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/*
* 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.
*/
#include <stdarg.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/sched.h>
#include <linux/adb.h>
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/machw.h>
#include <asm/mac_via.h>
#include <asm/io.h>
#include <asm/system.h>
#include <asm/init.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 TREQ 0x08 /* Transfer request (input) */
#define TACK 0x10 /* Transfer acknowledge (output) */
#define TIP 0x20 /* Transfer in progress (output) */
#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 */
#define SR_DATA 0x08 /* Shift register data */
#define SR_CLOCK 0x10 /* Shift register clock */
/* 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 void macii_interrupt(int irq, void *arg, struct pt_regs *regs);
static void macii_retransmit(int);
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 = {
"Mac II",
macii_probe,
macii_init,
macii_send_request,
macii_autopoll,
macii_poll,
macii_reset_bus
};
static enum macii_state {
idle,
sent_first_byte,
sending,
reading,
read_done,
awaiting_reply
} macii_state;
static int need_poll = 0;
static int command_byte = 0;
static int last_reply = 0;
static int last_active = 0;
static struct adb_request *current_req;
static struct adb_request *last_req;
static struct adb_request *retry_req;
static unsigned char reply_buf[16];
static unsigned char *reply_ptr;
static int reply_len;
static int reading_reply;
static int data_index;
static int first_byte;
static int prefix_len;
static int status = ST_IDLE|TREQ;
static int last_status;
static int driver_running = 0;
/* debug level 10 required for ADB logging (should be && debug_adb, ideally) */
/* 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 v0.4 for Unified ADB\n");
return 0;
}
/* Initialize the driver */
int macii_init(void)
{
unsigned long flags;
int err;
save_flags(flags);
cli();
err = macii_init_via();
if (err) return err;
err = request_irq(IRQ_MAC_ADB, macii_interrupt, IRQ_FLG_LOCK, "ADB",
macii_interrupt);
if (err) return err;
macii_state = idle;
restore_flags(flags);
return 0;
}
/* initialize the hardware */
static int macii_init_via(void)
{
unsigned char x;
/* Set the lines up. We want TREQ as input TACK|TIP as output */
via[DIRB] = (via[DIRB] | TACK | TIP) & ~TREQ;
/* Set up state: idle */
via[B] |= ST_IDLE;
last_status = via[B] & (ST_MASK|TREQ);
/* 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, tagged on the front of the request queue) */
static void macii_queue_poll(void)
{
static int device = 0;
static int in_poll=0;
static struct adb_request req;
unsigned long flags;
if (in_poll) printk("macii_queue_poll: double poll!\n");
in_poll++;
if (++device > 15) device = 1;
adb_request(&req, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
ADB_READREG(device, 0));
save_flags(flags);
cli();
req.next = current_req;
current_req = &req;
restore_flags(flags);
macii_start();
in_poll--;
}
/* Send an ADB retransmit (Talk, appended to the request queue) */
static void macii_retransmit(int device)
{
static int in_retransmit = 0;
static struct adb_request rt;
unsigned long flags;
if (in_retransmit) printk("macii_retransmit: double retransmit!\n");
in_retransmit++;
adb_request(&rt, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
ADB_READREG(device, 0));
save_flags(flags);
cli();
if (current_req != NULL) {
last_req->next = &rt;
last_req = &rt;
} else {
current_req = &rt;
last_req = &rt;
}
if (macii_state == idle) macii_start();
restore_flags(flags);
in_retransmit--;
}
/* 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 i;
i = macii_write(req);
if (i) return i;
if (sync) {
while (!req->complete) macii_poll();
}
return 0;
}
/* Send an ADB request */
static int macii_write(struct adb_request *req)
{
unsigned long flags;
if (req->nbytes < 2 || req->data[0] != ADB_PACKET) {
req->complete = 1;
return -EINVAL;
}
req->next = 0;
req->sent = 0;
req->complete = 0;
req->reply_len = 0;
save_flags(flags); cli();
if (current_req != NULL) {
last_req->next = req;
last_req = req;
} else {
current_req = req;
last_req = req;
if (macii_state == idle) macii_start();
}
restore_flags(flags);
return 0;
}
/* Start auto-polling */
static int macii_autopoll(int devs)
{
/* Just ping a random default address */
if (!(current_req || retry_req))
macii_retransmit( (last_active < 16 && last_active > 0) ? last_active : 3);
return 0;
}
/* Prod the chip without interrupts */
static void macii_poll(void)
{
unsigned long flags;
save_flags(flags); cli();
if (via[IFR] & SR_INT) macii_interrupt(0, 0, 0);
restore_flags(flags);
}
/* Reset the bus */
static int macii_reset_bus(void)
{
static struct adb_request req;
/* Command = 0, Address = ignored */
adb_request(&req, NULL, 0, 1, ADB_BUSRESET);
return 0;
}
/* Start sending ADB packet */
static void macii_start(void)
{
unsigned long flags;
struct adb_request *req;
req = current_req;
if (!req) return;
/* assert macii_state == idle */
if (macii_state != idle) {
printk("macii_start: called while driver busy (%p %x %x)!\n",
req, macii_state, (uint) via1[B] & (ST_MASK|TREQ));
return;
}
save_flags(flags); cli();
/*
* IRQ signaled ?? (means ADB controller wants to send, or might
* be end of packet if we were reading)
*/
if ((via[B] & TREQ) == 0) {
/*
* FIXME - we need to restart this on a timer
* or a collision at boot hangs us.
