drivers/macintosh/macio-adb.c

   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 <asm/prom.h>
  13 #include <linux/adb.h>
  14 #include <asm/io.h>
  15 #include <asm/pgtable.h>
  16 #include <asm/hydra.h>
  17 #include <asm/irq.h>
  18 #include <linux/init.h>
  19 #include <linux/ioport.h>
  20
  21 struct preg {
  22         unsigned char r;
  23         char pad[15];
  24 };
  25
  26 struct 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
  60 static volatile struct adb_regs __iomem *adb;
  61 static struct adb_request *current_req, *last_req;
  62 static DEFINE_SPINLOCK(macio_lock);
  63
  64 static int macio_probe(void);
  65 static int macio_init(void);
  66 static irqreturn_t macio_adb_interrupt(int irq, void *arg);
  67 static int macio_send_request(struct adb_request *req, int sync);
  68 static int macio_adb_autopoll(int devs);
  69 static void macio_adb_poll(void);
  70 static int macio_adb_reset_bus(void);
  71
  72 struct 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
  83 int 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
  95 int 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
 131 static 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
 143 static 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 */
 167 static 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
 202 static 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
 277 static 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 }