/*
 * Driver for ST5481 USB ISDN modem
 *
 * Author       Frode Isaksen
 * Copyright    2001 by Frode Isaksen      <fisaksen@bewan.com>
 *              2001 by Kai Germaschewski  <kai.germaschewski@gmx.de>
 *
 * This software may be used and distributed according to the terms
 * of the GNU General Public License, incorporated herein by reference.
 *
 */

#include <linux/init.h>
#include <linux/usb.h>
#include <linux/slab.h>
#include "st5481.h"

static int st5481_isoc_flatten(struct urb *urb);

/* ======================================================================
 * control pipe
 */

/*
 * Send the next endpoint 0 request stored in the FIFO.
 * Called either by the completion or by usb_ctrl_msg.
 */
static void usb_next_ctrl_msg(struct urb *urb,
                              struct st5481_adapter *adapter)
{
        struct st5481_ctrl *ctrl = &adapter->ctrl;
        int r_index;

        if (test_and_set_bit(0, &ctrl->busy)) {
                return;
        }

        if ((r_index = fifo_remove(&ctrl->msg_fifo.f)) < 0) {
                test_and_clear_bit(0, &ctrl->busy);
                return;
        }
        urb->setup_packet =
                (unsigned char *)&ctrl->msg_fifo.data[r_index];

        DBG(1, "request=0x%02x,value=0x%04x,index=%x",
            ((struct ctrl_msg *)urb->setup_packet)->dr.bRequest,
            ((struct ctrl_msg *)urb->setup_packet)->dr.wValue,
            ((struct ctrl_msg *)urb->setup_packet)->dr.wIndex);

        // Prepare the URB
        urb->dev = adapter->usb_dev;

        SUBMIT_URB(urb, GFP_ATOMIC);
}

/*
 * Asynchronous endpoint 0 request (async version of usb_control_msg).
 * The request will be queued up in a FIFO if the endpoint is busy.
 */
static void usb_ctrl_msg(struct st5481_adapter *adapter,
                         u8 request, u8 requesttype, u16 value, u16 index,
                         ctrl_complete_t complete, void *context)
{
        struct st5481_ctrl *ctrl = &adapter->ctrl;
        int w_index;
        struct ctrl_msg *ctrl_msg;

        if ((w_index = fifo_add(&ctrl->msg_fifo.f)) < 0) {
                WARNING("control msg FIFO full");
                return;
        }
        ctrl_msg = &ctrl->msg_fifo.data[w_index];

        ctrl_msg->dr.bRequestType = requesttype;
        ctrl_msg->dr.bRequest = request;
        ctrl_msg->dr.wValue = cpu_to_le16p(&value);
        ctrl_msg->dr.wIndex = cpu_to_le16p(&index);
        ctrl_msg->dr.wLength = 0;
        ctrl_msg->complete = complete;
        ctrl_msg->context = context;

        usb_next_ctrl_msg(ctrl->urb, adapter);
}

/*
 * Asynchronous endpoint 0 device request.
 */
void st5481_usb_device_ctrl_msg(struct st5481_adapter *adapter,
                                u8 request, u16 value,
                                ctrl_complete_t complete, void *context)
{
        usb_ctrl_msg(adapter, request,
                     USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                     value, 0, complete, context);
}

/*
 * Asynchronous pipe reset (async version of usb_clear_halt).
 */
void st5481_usb_pipe_reset(struct st5481_adapter *adapter,
                           u_char pipe,
                           ctrl_complete_t complete, void *context)
{
        DBG(1, "pipe=%02x", pipe);

        usb_ctrl_msg(adapter,
                     USB_REQ_CLEAR_FEATURE, USB_DIR_OUT | USB_RECIP_ENDPOINT,
                     0, pipe, complete, context);
}


