linux/drivers/macintosh/macio-adb.c
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   1// SPDX-License-Identifier: GPL-2.0
   2/*
   3 * Driver for the ADB controller in the Mac I/O (Hydra) chip.
   4 */
   5#include <stdarg.h>
   6#include <linux/types.h>
   7#include <linux/errno.h>
   8#include <linux/kernel.h>
   9#include <linux/delay.h>
  10#include <linux/spinlock.h>
  11#include <linux/interrupt.h>
  12#include <linux/pgtable.h>
  13#include <asm/prom.h>
  14#include <linux/adb.h>
  15#include <asm/io.h>
  16#include <asm/hydra.h>
  17#include <asm/irq.h>
  18#include <linux/init.h>
  19#include <linux/ioport.h>
  20
  21struct preg {
  22        unsigned char r;
  23        char pad[15];
  24};
  25
  26struct adb_regs {
  27        struct preg intr;
  28        struct preg data[9];
  29        struct preg intr_enb;
  30        struct preg dcount;
  31        struct preg error;
  32        struct preg ctrl;
  33        struct preg autopoll;
  34        struct preg active_hi;
  35        struct preg active_lo;
  36        struct preg test;
  37};
  38
  39/* Bits in intr and intr_enb registers */
  40#define DFB     1               /* data from bus */
  41#define TAG     2               /* transfer access grant */
  42
  43/* Bits in dcount register */
  44#define HMB     0x0f            /* how many bytes */
  45#define APD     0x10            /* auto-poll data */
  46
  47/* Bits in error register */
  48#define NRE     1               /* no response error */
  49#define DLE     2               /* data lost error */
  50
  51/* Bits in ctrl register */
  52#define TAR     1               /* transfer access request */
  53#define DTB     2               /* data to bus */
  54#define CRE     4               /* command response expected */
  55#define ADB_RST 8               /* ADB reset */
  56
  57/* Bits in autopoll register */
  58#define APE     1               /* autopoll enable */
  59
  60static volatile struct adb_regs __iomem *adb;
  61static struct adb_request *current_req, *last_req;
  62static DEFINE_SPINLOCK(macio_lock);
  63
  64static int macio_probe(void);
  65static int macio_init(void);
  66static irqreturn_t macio_adb_interrupt(int irq, void *arg);
  67static int macio_send_request(struct adb_request *req, int sync);
  68static int macio_adb_autopoll(int devs);
  69static void macio_adb_poll(void);
  70static int macio_adb_reset_bus(void);
  71
  72struct adb_driver macio_adb_driver = {
  73        .name         = "MACIO",
  74        .probe        = macio_probe,
  75        .init         = macio_init,
  76        .send_request = macio_send_request,
  77        .autopoll     = macio_adb_autopoll,
  78        .poll         = macio_adb_poll,
  79        .reset_bus    = macio_adb_reset_bus,
  80};
  81
  82int macio_probe(void)
  83{
  84        struct device_node *np;
  85
  86        np = of_find_compatible_node(NULL, "adb", "chrp,adb0");
  87        if (np) {
  88                of_node_put(np);
  89                return 0;
  90        }
  91        return -ENODEV;
  92}
  93
  94int macio_init(void)
  95{
  96        struct device_node *adbs;
  97        struct resource r;
  98        unsigned int irq;
  99
 100        adbs = of_find_compatible_node(NULL, "adb", "chrp,adb0");
 101        if (adbs == 0)
 102                return -ENXIO;
 103
 104        if (of_address_to_resource(adbs, 0, &r)) {
 105                of_node_put(adbs);
 106                return -ENXIO;
 107        }
 108        adb = ioremap(r.start, sizeof(struct adb_regs));
 109
 110        out_8(&adb->ctrl.r, 0);
 111        out_8(&adb->intr.r, 0);
 112        out_8(&adb->error.r, 0);
 113        out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
 114        out_8(&adb->active_lo.r, 0xff);
 115        out_8(&adb->autopoll.r, APE);
 116
 117        irq = irq_of_parse_and_map(adbs, 0);
 118        of_node_put(adbs);
 119        if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) {
 120                printk(KERN_ERR "ADB: can't get irq %d\n", irq);
 121                return -EAGAIN;
 122        }
 123        out_8(&adb->intr_enb.r, DFB | TAG);
 124
 125        printk("adb: mac-io driver 1.0 for unified ADB\n");
 126
 127        return 0;
 128}
 129
 130static int macio_adb_autopoll(int devs)
 131{
 132        unsigned long flags;
 133        
 134        spin_lock_irqsave(&macio_lock, flags);
 135        out_8(&adb->active_hi.r, devs >> 8);
 136        out_8(&adb->active_lo.r, devs);
 137        out_8(&adb->autopoll.r, devs? APE: 0);
 138        spin_unlock_irqrestore(&macio_lock, flags);
 139        return 0;
 140}
 141
 142static int macio_adb_reset_bus(void)
 143{
 144        unsigned long flags;
 145        int timeout = 1000000;
 146
 147        /* Hrm... we may want to not lock interrupts for so
 148         * long ... oh well, who uses that chip anyway ? :)
 149         * That function will be seldom used during boot
 150         * on rare machines, so...
