/*
 * Linux driver for TerraTec DMX 6Fire USB
 *
 * Firmware loader
 *
 * Author:      Torsten Schenk <torsten.schenk@zoho.com>
 * Created:     Jan 01, 2011
 * Copyright:   (C) Torsten Schenk
 *
 * 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.
 */

#include <linux/firmware.h>
#include <linux/module.h>
#include <linux/bitrev.h>
#include <linux/kernel.h>

#include "firmware.h"
#include "chip.h"

MODULE_FIRMWARE("6fire/dmx6firel2.ihx");
MODULE_FIRMWARE("6fire/dmx6fireap.ihx");
MODULE_FIRMWARE("6fire/dmx6firecf.bin");

enum {
        FPGA_BUFSIZE = 512, FPGA_EP = 2
};

/*
 * wMaxPacketSize of pcm endpoints.
 * keep synced with rates_in_packet_size and rates_out_packet_size in pcm.c
 * fpp: frames per isopacket
 *
 * CAUTION: keep sizeof <= buffer[] in usb6fire_fw_init
 */
static const u8 ep_w_max_packet_size[] = {
        0xe4, 0x00, 0xe4, 0x00, /* alt 1: 228 EP2 and EP6 (7 fpp) */
        0xa4, 0x01, 0xa4, 0x01, /* alt 2: 420 EP2 and EP6 (13 fpp)*/
        0x94, 0x01, 0x5c, 0x02  /* alt 3: 404 EP2 and 604 EP6 (25 fpp) */
};

static const u8 known_fw_versions[][4] = {
        { 0x03, 0x01, 0x0b, 0x00 }
};

struct ihex_record {
        u16 address;
        u8 len;
        u8 data[256];
        char error; /* true if an error occurred parsing this record */

        u8 max_len; /* maximum record length in whole ihex */

        /* private */
        const char *txt_data;
        unsigned int txt_length;
        unsigned int txt_offset; /* current position in txt_data */
};

static u8 usb6fire_fw_ihex_hex(const u8 *data, u8 *crc)
{
        u8 val = 0;
        int hval;

        hval = hex_to_bin(data[0]);
        if (hval >= 0)
                val |= (hval << 4);

        hval = hex_to_bin(data[1]);
        if (hval >= 0)
                val |= hval;

        *crc += val;
        return val;
}

/*
 * returns true if record is available, false otherwise.
 * iff an error occurred, false will be returned and record->error will be true.
 */
static bool usb6fire_fw_ihex_next_record(struct ihex_record *record)
{
        u8 crc = 0;
        u8 type;
        int i;

        record->error = false;

        /* find begin of record (marked by a colon) */
        while (record->txt_offset < record->txt_length
                        && record->txt_data[record->txt_offset] != ':')
                record->txt_offset++;
        if (record->txt_offset == record->txt_length)
                return false;

        /* number of characters needed for len, addr and type entries */
        record->txt_offset++;
        if (record->txt_offset + 8 > record->txt_length) {
                record->error = true;
                return false;
        }

        record->len = usb6fire_fw_ihex_hex(record->txt_data +
                        record->txt_offset, &crc);
        record->txt_offset += 2;
        record->address = usb6fire_fw_ihex_hex(record->txt_data +
                        record->txt_offset, &crc) << 8;
        record->txt_offset += 2;
        record->address |= usb6fire_fw_ihex_hex(record->txt_data +
                        record->txt_offset, &crc);
        record->txt_offset += 2;
        type = usb6fire_fw_ihex_hex(record->txt_data +
                        record->txt_offset, &crc);
        record->txt_offset += 2;

        /* number of characters needed for data and crc entries */
        if (record->txt_offset + 2 * (record->len + 1) > record->txt_length) {
                record->error = true;
                return false;
        }
        for (i = 0; i < record->len; i++) {
                record->data[i] = usb6fire_fw_ihex_hex(record->txt_data
                                + record->txt_offset, &crc);
                record->txt_offset += 2;
        }
        usb6fire_fw_ihex_hex(record->txt_data + record->txt_offset, &crc);
        if (crc) {
                record->error = true;
                return false;
        }

        if (type == 1 || !record->len) /* eof */
                return false;
        else if (type == 0)
                return true;
        else {
                record->error = true;
                return false;
        }
}

