1 // SPDX-License-Identifier: GPL-2.0
3 * Driver for the ADB controller in the Mac I/O (Hydra) chip.
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>
13 #include <linux/of_address.h>
14 #include <linux/of_irq.h>
15 #include <linux/adb.h>
18 #include <asm/hydra.h>
20 #include <linux/init.h>
21 #include <linux/ioport.h>
36 struct preg active_hi;
37 struct preg active_lo;
41 /* Bits in intr and intr_enb registers */
42 #define DFB 1 /* data from bus */
43 #define TAG 2 /* transfer access grant */
45 /* Bits in dcount register */
46 #define HMB 0x0f /* how many bytes */
47 #define APD 0x10 /* auto-poll data */
49 /* Bits in error register */
50 #define NRE 1 /* no response error */
51 #define DLE 2 /* data lost error */
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 */
59 /* Bits in autopoll register */
60 #define APE 1 /* autopoll enable */
62 static volatile struct adb_regs __iomem *adb;
63 static struct adb_request *current_req, *last_req;
64 static DEFINE_SPINLOCK(macio_lock);
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);
74 struct adb_driver macio_adb_driver = {
78 .send_request = macio_send_request,
79 .autopoll = macio_adb_autopoll,
80 .poll = macio_adb_poll,
81 .reset_bus = macio_adb_reset_bus,
86 struct device_node *np;
88 np = of_find_compatible_node(NULL, "adb", "chrp,adb0");
98 struct device_node *adbs;
102 adbs = of_find_compatible_node(NULL, "adb", "chrp,adb0");
106 if (of_address_to_resource(adbs, 0, &r)) {
110 adb = ioremap(r.start, sizeof(struct adb_regs));
116 out_8(&adb->ctrl.r, 0);
117 out_8(&adb->intr.r, 0);
118 out_8(&adb->error.r, 0);
119 out_8(&adb->active_hi.r, 0xff); /* for now, set all devices active */
120 out_8(&adb->active_lo.r, 0xff);
121 out_8(&adb->autopoll.r, APE);
123 irq = irq_of_parse_and_map(adbs, 0);
125 if (request_irq(irq, macio_adb_interrupt, 0, "ADB", (void *)0)) {
127 printk(KERN_ERR "ADB: can't get irq %d\n", irq);
130 out_8(&adb->intr_enb.r, DFB | TAG);
132 printk("adb: mac-io driver 1.0 for unified ADB\n");
137 static int macio_adb_autopoll(int devs)
141 spin_lock_irqsave(&macio_lock, flags);
142 out_8(&adb->active_hi.r, devs >> 8);
143 out_8(&adb->active_lo.r, devs);
144 out_8(&adb->autopoll.r, devs? APE: 0);
145 spin_unlock_irqrestore(&macio_lock, flags);
149 static int macio_adb_reset_bus(void)
152 int timeout = 1000000;
154 /* Hrm... we may want to not lock interrupts for so
155 * long ... oh well, who uses that chip anyway ? :)
156 * That function will be seldom used during boot
157 * on rare machines, so...
159 spin_lock_irqsave(&macio_lock, flags);
160 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | ADB_RST);
161 while ((in_8(&adb->ctrl.r) & ADB_RST) != 0) {
162 if (--timeout == 0) {
163 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) & ~ADB_RST);
164 spin_unlock_irqrestore(&macio_lock, flags);
168 spin_unlock_irqrestore(&macio_lock, flags);
172 /* Send an ADB command */
173 static int macio_send_request(struct adb_request *req, int sync)
178 if (req->data[0] != ADB_PACKET)
181 for (i = 0; i < req->nbytes - 1; ++i)
182 req->data[i] = req->data[i+1];
190 spin_lock_irqsave(&macio_lock, flags);
192 last_req->next = req;
195 current_req = last_req = req;
196 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
198 spin_unlock_irqrestore(&macio_lock, flags);
201 while (!req->complete)
208 static irqreturn_t macio_adb_interrupt(int irq, void *arg)
211 struct adb_request *req = NULL;
212 unsigned char ibuf[16];
218 spin_lock(&macio_lock);
219 if (in_8(&adb->intr.r) & TAG) {
223 /* put the current request in */
224 for (i = 0; i < req->nbytes; ++i)
225 out_8(&adb->data[i].r, req->data[i]);
226 out_8(&adb->dcount.r, req->nbytes & HMB);
228 if (req->reply_expected) {
229 out_8(&adb->ctrl.r, DTB + CRE);
231 out_8(&adb->ctrl.r, DTB);
232 current_req = req->next;
235 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
238 out_8(&adb->intr.r, 0);
241 if (in_8(&adb->intr.r) & DFB) {
243 err = in_8(&adb->error.r);
244 if (current_req && current_req->sent) {
245 /* this is the response to a command */
248 req->reply_len = in_8(&adb->dcount.r) & HMB;
249 for (i = 0; i < req->reply_len; ++i)
250 req->reply[i] = in_8(&adb->data[i].r);
252 current_req = req->next;
255 out_8(&adb->ctrl.r, in_8(&adb->ctrl.r) | TAR);
256 } else if (err == 0) {
258 n = in_8(&adb->dcount.r) & HMB;
259 for (i = 0; i < n; ++i)
260 ibuf[i] = in_8(&adb->data[i].r);
262 autopoll = (in_8(&adb->dcount.r) & APD) != 0;
264 out_8(&adb->error.r, 0);
265 out_8(&adb->intr.r, 0);
267 spin_unlock(&macio_lock);
268 if (complete && req) {
269 void (*done)(struct adb_request *) = req->done;
272 /* Here, we assume that if the request has a done member, the
273 * struct request will survive to setting req->complete to 1
279 adb_input(ibuf, ibuf_len, autopoll);
281 return IRQ_RETVAL(handled);
284 static void macio_adb_poll(void)
288 local_irq_save(flags);
289 if (in_8(&adb->intr.r) != 0)
290 macio_adb_interrupt(0, NULL);
291 local_irq_restore(flags);