/*
 * Streamzap Remote Control driver
 *
 * Copyright (c) 2005 Christoph Bartelmus <lirc@bartelmus.de>
 * Copyright (c) 2010 Jarod Wilson <jarod@wilsonet.com>
 *
 * This driver was based on the work of Greg Wickham and Adrian
 * Dewhurst. It was substantially rewritten to support correct signal
 * gaps and now maintains a delay buffer, which is used to present
 * consistent timing behaviour to user space applications. Without the
 * delay buffer an ugly hack would be required in lircd, which can
 * cause sluggish signal decoding in certain situations.
 *
 * Ported to in-kernel ir-core interface by Jarod Wilson
 *
 * This driver is based on the USB skeleton driver packaged with the
 * kernel; copyright (C) 2001-2003 Greg Kroah-Hartman (greg@kroah.com)
 *
 *  This program is free software; you can redistribute it and/or modify
 *  it under the terms of the GNU General Public License as published by
 *  the Free Software Foundation; either version 2 of the License, or
 *  (at your option) any later version.
 *
 *  This program is distributed in the hope that it will be useful,
 *  but WITHOUT ANY WARRANTY; without even the implied warranty of
 *  MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
 *  GNU General Public License for more details.
 */

#include <linux/device.h>
#include <linux/module.h>
#include <linux/slab.h>
#include <linux/ktime.h>
#include <linux/usb.h>
#include <linux/usb/input.h>
#include <media/rc-core.h>

#define DRIVER_VERSION  "1.61"
#define DRIVER_NAME     "streamzap"
#define DRIVER_DESC     "Streamzap Remote Control driver"

#define USB_STREAMZAP_VENDOR_ID         0x0e9c
#define USB_STREAMZAP_PRODUCT_ID        0x0000

/* table of devices that work with this driver */
static const struct usb_device_id streamzap_table[] = {
        /* Streamzap Remote Control */
        { USB_DEVICE(USB_STREAMZAP_VENDOR_ID, USB_STREAMZAP_PRODUCT_ID) },
        /* Terminating entry */
        { }
};

MODULE_DEVICE_TABLE(usb, streamzap_table);

#define SZ_PULSE_MASK 0xf0
#define SZ_SPACE_MASK 0x0f
#define SZ_TIMEOUT    0xff
#define SZ_RESOLUTION 256

/* number of samples buffered */
#define SZ_BUF_LEN 128

enum StreamzapDecoderState {
        PulseSpace,
        FullPulse,
        FullSpace,
        IgnorePulse
};

/* structure to hold our device specific stuff */
struct streamzap_ir {
        /* ir-core */
        struct rc_dev *rdev;

        /* core device info */
        struct device *dev;

        /* usb */
        struct usb_device       *usbdev;
        struct usb_interface    *interface;
        struct usb_endpoint_descriptor *endpoint;
        struct urb              *urb_in;

        /* buffer & dma */
        unsigned char           *buf_in;
        dma_addr_t              dma_in;
        unsigned int            buf_in_len;

        /* track what state we're in */
        enum StreamzapDecoderState decoder_state;
        /* tracks whether we are currently receiving some signal */
        bool                    idle;
        /* sum of signal lengths received since signal start */
        unsigned long           sum;
        /* start time of signal; necessary for gap tracking */
        ktime_t                 signal_last;
        ktime_t                 signal_start;
        bool                    timeout_enabled;

        char                    name[128];
        char                    phys[64];
};


/* local function prototypes */
static int streamzap_probe(struct usb_interface *interface,
                           const struct usb_device_id *id);
static void streamzap_disconnect(struct usb_interface *interface);
static void streamzap_callback(struct urb *urb);
static int streamzap_suspend(struct usb_interface *intf, pm_message_t message);
static int streamzap_resume(struct usb_interface *intf);

