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 <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 <linux/of.h>
  13 #include <linux/of_address.h>
  14 #include <linux/of_irq.h>
  15 #include <linux/adb.h>
  16
  17 #include <asm/io.h>
  18 #include <asm/hydra.h>
  19 #include <asm/irq.h>
  20 #include <linux/init.h>
  21 #include <linux/ioport.h>
  22
  23 struct preg {
  24         unsigned char r;
  25         char pad[15];
  26 };
  27
  28 struct adb_regs {
  29         struct preg intr;
  30         struct preg data[9];
  31         struct preg intr_enb;
  32         struct preg dcount;
  33         struct preg error;
  34         struct preg ctrl;
  35         struct preg autopoll;
  36         struct preg active_hi;
  37         struct preg active_lo;
  38         struct preg test;
  39 };
  40
  41 /* Bits in intr and intr_enb registers */
  42 #define DFB     1               /* data from bus */
  43 #define TAG     2               /* transfer access grant */
  44
  45 /* Bits in dcount register */
  46 #define HMB     0x0f            /* how many bytes */
  47 #define APD     0x10            /* auto-poll data */
  48
  49 /* Bits in error register */
  50 #define NRE     1               /* no response error */
  51 #define DLE     2               /* data lost error */
  52
  53 /* Bits in ctrl register */
  54 #define TAR     1               /* transfer access request */
  55 #define DTB     2               /* data to bus */
  56 #define CRE     4               /* command response expected */
  57 #define ADB_RST 8               /* ADB reset */
  58
  59 /* Bits in autopoll register */
  60 #define APE     1               /* autopoll enable */
  61
  62 static volatile struct adb_regs __iomem *adb;
  63 static struct adb_request *current_req, *last_req;
  64 static DEFINE_SPINLOCK(macio_lock);
  65
  66 static int macio_probe(void);
  67 static int macio_init(void);
  68 static irqreturn_t macio_adb_interrupt(int irq, void *arg);
  69 static int macio_send_request(struct adb_request *req, int sync);
  70 static int macio_adb_autopoll(int devs);
  71 static void macio_adb_poll(void);
  72 static int macio_adb_reset_bus(void);
  73
  74 struct adb_driver macio_adb_driver = {
  75         .name         = "MACIO",
  76         .probe        = macio_probe,
  77         .init         = macio_init,
  78         .send_request = macio_send_request,
  79         .autopoll     = macio_adb_autopoll,
  80         .poll         = macio_adb_poll,
  81         .reset_bus    = macio_adb_reset_bus,
  82 };
  83
  84 int macio_probe(void)
  85 {
  86         struct device_node *np __free(device_node) =
  87                 of_find_compatible_node(NULL, "adb", "chrp,adb0");
  88
  89         if (np)
  90                 return 0;
  91
  92         return -ENODEV;
  93 }
  94
  95 int macio_init(void)
  96 {
  97         struct device_node *adbs __free(device_node) =
  98                 of_find_compatible_node(NULL, "adb", "chrp,adb0");
  99         struct resource r;
 100         unsigned int irq;
 101
 102         if (!adbs)
 103                 return -ENXIO;
 104
 105         if (of_address_to_resource(adbs, 0, &r))
 106                 return -ENXIO;
 107
 108         adb = ioremap(r.start, sizeof(struct adb_regs));
 109         if (!adb)
 110                 return -ENOMEM;
 111
 112
 113         out_8(&adb->ctrl.r, 0);
 114         out_8(&adb->intr.r, 0);
 115         out_8(&adb->error.r, 0);
 116         out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
 117         out_8(&adb->active_lo.r, 0xff);
 118         out_8(&adb->autopoll.r, APE);
 119
 120         irq = irq_of_parse_and_map(adbs, 0);
 121         if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) {
 122                 iounmap(adb);
 123                 printk(KERN_ERR "ADB: can't get irq %d\n", irq);
 124                 return -EAGAIN;
 125         }
 126         out_8(&adb->intr_enb.r, DFB | TAG);
 127
 128         printk("adb: mac-io driver 1.0 for unified ADB\n");
 129
 130         return 0;
 131 }
 132
 133 static int macio_adb_autopoll(int devs)
 134 {
 135         unsigned long flags;
 136
 137         spin_lock_irqsave(&macio_lock, flags);
 138         out_8(&adb->active_hi.r, devs >> 8);
 139         out_8(&adb->active_lo.r, devs);
 140         out_8(&adb->autopoll.r, devs? APE: 0);
 141         spin_unlock_irqrestore(&macio_lock, flags);
 142         return 0;
 143 }
 144
 145 static int macio_adb_reset_bus(void)
 146 {
 147         unsigned long flags;
 148         int timeout = 1000000;
 149
 150         /* Hrm... we may want to not lock interrupts for so
 151          * long ... oh well, who uses that chip anyway ? :)
 152          * That function will be seldom used during boot
 153          * on rare machines, so...
