// SPDX-License-Identifier: GPL-2.0
/* 
 * Emagic EMI 2|6 usb audio interface firmware loader.
 * Copyright (C) 2002
 *      Tapio Laxström (tapio.laxstrom@iptime.fi)
 */
#include <linux/kernel.h>
#include <linux/errno.h>
#include <linux/slab.h>
#include <linux/module.h>
#include <linux/usb.h>
#include <linux/delay.h>
#include <linux/firmware.h>
#include <linux/ihex.h>

/* include firmware (variables)*/

/* FIXME: This is quick and dirty solution! */
#define SPDIF   /* if you want SPDIF comment next line */
//#undef SPDIF  /* if you want MIDI uncomment this line */ 

#ifdef SPDIF
#define FIRMWARE_FW "emi62/spdif.fw"
#else
#define FIRMWARE_FW "emi62/midi.fw"
#endif

#define EMI62_VENDOR_ID                 0x086a  /* Emagic Soft-und Hardware GmBH */
#define EMI62_PRODUCT_ID                0x0110  /* EMI 6|2m without firmware */

#define ANCHOR_LOAD_INTERNAL    0xA0    /* Vendor specific request code for Anchor Upload/Download (This one is implemented in the core) */
#define ANCHOR_LOAD_EXTERNAL    0xA3    /* This command is not implemented in the core. Requires firmware */
#define ANCHOR_LOAD_FPGA        0xA5    /* This command is not implemented in the core. Requires firmware. Emagic extension */
#define MAX_INTERNAL_ADDRESS    0x1B3F  /* This is the highest internal RAM address for the AN2131Q */
#define CPUCS_REG               0x7F92  /* EZ-USB Control and Status Register.  Bit 0 controls 8051 reset */ 
#define INTERNAL_RAM(address)   (address <= MAX_INTERNAL_ADDRESS)

static int emi62_writememory(struct usb_device *dev, int address,
                             const unsigned char *data, int length,
                             __u8 bRequest);
static int emi62_set_reset(struct usb_device *dev, unsigned char reset_bit);
static int emi62_load_firmware (struct usb_device *dev);
static int emi62_probe(struct usb_interface *intf, const struct usb_device_id *id);
static void emi62_disconnect(struct usb_interface *intf);

/* thanks to drivers/usb/serial/keyspan_pda.c code */
static int emi62_writememory(struct usb_device *dev, int address,
                             const unsigned char *data, int length,
                             __u8 request)
{
        int result;
        unsigned char *buffer =  kmemdup(data, length, GFP_KERNEL);

        if (!buffer) {
                dev_err(&dev->dev, "kmalloc(%d) failed.\n", length);
                return -ENOMEM;
        }
        /* Note: usb_control_msg returns negative value on error or length of the
         *               data that was written! */
        result = usb_control_msg (dev, usb_sndctrlpipe(dev, 0), request, 0x40, address, 0, buffer, length, 300);
        kfree (buffer);
        return result;
}

/* thanks to drivers/usb/serial/keyspan_pda.c code */
static int emi62_set_reset (struct usb_device *dev, unsigned char reset_bit)
{
        int response;
        dev_info(&dev->dev, "%s - %d\n", __func__, reset_bit);
        
        response = emi62_writememory (dev, CPUCS_REG, &reset_bit, 1, 0xa0);
        if (response < 0)
                dev_err(&dev->dev, "set_reset (%d) failed\n", reset_bit);
        return response;
}

#define FW_LOAD_SIZE            1023

static int emi62_load_firmware (struct usb_device *dev)
{
        const struct firmware *loader_fw = NULL;
        const struct firmware *bitstream_fw = NULL;
        const struct firmware *firmware_fw = NULL;
        const struct ihex_binrec *rec;
        int err = -ENOMEM;
        int i;
        __u32 addr;     /* Address to write */
        __u8 *buf;

        dev_dbg(&dev->dev, "load_firmware\n");
        buf = kmalloc(FW_LOAD_SIZE, GFP_KERNEL);
        if (!buf)
                goto wraperr;

        err = request_ihex_firmware(&loader_fw, "emi62/loader.fw", &dev->dev);
        if (err)
                goto nofw;

        err = request_ihex_firmware(&bitstream_fw, "emi62/bitstream.fw",
                                    &dev->dev);
        if (err)
                goto nofw;

        err = request_ihex_firmware(&firmware_fw, FIRMWARE_FW, &dev->dev);
        if (err) {
        nofw:
                goto wraperr;
        }

        /* Assert reset (stop the CPU in the EMI) */
        err = emi62_set_reset(dev,1);
        if (err < 0)
                goto wraperr;

        rec = (const struct ihex_binrec *)loader_fw->data;

        /* 1. We need to put the loader for the FPGA into the EZ-USB */
        while (rec) {
                err = emi62_writememory(dev, be32_to_cpu(rec->addr),
                                        rec->data, be16_to_cpu(rec->len),
                                        ANCHOR_LOAD_INTERNAL);
                if (err < 0)
                        goto wraperr;
                rec = ihex_next_binrec(rec);
        }