/*
  Physical level functions
*/

void st5481_ph_command(struct st5481_adapter *adapter, unsigned int command)
{
        DBG(8, "command=%s", ST5481_CMD_string(command));

        st5481_usb_device_ctrl_msg(adapter, TXCI, command, NULL, NULL);
}

/*
 * The request on endpoint 0 has completed.
 * Call the user provided completion routine and try
 * to send the next request.
 */
static void usb_ctrl_complete(struct urb *urb)
{
        struct st5481_adapter *adapter = urb->context;
        struct st5481_ctrl *ctrl = &adapter->ctrl;
        struct ctrl_msg *ctrl_msg;

        if (unlikely(urb->status < 0)) {
                switch (urb->status) {
                case -ENOENT:
                case -ESHUTDOWN:
                case -ECONNRESET:
                        DBG(1, "urb killed status %d", urb->status);
                        return; // Give up
                default:
                        WARNING("urb status %d", urb->status);
                        break;
                }
        }

        ctrl_msg = (struct ctrl_msg *)urb->setup_packet;

        if (ctrl_msg->dr.bRequest == USB_REQ_CLEAR_FEATURE) {
                /* Special case handling for pipe reset */
                le16_to_cpus(&ctrl_msg->dr.wIndex);
                usb_reset_endpoint(adapter->usb_dev, ctrl_msg->dr.wIndex);
        }

        if (ctrl_msg->complete)
                ctrl_msg->complete(ctrl_msg->context);

        clear_bit(0, &ctrl->busy);

        // Try to send next control message
        usb_next_ctrl_msg(urb, adapter);
        return;
}

/* ======================================================================
 * interrupt pipe
 */

/*
 * The interrupt endpoint will be called when any
 * of the 6 registers changes state (depending on masks).
 * Decode the register values and schedule a private event.
 * Called at interrupt.
 */
static void usb_int_complete(struct urb *urb)
{
        u8 *data = urb->transfer_buffer;
        u8 irqbyte;
        struct st5481_adapter *adapter = urb->context;
        int j;
        int status;

        switch (urb->status) {
        case 0:
                /* success */
                break;
        case -ECONNRESET:
        case -ENOENT:
        case -ESHUTDOWN:
                /* this urb is terminated, clean up */
                DBG(2, "urb shutting down with status: %d", urb->status);
                return;
        default:
                WARNING("nonzero urb status received: %d", urb->status);
                goto exit;
        }


        DBG_PACKET(2, data, INT_PKT_SIZE);

        if (urb->actual_length == 0) {
                goto exit;
        }

        irqbyte = data[MPINT];
        if (irqbyte & DEN_INT)
                FsmEvent(&adapter->d_out.fsm, EV_DOUT_DEN, NULL);

        if (irqbyte & DCOLL_INT)
                FsmEvent(&adapter->d_out.fsm, EV_DOUT_COLL, NULL);

        irqbyte = data[FFINT_D];
        if (irqbyte & OUT_UNDERRUN)
                FsmEvent(&adapter->d_out.fsm, EV_DOUT_UNDERRUN, NULL);

        if (irqbyte & OUT_DOWN)
                ;//             printk("OUT_DOWN\n");

        irqbyte = data[MPINT];
        if (irqbyte & RXCI_INT)
                FsmEvent(&adapter->l1m, data[CCIST] & 0x0f, NULL);

        for (j = 0; j < 2; j++)
                adapter->bcs[j].b_out.flow_event |= data[FFINT_B1 + j];

        urb->actual_length = 0;

exit:
        status = usb_submit_urb(urb, GFP_ATOMIC);
        if (status)
                WARNING("usb_submit_urb failed with result %d", status);
}

/* ======================================================================
 * initialization
 */

int st5481_setup_usb(struct st5481_adapter *adapter)
{
        struct usb_device *dev = adapter->usb_dev;
        struct st5481_ctrl *ctrl = &adapter->ctrl;
        struct st5481_intr *intr = &adapter->intr;
        struct usb_interface *intf;
        struct usb_host_interface *altsetting = NULL;
        struct usb_host_endpoint *endpoint;
        int status;
        struct urb *urb;
        u8 *buf;

        DBG(2, "");

        if ((status = usb_reset_configuration(dev)) < 0) {
                WARNING("reset_configuration failed,status=%d", status);
                return status;
        }

        intf = usb_ifnum_to_if(dev, 0);
        if (intf)
                altsetting = usb_altnum_to_altsetting(intf, 3);
        if (!altsetting)
                return -ENXIO;

