/*
 * Copyright (C) 2012 Red Hat
 *
 * based in parts on udlfb.c:
 * Copyright (C) 2009 Roberto De Ioris <roberto@unbit.it>
 * Copyright (C) 2009 Jaya Kumar <jayakumar.lkml@gmail.com>
 * Copyright (C) 2009 Bernie Thompson <bernie@plugable.com>
 *
 * This file is subject to the terms and conditions of the GNU General Public
 * License v2. See the file COPYING in the main directory of this archive for
 * more details.
 */
#include <drm/drmP.h>
#include <drm/drm_crtc_helper.h>
#include "udl_drv.h"

/* -BULK_SIZE as per usb-skeleton. Can we get full page and avoid overhead? */
#define BULK_SIZE 512

#define NR_USB_REQUEST_CHANNEL 0x12

#define MAX_TRANSFER (PAGE_SIZE*16 - BULK_SIZE)
#define WRITES_IN_FLIGHT (4)
#define MAX_VENDOR_DESCRIPTOR_SIZE 256

#define GET_URB_TIMEOUT HZ
#define FREE_URB_TIMEOUT (HZ*2)

static int udl_parse_vendor_descriptor(struct drm_device *dev,
                                       struct usb_device *usbdev)
{
        struct udl_device *udl = dev->dev_private;
        char *desc;
        char *buf;
        char *desc_end;

        u8 total_len = 0;

        buf = kzalloc(MAX_VENDOR_DESCRIPTOR_SIZE, GFP_KERNEL);
        if (!buf)
                return false;
        desc = buf;

        total_len = usb_get_descriptor(usbdev, 0x5f, /* vendor specific */
                                    0, desc, MAX_VENDOR_DESCRIPTOR_SIZE);
        if (total_len > 5) {
                DRM_INFO("vendor descriptor length:%x data:%11ph\n",
                        total_len, desc);

                if ((desc[0] != total_len) || /* descriptor length */
                    (desc[1] != 0x5f) ||   /* vendor descriptor type */
                    (desc[2] != 0x01) ||   /* version (2 bytes) */
                    (desc[3] != 0x00) ||
                    (desc[4] != total_len - 2)) /* length after type */
                        goto unrecognized;

                desc_end = desc + total_len;
                desc += 5; /* the fixed header we've already parsed */

                while (desc < desc_end) {
                        u8 length;
                        u16 key;

                        key = le16_to_cpu(*((u16 *) desc));
                        desc += sizeof(u16);
                        length = *desc;
                        desc++;

                        switch (key) {
                        case 0x0200: { /* max_area */
                                u32 max_area;
                                max_area = le32_to_cpu(*((u32 *)desc));
                                DRM_DEBUG("DL chip limited to %d pixel modes\n",
                                        max_area);
                                udl->sku_pixel_limit = max_area;
                                break;
                        }
                        default:
                                break;
                        }
                        desc += length;
                }
        }

        goto success;

unrecognized:
        /* allow udlfb to load for now even if firmware unrecognized */
        DRM_ERROR("Unrecognized vendor firmware descriptor\n");

success:
        kfree(buf);
        return true;
}

/*
 * Need to ensure a channel is selected before submitting URBs
 */
static int udl_select_std_channel(struct udl_device *udl)
{
        int ret;
        static const u8 set_def_chn[] = {0x57, 0xCD, 0xDC, 0xA7,
                                         0x1C, 0x88, 0x5E, 0x15,
                                         0x60, 0xFE, 0xC6, 0x97,
                                         0x16, 0x3D, 0x47, 0xF2};
        void *sendbuf;

        sendbuf = kmemdup(set_def_chn, sizeof(set_def_chn), GFP_KERNEL);
        if (!sendbuf)
                return -ENOMEM;

        ret = usb_control_msg(udl->udev,
                              usb_sndctrlpipe(udl->udev, 0),
                              NR_USB_REQUEST_CHANNEL,
                              (USB_DIR_OUT | USB_TYPE_VENDOR), 0, 0,
                              sendbuf, sizeof(set_def_chn),
                              USB_CTRL_SET_TIMEOUT);
        kfree(sendbuf);
        return ret < 0 ? ret : 0;
}

static void udl_release_urb_work(struct work_struct *work)
{
        struct urb_node *unode = container_of(work, struct urb_node,
                                              release_urb_work.work);

        up(&unode->dev->urbs.limit_sem);
}

void udl_urb_completion(struct urb *urb)
{
        struct urb_node *unode = urb->context;
        struct udl_device *udl = unode->dev;
        unsigned long flags;