/* usb specific object needed to register this driver with the usb subsystem */
static struct usb_driver streamzap_driver = {
        .name =         DRIVER_NAME,
        .probe =        streamzap_probe,
        .disconnect =   streamzap_disconnect,
        .suspend =      streamzap_suspend,
        .resume =       streamzap_resume,
        .id_table =     streamzap_table,
};

static void sz_push(struct streamzap_ir *sz, struct ir_raw_event rawir)
{
        dev_dbg(sz->dev, "Storing %s with duration %u us\n",
                (rawir.pulse ? "pulse" : "space"), rawir.duration);
        ir_raw_event_store_with_filter(sz->rdev, &rawir);
}

static void sz_push_full_pulse(struct streamzap_ir *sz,
                               unsigned char value)
{
        DEFINE_IR_RAW_EVENT(rawir);

        if (sz->idle) {
                int delta;

                sz->signal_last = sz->signal_start;
                sz->signal_start = ktime_get_real();

                delta = ktime_us_delta(sz->signal_start, sz->signal_last);
                rawir.pulse = false;
                if (delta > (15 * USEC_PER_SEC)) {
                        /* really long time */
                        rawir.duration = IR_MAX_DURATION;
                } else {
                        rawir.duration = delta;
                        rawir.duration -= sz->sum;
                        rawir.duration = US_TO_NS(rawir.duration);
                        rawir.duration = (rawir.duration > IR_MAX_DURATION) ?
                                         IR_MAX_DURATION : rawir.duration;
                }
                sz_push(sz, rawir);

                sz->idle = false;
                sz->sum = 0;
        }

        rawir.pulse = true;
        rawir.duration = ((int) value) * SZ_RESOLUTION;
        rawir.duration += SZ_RESOLUTION / 2;
        sz->sum += rawir.duration;
        rawir.duration = US_TO_NS(rawir.duration);
        rawir.duration = (rawir.duration > IR_MAX_DURATION) ?
                         IR_MAX_DURATION : rawir.duration;
        sz_push(sz, rawir);
}

static void sz_push_half_pulse(struct streamzap_ir *sz,
                               unsigned char value)
{
        sz_push_full_pulse(sz, (value & SZ_PULSE_MASK) >> 4);
}

static void sz_push_full_space(struct streamzap_ir *sz,
                               unsigned char value)
{
        DEFINE_IR_RAW_EVENT(rawir);

        rawir.pulse = false;
        rawir.duration = ((int) value) * SZ_RESOLUTION;
        rawir.duration += SZ_RESOLUTION / 2;
        sz->sum += rawir.duration;
        rawir.duration = US_TO_NS(rawir.duration);
        sz_push(sz, rawir);
}

static void sz_push_half_space(struct streamzap_ir *sz,
                               unsigned long value)
{
        sz_push_full_space(sz, value & SZ_SPACE_MASK);
}

/*
 * streamzap_callback - usb IRQ handler callback
 *
 * This procedure is invoked on reception of data from
 * the usb remote.
 */
static void streamzap_callback(struct urb *urb)
{
        struct streamzap_ir *sz;
        unsigned int i;
        int len;

        if (!urb)
                return;

        sz = urb->context;
        len = urb->actual_length;

        switch (urb->status) {
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /*
                 * this urb is terminated, clean up.
                 * sz might already be invalid at this point
                 */
                dev_err(sz->dev, "urb terminated, status: %d\n", urb->status);
                return;
        default:
                break;
        }

        dev_dbg(sz->dev, "%s: received urb, len %d\n", __func__, len);
        for (i = 0; i < len; i++) {
                dev_dbg(sz->dev, "sz->buf_in[%d]: %x\n",
                        i, (unsigned char)sz->buf_in[i]);
                switch (sz->decoder_state) {
                case PulseSpace:
                        if ((sz->buf_in[i] & SZ_PULSE_MASK) ==
                                SZ_PULSE_MASK) {
                                sz->decoder_state = FullPulse;
                                continue;
                        } else if ((sz->buf_in[i] & SZ_SPACE_MASK)
                                        == SZ_SPACE_MASK) {
                                sz_push_half_pulse(sz, sz->buf_in[i]);
                                sz->decoder_state = FullSpace;
                                continue;
                        } else {
                                sz_push_half_pulse(sz, sz->buf_in[i]);
                                sz_push_half_space(sz, sz->buf_in[i]);
                        }
                        break;
                case FullPulse:
                        sz_push_full_pulse(sz, sz->buf_in[i]);
                        sz->decoder_state = IgnorePulse;
                        break;
                case FullSpace:
                        if (sz->buf_in[i] == SZ_TIMEOUT) {
                                DEFINE_IR_RAW_EVENT(rawir);