        // Check if the config is sane
        if (altsetting->desc.bNumEndpoints != 7) {
                WARNING("expecting 7 got %d endpoints!", altsetting->desc.bNumEndpoints);
                return -EINVAL;
        }

        // The descriptor is wrong for some early samples of the ST5481 chip
        altsetting->endpoint[3].desc.wMaxPacketSize = cpu_to_le16(32);
        altsetting->endpoint[4].desc.wMaxPacketSize = cpu_to_le16(32);

        // Use alternative setting 3 on interface 0 to have 2B+D
        if ((status = usb_set_interface(dev, 0, 3)) < 0) {
                WARNING("usb_set_interface failed,status=%d", status);
                return status;
        }

        // Allocate URB for control endpoint
        urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!urb) {
                return -ENOMEM;
        }
        ctrl->urb = urb;

        // Fill the control URB
        usb_fill_control_urb(urb, dev,
                             usb_sndctrlpipe(dev, 0),
                             NULL, NULL, 0, usb_ctrl_complete, adapter);


        fifo_init(&ctrl->msg_fifo.f, ARRAY_SIZE(ctrl->msg_fifo.data));

        // Allocate URBs and buffers for interrupt endpoint
        urb = usb_alloc_urb(0, GFP_KERNEL);
        if (!urb) {
                goto err1;
        }
        intr->urb = urb;

        buf = kmalloc(INT_PKT_SIZE, GFP_KERNEL);
        if (!buf) {
                goto err2;
        }

        endpoint = &altsetting->endpoint[EP_INT-1];

        // Fill the interrupt URB
        usb_fill_int_urb(urb, dev,
                         usb_rcvintpipe(dev, endpoint->desc.bEndpointAddress),
                         buf, INT_PKT_SIZE,
                         usb_int_complete, adapter,
                         endpoint->desc.bInterval);

        return 0;
err2:
        usb_free_urb(intr->urb);
        intr->urb = NULL;
err1:
        usb_free_urb(ctrl->urb);
        ctrl->urb = NULL;

        return -ENOMEM;
}

/*
 * Release buffers and URBs for the interrupt and control
 * endpoint.
 */
void st5481_release_usb(struct st5481_adapter *adapter)
{
        struct st5481_intr *intr = &adapter->intr;
        struct st5481_ctrl *ctrl = &adapter->ctrl;

        DBG(1, "");

        // Stop and free Control and Interrupt URBs
        usb_kill_urb(ctrl->urb);
        kfree(ctrl->urb->transfer_buffer);
        usb_free_urb(ctrl->urb);
        ctrl->urb = NULL;

        usb_kill_urb(intr->urb);
        kfree(intr->urb->transfer_buffer);
        usb_free_urb(intr->urb);
        intr->urb = NULL;
}

/*
 *  Initialize the adapter.
 */
void st5481_start(struct st5481_adapter *adapter)
{
        static const u8 init_cmd_table[] = {
                SET_DEFAULT, 0,
                STT, 0,
                SDA_MIN, 0x0d,
                SDA_MAX, 0x29,
                SDELAY_VALUE, 0x14,
                GPIO_DIR, 0x01,
                GPIO_OUT, RED_LED,
//              FFCTRL_OUT_D,4,
//              FFCTRH_OUT_D,12,
                FFCTRL_OUT_B1, 6,
                FFCTRH_OUT_B1, 20,
                FFCTRL_OUT_B2, 6,
                FFCTRH_OUT_B2, 20,
                MPMSK, RXCI_INT + DEN_INT + DCOLL_INT,
                0
        };
        struct st5481_intr *intr = &adapter->intr;
        int i = 0;
        u8 request, value;

        DBG(8, "");

        adapter->leds = RED_LED;

        // Start receiving on the interrupt endpoint
        SUBMIT_URB(intr->urb, GFP_KERNEL);

        while ((request = init_cmd_table[i++])) {
                value = init_cmd_table[i++];
                st5481_usb_device_ctrl_msg(adapter, request, value, NULL, NULL);
        }
        st5481_ph_command(adapter, ST5481_CMD_PUP);
}

