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/*

 * Driver for the ADB controller in the Mac I/O (Hydra) chip.

 */

#include <stdarg.h>

#include <linux/types.h>

#include <linux/errno.h>

#include <linux/kernel.h>

#include <linux/delay.h>

#include <linux/sched.h>

#include <linux/spinlock.h>

#include <asm/prom.h>

#include <linux/adb.h>

#include <asm/io.h>

#include <asm/pgtable.h>

#include <asm/hydra.h>

#include <asm/irq.h>

#include <asm/system.h>

#include <linux/init.h>

struct preg {

        unsigned char r;

        char pad[15];

};

struct adb_regs {

        struct preg intr;

        struct preg data[9];

        struct preg intr_enb;

        struct preg dcount;

        struct preg error;

        struct preg ctrl;

        struct preg autopoll;

        struct preg active_hi;

        struct preg active_lo;

        struct preg test;

};

/* Bits in intr and intr_enb registers */

#define DFB     1               /* data from bus */

#define TAG     2               /* transfer access grant */

/* Bits in dcount register */

#define HMB     0x0f            /* how many bytes */

#define APD     0x10            /* auto-poll data */

/* Bits in error register */

#define NRE     1               /* no response error */

#define DLE     2               /* data lost error */

/* Bits in ctrl register */

#define TAR     1               /* transfer access request */

#define DTB     2               /* data to bus */

#define CRE     4               /* command response expected */

#define ADB_RST 8               /* ADB reset */

/* Bits in autopoll register */

#define APE     1               /* autopoll enable */

static volatile struct adb_regs *adb;

static struct adb_request *current_req, *last_req;

static spinlock_t macio_lock = SPIN_LOCK_UNLOCKED;

static int macio_probe(void);

static int macio_init(void);

static void macio_adb_interrupt(int irq, void *arg, struct pt_regs *regs);

static int macio_send_request(struct adb_request *req, int sync);

static int macio_adb_autopoll(int devs);

static void macio_adb_poll(void);

static int macio_adb_reset_bus(void);

struct adb_driver macio_adb_driver = {

        "MACIO",

        macio_probe,

        macio_init,

        macio_send_request,

        /*macio_write,*/

        macio_adb_autopoll,

        macio_adb_poll,

        macio_adb_reset_bus

};

int macio_probe(void)

{

        return find_compatible_devices("adb", "chrp,adb0")? 0: -ENODEV;

}

int macio_init(void)

{

        struct device_node *adbs;

        adbs = find_compatible_devices("adb", "chrp,adb0");

        if (adbs == 0)

                return -ENXIO;

#if 0

        { int i;

        printk("macio_adb_init: node = %p, addrs =", adbs->node);

        for (i = 0; i < adbs->n_addrs; ++i)

                printk(" %x(%x)", adbs->addrs[i].address, adbs->addrs[i].size);

        printk(", intrs =");

        for (i = 0; i < adbs->n_intrs; ++i)

                printk(" %x", adbs->intrs[i].line);

        printk("\n"); }

#endif

        adb = (volatile struct adb_regs *)

                ioremap(adbs->addrs->address, sizeof(struct adb_regs));

        out_8(&adb->ctrl.r, 0);

        out_8(&adb->intr.r, 0);

        out_8(&adb->error.r, 0);

        out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */

        out_8(&adb->active_lo.r, 0xff);

        out_8(&adb->autopoll.r, APE);

        if (request_irq(adbs->intrs[0].line, macio_adb_interrupt,

                        0, "ADB", (void *)0)) {

                printk(KERN_ERR "ADB: can't get irq %d\n",

                       adbs->intrs[0].line);

                return -EAGAIN;

        }

        out_8(&adb->intr_enb.r, DFB | TAG);

        printk("adb: mac-io driver 1.0 for unified ADB\n");

        return 0;

}

static int macio_adb_autopoll(int devs)

{

        unsigned long flags;

        spin_lock_irqsave(&macio_lock, flags);

        out_8(&adb->active_hi.r, devs >> 8);

        out_8(&adb->active_lo.r, devs);

        out_8(&adb->autopoll.r, devs? APE: 0);

        spin_unlock_irqrestore(&macio_lock, flags);

        return 0;

}

static int macio_adb_reset_bus(void)

{

        unsigned long flags;

        int timeout = 1000000;

        /* Hrm... we may want to not lock interrupts for so

         * long ... oh well, who uses that chip anyway ? :)

         * That function will be seldomly used during boot

         * on rare machines, so...

