android_kernel_xiaomi_sm8350/drivers/macintosh/via-macii.c
Finn Thain d95fd5fce8 m68k: Mac II ADB fixes
Fix a crash caused by requests placed in the queue with the completed flag
already set. This lead to some ADB_SYNC requests returning early and their
request structs being popped off the stack while still queued. Stack corruption
ensued or an invalid request callback pointer was invoked or both. Eliminate
macii_retransmit() and its buggy implementation of macii_write(). Have
macii_queue_poll() fully initialise the request queues.

Fix a bug in macii_queue_poll() where the last_req pointer was not being set.
This caused some requests to leave the queue before being completed (and would
also corrupt the stack under certain conditions).

Fix a race in macii_start that could set the state machine to "reading" while
current_req was null.

No longer send poll commands with the ADBREQ_REPLY flag -- doing that caused
the replies to be stored in the request buffer where they were forgotten
about.

Don't autopoll by continuously sending new Talk commands. Get the controller to
do that for us. This reduces the ADB interrupt rate on an idle bus to about 5
per second. Only autopoll the devices that were probed.

Explicitly clear the interrupt flag when polling.

Use disable_irq rather than local_irq_save when polling.

Remove excess local_irq_save/restore pairs.

Improve bus timeout and service request detection.

Remove unused code (last_reply, adb_dir etc) and unneeded code (prefix_len,
first_byte etc).

Change TIP and TACK to their correct names on this ADB controller (ST_EVEN and
ST_ODD).

Add some commentry.

Add a generous quantity of sanity checks (BUG_ONs).

Let m68k macs use the adb_sync boot param too.

Tested on Mac II, Mac IIci, Quadra 650, Quadra 700 etc.

Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Geert Uytterhoeven <geert@linux-m68k.org>
Signed-off-by: Linus Torvalds <torvalds@linux-foundation.org>
2007-05-04 17:59:07 -07:00

552 lines
14 KiB
C

/*
* 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 <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 <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/machw.h>
#include <asm/mac_via.h>
#include <asm/system.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 = {
"Mac II",
macii_probe,
macii_init,
macii_send_request,
macii_autopoll,
macii_poll,
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 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)
{
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, IRQ_FLG_LOCK, "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;
}