/**
 *
 * @file ioctl.c
 * @author Guillermo Marcus
 * @date 2009-04-05
 * @brief Contains the functions handling the different ioctl calls.
 *
 */
#include <linux/version.h>
#include <linux/string.h>
#include <linux/slab.h>
#include <linux/types.h>
#include <linux/init.h>
#include <linux/module.h>
#include <linux/pci.h>
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/fs.h>
#include <linux/cdev.h>
#include <linux/sysfs.h>
#include <asm/atomic.h>
#include <linux/pagemap.h>
#include <linux/spinlock.h>
#include <linux/list.h>
#include <linux/scatterlist.h>
#include <linux/vmalloc.h>
#include <linux/stat.h>
#include <linux/interrupt.h>
#include <linux/wait.h>
#include <linux/sched.h>
#include <linux/iommu.h>

#include "pcilib/version.h"

#include "base.h"

/** Declares a variable of the given type with the given name and copies it from userspace */
#define READ_FROM_USER(type, name) \
	type name; \
	if ((ret = copy_from_user(&name, (type*)arg, sizeof(name))) != 0) \
		return -EFAULT;

/** Writes back the given variable with the given type to userspace */
#define WRITE_TO_USER(type, name) \
	if ((ret = copy_to_user((type*)arg, &name, sizeof(name))) != 0) \
		return -EFAULT;

/**
 *
 * Sets the mmap mode for following mmap() calls.
 *
 * @param arg Not a pointer, but either PCIDRIVER_MMAP_PCI or PCIDRIVER_MMAP_KMEM
 *
 */
static int ioctl_mmap_mode(pcidriver_privdata_t *privdata, unsigned long arg)
{
    if ((arg != PCIDRIVER_MMAP_PCI) && (arg != PCIDRIVER_MMAP_KMEM) && (arg != PCIDRIVER_MMAP_AREA))
        return -EINVAL;

    /* change the mode */
    privdata->mmap_mode = arg;

    return 0;
}

/**
 *
 * Sets the mmap area (BAR) for following mmap() calls.
 *
 */
static int ioctl_mmap_area(pcidriver_privdata_t *privdata, unsigned long arg)
{
    /* validate input */
    if ((arg < PCIDRIVER_BAR0) || (arg > PCIDRIVER_BAR5))
        return -EINVAL;

    /* change the PCI area to mmap */
    privdata->mmap_area = arg;

    return 0;
}

/**
 * Reads/writes a byte/word/dword of the device's PCI config.
 */
static int ioctl_pci_config_read_write(pcidriver_privdata_t *privdata, unsigned int cmd, unsigned long arg)
{
#ifdef PCIDRIVER_DUMMY_DEVICE
    return -ENXIO;
#else /* PCIDRIVER_DUMMY_DEVICE */
    int ret;
    READ_FROM_USER(pci_cfg_cmd, pci_cmd);

    if (cmd == PCIDRIVER_IOC_PCI_CFG_RD) {
      switch (pci_cmd.size) {
        case PCIDRIVER_PCI_CFG_SZ_BYTE:
            ret = pci_read_config_byte( privdata->pdev, pci_cmd.addr, &(pci_cmd.val.byte) );
            break;
        case PCIDRIVER_PCI_CFG_SZ_WORD:
            ret = pci_read_config_word( privdata->pdev, pci_cmd.addr, &(pci_cmd.val.word) );
            break;
        case PCIDRIVER_PCI_CFG_SZ_DWORD:
            ret = pci_read_config_dword( privdata->pdev, pci_cmd.addr, &(pci_cmd.val.dword) );
            break;
        default:
            return -EINVAL;		/* Wrong size setting */
      }
    } else {
      switch (pci_cmd.size) {
        case PCIDRIVER_PCI_CFG_SZ_BYTE:
            ret = pci_write_config_byte( privdata->pdev, pci_cmd.addr, pci_cmd.val.byte );
            break;
        case PCIDRIVER_PCI_CFG_SZ_WORD:
            ret = pci_write_config_word( privdata->pdev, pci_cmd.addr, pci_cmd.val.word );
            break;
        case PCIDRIVER_PCI_CFG_SZ_DWORD:
            ret = pci_write_config_dword( privdata->pdev, pci_cmd.addr, pci_cmd.val.dword );
            break;
        default:
            return -EINVAL;		/* Wrong size setting */
            break;
      }
    }

    WRITE_TO_USER(pci_cfg_cmd, pci_cmd);

    return 0;
#endif /* PCIDRIVER_DUMMY_DEVICE */
}

/**
 * Gets the PCI information for the device.
 */
static int ioctl_pci_info(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;