* Never set macii_state to idle here, or macii_start
* won't be called again from send_request!
* (need to re-check other cases ...)
*/
/*
* if the interrupt handler set the need_poll
* flag, it's hopefully a SRQ poll or re-Talk
* so we try to send here anyway
*/
if (!need_poll) {
if (console_loglevel == 10)
printk("macii_start: device busy - retry %p state %d status %x!\n",
req, macii_state,
(uint) via[B] & (ST_MASK|TREQ));
retry_req = req;
/* set ADB status here ? */
restore_flags(flags);
return;
} else {
need_poll = 0;
}
}
/*
* Another retry pending? (sanity check)
*/
if (retry_req) {
retry_req = NULL;
}
/* Now send it. Be careful though, that first byte of the request */
/* is actually ADB_PACKET; the real data begins at index 1! */
/* 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 = sent_first_byte;
data_index = 2;
restore_flags(flags);
}
/*
* The notorious ADB interrupt handler - does all of the protocol handling,
* except for starting new send operations. Relies heavily on the ADB
* controller sending and receiving data, thereby generating SR interrupts
* for us. This means there has to be always activity on the ADB bus, otherwise
* the whole process dies and has to be re-kicked by sending TALK requests ...
* CUDA-based Macs seem to solve this with the autopoll option, for MacII-type
* ADB the problem isn't solved yet (retransmit of the latest active TALK seems
* a good choice; either on timeout or on a timer interrupt).
*
* 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 seems to be 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 signaled by asserting /IRQ on the interrupt
* line. Timeouts are signaled by a sequence of 4 0xFF, with /IRQ asserted on
* every other byte. SRQ is probably signaled by 3 or more 0xFF tacked on the
* end of a packet. (Thanks to Guido Koerber for eavesdropping on the ADB
* protocol with a logic analyzer!!)
*
* Note: As of 21/10/97, the MacII ADB part works including timeout detection
* and retransmit (Talk to the last active device).
*/
void macii_interrupt(int irq, void *arg, struct pt_regs *regs)
{
int x, adbdir;
unsigned long flags;
struct adb_request *req;
last_status = status;
/* prevent races due to SCSI enabling ints */
save_flags(flags); cli();
if (driver_running) {
restore_flags(flags);
return;
}
driver_running = 1;
status = via[B] & (ST_MASK|TREQ);
adbdir = via[ACR] & SR_OUT;
switch (macii_state) {
case idle:
x = via[SR];
first_byte = x;
/* set ADB state = even for first data byte */
via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
reply_buf[0] = first_byte; /* was command_byte?? */
reply_ptr = reply_buf + 1;
reply_len = 1;
prefix_len = 1;
reading_reply = 0;
macii_state = reading;
break;
case awaiting_reply:
/* handshake etc. for II ?? */
x = via[SR];
first_byte = x;
/* set ADB state = even for first data byte */
via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
current_req->reply[0] = first_byte;
reply_ptr = current_req->reply + 1;
reply_len = 1;
prefix_len = 1;
reading_reply = 1;
macii_state = reading;
break;
case sent_first_byte:
req = current_req;
/* maybe we're already done (Talk, or Poll)? */
if (data_index >= req->nbytes) {
/* reset to shift in */
/* If it's a Listen command and we're done, someone's doing weird stuff. */
if (((command_byte & 0x0C) == 0x08)
&& (console_loglevel == 10))
printk("macii_interrupt: listen command with no data: %x!\n",
command_byte);
/* 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;
req->sent = 1;
if (req->reply_expected) {
macii_state = awaiting_reply;
} else {
req->complete = 1;
current_req = req->next;
if (req->done) (*req->done)(req);
macii_state = idle;
if (current_req || retry_req)
macii_start();
else
macii_retransmit((command_byte & 0xF0) >> 4);
}
} else {
/* SR already set to shift out; send byte */
via[SR] = current_req->data[data_index++];
/* set state to ST_EVEN (first byte was: ST_CMD) */
via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
macii_state = sending;
}
break;
case sending:
req = current_req;
if (data_index >= req->nbytes) {
/* 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;
req->sent = 1;
if (req->reply_expected) {
macii_state = awaiting_reply;
} else {
req->complete = 1;
current_req = req->next;
if (req->done) (*req->done)(req);
macii_state = idle;
if (current_req || retry_req)
macii_start();
else
macii_retransmit((command_byte & 0xF0) >> 4);
}
} else {
via[SR] = req->data[data_index++];
/* invert state bits, toggle ODD/EVEN */
via[B] ^= ST_MASK;
}
break;
case reading:
/* timeout / SRQ handling for II hw */
if( (first_byte == 0xFF && (reply_len-prefix_len)==2
&& memcmp(reply_ptr-2,"\xFF\xFF",2)==0) ||
((reply_len-prefix_len)==3
&& memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0))
{
/*
* possible timeout (in fact, most probably a
* timeout, since SRQ can't be signaled without
* transfer on the bus).