 154          */
 155         spin_lock_irqsave(&macio_lock, flags);
 156         out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
 157         while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
 158                 if (--timeout == 0) {
 159                         out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
 160                         spin_unlock_irqrestore(&macio_lock, flags);
 161                         return -1;
 162                 }
 163         }
 164         spin_unlock_irqrestore(&macio_lock, flags);
 165         return 0;
 166 }
 167
 168 /* Send an ADB command */
 169 static int macio_send_request(struct adb_request *req, int sync)
 170 {
 171         unsigned long flags;
 172         int i;
 173
 174         if (req->data[0] != ADB_PACKET)
 175                 return -EINVAL;
 176
 177         for (i = 0; i < req->nbytes - 1; ++i)
 178                 req->data[i] = req->data[i+1];
 179         --req->nbytes;
 180
 181         req->next = NULL;
 182         req->sent = 0;
 183         req->complete = 0;
 184         req->reply_len = 0;
 185
 186         spin_lock_irqsave(&macio_lock, flags);
 187         if (current_req) {
 188                 last_req->next = req;
 189                 last_req = req;
 190         } else {
 191                 current_req = last_req = req;
 192                 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 193         }
 194         spin_unlock_irqrestore(&macio_lock, flags);
 195
 196         if (sync) {
 197                 while (!req->complete)
 198                         macio_adb_poll();
 199         }
 200
 201         return 0;
 202 }
 203
 204 static irqreturn_t macio_adb_interrupt(int irq, void *arg)
 205 {
 206         int i, n, err;
 207         struct adb_request *req = NULL;
 208         unsigned char ibuf[16];
 209         int ibuf_len = 0;
 210         int complete = 0;
 211         int autopoll = 0;
 212         int handled = 0;
 213
 214         spin_lock(&macio_lock);
 215         if (in_8(&adb->intr.r) & TAG) {
 216                 handled = 1;
 217                 req = current_req;
 218                 if (req) {
 219                         /* put the current request in */
 220                         for (i = 0; i < req->nbytes; ++i)
 221                                 out_8(&adb->data[i].r, req->data[i]);
 222                         out_8(&adb->dcount.r, req->nbytes & HMB);
 223                         req->sent = 1;
 224                         if (req->reply_expected) {
 225                                 out_8(&adb->ctrl.r, DTB + CRE);
 226                         } else {
 227                                 out_8(&adb->ctrl.r, DTB);
 228                                 current_req = req->next;
 229                                 complete = 1;
 230                                 if (current_req)
 231                                         out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 232                         }
 233                 }
 234                 out_8(&adb->intr.r, 0);
 235         }
 236
 237         if (in_8(&adb->intr.r) & DFB) {
 238                 handled = 1;
 239                 err = in_8(&adb->error.r);
 240                 if (current_req && current_req->sent) {
 241                         /* this is the response to a command */
 242                         req = current_req;
 243                         if (err == 0) {
 244                                 req->reply_len = in_8(&adb->dcount.r) & HMB;
 245                                 for (i = 0; i < req->reply_len; ++i)
 246                                         req->reply[i] = in_8(&adb->data[i].r);
 247                         }
 248                         current_req = req->next;
 249                         complete = 1;
 250                         if (current_req)
 251                                 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
 252                 } else if (err == 0) {
 253                         /* autopoll data */
 254                         n = in_8(&adb->dcount.r) & HMB;
 255                         for (i = 0; i < n; ++i)
 256                                 ibuf[i] = in_8(&adb->data[i].r);
 257                         ibuf_len = n;
 258                         autopoll = (in_8(&adb->dcount.r) & APD) != 0;
 259                 }
 260                 out_8(&adb->error.r, 0);
 261                 out_8(&adb->intr.r, 0);
 262         }
 263         spin_unlock(&macio_lock);
 264         if (complete && req) {
 265             void (*done)(struct adb_request *) = req->done;
 266             mb();
 267             req->complete = 1;
 268             /* Here, we assume that if the request has a done member, the
 269              * struct request will survive to setting req->complete to 1
 270              */
 271             if (done)
 272                 (*done)(req);
 273         }
 274         if (ibuf_len)
 275                 adb_input(ibuf, ibuf_len, autopoll);
 276
 277         return IRQ_RETVAL(handled);
 278 }
 279
 280 static void macio_adb_poll(void)
 281 {
 282         unsigned long flags;
 283
 284         local_irq_save(flags);
 285         if (in_8(&adb->intr.r) != 0)
 286                 macio_adb_interrupt(0, NULL);
 287         local_irq_restore(flags);
 288 }