#ifdef PCIDRIVER_DUMMY_DEVICE
    READ_FROM_USER(pcilib_board_info_t, pci_info);
    memset(&pci_info, 0, sizeof(pci_info));
    WRITE_TO_USER(pcilib_board_info_t, pci_info);
#else /* PCIDRIVER_DUMMY_DEVICE */
    int bar;

    READ_FROM_USER(pcilib_board_info_t, pci_info);

    pci_info.vendor_id = privdata->pdev->vendor;
    pci_info.device_id = privdata->pdev->device;
    pci_info.bus = privdata->pdev->bus->number;
    pci_info.slot = PCI_SLOT(privdata->pdev->devfn);
    pci_info.devfn = privdata->pdev->devfn;
    pci_info.func = PCI_FUNC(privdata->pdev->devfn);

    if ((ret = pci_read_config_byte(privdata->pdev, PCI_INTERRUPT_PIN, &(pci_info.interrupt_pin))) != 0)
        return ret;

    if ((ret = pci_read_config_byte(privdata->pdev, PCI_INTERRUPT_LINE, &(pci_info.interrupt_line))) != 0)
        return ret;

    for (bar = 0; bar < 6; bar++) {
        pci_info.bar_start[bar] = pci_resource_start(privdata->pdev, bar);
        pci_info.bar_length[bar] = pci_resource_len(privdata->pdev, bar);
        pci_info.bar_flags[bar] = pci_resource_flags(privdata->pdev, bar);
    }

    WRITE_TO_USER(pcilib_board_info_t, pci_info);
#endif /* PCIDRIVER_DUMMY_DEVICE */

    return 0;
}

/**
 *
 * Allocates kernel memory.
 *
 * @see pcidriver_kmem_alloc
 *
 */
static int ioctl_kmem_alloc(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int err, ret;

    READ_FROM_USER(kmem_handle_t, khandle);
    err = pcidriver_kmem_alloc(privdata, &khandle);
    WRITE_TO_USER(kmem_handle_t, khandle);

    return err;
}

/**
 *
 * Frees kernel memory.
 *
 * @see pcidriver_kmem_free
 *
 */
static int ioctl_kmem_free(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;
    READ_FROM_USER(kmem_handle_t, khandle);

    if ((ret = pcidriver_kmem_free(privdata, &khandle)) != 0)
        return ret;

    return 0;
}

/**
 *
 * Syncs kernel memory.
 *
 * @see pcidriver_kmem_sync
 *
 */
static int ioctl_kmem_sync(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;
    READ_FROM_USER(kmem_sync_t, ksync);

    if ((ret =  pcidriver_kmem_sync(privdata, &ksync)) != 0)
        return ret;

    WRITE_TO_USER(kmem_sync_t, ksync);

    return 0;
}

/*
 *
 * Maps the given scatter/gather list from memory to PCI bus addresses.
 *
 * @see pcidriver_umem_sgmap
 *
 */
static int ioctl_umem_sgmap(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;
    READ_FROM_USER(umem_handle_t, uhandle);

    if ((ret = pcidriver_umem_sgmap(privdata, &uhandle)) != 0)
        return ret;

    WRITE_TO_USER(umem_handle_t, uhandle);

    return 0;
}

/**
 *
 * Unmaps the given scatter/gather list.
 *
 * @see pcidriver_umem_sgunmap
 *
 */
static int ioctl_umem_sgunmap(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;
    pcidriver_umem_entry_t *umem_entry;
    READ_FROM_USER(umem_handle_t, uhandle);

    /* Find the associated umem_entry for this buffer,
     * return -EINVAL if the specified handle id is invalid */
    if ((umem_entry = pcidriver_umem_find_entry_id(privdata, uhandle.handle_id)) == NULL)
        return -EINVAL;

    if ((ret = pcidriver_umem_sgunmap(privdata, umem_entry)) != 0)
        return ret;

    return 0;
}

/**
 *
 * Copies the scatter/gather list from kernelspace to userspace.
 *
 * @see pcidriver_umem_sgget
 *
 */
static int ioctl_umem_sgget(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;
    READ_FROM_USER(umem_sglist_t, usglist);

    /* The umem_sglist_t has a pointer to the scatter/gather list itself which
     * needs to be copied separately. The number of elements is stored in ->nents.
     * As the list can get very big, we need to use vmalloc. */
    if ((usglist.sg = vmalloc(usglist.nents * sizeof(umem_sgentry_t))) == NULL)
        return -ENOMEM;