                                rawir.pulse = false;
                                rawir.duration = sz->rdev->timeout;
                                sz->idle = true;
                                if (sz->timeout_enabled)
                                        sz_push(sz, rawir);
                                ir_raw_event_handle(sz->rdev);
                                ir_raw_event_reset(sz->rdev);
                        } else {
                                sz_push_full_space(sz, sz->buf_in[i]);
                        }
                        sz->decoder_state = PulseSpace;
                        break;
                case IgnorePulse:
                        if ((sz->buf_in[i] & SZ_SPACE_MASK) ==
                                SZ_SPACE_MASK) {
                                sz->decoder_state = FullSpace;
                                continue;
                        }
                        sz_push_half_space(sz, sz->buf_in[i]);
                        sz->decoder_state = PulseSpace;
                        break;
                }
        }

        ir_raw_event_handle(sz->rdev);
        usb_submit_urb(urb, GFP_ATOMIC);

        return;
}

static struct rc_dev *streamzap_init_rc_dev(struct streamzap_ir *sz)
{
        struct rc_dev *rdev;
        struct device *dev = sz->dev;
        int ret;

        rdev = rc_allocate_device(RC_DRIVER_IR_RAW);
        if (!rdev) {
                dev_err(dev, "remote dev allocation failed\n");
                goto out;
        }

        snprintf(sz->name, sizeof(sz->name), "Streamzap PC Remote Infrared Receiver (%04x:%04x)",
                 le16_to_cpu(sz->usbdev->descriptor.idVendor),
                 le16_to_cpu(sz->usbdev->descriptor.idProduct));
        usb_make_path(sz->usbdev, sz->phys, sizeof(sz->phys));
        strlcat(sz->phys, "/input0", sizeof(sz->phys));

        rdev->device_name = sz->name;
        rdev->input_phys = sz->phys;
        usb_to_input_id(sz->usbdev, &rdev->input_id);
        rdev->dev.parent = dev;
        rdev->priv = sz;
        rdev->allowed_protocols = RC_PROTO_BIT_ALL_IR_DECODER;
        rdev->driver_name = DRIVER_NAME;
        rdev->map_name = RC_MAP_STREAMZAP;

        ret = rc_register_device(rdev);
        if (ret < 0) {
                dev_err(dev, "remote input device register failed\n");
                goto out;
        }

        return rdev;

out:
        rc_free_device(rdev);
        return NULL;
}

/*
 *      streamzap_probe
 *
 *      Called by usb-core to associated with a candidate device
 *      On any failure the return value is the ERROR
 *      On success return 0
 */
static int streamzap_probe(struct usb_interface *intf,
                           const struct usb_device_id *id)
{
        struct usb_device *usbdev = interface_to_usbdev(intf);
        struct usb_host_interface *iface_host;
        struct streamzap_ir *sz = NULL;
        char buf[63], name[128] = "";
        int retval = -ENOMEM;
        int pipe, maxp;

        /* Allocate space for device driver specific data */
        sz = kzalloc(sizeof(struct streamzap_ir), GFP_KERNEL);
        if (!sz)
                return -ENOMEM;

        sz->usbdev = usbdev;
        sz->interface = intf;

        /* Check to ensure endpoint information matches requirements */
        iface_host = intf->cur_altsetting;

        if (iface_host->desc.bNumEndpoints != 1) {
                dev_err(&intf->dev, "%s: Unexpected desc.bNumEndpoints (%d)\n",
                        __func__, iface_host->desc.bNumEndpoints);
                retval = -ENODEV;
                goto free_sz;
        }

        sz->endpoint = &(iface_host->endpoint[0].desc);
        if (!usb_endpoint_dir_in(sz->endpoint)) {
                dev_err(&intf->dev, "%s: endpoint doesn't match input device 02%02x\n",
                        __func__, sz->endpoint->bEndpointAddress);
                retval = -ENODEV;
                goto free_sz;
        }

        if (!usb_endpoint_xfer_int(sz->endpoint)) {
                dev_err(&intf->dev, "%s: endpoint attributes don't match xfer 02%02x\n",
                        __func__, sz->endpoint->bmAttributes);
                retval = -ENODEV;
                goto free_sz;
        }

        pipe = usb_rcvintpipe(usbdev, sz->endpoint->bEndpointAddress);
        maxp = usb_maxpacket(usbdev, pipe, usb_pipeout(pipe));

        if (maxp == 0) {
                dev_err(&intf->dev, "%s: endpoint Max Packet Size is 0!?!\n",
                        __func__);
                retval = -ENODEV;
                goto free_sz;
        }