        /* De-assert reset (let the CPU run) */
        err = emi62_set_reset(dev,0);
        if (err < 0)
                goto wraperr;
        msleep(250);    /* let device settle */

        /* 2. We upload the FPGA firmware into the EMI
         * Note: collect up to 1023 (yes!) bytes and send them with
         * a single request. This is _much_ faster! */
        rec = (const struct ihex_binrec *)bitstream_fw->data;
        do {
                i = 0;
                addr = be32_to_cpu(rec->addr);

                /* intel hex records are terminated with type 0 element */
                while (rec && (i + be16_to_cpu(rec->len) < FW_LOAD_SIZE)) {
                        memcpy(buf + i, rec->data, be16_to_cpu(rec->len));
                        i += be16_to_cpu(rec->len);
                        rec = ihex_next_binrec(rec);
                }
                err = emi62_writememory(dev, addr, buf, i, ANCHOR_LOAD_FPGA);
                if (err < 0)
                        goto wraperr;
        } while (rec);

        /* Assert reset (stop the CPU in the EMI) */
        err = emi62_set_reset(dev,1);
        if (err < 0)
                goto wraperr;

        /* 3. We need to put the loader for the firmware into the EZ-USB (again...) */
        for (rec = (const struct ihex_binrec *)loader_fw->data;
             rec; rec = ihex_next_binrec(rec)) {
                err = emi62_writememory(dev, be32_to_cpu(rec->addr),
                                        rec->data, be16_to_cpu(rec->len),
                                        ANCHOR_LOAD_INTERNAL);
                if (err < 0)
                        goto wraperr;
        }

        /* De-assert reset (let the CPU run) */
        err = emi62_set_reset(dev,0);
        if (err < 0)
                goto wraperr;
        msleep(250);    /* let device settle */

        /* 4. We put the part of the firmware that lies in the external RAM into the EZ-USB */

        for (rec = (const struct ihex_binrec *)firmware_fw->data;
             rec; rec = ihex_next_binrec(rec)) {
                if (!INTERNAL_RAM(be32_to_cpu(rec->addr))) {
                        err = emi62_writememory(dev, be32_to_cpu(rec->addr),
                                                rec->data, be16_to_cpu(rec->len),
                                                ANCHOR_LOAD_EXTERNAL);
                        if (err < 0)
                                goto wraperr;
                }
        }

        /* Assert reset (stop the CPU in the EMI) */
        err = emi62_set_reset(dev,1);
        if (err < 0)
                goto wraperr;

        for (rec = (const struct ihex_binrec *)firmware_fw->data;
             rec; rec = ihex_next_binrec(rec)) {
                if (INTERNAL_RAM(be32_to_cpu(rec->addr))) {
                        err = emi62_writememory(dev, be32_to_cpu(rec->addr),
                                                rec->data, be16_to_cpu(rec->len),
                                                ANCHOR_LOAD_EXTERNAL);
                        if (err < 0)
                                goto wraperr;
                }
        }

        /* De-assert reset (let the CPU run) */
        err = emi62_set_reset(dev,0);
        if (err < 0)
                goto wraperr;
        msleep(250);    /* let device settle */

        release_firmware(loader_fw);
        release_firmware(bitstream_fw);
        release_firmware(firmware_fw);

        kfree(buf);

        /* return 1 to fail the driver inialization
         * and give real driver change to load */
        return 1;

wraperr:
        if (err < 0)
                dev_err(&dev->dev,"%s - error loading firmware: error = %d\n",
                        __func__, err);
        release_firmware(loader_fw);
        release_firmware(bitstream_fw);
        release_firmware(firmware_fw);

        kfree(buf);
        dev_err(&dev->dev, "Error\n");
        return err;
}

static const struct usb_device_id id_table[] = {
        { USB_DEVICE(EMI62_VENDOR_ID, EMI62_PRODUCT_ID) },
        { }                                             /* Terminating entry */
};

MODULE_DEVICE_TABLE (usb, id_table);

static int emi62_probe(struct usb_interface *intf, const struct usb_device_id *id)
{
        struct usb_device *dev = interface_to_usbdev(intf);
        dev_dbg(&intf->dev, "emi62_probe\n");

        dev_info(&intf->dev, "%s start\n", __func__);

        emi62_load_firmware(dev);

        /* do not return the driver context, let real audio driver do that */
        return -EIO;
}

static void emi62_disconnect(struct usb_interface *intf)
{
}

static struct usb_driver emi62_driver = {
        .name           = "emi62 - firmware loader",
        .probe          = emi62_probe,
        .disconnect     = emi62_disconnect,
        .id_table       = id_table,
};

module_usb_driver(emi62_driver);

MODULE_AUTHOR("Tapio Laxström");
MODULE_DESCRIPTION("Emagic EMI 6|2m firmware loader.");
MODULE_LICENSE("GPL");

MODULE_FIRMWARE("emi62/loader.fw");
MODULE_FIRMWARE("emi62/bitstream.fw");
MODULE_FIRMWARE(FIRMWARE_FW);
/* vi:ai:syntax=c:sw=8:ts=8:tw=80
 */