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
macio_probe(void)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
macio_init(void)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
macio_adb_autopoll(int devs)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
macio_adb_reset_bus(void)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 */
macio_send_request(struct adb_request * req,int sync)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
macio_adb_interrupt(int irq,void * arg)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
macio_adb_poll(void)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