* The last three bytes seen were FF, together
* with the starting byte (in case we started
* on 'idle' or 'awaiting_reply') this probably
* makes four. So this is mostl likely #5!
* The timeout signal is a pattern 1 0 1 0 0..
* on /INT, meaning we missed it :-(
*/
x = via[SR];
if (x != 0xFF) printk("macii_interrupt: mistaken timeout/SRQ!\n");
if ((status & TREQ) == (last_status & TREQ)) {
/* Not a timeout. Unsolicited SRQ? weird. */
/* Terminate the SRQ packet and poll */
need_poll = 1;
}
/* There's no packet to get, so reply is blank */
via[B] ^= ST_MASK;
reply_ptr -= (reply_len-prefix_len);
reply_len = prefix_len;
macii_state = read_done;
break;
} /* end timeout / SRQ handling for II hw. */
if((reply_len-prefix_len)>3
&& memcmp(reply_ptr-3,"\xFF\xFF\xFF",3)==0)
{
/* SRQ tacked on data packet */
/* Terminate the packet (SRQ never ends) */
x = via[SR];
macii_state = read_done;
reply_len -= 3;
reply_ptr -= 3;
need_poll = 1;
/* need to continue; next byte not seen else */
} else {
/* Sanity check */
if (reply_len > 15) reply_len = 0;
/* read byte */
x = via[SR];
*reply_ptr = x;
reply_ptr++;
reply_len++;
}
/* The usual handshake ... */
/*
* NetBSD hints that the next to last byte
* is sent with IRQ !!
* Guido found out it's the last one (0x0),
* but IRQ should be asserted already.
* Problem with timeout detection: First
* transition to /IRQ might be second
* byte of timeout packet!
* Timeouts are signaled by 4x FF.
*/
if (!(status & TREQ) && (x == 0x00)) { /* != 0xFF */
/* invert state bits, toggle ODD/EVEN */
via[B] ^= ST_MASK;
/* adjust packet length */
reply_len--;
reply_ptr--;
macii_state = read_done;
} else {
/* not caught: ST_CMD */
/* required for re-entry 'reading'! */
if ((status & ST_MASK) == ST_IDLE) {
/* (in)sanity check - set even */
via[B] = (via[B] & ~ST_MASK) | ST_EVEN;
} else {
/* invert state bits */
via[B] ^= ST_MASK;
}
}
break;
case read_done:
x = via[SR];
if (reading_reply) {
req = current_req;
req->reply_len = reply_ptr - req->reply;
req->complete = 1;
current_req = req->next;
if (req->done) (*req->done)(req);
} else {
adb_input(reply_buf, reply_ptr - reply_buf,
regs, 0);
}
/*
* remember this device ID; it's the latest we got a
* reply from!
*/
last_reply = command_byte;
last_active = (command_byte & 0xF0) >> 4;
/* SRQ seen before, initiate poll now */
if (need_poll) {
macii_state = idle;
macii_queue_poll();
need_poll = 0;
break;
}
/* /IRQ seen, so the ADB controller has data for us */
if (!(status & TREQ)) {
/* set ADB state to idle */
via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
macii_state = reading;
reply_buf[0] = command_byte;
reply_ptr = reply_buf + 1;
reply_len = 1;
prefix_len = 1;
reading_reply = 0;
} else {
/* no IRQ, send next packet or wait */
macii_state = idle;
if (current_req)
macii_start();
else
macii_retransmit(last_active);
}
break;
default:
break;
}
/* reset mutex and interrupts */
driver_running = 0;
restore_flags(flags);
}
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