    /* copy array to kernel structure */
    ret = copy_from_user(usglist.sg, ((umem_sglist_t *)arg)->sg, (usglist.nents)*sizeof(umem_sgentry_t));
    if (ret) return -EFAULT;

    if ((ret = pcidriver_umem_sgget(privdata, &usglist)) != 0)
        return ret;

    /* write data to user space */
    ret = copy_to_user(((umem_sglist_t *)arg)->sg, usglist.sg, (usglist.nents)*sizeof(umem_sgentry_t));
    if (ret) return -EFAULT;

    /* free array memory */
    vfree(usglist.sg);

    /* restore sg pointer to vma address in user space before copying */
    usglist.sg = ((umem_sglist_t *)arg)->sg;

    WRITE_TO_USER(umem_sglist_t, usglist);

    return 0;
}

/**
 *
 * Syncs user memory.
 *
 * @see pcidriver_umem_sync
 *
 */
static int ioctl_umem_sync(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;
    READ_FROM_USER(umem_handle_t, uhandle);

    return pcidriver_umem_sync( privdata, &uhandle );
}

/**
 *
 * Waits for an interrupt
 *
 * @param arg Not a pointer, but the irq source to wait for (unsigned int)
 *
 */
static int ioctl_wait_interrupt(pcidriver_privdata_t *privdata, unsigned long arg)
{
#ifdef ENABLE_IRQ
    int ret;
    unsigned long timeout;
    unsigned int irq_source;
    unsigned long temp = 0;

    READ_FROM_USER(interrupt_wait_t, irq_handle);

    irq_source = irq_handle.source;

    if (irq_source >= PCIDRIVER_INT_MAXSOURCES)
        return -EFAULT;						/* User tried to overrun the IRQ_SOURCES array */

    timeout = jiffies + (irq_handle.timeout * HZ / 1000000);

    /* Thanks to Joern for the correction and tips! */
    /* done this way to avoid wrong behaviour (endless loop) of the compiler in AMD platforms */
    do {
        /* We wait here with an interruptible timeout. This will be interrupted
                 * by int.c:check_acknowledge_channel() as soon as in interrupt for
                 * the specified source arrives. */
        wait_event_interruptible_timeout( (privdata->irq_queues[irq_source]), (atomic_read(&(privdata->irq_outstanding[irq_source])) > 0), (10*HZ/1000) );

        if (atomic_add_negative( -1, &(privdata->irq_outstanding[irq_source])) )
            atomic_inc( &(privdata->irq_outstanding[irq_source]) );
        else
            temp = 1;
    } while ((!temp)&&(jiffies < timeout));

    if ((temp)&&(irq_handle.count)) {
        while (!atomic_add_negative( -1, &(privdata->irq_outstanding[irq_source]))) temp++;
        atomic_inc( &(privdata->irq_outstanding[irq_source]) );
    }

    irq_handle.count = temp;

    WRITE_TO_USER(interrupt_wait_t, irq_handle);

    return 0;
#else
    mod_info("Asked to wait for interrupt but interrupts are not enabled in the driver\n");
    return -EFAULT;
#endif
}

/**
 *
 * Clears the interrupt wait queue.
 *
 * @param arg Not a pointer, but the irq source (unsigned int)
 * @returns -EFAULT if the user specified an irq source out of range
 *
 */
static int ioctl_clear_ioq(pcidriver_privdata_t *privdata, unsigned long arg)
{
#ifdef ENABLE_IRQ
    unsigned int irq_source;

    if (arg >= PCIDRIVER_INT_MAXSOURCES)
        return -EFAULT;

    irq_source = arg;
    atomic_set(&(privdata->irq_outstanding[irq_source]), 0);

    return 0;
#else
    mod_info("Asked to wait for interrupt but interrupts are not enabled in the driver\n");
    return -EFAULT;
#endif
}


/**
 *
 * Gets the device and API versions.
 *
 * @see pcilib_driver_version_t
 *
 */
static int ioctl_version(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;
    pcilib_driver_version_t info;

    info = (pcilib_driver_version_t) {
        .version = PCILIB_VERSION,
         .interface = PCIDRIVER_INTERFACE_VERSION,
          .ioctls = PCIDRIVER_IOC_MAX + 1
    };

    WRITE_TO_USER(pcilib_driver_version_t, info);

    return 0;
}

/**
 *
 * Gets current device and driver configuration
 *
 * @see pcilib_device_state_t
 *
 */
static int ioctl_device_state(pcidriver_privdata_t *privdata, unsigned long arg)
{
    int ret;
    pcilib_device_state_t info;

