1 files changed, 550 insertions, 0 deletions

diff --git a/drivers/macintosh/via-macii.c b/drivers/macintosh/via-macii.c
new file mode 100644
index 000000000..cf6f7d52d
--- /dev/null
+++ b/drivers/macintosh/via-macii.c
@@ -0,0 +1,550 @@
+// SPDX-License-Identifier: GPL-2.0
+/*
+ * Device driver for the via ADB on (many) Mac II-class machines
+ *
+ * Based on the original ADB keyboard handler Copyright (c) 1997 Alan Cox
+ * Also derived from code Copyright (C) 1996 Paul Mackerras.
+ *
+ * With various updates provided over the years by Michael Schmitz,
+ * Guideo Koerber and others.
+ *
+ * Rewrite for Unified ADB by Joshua M. Thompson (funaho@jurai.org)
+ *
+ * 1999-08-02 (jmt) - Initial rewrite for Unified ADB.
+ * 2000-03-29 Tony Mantler <tonym@mac.linux-m68k.org>
+ * 				- Big overhaul, should actually work now.
+ * 2006-12-31 Finn Thain - Another overhaul.
+ *
+ * Suggested reading:
+ *   Inside Macintosh, ch. 5 ADB Manager
+ *   Guide to the Macinstosh Family Hardware, ch. 8 Apple Desktop Bus
+ *   Rockwell R6522 VIA datasheet
+ *
+ * Apple's "ADB Analyzer" bus sniffer is invaluable:
+ *   ftp://ftp.apple.com/developer/Tool_Chest/Devices_-_Hardware/Apple_Desktop_Bus/
+ */
+ 
+#include <stdarg.h>
+#include <linux/types.h>
+#include <linux/errno.h>
+#include <linux/kernel.h>
+#include <linux/delay.h>
+#include <linux/adb.h>
+#include <linux/interrupt.h>
+#include <linux/init.h>
+#include <asm/macintosh.h>
+#include <asm/macints.h>
+#include <asm/mac_via.h>
+
+static volatile unsigned char *via;
+
+/* VIA registers - spaced 0x200 bytes apart */
+#define RS		0x200		/* skip between registers */
+#define B		0		/* B-side data */
+#define A		RS		/* A-side data */
+#define DIRB		(2*RS)		/* B-side direction (1=output) */
+#define DIRA		(3*RS)		/* A-side direction (1=output) */
+#define T1CL		(4*RS)		/* Timer 1 ctr/latch (low 8 bits) */
+#define T1CH		(5*RS)		/* Timer 1 counter (high 8 bits) */
+#define T1LL		(6*RS)		/* Timer 1 latch (low 8 bits) */
+#define T1LH		(7*RS)		/* Timer 1 latch (high 8 bits) */
+#define T2CL		(8*RS)		/* Timer 2 ctr/latch (low 8 bits) */
+#define T2CH		(9*RS)		/* Timer 2 counter (high 8 bits) */
+#define SR		(10*RS)		/* Shift register */
+#define ACR		(11*RS)		/* Auxiliary control register */
+#define PCR		(12*RS)		/* Peripheral control register */
+#define IFR		(13*RS)		/* Interrupt flag register */
+#define IER		(14*RS)		/* Interrupt enable register */
+#define ANH		(15*RS)		/* A-side data, no handshake */
+
+/* Bits in B data register: all active low */
+#define CTLR_IRQ	0x08		/* Controller rcv status (input) */
+#define ST_MASK		0x30		/* mask for selecting ADB state bits */
+
+/* Bits in ACR */
+#define SR_CTRL		0x1c		/* Shift register control bits */
+#define SR_EXT		0x0c		/* Shift on external clock */
+#define SR_OUT		0x10		/* Shift out if 1 */
+
+/* Bits in IFR and IER */
+#define IER_SET		0x80		/* set bits in IER */
+#define IER_CLR		0		/* clear bits in IER */
+#define SR_INT		0x04		/* Shift register full/empty */
+
+/* ADB transaction states according to GMHW */
+#define ST_CMD		0x00		/* ADB state: command byte */
+#define ST_EVEN		0x10		/* ADB state: even data byte */
+#define ST_ODD		0x20		/* ADB state: odd data byte */
+#define ST_IDLE		0x30		/* ADB state: idle, nothing to send */
+
+static int  macii_init_via(void);
+static void macii_start(void);
+static irqreturn_t macii_interrupt(int irq, void *arg);
+static void macii_queue_poll(void);
+
+static int macii_probe(void);
+static int macii_init(void);
+static int macii_send_request(struct adb_request *req, int sync);
