// SPDX-License-Identifier: GPL-2.0
/*
 * I/O Processor (IOP) ADB Driver
 * Written and (C) 1999 by Joshua M. Thompson (funaho@jurai.org)
 * Based on via-cuda.c by Paul Mackerras.
 *
 * 1999-07-01 (jmt) - First implementation for new driver architecture.
 *
 * 1999-07-31 (jmt) - First working version.
 *
 * TODO:
 *
 * o Implement SRQ handling.
 */

#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/proc_fs.h>

#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/mac_iop.h>
#include <asm/mac_oss.h>
#include <asm/adb_iop.h>

#include <linux/adb.h>

/*#define DEBUG_ADB_IOP*/

static struct adb_request *current_req;
static struct adb_request *last_req;
#if 0
static unsigned char reply_buff[16];
static unsigned char *reply_ptr;
#endif

static enum adb_iop_state {
        idle,
        sending,
        awaiting_reply
} adb_iop_state;

static void adb_iop_start(void);
static int adb_iop_probe(void);
static int adb_iop_init(void);
static int adb_iop_send_request(struct adb_request *, int);
static int adb_iop_write(struct adb_request *);
static int adb_iop_autopoll(int);
static void adb_iop_poll(void);
static int adb_iop_reset_bus(void);

struct adb_driver adb_iop_driver = {
        .name         = "ISM IOP",
        .probe        = adb_iop_probe,
        .init         = adb_iop_init,
        .send_request = adb_iop_send_request,
        .autopoll     = adb_iop_autopoll,
        .poll         = adb_iop_poll,
        .reset_bus    = adb_iop_reset_bus
};

static void adb_iop_end_req(struct adb_request *req, int state)
{
        req->complete = 1;
        current_req = req->next;
        if (req->done)
                (*req->done)(req);
        adb_iop_state = state;
}

/*
 * Completion routine for ADB commands sent to the IOP.
 *
 * This will be called when a packet has been successfully sent.
 */

static void adb_iop_complete(struct iop_msg *msg)
{
        struct adb_request *req;
        unsigned long flags;

        local_irq_save(flags);

        req = current_req;
        if ((adb_iop_state == sending) && req && req->reply_expected) {
                adb_iop_state = awaiting_reply;
        }

        local_irq_restore(flags);
}

/*
 * Listen for ADB messages from the IOP.
 *
 * This will be called when unsolicited messages (usually replies to TALK
 * commands or autopoll packets) are received.
 */

static void adb_iop_listen(struct iop_msg *msg)
{
        struct adb_iopmsg *amsg = (struct adb_iopmsg *)msg->message;
        struct adb_request *req;
        unsigned long flags;
#ifdef DEBUG_ADB_IOP
        int i;
#endif

        local_irq_save(flags);

        req = current_req;

#ifdef DEBUG_ADB_IOP
        printk("adb_iop_listen %p: rcvd packet, %d bytes: %02X %02X", req,
               (uint)amsg->count + 2, (uint)amsg->flags, (uint)amsg->cmd);
        for (i = 0; i < amsg->count; i++)
                printk(" %02X", (uint)amsg->data[i]);
        printk("\n");
#endif

        /* Handle a timeout. Timeout packets seem to occur even after */
        /* we've gotten a valid reply to a TALK, so I'm assuming that */
        /* a "timeout" is actually more like an "end-of-data" signal. */
        /* We need to send back a timeout packet to the IOP to shut   */
        /* it up, plus complete the current request, if any.          */

