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android_kernel_xiaomi_sm8350/drivers/macintosh/via-macii.c
David Howells 7d12e780e0 IRQ: Maintain regs pointer globally rather than passing to IRQ handlers 
Maintain a per-CPU global "struct pt_regs *" variable which can be used instead
of passing regs around manually through all ~1800 interrupt handlers in the
Linux kernel.

The regs pointer is used in few places, but it potentially costs both stack
space and code to pass it around.  On the FRV arch, removing the regs parameter
from all the genirq function results in a 20% speed up of the IRQ exit path
(ie: from leaving timer_interrupt() to leaving do_IRQ()).

Where appropriate, an arch may override the generic storage facility and do
something different with the variable.  On FRV, for instance, the address is
maintained in GR28 at all times inside the kernel as part of general exception
handling.

Having looked over the code, it appears that the parameter may be handed down
through up to twenty or so layers of functions.  Consider a USB character
device attached to a USB hub, attached to a USB controller that posts its
interrupts through a cascaded auxiliary interrupt controller.  A character
device driver may want to pass regs to the sysrq handler through the input
layer which adds another few layers of parameter passing.

I've build this code with allyesconfig for x86_64 and i386.  I've runtested the
main part of the code on FRV and i386, though I can't test most of the drivers.
I've also done partial conversion for powerpc and MIPS - these at least compile
with minimal configurations.

This will affect all archs.  Mostly the changes should be relatively easy.
Take do_IRQ(), store the regs pointer at the beginning, saving the old one:

	struct pt_regs *old_regs = set_irq_regs(regs);

And put the old one back at the end:

	set_irq_regs(old_regs);

Don't pass regs through to generic_handle_irq() or __do_IRQ().

In timer_interrupt(), this sort of change will be necessary:

	-	update_process_times(user_mode(regs));
	-	profile_tick(CPU_PROFILING, regs);
	+	update_process_times(user_mode(get_irq_regs()));
	+	profile_tick(CPU_PROFILING);

I'd like to move update_process_times()'s use of get_irq_regs() into itself,
except that i386, alone of the archs, uses something other than user_mode().

Some notes on the interrupt handling in the drivers:

 (*) input_dev() is now gone entirely.  The regs pointer is no longer stored in
     the input_dev struct.

 (*) finish_unlinks() in drivers/usb/host/ohci-q.c needs checking.  It does
     something different depending on whether it's been supplied with a regs
     pointer or not.

 (*) Various IRQ handler function pointers have been moved to type
     irq_handler_t.

Signed-Off-By: David Howells <dhowells@redhat.com>
(cherry picked from 1b16e7ac850969f38b375e511e3fa2f474a33867 commit)
2006-10-05 15:10:12 +01:00

653 lines
17 KiB
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Raw Blame History

/*
* 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.
*/
#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 <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/io.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 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 irqreturn_t macii_interrupt(int irq, void *arg);
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,
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 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) return err;
err = request_irq(IRQ_MAC_ADB, macii_interrupt, IRQ_FLG_LOCK, "ADB",
macii_interrupt);
if (err) return err;
macii_state = idle;
local_irq_restore(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));
local_irq_save(flags);
req.next = current_req;
current_req = &req;
local_irq_restore(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));
local_irq_save(flags);
if (current_req != NULL) {
last_req->next = &rt;
last_req = &rt;
} else {
current_req = &rt;
last_req = &rt;
}
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;
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->nbytes > 15) {
req->complete = 1;
return -EINVAL;
}
req->next = NULL;
req->sent = 0;
req->complete = 0;
req->reply_len = 0;
local_irq_save(flags);
if (current_req != NULL) {
last_req->next = req;
last_req = req;
} else {
current_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;
}
/* 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, NULL);
local_irq_restore(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;
}
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)
*/
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 = 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 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).
*/
static irqreturn_t macii_interrupt(int irq, void *arg)
{
int x, adbdir;
unsigned long flags;
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;
}
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 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;
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++];
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:
/* 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;
}
/* 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) == 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;
}
}
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, 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;
}
/* 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);
}
break;
default:
break;
}
/* reset mutex and interrupts */
driver_running = 0;
local_irq_restore(flags);
return IRQ_HANDLED;
}
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