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