+static int macii_write(struct adb_request *req);
+static int macii_autopoll(int devs);
+static void macii_poll(void);
+static int macii_reset_bus(void);
+
+struct adb_driver via_macii_driver = {
+	.name         = "Mac II",
+	.probe        = macii_probe,
+	.init         = macii_init,
+	.send_request = macii_send_request,
+	.autopoll     = macii_autopoll,
+	.poll         = macii_poll,
+	.reset_bus    = macii_reset_bus,
+};
+
+static enum macii_state {
+	idle,
+	sending,
+	reading,
+	read_done,
+} macii_state;
+
+static struct adb_request *current_req; /* first request struct in the queue */
+static struct adb_request *last_req;     /* last request struct in the queue */
+static unsigned char reply_buf[16];        /* storage for autopolled replies */
+static unsigned char *reply_ptr;     /* next byte in reply_buf or req->reply */
+static int reading_reply;        /* store reply in reply_buf else req->reply */
+static int data_index;      /* index of the next byte to send from req->data */
+static int reply_len; /* number of bytes received in reply_buf or req->reply */
+static int status;          /* VIA's ADB status bits captured upon interrupt */
+static int last_status;              /* status bits as at previous interrupt */
+static int srq_asserted;     /* have to poll for the device that asserted it */
+static int command_byte;         /* the most recent command byte transmitted */
+static int autopoll_devs;      /* bits set are device addresses to be polled */
+
+/* Sanity check for request queue. Doesn't check for cycles. */
+static int request_is_queued(struct adb_request *req) {
+	struct adb_request *cur;
+	unsigned long flags;
+	local_irq_save(flags);
+	cur = current_req;
+	while (cur) {
+		if (cur == req) {
+			local_irq_restore(flags);
+			return 1;
+		}
+		cur = cur->next;
+	}
+	local_irq_restore(flags);
+	return 0;
+}
+
+/* Check for MacII style ADB */
+static int macii_probe(void)
+{
+	if (macintosh_config->adb_type != MAC_ADB_II) return -ENODEV;
+
+	via = via1;
+
+	printk("adb: Mac II ADB Driver v1.0 for Unified ADB\n");
+	return 0;
+}
+
+/* Initialize the driver */
+int macii_init(void)
+{
+	unsigned long flags;
+	int err;
+	
+	local_irq_save(flags);
+	
+	err = macii_init_via();
+	if (err) goto out;
+
+	err = request_irq(IRQ_MAC_ADB, macii_interrupt, 0, "ADB",
+			  macii_interrupt);
+	if (err) goto out;
+
+	macii_state = idle;
+out:
+	local_irq_restore(flags);
+	return err;
+}
+
+/* initialize the hardware */	
+static int macii_init_via(void)
+{
+	unsigned char x;
+
+	/* We want CTLR_IRQ as input and ST_EVEN | ST_ODD as output lines. */
+	via[DIRB] = (via[DIRB] | ST_EVEN | ST_ODD) & ~CTLR_IRQ;
+
+	/* Set up state: idle */
+	via[B] |= ST_IDLE;
+	last_status = via[B] & (ST_MASK|CTLR_IRQ);
+
+	/* Shift register on input */
+	via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;
+
+	/* Wipe any pending data and int */
+	x = via[SR];
+
+	return 0;
+}
+
+/* Send an ADB poll (Talk Register 0 command prepended to the request queue) */
+static void macii_queue_poll(void)
+{
+	/* No point polling the active device as it will never assert SRQ, so
+	 * poll the next device in the autopoll list. This could leave us
+	 * stuck in a polling loop if an unprobed device is asserting SRQ.
+	 * In theory, that could only happen if a device was plugged in after
+	 * probing started. Unplugging it again will break the cycle.
+	 * (Simply polling the next higher device often ends up polling almost
+	 * every device (after wrapping around), which takes too long.)
