1 // SPDX-License-Identifier: GPL-2.0
3  * Device driver for the via ADB on (many) Mac II-class machines
5  * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox
13  * 1999-08-02 (jmt) - Initial rewrite for Unified ADB.
14  * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org>
15  *            - Big overhaul, should actually work now.
16  * 2006-12-31 Finn Thain - Another overhaul.
24  *   ftp://ftp.apple.com/developer/Tool_Chest/Devices_-_Hardware/Apple_Desktop_Bus/
32 #include <linux/init.h>
39 /* VIA registers - spaced 0x200 bytes apart */
41 #define B		0		/* B-side data */
42 #define A		RS		/* A-side data */
43 #define DIRB		(2*RS)		/* B-side direction (1=output) */
44 #define DIRA		(3*RS)		/* A-side direction (1=output) */
56 #define ANH		(15*RS)		/* A-side data, no handshake */
64 #define SR_EXT		0x0c		/* Shift on external clock */
100 	.init         = macii_init,
103 	.poll         = macii_poll,
116 static unsigned char *reply_ptr;     /* next byte in reply_buf or req->reply */
117 static bool reading_reply;       /* store reply in reply_buf else req->reply */
118 static int data_index;      /* index of the next byte to send from req->data */
119 static int reply_len; /* number of bytes received in reply_buf or req->reply */
121 static bool bus_timeout;                   /* no data was sent by the device */
122 static bool srq_asserted;    /* have to poll for the device that asserted it */
126 static unsigned int autopoll_devs;  /* bits set are device addresses to poll */
131 	if (macintosh_config->adb_type != MAC_ADB_II)  in macii_probe()
132 		return -ENODEV;  in macii_probe()
169 	/* Shift register on input */  in macii_init_via()
178 /* Send an ADB poll (Talk Register 0 command prepended to the request queue) */
193 	/* The device most recently polled may not be the best device to poll  in macii_queue_poll()
203 		higher_devs = autopoll_devs & -(1 << (poll_addr + 1));  in macii_queue_poll()
204 		poll_addr = ffs(higher_devs ? higher_devs : autopoll_devs) - 1;  in macii_queue_poll()
210 	/* No need to repeat this Talk command. The transceiver will do that  in macii_queue_poll()
231 /* Send an ADB request; if sync, poll out the reply 'till it's done */
241 		while (!req->complete)  in macii_send_request()
252 	if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {  in macii_write()
253 		req->complete = 1;  in macii_write()
254 		return -EINVAL;  in macii_write()
257 	req->next = NULL;  in macii_write()
258 	req->sent = 0;  in macii_write()
259 	req->complete = 0;  in macii_write()
260 	req->reply_len = 0;  in macii_write()
265 		last_req->next = req;  in macii_write()
279 /* Start auto-polling */
286 	/* bit 1 == device 1, and so on. */  in macii_autopoll()
330 	 * And req->nbytes is the number of bytes of real data plus one.  in macii_start()
336 	via[SR] = req->data[1];  in macii_start()
348  * The notorious ADB interrupt handler - does all of the protocol handling.
349  * Relies on the ADB controller sending and receiving data, thereby
351  * to be activity on the ADB bus. The chip will poll to achieve this.
354  * sees a transition on the PB4 and PB5 lines it will crank over the VIA shift
358  * Request with no reply expected (and empty transceiver buffer):
359  *     CMD -> IDLE
361  *     CMD -> EVEN -> ODD -> EVEN -> ... -> IDLE
363  *     IDLE -> EVEN -> ODD -> EVEN -> ... -> IDLE
418 			/* /CTLR_IRQ de-asserted after the command byte means  in macii_interrupt()
423 			last_cmd = req->data[1];  in macii_interrupt()
446 		} else if (data_index >= req->nbytes) {  in macii_interrupt()
447 			req->sent = 1;  in macii_interrupt()
449 			if (req->reply_expected) {  in macii_interrupt()
453 				reply_ptr = req->reply;  in macii_interrupt()
454 				*reply_ptr = req->data[1];  in macii_interrupt()
459 			} else if ((req->data[1] & OP_MASK) == TALK) {  in macii_interrupt()
464 				*reply_ptr = req->data[1];  in macii_interrupt()
470 				req->complete = 1;  in macii_interrupt()
471 				current_req = req->next;  in macii_interrupt()
472 				if (req->done)  in macii_interrupt()
473 					(*req->done)(req);  in macii_interrupt()
477 				req->complete = 1;  in macii_interrupt()
478 				current_req = req->next;  in macii_interrupt()
479 				if (req->done)  in macii_interrupt()
480 					(*req->done)(req);  in macii_interrupt()
484 			via[SR] = req->data[data_index++];  in macii_interrupt()
515 					req->reply_len = reply_len;  in macii_interrupt()
517 					req->complete = 1;  in macii_interrupt()
518 					current_req = req->next;  in macii_interrupt()
519 					if (req->done)  in macii_interrupt()
520 						(*req->done)(req);  in macii_interrupt()