DEV; devnum++) {
                if (ilo_hwdev[devnum] == 0) {
                        ilo_hwdev[devnum] = 1;
                        break;
                }
        }

        if (devnum == MAX_ILO_DEV) {
                dev_err(&pdev->dev, "Error finding free device\n");
                return -ENODEV;
        }

        /* track global allocations for this device */
        error = -ENOMEM;
        ilo_hw = kzalloc(sizeof(*ilo_hw), GFP_KERNEL);
        if (!ilo_hw)
                goto out;

        ilo_hw->ilo_dev = pdev;
        spin_lock_init(&ilo_hw->alloc_lock);
        spin_lock_init(&ilo_hw->fifo_lock);
        spin_lock_init(&ilo_hw->open_lock);

        error = pci_enable_device(pdev);
        if (error)
                goto free;

        pci_set_master(pdev);

        error = pci_request_regions(pdev, ILO_NAME);
        if (error)
                goto disable;

        error = ilo_map_device(pdev, ilo_hw);
        if (error)
                goto free_regions;

        pci_set_drvdata(pdev, ilo_hw);
        clear_device(ilo_hw);

        error = request_irq(pdev->irq, ilo_isr, IRQF_SHARED, "hpilo", ilo_hw);
        if (error)
                goto unmap;

        ilo_enable_interrupts(ilo_hw);

        cdev_init(&ilo_hw->cdev, &ilo_fops);
        ilo_hw->cdev.owner = THIS_MODULE;
        start = devnum * max_ccb;
        error = cdev_add(&ilo_hw->cdev, MKDEV(ilo_major, start), max_ccb);
        if (error) {
                dev_err(&pdev->dev, "Could not add cdev\n");
                goto remove_isr;
        }

        for (minor = 0 ; minor < max_ccb; minor++) {
                struct device *dev;
                dev = device_create(ilo_class, &pdev->dev,
                                    MKDEV(ilo_major, minor), NULL,
                                    "hpilo!d%dccb%d", devnum, minor);
                if (IS_ERR(dev))
                        dev_err(&pdev->dev, "Could not create files\n");
        }

        return 0;
remove_isr:
        ilo_disable_interrupts(ilo_hw);
        free_irq(pdev->irq, ilo_hw);
unmap:
        ilo_unmap_device(pdev, ilo_hw);
free_regions:
        pci_release_regions(pdev);
disable:
/*      pci_disable_device(pdev);  see comment in ilo_remove */
free:
        kfree(ilo_hw);
out:
        ilo_hwdev[devnum] = 0;
        return error;
}

static struct pci_device_id ilo_devices[] = {
        { PCI_DEVICE(PCI_VENDOR_ID_COMPAQ, 0xB204) },
        { PCI_DEVICE(PCI_VENDOR_ID_HP, 0x3307) },
        { }
};
MODULE_DEVICE_TABLE(pci, ilo_devices);

static struct pci_driver ilo_driver = {
        .name     = ILO_NAME,
        .id_table = ilo_devices,
        .probe    = ilo_probe,
        .remove   = ilo_remove,
};

static int __init ilo_init(void)
{
        int error;
        dev_t dev;

        ilo_class = class_create(THIS_MODULE, "iLO");
        if (IS_ERR(ilo_class)) {
                error = PTR_ERR(ilo_class);
                goto out;
        }

        error = alloc_chrdev_region(&dev, 0, MAX_OPEN, ILO_NAME);
        if (error)
                goto class_destroy;

        ilo_major = MAJOR(dev);

        error = pci_register_driver(&ilo_driver);
        if (error)
                goto chr_remove;

        return 0;
chr_remove:
        unregister_chrdev_region(dev, MAX_OPEN);
class_destroy:
        class_destroy(ilo_class);
out:
        return error;
}

static void __exit ilo_exit(void)
{
        pci_unregister_driver(&ilo_driver);
        unregister_chrdev_region(MKDEV(ilo_major, 0), MAX_OPEN);
        class_destroy(ilo_class);
}

MODULE_VERSION("1.4.1");
MODULE_ALIAS(ILO_NAME);
MODULE_DESCRIPTION(ILO_NAME);
MODULE_AUTHOR("David Altobelli <david.altobelli@hp.com>");
MODULE_LICENSE("GPL v2");

module_param(max_ccb, uint, 0444);
MODULE_PARM_DESC(max_ccb, "Maximum number of HP iLO channels to attach (16)");

module_init(ilo_init);
module_exit(ilo_exit);