+	 */
+	int device_mask;
+	int next_device;
+	static struct adb_request req;
+
+	if (!autopoll_devs) return;
+
+	device_mask = (1 << (((command_byte & 0xF0) >> 4) + 1)) - 1;
+	if (autopoll_devs & ~device_mask)
+		next_device = ffs(autopoll_devs & ~device_mask) - 1;
+	else
+		next_device = ffs(autopoll_devs) - 1;
+
+	BUG_ON(request_is_queued(&req));
+
+	adb_request(&req, NULL, ADBREQ_NOSEND, 1,
+	            ADB_READREG(next_device, 0));
+
+	req.sent = 0;
+	req.complete = 0;
+	req.reply_len = 0;
+	req.next = current_req;
+
+	if (current_req != NULL) {
+		current_req = &req;
+	} else {
+		current_req = &req;
+		last_req = &req;
+	}
+}
+
+/* Send an ADB request; if sync, poll out the reply 'till it's done */
+static int macii_send_request(struct adb_request *req, int sync)
+{
+	int err;
+	unsigned long flags;
+
+	BUG_ON(request_is_queued(req));
+
+	local_irq_save(flags);
+	err = macii_write(req);
+	local_irq_restore(flags);
+
+	if (!err && sync) {
+		while (!req->complete) {
+			macii_poll();
+		}
+		BUG_ON(request_is_queued(req));
+	}
+
+	return err;
+}
+
+/* Send an ADB request (append to request queue) */
+static int macii_write(struct adb_request *req)
+{
+	if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
+		req->complete = 1;
+		return -EINVAL;
+	}
+	
+	req->next = NULL;
+	req->sent = 0;
+	req->complete = 0;
+	req->reply_len = 0;
+
+	if (current_req != NULL) {
+		last_req->next = req;
+		last_req = req;
+	} else {
+		current_req = req;
+		last_req = req;
+		if (macii_state == idle) macii_start();
+	}
+	return 0;
+}
+
+/* Start auto-polling */
+static int macii_autopoll(int devs)
+{
+	static struct adb_request req;
+	unsigned long flags;
+	int err = 0;
+
+	/* bit 1 == device 1, and so on. */
+	autopoll_devs = devs & 0xFFFE;
+
+	if (!autopoll_devs) return 0;
+
+	local_irq_save(flags);
+
+	if (current_req == NULL) {
+		/* Send a Talk Reg 0. The controller will repeatedly transmit
+		 * this as long as it is idle.
+		 */
+		adb_request(&req, NULL, ADBREQ_NOSEND, 1,
+		            ADB_READREG(ffs(autopoll_devs) - 1, 0));
+		err = macii_write(&req);
+	}
+
+	local_irq_restore(flags);
+	return err;
+}
+
+static inline int need_autopoll(void) {
+	/* Was the last command Talk Reg 0
+	 * and is the target on the autopoll list?
+	 */
+	if ((command_byte & 0x0F) == 0x0C &&
+	    ((1 << ((command_byte & 0xF0) >> 4)) & autopoll_devs))
+		return 0;
+	return 1;
+}
+
+/* Prod the chip without interrupts */
+static void macii_poll(void)
+{
+	disable_irq(IRQ_MAC_ADB);
+	macii_interrupt(0, NULL);
+	enable_irq(IRQ_MAC_ADB);
+}
+
+/* Reset the bus */
+static int macii_reset_bus(void)
+{
+	static struct adb_request req;
+	
+	if (request_is_queued(&req))
+		return 0;
+
+	/* Command = 0, Address = ignored */
+	adb_request(&req, NULL, 0, 1, ADB_BUSRESET);
+
+	/* Don't want any more requests during the Global Reset low time. */
+	udelay(3000);
+
+	return 0;
+}
+
+/* Start sending ADB packet */
+static void macii_start(void)
+{
+	struct adb_request *req;
+
+	req = current_req;
+
+	BUG_ON(req == NULL);
+
+	BUG_ON(macii_state != idle);
+
+	/* Now send it. Be careful though, that first byte of the request
+	 * is actually ADB_PACKET; the real data begins at index 1!
+	 * And req->nbytes is the number of bytes of real data plus one.
+	 */
+
+	/* store command byte */
+	command_byte = req->data[1];
+	/* Output mode */
+	via[ACR] |= SR_OUT;
+	/* Load data */
+	via[SR] = req->data[1];
+	/* set ADB state to 'command' */
+	via[B] = (via[B] & ~ST_MASK) | ST_CMD;
+
+	macii_state = sending;
+	data_index = 2;
+}
+
+/*
+ * The notorious ADB interrupt handler - does all of the protocol handling.
+ * Relies on the ADB controller sending and receiving data, thereby
+ * generating shift register interrupts (SR_INT) for us. This means there has
+ * to be activity on the ADB bus. The chip will poll to achieve this.
+ *
+ * The basic ADB state machine was left unchanged from the original MacII code
+ * by Alan Cox, which was based on the CUDA driver for PowerMac. 
+ * The syntax of the ADB status lines is totally different on MacII,
+ * though. MacII uses the states Command -> Even -> Odd -> Even ->...-> Idle
+ * for sending and Idle -> Even -> Odd -> Even ->...-> Idle for receiving.
+ * Start and end of a receive packet are signalled by asserting /IRQ on the
+ * interrupt line (/IRQ means the CTLR_IRQ bit in port B; not to be confused
+ * with the VIA shift register interrupt. /IRQ never actually interrupts the
+ * processor, it's just an ordinary input.)