#ifdef PCIDRIVER_DUMMY_DEVICE
    memset(&info, 0, sizeof(info));
#else /* PCIDRIVER_DUMMY_DEVICE */
    info = (pcilib_device_state_t) {
        .iommu = iommu_present(privdata->pdev->dev.bus),
         .mps = pcidriver_pcie_get_mps(privdata->pdev),
          .readrq = pcie_get_readrq(privdata->pdev),
           .dma_mask = privdata->pdev->dma_mask
    };
#endif /* PCIDRIVER_DUMMY_DEVICE */


    WRITE_TO_USER(pcilib_device_state_t, info);

    return 0;
}


/**
 *
 * Sets DMA mask for the following DMA mappings.
 *
 * @param arg Not a pointer, but a number of bits
 *
 */
static int ioctl_set_dma_mask(pcidriver_privdata_t *privdata, unsigned long arg)
{
#ifndef PCIDRIVER_DUMMY_DEVICE
    int err;

    if ((arg < 24) || (arg > 64))
        return -EINVAL;

    err = pci_set_dma_mask(privdata->pdev, DMA_BIT_MASK(arg));
    if (err < 0) {
        printk(KERN_ERR "pci_set_dma_mask(%lu) failed\n", arg);
        return err;
    }
#endif /* ! PCIDRIVER_DUMMY_DEVICE */

    return 0;
}

/**
 *
 * Sets Max Payload Size.
 *
 * @param arg Not a pointer, but payload size in bits
 *
 */
static int ioctl_set_mps(pcidriver_privdata_t *privdata, unsigned long arg)
{
#ifndef PCIDRIVER_DUMMY_DEVICE
    int err;

    if ((arg != 128) && (arg != 256) && (arg != 512))
        return -EINVAL;

    err = pcidriver_pcie_set_mps(privdata->pdev, arg);
    if (err < 0) {
        printk(KERN_ERR "pcie_set_mps(%lu) failed\n", arg);
        return err;
    }
#endif /* ! PCIDRIVER_DUMMY_DEVICE */

    return 0;
}


/**
 *
 * This function handles all ioctl file operations.
 * Generally, the data of the ioctl is copied from userspace to kernelspace, a separate
 * function is called to handle the ioctl itself, then the data is copied back to userspace.
 *
 * @returns -EFAULT when an invalid memory pointer is passed
 *
 */
long pcidriver_ioctl(struct file *filp, unsigned int cmd, unsigned long arg)
{
    pcidriver_privdata_t *privdata = filp->private_data;

    /* Select the appropiate command */
    switch (cmd) {
    case PCIDRIVER_IOC_MMAP_MODE:
        return ioctl_mmap_mode(privdata, arg);

    case PCIDRIVER_IOC_MMAP_AREA:
        return ioctl_mmap_area(privdata, arg);

    case PCIDRIVER_IOC_PCI_CFG_RD:
    case PCIDRIVER_IOC_PCI_CFG_WR:
        return ioctl_pci_config_read_write(privdata, cmd, arg);

    case PCIDRIVER_IOC_PCI_INFO:
        return ioctl_pci_info(privdata, arg);

    case PCIDRIVER_IOC_KMEM_ALLOC:
        return ioctl_kmem_alloc(privdata, arg);

    case PCIDRIVER_IOC_KMEM_FREE:
        return ioctl_kmem_free(privdata, arg);

    case PCIDRIVER_IOC_KMEM_SYNC:
        return ioctl_kmem_sync(privdata, arg);

    case PCIDRIVER_IOC_UMEM_SGMAP:
        return ioctl_umem_sgmap(privdata, arg);

    case PCIDRIVER_IOC_UMEM_SGUNMAP:
        return ioctl_umem_sgunmap(privdata, arg);

    case PCIDRIVER_IOC_UMEM_SGGET:
        return ioctl_umem_sgget(privdata, arg);

    case PCIDRIVER_IOC_UMEM_SYNC:
        return ioctl_umem_sync(privdata, arg);

    case PCIDRIVER_IOC_WAITI:
        return ioctl_wait_interrupt(privdata, arg);

    case PCIDRIVER_IOC_CLEAR_IOQ:
        return ioctl_clear_ioq(privdata, arg);

    case PCIDRIVER_IOC_VERSION:
        return ioctl_version(privdata, arg);

    case PCIDRIVER_IOC_DEVICE_STATE:
        return ioctl_device_state(privdata, arg);

    case PCIDRIVER_IOC_DMA_MASK:
        return ioctl_set_dma_mask(privdata, arg);

    case PCIDRIVER_IOC_MPS:
        return ioctl_set_mps(privdata, arg);

    default:
        return -EINVAL;
    }
}