// SPDX-License-Identifier: GPL-2.0-only
/*
 * motu-transaction.c - a part of driver for MOTU FireWire series
 *
 * Copyright (c) 2015-2017 Takashi Sakamoto <o-takashi@sakamocchi.jp>
 */


#include "motu.h"

#define SND_MOTU_ADDR_BASE      0xfffff0000000ULL
#define ASYNC_ADDR_HI  0x0b04
#define ASYNC_ADDR_LO  0x0b08

int snd_motu_transaction_read(struct snd_motu *motu, u32 offset, __be32 *reg,
                              size_t size)
{
        int tcode;

        if (size % sizeof(__be32) > 0 || size <= 0)
                return -EINVAL;
        if (size == sizeof(__be32))
                tcode = TCODE_READ_QUADLET_REQUEST;
        else
                tcode = TCODE_READ_BLOCK_REQUEST;

        return snd_fw_transaction(motu->unit, tcode,
                                  SND_MOTU_ADDR_BASE + offset, reg, size, 0);
}

int snd_motu_transaction_write(struct snd_motu *motu, u32 offset, __be32 *reg,
                               size_t size)
{
        int tcode;

        if (size % sizeof(__be32) > 0 || size <= 0)
                return -EINVAL;
        if (size == sizeof(__be32))
                tcode = TCODE_WRITE_QUADLET_REQUEST;
        else
                tcode = TCODE_WRITE_BLOCK_REQUEST;

        return snd_fw_transaction(motu->unit, tcode,
                                  SND_MOTU_ADDR_BASE + offset, reg, size, 0);
}

static void handle_message(struct fw_card *card, struct fw_request *request,
                           int tcode, int destination, int source,
                           int generation, unsigned long long offset,
                           void *data, size_t length, void *callback_data)
{
        struct snd_motu *motu = callback_data;
        __be32 *buf = (__be32 *)data;

        if (tcode != TCODE_WRITE_QUADLET_REQUEST) {
                fw_send_response(card, request, RCODE_COMPLETE);
                return;
        }

        if (offset != motu->async_handler.offset || length != 4) {
                fw_send_response(card, request, RCODE_ADDRESS_ERROR);
                return;
        }

        scoped_guard(spinlock_irqsave, &motu->lock) {
                motu->msg = be32_to_cpu(*buf);
        }

        fw_send_response(card, request, RCODE_COMPLETE);

        wake_up(&motu->hwdep_wait);
}

int snd_motu_transaction_reregister(struct snd_motu *motu)
{
        struct fw_device *device = fw_parent_device(motu->unit);
        __be32 data;
        int err;

        if (motu->async_handler.callback_data == NULL)
                return -EINVAL;

        /* Register messaging address. Block transaction is not allowed. */
        data = cpu_to_be32((device->card->node_id << 16) |
                           (motu->async_handler.offset >> 32));
        err = snd_motu_transaction_write(motu, ASYNC_ADDR_HI, &data,
                                         sizeof(data));
        if (err < 0)
                return err;

        data = cpu_to_be32(motu->async_handler.offset);
        return snd_motu_transaction_write(motu, ASYNC_ADDR_LO, &data,
                                          sizeof(data));
}

int snd_motu_transaction_register(struct snd_motu *motu)
{
        static const struct fw_address_region resp_register_region = {
                .start  = 0xffffe0000000ull,
                .end    = 0xffffe000ffffull,
        };
        int err;

        /* Perhaps, 4 byte messages are transferred. */
        motu->async_handler.length = 4;
        motu->async_handler.address_callback = handle_message;
        motu->async_handler.callback_data = motu;

        err = fw_core_add_address_handler(&motu->async_handler,
                                          &resp_register_region);
        if (err < 0)
                return err;

        err = snd_motu_transaction_reregister(motu);
        if (err < 0) {
                fw_core_remove_address_handler(&motu->async_handler);
                motu->async_handler.address_callback = NULL;
        }

        return err;
}

void snd_motu_transaction_unregister(struct snd_motu *motu)
{
        __be32 data;

        if (motu->async_handler.address_callback != NULL)
                fw_core_remove_address_handler(&motu->async_handler);
        motu->async_handler.address_callback = NULL;

        /* Unregister the address. */
        data = cpu_to_be32(0x00000000);
        snd_motu_transaction_write(motu, ASYNC_ADDR_HI, &data, sizeof(data));
        snd_motu_transaction_write(motu, ASYNC_ADDR_LO, &data, sizeof(data));
}