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