+ */
+static irqreturn_t macii_interrupt(int irq, void *arg)
+{
+	int x;
+	static int entered;
+	struct adb_request *req;
+
+	if (!arg) {
+		/* Clear the SR IRQ flag when polling. */
+		if (via[IFR] & SR_INT)
+			via[IFR] = SR_INT;
+		else
+			return IRQ_NONE;
+	}
+
+	BUG_ON(entered++);
+
+	last_status = status;
+	status = via[B] & (ST_MASK|CTLR_IRQ);
+
+	switch (macii_state) {
+		case idle:
+			if (reading_reply) {
+				reply_ptr = current_req->reply;
+			} else {
+				BUG_ON(current_req != NULL);
+				reply_ptr = reply_buf;
+			}
+
+			x = via[SR];
+
+			if ((status & CTLR_IRQ) && (x == 0xFF)) {
+				/* Bus timeout without SRQ sequence:
+				 *     data is "FF" while CTLR_IRQ is "H"
+				 */
+				reply_len = 0;
+				srq_asserted = 0;
+				macii_state = read_done;
+			} else {
+				macii_state = reading;
+				*reply_ptr = x;
+				reply_len = 1;
+			}
+
+			/* set ADB state = even for first data byte */
+			via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
+			break;
+
+		case sending:
+			req = current_req;
+			if (data_index >= req->nbytes) {
+				req->sent = 1;
+				macii_state = idle;
+
+				if (req->reply_expected) {
+					reading_reply = 1;
+				} else {
+					req->complete = 1;
+					current_req = req->next;
+					if (req->done) (*req->done)(req);
+
+					if (current_req)
+						macii_start();
+					else
+						if (need_autopoll())
+							macii_autopoll(autopoll_devs);
+				}
+
+				if (macii_state == idle) {
+					/* reset to shift in */
+					via[ACR] &= ~SR_OUT;
+					x = via[SR];
+					/* set ADB state idle - might get SRQ */
+					via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
+				}
+			} else {
+				via[SR] = req->data[data_index++];
+
+				if ( (via[B] & ST_MASK) == ST_CMD ) {
+					/* just sent the command byte, set to EVEN */
+					via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
+				} else {
+					/* invert state bits, toggle ODD/EVEN */
+					via[B] ^= ST_MASK;
+				}
+			}
+			break;
+
+		case reading:
+			x = via[SR];
+			BUG_ON((status & ST_MASK) == ST_CMD ||
+			       (status & ST_MASK) == ST_IDLE);
+
+			/* Bus timeout with SRQ sequence:
+			 *     data is "XX FF"      while CTLR_IRQ is "L L"
+			 * End of packet without SRQ sequence:
+			 *     data is "XX...YY 00" while CTLR_IRQ is "L...H L"
+			 * End of packet SRQ sequence:
+			 *     data is "XX...YY 00" while CTLR_IRQ is "L...L L"
+			 * (where XX is the first response byte and
+			 * YY is the last byte of valid response data.)
+			 */
+
+			srq_asserted = 0;
+			if (!(status & CTLR_IRQ)) {
+				if (x == 0xFF) {
+					if (!(last_status & CTLR_IRQ)) {
+						macii_state = read_done;
+						reply_len = 0;
+						srq_asserted = 1;
+					}
+				} else if (x == 0x00) {
+					macii_state = read_done;
+					if (!(last_status & CTLR_IRQ))
+						srq_asserted = 1;
+				}
+			}
+
+			if (macii_state == reading) {
+				BUG_ON(reply_len > 15);
+				reply_ptr++;
+				*reply_ptr = x;
+				reply_len++;
+			}
+
+			/* invert state bits, toggle ODD/EVEN */
+			via[B] ^= ST_MASK;
+			break;
+
+		case read_done:
+			x = via[SR];
+
+			if (reading_reply) {
+				reading_reply = 0;
+				req = current_req;
+				req->reply_len = reply_len;
+				req->complete = 1;
+				current_req = req->next;
+				if (req->done) (*req->done)(req);
+			} else if (reply_len && autopoll_devs)
+				adb_input(reply_buf, reply_len, 0);
+
+			macii_state = idle;
+
+			/* SRQ seen before, initiate poll now */
+			if (srq_asserted)
+				macii_queue_poll();
+
+			if (current_req)
+				macii_start();
+			else
+				if (need_autopoll())
+					macii_autopoll(autopoll_devs);
+
+			if (macii_state == idle)
+				via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
+			break;
+
+		default:
+		break;
+	}
+
+	entered--;
+	return IRQ_HANDLED;
+}