linux/drivers/macintosh/macio-adb.c
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   1/*
   2 * Driver for the ADB controller in the Mac I/O (Hydra) chip.
   3 */
   4#include <stdarg.h>
   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 <asm/prom.h>
  12#include <linux/adb.h>
  13#include <asm/io.h>
  14#include <asm/pgtable.h>
  15#include <asm/hydra.h>
  16#include <asm/irq.h>
  17#include <asm/system.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        "MACIO",
  74        macio_probe,
  75        macio_init,
  76        macio_send_request,
  77        /*macio_write,*/
  78        macio_adb_autopoll,
  79        macio_adb_poll,
  80        macio_adb_reset_bus
  81};
  82
  83int macio_probe(void)
  84{
  85        struct device_node *np;
  86
  87        np = of_find_compatible_node(NULL, "adb", "chrp,adb0");
  88        if (np) {
  89                of_node_put(np);
  90                return 0;
  91        }
  92        return -ENODEV;
  93}
  94
  95int macio_init(void)
  96{
  97        struct device_node *adbs;
  98        struct resource r;
  99        unsigned int irq;
 100
 101        adbs = of_find_compatible_node(NULL, "adb", "chrp,adb0");
 102        if (adbs == 0)
 103                return -ENXIO;
 104
 105        if (of_address_to_resource(adbs, 0, &r)) {
 106                of_node_put(adbs);
 107                return -ENXIO;
 108        }
 109        adb = ioremap(r.start, sizeof(struct adb_regs));
 110
 111        out_8(&adb->ctrl.r, 0);
 112        out_8(&adb->intr.r, 0);
 113        out_8(&adb->error.r, 0);
 114        out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
 115        out_8(&adb->active_lo.r, 0xff);
 116        out_8(&adb->autopoll.r, APE);
 117
 118        irq = irq_of_parse_and_map(adbs, 0);
 119        of_node_put(adbs);
 120        if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) {
 121                printk(KERN_ERR "ADB: can't get irq %d\n", irq);
 122                return -EAGAIN;
 123        }
 124        out_8(&adb->intr_enb.r, DFB | TAG);
 125
 126        printk("adb: mac-io driver 1.0 for unified ADB\n");
 127
 128        return 0;
 129}
 130
 131static int macio_adb_autopoll(int devs)
 132{
 133        unsigned long flags;
 134        
 135        spin_lock_irqsave(&macio_lock, flags);
 136        out_8(&adb->active_hi.r, devs >> 8);
 137        out_8(&adb->active_lo.r, devs);
 138        out_8(&adb->autopoll.r, devs? APE: 0);
 139        spin_unlock_irqrestore(&macio_lock, flags);
 140        return 0;
 141}
 142
 143static int macio_adb_reset_bus(void)
 144{
 145        unsigned long flags;
 146        int timeout = 1000000;
 147
 148        /* Hrm... we may want to not lock interrupts for so
 149         * long ... oh well, who uses that chip anyway ? :)
 150         * That function will be seldom used during boot
 151         * on rare machines, so...
 152         */
 153        spin_lock_irqsave(&macio_lock, flags);
 154        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
 155        while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
 156                if (--timeout == 0) {
 157                        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
 158                        spin_unlock_irqrestore(&macio_lock, flags);
 159                        return -1;
 160                }
 161        }
 162        spin_unlock_irqrestore(&macio_lock, flags);
 163        return 0;
 164}
 165
 166/* Send an ADB command */
 167static int macio_send_request(struct adb_request *req, int sync)
 168{
 169        unsigned long flags;
 170        int i;
 171        
 172        if (req->data[0] != ADB_PACKET)
 173                return -EINVAL;
 174        
 175        for (i = 0; i < req->nbytes - 1; ++i)
 176                req->data[i] = req->data[i+1];
 177        --req->nbytes;
 178        
 179        req->next = NULL;
 180        req->sent = 0;
 181        req->complete = 0;
 182        req->reply_len = 0;
 183
 184        spin_lock_irqsave(&macio_lock, flags);
 185        if (current_req != 0) {
 186                last_req->next = req;
 187                last_req = req;
 188        } else {
 189                current_req = last_req = req;
 190                out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 191        }
 192        spin_unlock_irqrestore(&macio_lock, flags);
 193        
 194        if (sync) {
 195                while (!req->complete)
 196                        macio_adb_poll();
 197        }
 198
 199        return 0;
 200}
 201
 202static irqreturn_t macio_adb_interrupt(int irq, void *arg)
 203{
 204        int i, n, err;
 205        struct adb_request *req = NULL;
 206        unsigned char ibuf[16];
 207        int ibuf_len = 0;
 208        int complete = 0;
 209        int autopoll = 0;
 210        int handled = 0;
 211
 212        spin_lock(&macio_lock);
 213        if (in_8(&adb->intr.r) & TAG) {
 214                handled = 1;
 215                if ((req = current_req) != 0) {
 216                        /* put the current request in */
 217                        for (i = 0; i < req->nbytes; ++i)
 218                                out_8(&adb->data[i].r, req->data[i]);
 219                        out_8(&adb->dcount.r, req->nbytes & HMB);
 220                        req->sent = 1;
 221                        if (req->reply_expected) {
 222                                out_8(&adb->ctrl.r, DTB + CRE);
 223                        } else {
 224                                out_8(&adb->ctrl.r, DTB);
 225                                current_req = req->next;
 226                                complete = 1;
 227                                if (current_req)
 228                                        out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 229                        }
 230                }
 231                out_8(&adb->intr.r, 0);
 232        }
 233
 234        if (in_8(&adb->intr.r) & DFB) {
 235                handled = 1;
 236                err = in_8(&adb->error.r);
 237                if (current_req && current_req->sent) {
 238                        /* this is the response to a command */
 239                        req = current_req;
 240                        if (err == 0) {
 241                                req->reply_len = in_8(&adb->dcount.r) & HMB;
 242                                for (i = 0; i < req->reply_len; ++i)
 243                                        req->reply[i] = in_8(&adb->data[i].r);
 244                        }
 245                        current_req = req->next;
 246                        complete = 1;
 247                        if (current_req)
 248                                out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 249                } else if (err == 0) {
 250                        /* autopoll data */
 251                        n = in_8(&adb->dcount.r) & HMB;
 252                        for (i = 0; i < n; ++i)
 253                                ibuf[i] = in_8(&adb->data[i].r);
 254                        ibuf_len = n;
 255                        autopoll = (in_8(&adb->dcount.r) & APD) != 0;
 256                }
 257                out_8(&adb->error.r, 0);
 258                out_8(&adb->intr.r, 0);
 259        }
 260        spin_unlock(&macio_lock);
 261        if (complete && req) {
 262            void (*done)(struct adb_request *) = req->done;
 263            mb();
 264            req->complete = 1;
 265            /* Here, we assume that if the request has a done member, the
 266             * struct request will survive to setting req->complete to 1
 267             */
 268            if (done)
 269                (*done)(req);
 270        }
 271        if (ibuf_len)
 272                adb_input(ibuf, ibuf_len, autopoll);
 273
 274        return IRQ_RETVAL(handled);
 275}
 276
 277static void macio_adb_poll(void)
 278{
 279        unsigned long flags;
 280
 281        local_irq_save(flags);
 282        if (in_8(&adb->intr.r) != 0)
 283                macio_adb_interrupt(0, NULL);
 284        local_irq_restore(flags);
 285}
 286