* 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 <fthain@telegraphics.com.au> - 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 <asm/macints.h>
#include <asm/machw.h>
#include <asm/mac_via.h>
-#include <asm/io.h>
#include <asm/system.h>
static volatile unsigned char *via;
#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 CTLR_IRQ 0x08 /* Controller rcv status (input) */
#define ST_MASK 0x30 /* mask for selecting ADB state bits */
/* Bits in ACR */
#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 */
static int macii_init_via(void);
static void macii_start(void);
static irqreturn_t macii_interrupt(int irq, void *arg);
-static void macii_retransmit(int);
static void macii_queue_poll(void);
static int macii_probe(void);
sending,
reading,
read_done,
- awaiting_reply
} macii_state;
-static int need_poll;
-static int command_byte;
-static int last_reply;
-static int last_active;
-
-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;
-
-/* debug level 10 required for ADB logging (should be && debug_adb, ideally) */
+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 req->data or reply_buf */
+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)
local_irq_save(flags);
err = macii_init_via();
- if (err) return err;
+ if (err) goto out;
err = request_irq(IRQ_MAC_ADB, macii_interrupt, IRQ_FLG_LOCK, "ADB",
macii_interrupt);
- if (err) return err;
+ if (err) goto out;
macii_state = idle;
+out:
local_irq_restore(flags);
- return 0;
+ return err;
}
/* initialize the hardware */
{
unsigned char x;
- /* Set the lines up. We want TREQ as input TACK|TIP as output */
- via[DIRB] = (via[DIRB] | TACK | TIP) & ~TREQ;
+ /* 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|TREQ);
+ last_status = via[B] & (ST_MASK|CTLR_IRQ);
/* Shift register on input */
via[ACR] = (via[ACR] & ~SR_CTRL) | SR_EXT;
return 0;
}
-/* Send an ADB poll (Talk Register 0 command, tagged on the front of the request queue) */
+/* Send an ADB poll (Talk Register 0 command prepended to the request queue) */
static void macii_queue_poll(void)
{
- static int device = 0;
- static int in_poll=0;
+ /* 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;
- 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));
-
- local_irq_save(flags);
-
- req.next = current_req;
- current_req = &req;
- local_irq_restore(flags);
- macii_start();
- in_poll--;
-}
+ if (!autopoll_devs) return;
-/* 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");
+ 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;
- in_retransmit++;
+ BUG_ON(request_is_queued(&req));
- adb_request(&rt, NULL, ADBREQ_REPLY|ADBREQ_NOSEND, 1,
- ADB_READREG(device, 0));
+ adb_request(&req, NULL, ADBREQ_NOSEND, 1,
+ ADB_READREG(next_device, 0));
- local_irq_save(flags);
+ req.sent = 0;
+ req.complete = 0;
+ req.reply_len = 0;
+ req.next = current_req;
if (current_req != NULL) {
- last_req->next = &rt;
- last_req = &rt;
+ current_req = &req;
} else {
- current_req = &rt;
- last_req = &rt;
+ current_req = &req;
+ last_req = &req;
}
-
- if (macii_state == idle) macii_start();
-
- local_irq_restore(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;
+ int err;
+ unsigned long flags;
- i = macii_write(req);
- if (i) return i;
+ BUG_ON(request_is_queued(req));
- if (sync) {
- while (!req->complete) macii_poll();
+ 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 0;
+
+ return err;
}
-/* Send an ADB request */
+/* Send an ADB request (append to request queue) */
static int macii_write(struct adb_request *req)
{
- unsigned long flags;
-
if (req->nbytes < 2 || req->data[0] != ADB_PACKET || req->nbytes > 15) {
req->complete = 1;
return -EINVAL;
req->complete = 0;
req->reply_len = 0;
- local_irq_save(flags);
-
if (current_req != NULL) {
last_req->next = req;
last_req = req;
last_req = req;
if (macii_state == idle) macii_start();
}
-
- local_irq_restore(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;
+ 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)
{
- unsigned long flags;
-
- local_irq_save(flags);
- if (via[IFR] & SR_INT) macii_interrupt(0, NULL);
- local_irq_restore(flags);
+ disable_irq(IRQ_MAC_ADB);
+ macii_interrupt(0, NULL);
+ enable_irq(IRQ_MAC_ADB);
}
/* Reset the bus */
{
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)
{
- 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;
- }
- local_irq_save(flags);
-
- /*
- * IRQ signaled ?? (means ADB controller wants to send, or might
- * be end of packet if we were reading)
- */
-#if 0 /* FIXME: This is broke broke broke, for some reason */
- if ((via[B] & TREQ) == 0) {
- printk("macii_start: weird poll stuff. huh?\n");
- /*
- * 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 ? */
- local_irq_restore(flags);
- return;
- } else {
- need_poll = 0;
- }
- }
-#endif
- /*
- * Another retry pending? (sanity check)
+ 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.