 151         */
 152        spin_lock_irqsave(&macio_lock, flags);
 153        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
 154        while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
 155                if (--timeout == 0) {
 156                        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
 157                        spin_unlock_irqrestore(&macio_lock, flags);
 158                        return -1;
 159                }
 160        }
 161        spin_unlock_irqrestore(&macio_lock, flags);
 162        return 0;
 163}
 164
 165/* Send an ADB command */
 166static int macio_send_request(struct adb_request *req, int sync)
 167{
 168        unsigned long flags;
 169        int i;
 170        
 171        if (req->data[0] != ADB_PACKET)
 172                return -EINVAL;
 173        
 174        for (i = 0; i < req->nbytes - 1; ++i)
 175                req->data[i] = req->data[i+1];
 176        --req->nbytes;
 177        
 178        req->next = NULL;
 179        req->sent = 0;
 180        req->complete = 0;
 181        req->reply_len = 0;
 182
 183        spin_lock_irqsave(&macio_lock, flags);
 184        if (current_req != 0) {
 185                last_req->next = req;
 186                last_req = req;
 187        } else {
 188                current_req = last_req = req;
 189                out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 190        }
 191        spin_unlock_irqrestore(&macio_lock, flags);
 192        
 193        if (sync) {
 194                while (!req->complete)
 195                        macio_adb_poll();
 196        }
 197
 198        return 0;
 199}
 200
 201static irqreturn_t macio_adb_interrupt(int irq, void *arg)
 202{
 203        int i, n, err;
 204        struct adb_request *req = NULL;
 205        unsigned char ibuf[16];
 206        int ibuf_len = 0;
 207        int complete = 0;
 208        int autopoll = 0;
 209        int handled = 0;
 210
 211        spin_lock(&macio_lock);
 212        if (in_8(&adb->intr.r) & TAG) {
 213                handled = 1;
 214                if ((req = current_req) != 0) {
 215                        /* put the current request in */
 216                        for (i = 0; i < req->nbytes; ++i)
 217                                out_8(&adb->data[i].r, req->data[i]);
 218                        out_8(&adb->dcount.r, req->nbytes & HMB);
 219                        req->sent = 1;
 220                        if (req->reply_expected) {
 221                                out_8(&adb->ctrl.r, DTB + CRE);
 222                        } else {
 223                                out_8(&adb->ctrl.r, DTB);
 224                                current_req = req->next;
 225                                complete = 1;
 226                                if (current_req)
 227                                        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 228                        }
 229                }
 230                out_8(&adb->intr.r, 0);
 231        }
 232
 233        if (in_8(&adb->intr.r) & DFB) {
 234                handled = 1;
 235                err = in_8(&adb->error.r);
 236                if (current_req && current_req->sent) {
 237                        /* this is the response to a command */
 238                        req = current_req;
 239                        if (err == 0) {
 240                                req->reply_len = in_8(&adb->dcount.r) & HMB;
 241                                for (i = 0; i < req->reply_len; ++i)
 242                                        req->reply[i] = in_8(&adb->data[i].r);
 243                        }
 244                        current_req = req->next;
 245                        complete = 1;
 246                        if (current_req)
 247                                out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 248                } else if (err == 0) {
 249                        /* autopoll data */
 250                        n = in_8(&adb->dcount.r) & HMB;
 251                        for (i = 0; i < n; ++i)
 252                                ibuf[i] = in_8(&adb->data[i].r);
 253                        ibuf_len = n;
 254                        autopoll = (in_8(&adb->dcount.r) & APD) != 0;
 255                }
 256                out_8(&adb->error.r, 0);
 257                out_8(&adb->intr.r, 0);
 258        }
 259        spin_unlock(&macio_lock);
 260        if (complete && req) {
 261            void (*done)(struct adb_request *) = req->done;
 262            mb();
 263            req->complete = 1;
 264            /* Here, we assume that if the request has a done member, the
 265             * struct request will survive to setting req->complete to 1
 266             */
 267            if (done)
 268                (*done)(req);
 269        }
 270        if (ibuf_len)
 271                adb_input(ibuf, ibuf_len, autopoll);
 272
 273        return IRQ_RETVAL(handled);
 274}
 275
 276static void macio_adb_poll(void)
 277{
 278        unsigned long flags;
 279
 280        local_irq_save(flags);
 281        if (in_8(&adb->intr.r) != 0)
 282                macio_adb_interrupt(0, NULL);
 283        local_irq_restore(flags);
 284}
 285
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