        /* Allocate the USB buffer and IRQ URB */
        sz->buf_in = usb_alloc_coherent(usbdev, maxp, GFP_ATOMIC, &sz->dma_in);
        if (!sz->buf_in)
                goto free_sz;

        sz->urb_in = usb_alloc_urb(0, GFP_KERNEL);
        if (!sz->urb_in)
                goto free_buf_in;

        sz->dev = &intf->dev;
        sz->buf_in_len = maxp;

        if (usbdev->descriptor.iManufacturer
            && usb_string(usbdev, usbdev->descriptor.iManufacturer,
                          buf, sizeof(buf)) > 0)
                strlcpy(name, buf, sizeof(name));

        if (usbdev->descriptor.iProduct
            && usb_string(usbdev, usbdev->descriptor.iProduct,
                          buf, sizeof(buf)) > 0)
                snprintf(name + strlen(name), sizeof(name) - strlen(name),
                         " %s", buf);

        sz->rdev = streamzap_init_rc_dev(sz);
        if (!sz->rdev)
                goto rc_dev_fail;

        sz->idle = true;
        sz->decoder_state = PulseSpace;
        /* FIXME: don't yet have a way to set this */
        sz->timeout_enabled = true;
        sz->rdev->timeout = ((US_TO_NS(SZ_TIMEOUT * SZ_RESOLUTION) &
                                IR_MAX_DURATION) | 0x03000000);
        #if 0
        /* not yet supported, depends on patches from maxim */
        /* see also: LIRC_GET_REC_RESOLUTION and LIRC_SET_REC_TIMEOUT */
        sz->min_timeout = US_TO_NS(SZ_TIMEOUT * SZ_RESOLUTION);
        sz->max_timeout = US_TO_NS(SZ_TIMEOUT * SZ_RESOLUTION);
        #endif

        sz->signal_start = ktime_get_real();

        /* Complete final initialisations */
        usb_fill_int_urb(sz->urb_in, usbdev, pipe, sz->buf_in,
                         maxp, (usb_complete_t)streamzap_callback,
                         sz, sz->endpoint->bInterval);
        sz->urb_in->transfer_dma = sz->dma_in;
        sz->urb_in->transfer_flags |= URB_NO_TRANSFER_DMA_MAP;

        usb_set_intfdata(intf, sz);

        if (usb_submit_urb(sz->urb_in, GFP_ATOMIC))
                dev_err(sz->dev, "urb submit failed\n");

        dev_info(sz->dev, "Registered %s on usb%d:%d\n", name,
                 usbdev->bus->busnum, usbdev->devnum);

        return 0;

rc_dev_fail:
        usb_free_urb(sz->urb_in);
free_buf_in:
        usb_free_coherent(usbdev, maxp, sz->buf_in, sz->dma_in);
free_sz:
        kfree(sz);

        return retval;
}

/*
 * streamzap_disconnect
 *
 * Called by the usb core when the device is removed from the system.
 *
 * This routine guarantees that the driver will not submit any more urbs
 * by clearing dev->usbdev.  It is also supposed to terminate any currently
 * active urbs.  Unfortunately, usb_bulk_msg(), used in streamzap_read(),
 * does not provide any way to do this.
 */
static void streamzap_disconnect(struct usb_interface *interface)
{
        struct streamzap_ir *sz = usb_get_intfdata(interface);
        struct usb_device *usbdev = interface_to_usbdev(interface);

        usb_set_intfdata(interface, NULL);

        if (!sz)
                return;

        sz->usbdev = NULL;
        rc_unregister_device(sz->rdev);
        usb_kill_urb(sz->urb_in);
        usb_free_urb(sz->urb_in);
        usb_free_coherent(usbdev, sz->buf_in_len, sz->buf_in, sz->dma_in);

        kfree(sz);
}

static int streamzap_suspend(struct usb_interface *intf, pm_message_t message)
{
        struct streamzap_ir *sz = usb_get_intfdata(intf);

        usb_kill_urb(sz->urb_in);

        return 0;
}

static int streamzap_resume(struct usb_interface *intf)
{
        struct streamzap_ir *sz = usb_get_intfdata(intf);

        if (usb_submit_urb(sz->urb_in, GFP_ATOMIC)) {
                dev_err(sz->dev, "Error submitting urb\n");
                return -EIO;
        }

        return 0;
}

module_usb_driver(streamzap_driver);

MODULE_AUTHOR("Jarod Wilson <jarod@wilsonet.com>");
MODULE_DESCRIPTION(DRIVER_DESC);
MODULE_LICENSE("GPL");