/*
   * 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[][2] = {
  	{ 0x03, 0x01 }
  };
  
  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.
  ", 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.
  ", 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.
  ", 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.
  ", 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.
  ", 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.
  ", 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.
  ",
  				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.
  ");
  		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.
  ");
  			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.
  ");
  		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, 2))
  			return 0;
  
  	snd_printk(KERN_ERR PREFIX "invalid fimware version in device: %4ph. "
  			"please reconnect to power. if this failure "
  			"still happens, check your firmware installation.",
  			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.
  ");
  		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("
  ");
  		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("
  ");
  		return -EIO;
  	}
  	return 0;
  }