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 .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 } 285