        if (amsg->flags & ADB_IOP_TIMEOUT) {
                msg->reply[0] = ADB_IOP_TIMEOUT | ADB_IOP_AUTOPOLL;
                msg->reply[1] = 0;
                msg->reply[2] = 0;
                if (req && (adb_iop_state != idle)) {
                        adb_iop_end_req(req, idle);
                }
        } else {
                /* TODO: is it possible for more than one chunk of data  */
                /*       to arrive before the timeout? If so we need to */
                /*       use reply_ptr here like the other drivers do.  */
                if ((adb_iop_state == awaiting_reply) &&
                    (amsg->flags & ADB_IOP_EXPLICIT)) {
                        req->reply_len = amsg->count + 1;
                        memcpy(req->reply, &amsg->cmd, req->reply_len);
                } else {
                        adb_input(&amsg->cmd, amsg->count + 1,
                                  amsg->flags & ADB_IOP_AUTOPOLL);
                }
                memcpy(msg->reply, msg->message, IOP_MSG_LEN);
        }
        iop_complete_message(msg);
        local_irq_restore(flags);
}

/*
 * Start sending an ADB packet, IOP style
 *
 * There isn't much to do other than hand the packet over to the IOP
 * after encapsulating it in an adb_iopmsg.
 */

static void adb_iop_start(void)
{
        unsigned long flags;
        struct adb_request *req;
        struct adb_iopmsg amsg;
#ifdef DEBUG_ADB_IOP
        int i;
#endif

        /* get the packet to send */
        req = current_req;
        if (!req)
                return;

        local_irq_save(flags);

#ifdef DEBUG_ADB_IOP
        printk("adb_iop_start %p: sending packet, %d bytes:", req, req->nbytes);
        for (i = 0; i < req->nbytes; i++)
                printk(" %02X", (uint)req->data[i]);
        printk("\n");
#endif

        /* The IOP takes MacII-style packets, so */
        /* strip the initial ADB_PACKET byte.    */

        amsg.flags = ADB_IOP_EXPLICIT;
        amsg.count = req->nbytes - 2;

        /* amsg.data immediately follows amsg.cmd, effectively making */
        /* amsg.cmd a pointer to the beginning of a full ADB packet.  */
        memcpy(&amsg.cmd, req->data + 1, req->nbytes - 1);

        req->sent = 1;
        adb_iop_state = sending;
        local_irq_restore(flags);

        /* Now send it. The IOP manager will call adb_iop_complete */
        /* when the packet has been sent.                          */

        iop_send_message(ADB_IOP, ADB_CHAN, req, sizeof(amsg), (__u8 *)&amsg,
                         adb_iop_complete);
}

int adb_iop_probe(void)
{
        if (!iop_ism_present)
                return -ENODEV;
        return 0;
}

int adb_iop_init(void)
{
        pr_info("adb: IOP ISM driver v0.4 for Unified ADB\n");
        iop_listen(ADB_IOP, ADB_CHAN, adb_iop_listen, "ADB");
        return 0;
}

int adb_iop_send_request(struct adb_request *req, int sync)
{
        int err;

        err = adb_iop_write(req);
        if (err)
                return err;

        if (sync) {
                while (!req->complete)
                        adb_iop_poll();
        }
        return 0;
}

static int adb_iop_write(struct adb_request *req)
{
        unsigned long flags;

        if ((req->nbytes < 2) || (req->data[0] != ADB_PACKET)) {
                req->complete = 1;
                return -EINVAL;
        }

        local_irq_save(flags);

        req->next = NULL;
        req->sent = 0;
        req->complete = 0;
        req->reply_len = 0;

        if (current_req != 0) {
                last_req->next = req;
                last_req = req;
        } else {
                current_req = req;
                last_req = req;
        }

        local_irq_restore(flags);

        if (adb_iop_state == idle)
                adb_iop_start();
        return 0;
}

int adb_iop_autopoll(int devs)
{
        /* TODO: how do we enable/disable autopoll? */
        return 0;
}

void adb_iop_poll(void)
{
        if (adb_iop_state == idle)
                adb_iop_start();
        iop_ism_irq_poll(ADB_IOP);
}

int adb_iop_reset_bus(void)
{
        struct adb_request req = {
                .reply_expected = 0,
                .nbytes = 2,
                .data = { ADB_PACKET, 0 },
        };

        adb_iop_write(&req);
        while (!req.complete) {
                adb_iop_poll();
                schedule();
        }

        return 0;
}