#include <linux/mman.h>

#include <rtdm/rtdm_driver.h>


#define BUFFER_SIZE     100000


struct demodrv_context {
    void *buf;
};


static void demo_vm_close(struct vm_area_struct *vma)
{
    printk("releasing %p, data = %p\n", vma, vma->vm_private_data);
}


static struct vm_operations_struct mmap_ops = {
    .close = demo_vm_close,
};


int demo_open_rt(struct rtdm_dev_context    *context,
                 rtdm_user_info_t           *user_info,
                 int                        oflags)
{
    struct demodrv_context  *my_context;
    unsigned long vaddr;


    my_context = (struct demodrv_context *)context->dev_private;

    my_context->buf = kmalloc(BUFFER_SIZE, 0);
    /* mark pages reserved so that remap_pfn_range works */
    for (vaddr = (unsigned long)my_context->buf;
         vaddr < (unsigned long)my_context->buf + BUFFER_SIZE;
         vaddr += PAGE_SIZE)
        SetPageReserved(virt_to_page(vaddr));
    *(int *)my_context->buf = 1234;

    return 0;
}


int demo_close_rt(struct rtdm_dev_context   *context,
                  rtdm_user_info_t          *user_info)
{
    struct demodrv_context  *my_context;


    my_context = (struct demodrv_context *)context->dev_private;

    printk("%d\n", *((int *)my_context->buf + 1000));

    kfree(my_context->buf);

    return 0;
}


int demo_ioctl_rt(struct rtdm_dev_context   *context,
                  rtdm_user_info_t          *user_info,
                  int                       request,
                  void                      *arg)
{
    struct demodrv_context  *my_context;
    int err;


    my_context = (struct demodrv_context *)context->dev_private;

    printk("buf = %p:%x\n", my_context->buf, *(int *)my_context->buf);

    err = rtdm_mmap_to_user(user_info, my_context->buf, BUFFER_SIZE,
                            PROT_READ|PROT_WRITE, (void **)arg, &mmap_ops,
                            0x12345678);
    printk("rtdm_mmap = %p %d\n", *(void **)arg, err);

    return 0;
}


static struct rtdm_device demo_device = {
    struct_version:     RTDM_DEVICE_STRUCT_VER,

    device_flags:       RTDM_NAMED_DEVICE,
    context_size:       sizeof(struct demodrv_context),
    device_name:        "demodev0",

    open_rt:            NULL,
    open_nrt:           demo_open_rt,

    ops: {
        close_rt:       NULL,
        close_nrt:      demo_close_rt,

        ioctl_rt:       NULL,
        ioctl_nrt:      demo_ioctl_rt,

        read_rt:        NULL,
        read_nrt:       NULL,

        write_rt:       NULL,
        write_nrt:      NULL,

        recvmsg_rt:     NULL,
        recvmsg_nrt:    NULL,

        sendmsg_rt:     NULL,
        sendmsg_nrt:    NULL,
    },

    device_class:       RTDM_CLASS_EXPERIMENTAL,
    device_sub_class:   222,
    driver_name:        "demodrv",
    peripheral_name:    "demodev",
    provider_name:      "-",
    proc_name:          demo_device.device_name,
};

int init_module(void)
{
    int ret;


    ret = rtdm_dev_register(&demo_device);
    printk("rtdm_dev_register = %d\n", ret);

    return ret;
}


void cleanup_module(void)
{
    rtdm_dev_unregister(&demo_device, 1000);
}