/*
 * Reset the adapter to default values.
 */
void st5481_stop(struct st5481_adapter *adapter)
{
        DBG(8, "");

        st5481_usb_device_ctrl_msg(adapter, SET_DEFAULT, 0, NULL, NULL);
}

/* ======================================================================
 * isochronous USB  helpers
 */

static void
fill_isoc_urb(struct urb *urb, struct usb_device *dev,
              unsigned int pipe, void *buf, int num_packets,
              int packet_size, usb_complete_t complete,
              void *context)
{
        int k;

        urb->dev = dev;
        urb->pipe = pipe;
        urb->interval = 1;
        urb->transfer_buffer = buf;
        urb->number_of_packets = num_packets;
        urb->transfer_buffer_length = num_packets * packet_size;
        urb->actual_length = 0;
        urb->complete = complete;
        urb->context = context;
        urb->transfer_flags = URB_ISO_ASAP;
        for (k = 0; k < num_packets; k++) {
                urb->iso_frame_desc[k].offset = packet_size * k;
                urb->iso_frame_desc[k].length = packet_size;
                urb->iso_frame_desc[k].actual_length = 0;
        }
}

int
st5481_setup_isocpipes(struct urb *urb[2], struct usb_device *dev,
                       unsigned int pipe, int num_packets,
                       int packet_size, int buf_size,
                       usb_complete_t complete, void *context)
{
        int j, retval;
        unsigned char *buf;

        for (j = 0; j < 2; j++) {
                retval = -ENOMEM;
                urb[j] = usb_alloc_urb(num_packets, GFP_KERNEL);
                if (!urb[j])
                        goto err;

                // Allocate memory for 2000bytes/sec (16Kb/s)
                buf = kmalloc(buf_size, GFP_KERNEL);
                if (!buf)
                        goto err;

                // Fill the isochronous URB
                fill_isoc_urb(urb[j], dev, pipe, buf,
                              num_packets, packet_size, complete,
                              context);
        }
        return 0;

err:
        for (j = 0; j < 2; j++) {
                if (urb[j]) {
                        kfree(urb[j]->transfer_buffer);
                        urb[j]->transfer_buffer = NULL;
                        usb_free_urb(urb[j]);
                        urb[j] = NULL;
                }
        }
        return retval;
}

void st5481_release_isocpipes(struct urb *urb[2])
{
        int j;

        for (j = 0; j < 2; j++) {
                usb_kill_urb(urb[j]);
                kfree(urb[j]->transfer_buffer);
                usb_free_urb(urb[j]);
                urb[j] = NULL;
        }
}

/*
 * Decode frames received on the B/D channel.
 * Note that this function will be called continuously
 * with 64Kbit/s / 16Kbit/s of data and hence it will be
 * called 50 times per second with 20 ISOC descriptors.
 * Called at interrupt.
 */
static void usb_in_complete(struct urb *urb)
{
        struct st5481_in *in = urb->context;
        unsigned char *ptr;
        struct sk_buff *skb;
        int len, count, status;

        if (unlikely(urb->status < 0)) {
                switch (urb->status) {
                case -ENOENT:
                case -ESHUTDOWN:
                case -ECONNRESET:
                        DBG(1, "urb killed status %d", urb->status);
                        return; // Give up
                default:
                        WARNING("urb status %d", urb->status);
                        break;
                }
        }

        DBG_ISO_PACKET(0x80, urb);

        len = st5481_isoc_flatten(urb);
        ptr = urb->transfer_buffer;
        while (len > 0) {
                if (in->mode == L1_MODE_TRANS) {
                        memcpy(in->rcvbuf, ptr, len);
                        status = len;
                        len = 0;
                } else {
                        status = isdnhdlc_decode(&in->hdlc_state, ptr, len, &count,
                                                 in->rcvbuf, in->bufsize);
                        ptr += count;
                        len -= count;
                }

                if (status > 0) {
                        // Good frame received
                        DBG(4, "count=%d", status);
                        DBG_PACKET(0x400, in->rcvbuf, status);
                        if (!(skb = dev_alloc_skb(status))) {
                                WARNING("receive out of memory\n");
                                break;
                        }
                        memcpy(skb_put(skb, status), in->rcvbuf, status);
                        in->hisax_if->l1l2(in->hisax_if, PH_DATA | INDICATION, skb);
                } else if (status == -HDLC_CRC_ERROR) {
                        INFO("CRC error");
                } else if (status == -HDLC_FRAMING_ERROR) {
                        INFO("framing error");
                } else if (status == -HDLC_LENGTH_ERROR) {
                        INFO("length error");
                }
        }