        /* sync/async unlink faults aren't errors */
        if (urb->status) {
                if (!(urb->status == -ENOENT ||
                    urb->status == -ECONNRESET ||
                    urb->status == -ESHUTDOWN)) {
                        DRM_ERROR("%s - nonzero write bulk status received: %d\n",
                                __func__, urb->status);
                        atomic_set(&udl->lost_pixels, 1);
                }
        }

        urb->transfer_buffer_length = udl->urbs.size; /* reset to actual */

        spin_lock_irqsave(&udl->urbs.lock, flags);
        list_add_tail(&unode->entry, &udl->urbs.list);
        udl->urbs.available++;
        spin_unlock_irqrestore(&udl->urbs.lock, flags);

#if 0
        /*
         * When using fb_defio, we deadlock if up() is called
         * while another is waiting. So queue to another process.
         */
        if (fb_defio)
                schedule_delayed_work(&unode->release_urb_work, 0);
        else
#endif
                up(&udl->urbs.limit_sem);
}

static void udl_free_urb_list(struct drm_device *dev)
{
        struct udl_device *udl = dev->dev_private;
        int count = udl->urbs.count;
        struct list_head *node;
        struct urb_node *unode;
        struct urb *urb;
        int ret;
        unsigned long flags;

        DRM_DEBUG("Waiting for completes and freeing all render urbs\n");

        /* keep waiting and freeing, until we've got 'em all */
        while (count--) {

                /* Getting interrupted means a leak, but ok at shutdown*/
                ret = down_interruptible(&udl->urbs.limit_sem);
                if (ret)
                        break;

                spin_lock_irqsave(&udl->urbs.lock, flags);

                node = udl->urbs.list.next; /* have reserved one with sem */
                list_del_init(node);

                spin_unlock_irqrestore(&udl->urbs.lock, flags);

                unode = list_entry(node, struct urb_node, entry);
                urb = unode->urb;

                /* Free each separately allocated piece */
                usb_free_coherent(urb->dev, udl->urbs.size,
                                  urb->transfer_buffer, urb->transfer_dma);
                usb_free_urb(urb);
                kfree(node);
        }
        udl->urbs.count = 0;
}

static int udl_alloc_urb_list(struct drm_device *dev, int count, size_t size)
{
        struct udl_device *udl = dev->dev_private;
        int i = 0;
        struct urb *urb;
        struct urb_node *unode;
        char *buf;

        spin_lock_init(&udl->urbs.lock);

        udl->urbs.size = size;
        INIT_LIST_HEAD(&udl->urbs.list);

        while (i < count) {
                unode = kzalloc(sizeof(struct urb_node), GFP_KERNEL);
                if (!unode)
                        break;
                unode->dev = udl;

                INIT_DELAYED_WORK(&unode->release_urb_work,
                          udl_release_urb_work);

                urb = usb_alloc_urb(0, GFP_KERNEL);
                if (!urb) {
                        kfree(unode);
                        break;
                }
                unode->urb = urb;

                buf = usb_alloc_coherent(udl->udev, MAX_TRANSFER, GFP_KERNEL,
                                         &urb->transfer_dma);
                if (!buf) {
                        kfree(unode);
                        usb_free_urb(urb);
                        break;
                }

