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 <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
  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         .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
  82 int 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
  94 int 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
 130 static 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
 142 static 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 */
 166 static 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
 201 static 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
 276 static 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 }