static int usb6fire_fw_ihex_init(const struct firmware *fw,
                struct ihex_record *record)
{
        record->txt_data = fw->data;
        record->txt_length = fw->size;
        record->txt_offset = 0;
        record->max_len = 0;
        /* read all records, if loop ends, record->error indicates,
         * whether ihex is valid. */
        while (usb6fire_fw_ihex_next_record(record))
                record->max_len = max(record->len, record->max_len);
        if (record->error)
                return -EINVAL;
        record->txt_offset = 0;
        return 0;
}

static int usb6fire_fw_ezusb_write(struct usb_device *device,
                int type, int value, char *data, int len)
{
        int ret;

        ret = usb_control_msg(device, usb_sndctrlpipe(device, 0), type,
                        USB_DIR_OUT | USB_TYPE_VENDOR | USB_RECIP_DEVICE,
                        value, 0, data, len, HZ);
        if (ret < 0)
                return ret;
        else if (ret != len)
                return -EIO;
        return 0;
}

static int usb6fire_fw_ezusb_read(struct usb_device *device,
                int type, int value, char *data, int len)
{
        int ret = usb_control_msg(device, usb_rcvctrlpipe(device, 0), type,
                        USB_DIR_IN | USB_TYPE_VENDOR | USB_RECIP_DEVICE, value,
                        0, data, len, HZ);
        if (ret < 0)
                return ret;
        else if (ret != len)
                return -EIO;
        return 0;
}

static int usb6fire_fw_fpga_write(struct usb_device *device,
                char *data, int len)
{
        int actual_len;
        int ret;

        ret = usb_bulk_msg(device, usb_sndbulkpipe(device, FPGA_EP), data, len,
                        &actual_len, HZ);
        if (ret < 0)
                return ret;
        else if (actual_len != len)
                return -EIO;
        return 0;
}

static int usb6fire_fw_ezusb_upload(
                struct usb_interface *intf, const char *fwname,
                unsigned int postaddr, u8 *postdata, unsigned int postlen)
{
        int ret;
        u8 data;
        struct usb_device *device = interface_to_usbdev(intf);
        const struct firmware *fw = NULL;
        struct ihex_record *rec = kmalloc(sizeof(struct ihex_record),
                        GFP_KERNEL);

        if (!rec)
                return -ENOMEM;

        ret = request_firmware(&fw, fwname, &device->dev);
        if (ret < 0) {
                kfree(rec);
                snd_printk(KERN_ERR PREFIX "error requesting ezusb "
                                "firmware %s.\n", fwname);
                return ret;
        }
        ret = usb6fire_fw_ihex_init(fw, rec);
        if (ret < 0) {
                kfree(rec);
                release_firmware(fw);
                snd_printk(KERN_ERR PREFIX "error validating ezusb "
                                "firmware %s.\n", fwname);
                return ret;
        }
        /* upload firmware image */
        data = 0x01; /* stop ezusb cpu */
        ret = usb6fire_fw_ezusb_write(device, 0xa0, 0xe600, &data, 1);
        if (ret < 0) {
                kfree(rec);
                release_firmware(fw);
                snd_printk(KERN_ERR PREFIX "unable to upload ezusb "
                                "firmware %s: begin message.\n", fwname);
                return ret;
        }

        while (usb6fire_fw_ihex_next_record(rec)) { /* write firmware */
                ret = usb6fire_fw_ezusb_write(device, 0xa0, rec->address,
                                rec->data, rec->len);
                if (ret < 0) {
                        kfree(rec);
                        release_firmware(fw);
                        snd_printk(KERN_ERR PREFIX "unable to upload ezusb "
                                        "firmware %s: data urb.\n", fwname);
                        return ret;
                }
        }

        release_firmware(fw);
        kfree(rec);
        if (postdata) { /* write data after firmware has been uploaded */
                ret = usb6fire_fw_ezusb_write(device, 0xa0, postaddr,
                                postdata, postlen);
                if (ret < 0) {
                        snd_printk(KERN_ERR PREFIX "unable to upload ezusb "
                                        "firmware %s: post urb.\n", fwname);
                        return ret;
                }
        }

        data = 0x00; /* resume ezusb cpu */
        ret = usb6fire_fw_ezusb_write(device, 0xa0, 0xe600, &data, 1);
        if (ret < 0) {
                snd_printk(KERN_ERR PREFIX "unable to upload ezusb "
                                "firmware %s: end message.\n", fwname);
                return ret;
        }
        return 0;
}

static int usb6fire_fw_fpga_upload(
                struct usb_interface *intf, const char *fwname)
{
        int ret;
        int i;
        struct usb_device *device = interface_to_usbdev(intf);
        u8 *buffer = kmalloc(FPGA_BUFSIZE, GFP_KERNEL);
        const char *c;
        const char *end;
        const struct firmware *fw;