        // Prepare URB for next transfer
        urb->dev = in->adapter->usb_dev;
        urb->actual_length = 0;

        SUBMIT_URB(urb, GFP_ATOMIC);
}

int st5481_setup_in(struct st5481_in *in)
{
        struct usb_device *dev = in->adapter->usb_dev;
        int retval;

        DBG(4, "");

        in->rcvbuf = kmalloc(in->bufsize, GFP_KERNEL);
        retval = -ENOMEM;
        if (!in->rcvbuf)
                goto err;

        retval = st5481_setup_isocpipes(in->urb, dev,
                                        usb_rcvisocpipe(dev, in->ep),
                                        in->num_packets,  in->packet_size,
                                        in->num_packets * in->packet_size,
                                        usb_in_complete, in);
        if (retval)
                goto err_free;
        return 0;

err_free:
        kfree(in->rcvbuf);
err:
        return retval;
}

void st5481_release_in(struct st5481_in *in)
{
        DBG(2, "");

        st5481_release_isocpipes(in->urb);
}

/*
 * Make the transfer_buffer contiguous by
 * copying from the iso descriptors if necessary.
 */
static int st5481_isoc_flatten(struct urb *urb)
{
        struct usb_iso_packet_descriptor *pipd, *pend;
        unsigned char *src, *dst;
        unsigned int len;

        if (urb->status < 0) {
                return urb->status;
        }
        for (pipd = &urb->iso_frame_desc[0],
                     pend = &urb->iso_frame_desc[urb->number_of_packets],
                     dst = urb->transfer_buffer;
             pipd < pend;
             pipd++) {

                if (pipd->status < 0) {
                        return (pipd->status);
                }

                len = pipd->actual_length;
                pipd->actual_length = 0;
                src = urb->transfer_buffer + pipd->offset;

                if (src != dst) {
                        // Need to copy since isoc buffers not full
                        while (len--) {
                                *dst++ = *src++;
                        }
                } else {
                        // No need to copy, just update destination buffer
                        dst += len;
                }
        }
        // Return size of flattened buffer
        return (dst - (unsigned char *)urb->transfer_buffer);
}

static void st5481_start_rcv(void *context)
{
        struct st5481_in *in = context;
        struct st5481_adapter *adapter = in->adapter;

        DBG(4, "");

        in->urb[0]->dev = adapter->usb_dev;
        SUBMIT_URB(in->urb[0], GFP_KERNEL);

        in->urb[1]->dev = adapter->usb_dev;
        SUBMIT_URB(in->urb[1], GFP_KERNEL);
}

void st5481_in_mode(struct st5481_in *in, int mode)
{
        if (in->mode == mode)
                return;

        in->mode = mode;

        usb_unlink_urb(in->urb[0]);
        usb_unlink_urb(in->urb[1]);

        if (in->mode != L1_MODE_NULL) {
                if (in->mode != L1_MODE_TRANS) {
                        u32 features = HDLC_BITREVERSE;

                        if (in->mode == L1_MODE_HDLC_56K)
                                features |= HDLC_56KBIT;
                        isdnhdlc_rcv_init(&in->hdlc_state, features);
                }
                st5481_usb_pipe_reset(in->adapter, in->ep, NULL, NULL);
                st5481_usb_device_ctrl_msg(in->adapter, in->counter,
                                           in->packet_size,
                                           NULL, NULL);
                st5481_start_rcv(in);
        } else {
                st5481_usb_device_ctrl_msg(in->adapter, in->counter,
                                           0, NULL, NULL);
        }
}