                /* urb->transfer_buffer_length set to actual before submit */
                usb_fill_bulk_urb(urb, udl->udev, usb_sndbulkpipe(udl->udev, 1),
                        buf, size, udl_urb_completion, unode);
                urb->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

                list_add_tail(&unode->entry, &udl->urbs.list);

                i++;
        }

        sema_init(&udl->urbs.limit_sem, i);
        udl->urbs.count = i;
        udl->urbs.available = i;

        DRM_DEBUG("allocated %d %d byte urbs\n", i, (int) size);

        return i;
}

struct urb *udl_get_urb(struct drm_device *dev)
{
        struct udl_device *udl = dev->dev_private;
        int ret = 0;
        struct list_head *entry;
        struct urb_node *unode;
        struct urb *urb = NULL;
        unsigned long flags;

        /* Wait for an in-flight buffer to complete and get re-queued */
        ret = down_timeout(&udl->urbs.limit_sem, GET_URB_TIMEOUT);
        if (ret) {
                atomic_set(&udl->lost_pixels, 1);
                DRM_INFO("wait for urb interrupted: %x available: %d\n",
                       ret, udl->urbs.available);
                goto error;
        }

        spin_lock_irqsave(&udl->urbs.lock, flags);

        BUG_ON(list_empty(&udl->urbs.list)); /* reserved one with limit_sem */
        entry = udl->urbs.list.next;
        list_del_init(entry);
        udl->urbs.available--;

        spin_unlock_irqrestore(&udl->urbs.lock, flags);

        unode = list_entry(entry, struct urb_node, entry);
        urb = unode->urb;

error:
        return urb;
}

int udl_submit_urb(struct drm_device *dev, struct urb *urb, size_t len)
{
        struct udl_device *udl = dev->dev_private;
        int ret;

        BUG_ON(len > udl->urbs.size);

        urb->transfer_buffer_length = len; /* set to actual payload len */
        ret = usb_submit_urb(urb, GFP_ATOMIC);
        if (ret) {
                udl_urb_completion(urb); /* because no one else will */
                atomic_set(&udl->lost_pixels, 1);
                DRM_ERROR("usb_submit_urb error %x\n", ret);
        }
        return ret;
}

int udl_driver_load(struct drm_device *dev, unsigned long flags)
{
        struct usb_device *udev = (void*)flags;
        struct udl_device *udl;
        int ret = -ENOMEM;

        DRM_DEBUG("\n");
        udl = kzalloc(sizeof(struct udl_device), GFP_KERNEL);
        if (!udl)
                return -ENOMEM;

        udl->udev = udev;
        udl->ddev = dev;
        dev->dev_private = udl;

        if (!udl_parse_vendor_descriptor(dev, udl->udev)) {
                ret = -ENODEV;
                DRM_ERROR("firmware not recognized. Assume incompatible device\n");
                goto err;
        }

        if (udl_select_std_channel(udl))
                DRM_ERROR("Selecting channel failed\n");

        if (!udl_alloc_urb_list(dev, WRITES_IN_FLIGHT, MAX_TRANSFER)) {
                DRM_ERROR("udl_alloc_urb_list failed\n");
                goto err;
        }

        DRM_DEBUG("\n");
        ret = udl_modeset_init(dev);
        if (ret)
                goto err;

        ret = udl_fbdev_init(dev);
        if (ret)
                goto err;

        ret = drm_vblank_init(dev, 1);
        if (ret)
                goto err_fb;

        drm_kms_helper_poll_init(dev);

        return 0;
err_fb:
        udl_fbdev_cleanup(dev);
err:
        if (udl->urbs.count)
                udl_free_urb_list(dev);
        kfree(udl);
        DRM_ERROR("%d\n", ret);
        return ret;
}

int udl_drop_usb(struct drm_device *dev)
{
        udl_free_urb_list(dev);
        return 0;
}

void udl_driver_unload(struct drm_device *dev)
{
        struct udl_device *udl = dev->dev_private;

        drm_kms_helper_poll_fini(dev);

        if (udl->urbs.count)
                udl_free_urb_list(dev);

        udl_fbdev_cleanup(dev);
        udl_modeset_cleanup(dev);
        kfree(udl);
}