*/
- 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 */
macii_state = sending;
data_index = 2;
-
- local_irq_restore(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 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 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).
+ * 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, adbdir;
- unsigned long flags;
+ int x;
+ static int entered;
struct adb_request *req;
- last_status = status;
-
- /* prevent races due to SCSI enabling ints */
- local_irq_save(flags);
-
- if (driver_running) {
- local_irq_restore(flags);
- return IRQ_NONE;
+ if (!arg) {
+ /* Clear the SR IRQ flag when polling. */
+ if (via[IFR] & SR_INT)
+ via[IFR] = SR_INT;
+ else
+ return IRQ_NONE;
}
- driver_running = 1;
-
- status = via[B] & (ST_MASK|TREQ);
- adbdir = via[ACR] & SR_OUT;
+ 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];
- 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;
+ 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;
+ }
- 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 sending:
req = current_req;
if (data_index >= req->nbytes) {
- /* print an error message if a listen command has no data */
- if (((command_byte & 0x0C) == 0x08)
- /* && (console_loglevel == 10) */
- && (data_index == 2))
- printk("MacII ADB: 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;
+ macii_state = idle;
if (req->reply_expected) {
- macii_state = awaiting_reply;
+ reading_reply = 1;
} else {
req->complete = 1;
current_req = req->next;
if (req->done) (*req->done)(req);
- macii_state = idle;
- if (current_req || retry_req)
+
+ if (current_req)
macii_start();
else
- macii_retransmit((command_byte & 0xF0) >> 4);
+ 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++];
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.)
+ */
- /* 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 ADB: 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;
+ 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;
}
- /* 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;
+ }
+
+ if (macii_state == reading) {
+ BUG_ON(reply_len > 15);
reply_ptr++;
+ *reply_ptr = x;
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) == 0) && (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;
- }
- }
+ /* 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_ptr - req->reply;
+ req->reply_len = reply_len;
req->complete = 1;
current_req = req->next;
if (req->done) (*req->done)(req);
- } else {
- adb_input(reply_buf, reply_ptr - reply_buf, 0);
- }
+ } else if (reply_len && autopoll_devs)
+ adb_input(reply_buf, reply_len, 0);
- /*
- * remember this device ID; it's the latest we got a
- * reply from!
- */
- last_reply = command_byte;
- last_active = (command_byte & 0xF0) >> 4;
+ macii_state = idle;
/* SRQ seen before, initiate poll now */
- if (need_poll) {
- macii_state = idle;
+ if (srq_asserted)
macii_queue_poll();
- need_poll = 0;
- break;
- }
-
- /* set ADB state to idle */
- via[B] = (via[B] & ~ST_MASK) | ST_IDLE;
-
- /* /IRQ seen, so the ADB controller has data for us */
- if ((via[B] & TREQ) != 0) {
- 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);
- }
+ 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;
}
- /* reset mutex and interrupts */
- driver_running = 0;
- local_irq_restore(flags);
+
+ entered--;
return IRQ_HANDLED;
}
projects / linux-2.6 / commitdiff