         */

        spin_lock_irqsave(&macio_lock, flags);

        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);

        while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {

                if (--timeout == 0) {

                        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);

                        return -1;

                }

        }

        spin_unlock_irqrestore(&macio_lock, flags);

        return 0;

}

/* Send an ADB command */

static int macio_send_request(struct adb_request *req, int sync)

{

        unsigned long flags;

        int i;

        if (req->data[0] != ADB_PACKET)

                return -EINVAL;

        for (i = 0; i < req->nbytes - 1; ++i)

                req->data[i] = req->data[i+1];

        --req->nbytes;

        req->next = 0;

        req->sent = 0;

        req->complete = 0;

        req->reply_len = 0;

        spin_lock_irqsave(&macio_lock, flags);

        if (current_req != 0) {

                last_req->next = req;

                last_req = req;

        } else {

                current_req = last_req = req;

                out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);

        }

        spin_unlock_irqrestore(&macio_lock, flags);

        if (sync) {

                while (!req->complete)

                        macio_adb_poll();

        }

        return 0;

}

static void macio_adb_interrupt(int irq, void *arg, struct pt_regs *regs)

{

        int i, n, err;

        struct adb_request *req;

        unsigned char ibuf[16];

        int ibuf_len = 0;

        int complete = 0;

        int autopoll = 0;

        spin_lock(&macio_lock);

        if (in_8(&adb->intr.r) & TAG) {

                if ((req = current_req) != 0) {

                        /* put the current request in */

                        for (i = 0; i < req->nbytes; ++i)

                                out_8(&adb->data[i].r, req->data[i]);

                        out_8(&adb->dcount.r, req->nbytes & HMB);

                        req->sent = 1;

                        if (req->reply_expected) {

                                out_8(&adb->ctrl.r, DTB + CRE);

                        } else {

                                out_8(&adb->ctrl.r, DTB);

                                current_req = req->next;

                                complete = 1;

                                if (current_req)

                                        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);

                        }

                }

                out_8(&adb->intr.r, 0);

        }

        if (in_8(&adb->intr.r) & DFB) {

                err = in_8(&adb->error.r);

                if (current_req && current_req->sent) {

                        /* this is the response to a command */

                        req = current_req;

                        if (err == 0) {

                                req->reply_len = in_8(&adb->dcount.r) & HMB;

                                for (i = 0; i < req->reply_len; ++i)

                                        req->reply[i] = in_8(&adb->data[i].r);

                        }

                        current_req = req->next;

                        complete = 1;

                        if (current_req)

                                out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);

                } else if (err == 0) {

                        /* autopoll data */

                        n = in_8(&adb->dcount.r) & HMB;

                        for (i = 0; i < n; ++i)

                                ibuf[i] = in_8(&adb->data[i].r);

                        ibuf_len = n;

                        autopoll = (in_8(&adb->dcount.r) & APD) != 0;

                }

                out_8(&adb->error.r, 0);

                out_8(&adb->intr.r, 0);

        }

        spin_unlock(&macio_lock);

        if (complete && req) {

            void (*done)(struct adb_request *) = req->done;

            mb();

            req->complete = 1;

            /* Here, we assume that if the request has a done member, the

             * struct request will survive to setting req->complete to 1

             */

            if (done)

                (*done)(req);

        }

        if (ibuf_len)

                adb_input(ibuf, ibuf_len, regs, autopoll);

}

static void macio_adb_poll(void)

{

        unsigned long flags;

        local_irq_save(flags);

        if (in_8(&adb->intr.r) != 0)

                macio_adb_interrupt(0, 0, 0);

        local_irq_restore(flags);

}