        if (!buffer)
                return -ENOMEM;

        ret = request_firmware(&fw, fwname, &device->dev);
        if (ret < 0) {
                snd_printk(KERN_ERR PREFIX "unable to get fpga firmware %s.\n",
                                fwname);
                kfree(buffer);
                return -EIO;
        }

        c = fw->data;
        end = fw->data + fw->size;

        ret = usb6fire_fw_ezusb_write(device, 8, 0, NULL, 0);
        if (ret < 0) {
                kfree(buffer);
                release_firmware(fw);
                snd_printk(KERN_ERR PREFIX "unable to upload fpga firmware: "
                                "begin urb.\n");
                return ret;
        }

        while (c != end) {
                for (i = 0; c != end && i < FPGA_BUFSIZE; i++, c++)
                        buffer[i] = byte_rev_table[(u8) *c];

                ret = usb6fire_fw_fpga_write(device, buffer, i);
                if (ret < 0) {
                        release_firmware(fw);
                        kfree(buffer);
                        snd_printk(KERN_ERR PREFIX "unable to upload fpga "
                                        "firmware: fw urb.\n");
                        return ret;
                }
        }
        release_firmware(fw);
        kfree(buffer);

        ret = usb6fire_fw_ezusb_write(device, 9, 0, NULL, 0);
        if (ret < 0) {
                snd_printk(KERN_ERR PREFIX "unable to upload fpga firmware: "
                                "end urb.\n");
                return ret;
        }
        return 0;
}

/* check, if the firmware version the devices has currently loaded
 * is known by this driver. 'version' needs to have 4 bytes version
 * info data. */
static int usb6fire_fw_check(u8 *version)
{
        int i;

        for (i = 0; i < ARRAY_SIZE(known_fw_versions); i++)
                if (!memcmp(version, known_fw_versions + i, 4))
                        return 0;

        snd_printk(KERN_ERR PREFIX "invalid fimware version in device: %*ph. "
                        "please reconnect to power. if this failure "
                        "still happens, check your firmware installation.",
                        4, version);
        return -EINVAL;
}

int usb6fire_fw_init(struct usb_interface *intf)
{
        int i;
        int ret;
        struct usb_device *device = interface_to_usbdev(intf);
        /* buffer: 8 receiving bytes from device and
         * sizeof(EP_W_MAX_PACKET_SIZE) bytes for non-const copy */
        u8 buffer[12];

        ret = usb6fire_fw_ezusb_read(device, 1, 0, buffer, 8);
        if (ret < 0) {
                snd_printk(KERN_ERR PREFIX "unable to receive device "
                                "firmware state.\n");
                return ret;
        }
        if (buffer[0] != 0xeb || buffer[1] != 0xaa || buffer[2] != 0x55) {
                snd_printk(KERN_ERR PREFIX "unknown device firmware state "
                                "received from device: ");
                for (i = 0; i < 8; i++)
                        snd_printk("%02x ", buffer[i]);
                snd_printk("\n");
                return -EIO;
        }
        /* do we need fpga loader ezusb firmware? */
        if (buffer[3] == 0x01) {
                ret = usb6fire_fw_ezusb_upload(intf,
                                "6fire/dmx6firel2.ihx", 0, NULL, 0);
                if (ret < 0)
                        return ret;
                return FW_NOT_READY;
        }
        /* do we need fpga firmware and application ezusb firmware? */
        else if (buffer[3] == 0x02) {
                ret = usb6fire_fw_check(buffer + 4);
                if (ret < 0)
                        return ret;
                ret = usb6fire_fw_fpga_upload(intf, "6fire/dmx6firecf.bin");
                if (ret < 0)
                        return ret;
                memcpy(buffer, ep_w_max_packet_size,
                                sizeof(ep_w_max_packet_size));
                ret = usb6fire_fw_ezusb_upload(intf, "6fire/dmx6fireap.ihx",
                                0x0003, buffer, sizeof(ep_w_max_packet_size));
                if (ret < 0)
                        return ret;
                return FW_NOT_READY;
        }
        /* all fw loaded? */
        else if (buffer[3] == 0x03)
                return usb6fire_fw_check(buffer + 4);
        /* unknown data? */
        else {
                snd_printk(KERN_ERR PREFIX "unknown device firmware state "
                                "received from device: ");
                for (i = 0; i < 8; i++)
                        snd_printk("%02x ", buffer[i]);
                snd_printk("\n");
                return -EIO;
        }
        return 0;
}