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minix/drivers/printer/printer.c
Cristiano Giuffrida 1f5841c8ed Basic System Event Framework (SEF) with ping and live update. 
SYSLIB CHANGES:
- SEF must be used by every system process and is thereby part of the system
library.
- The framework provides a receive() interface (sef_receive) for system
processes to automatically catch known system even messages and process them.
- SEF provides a default behavior for each type of system event, but allows
system processes to register callbacks to override the default behavior.
- Custom (local to the process) or predefined (provided by SEF) callback
implementations can be registered to SEF.
- SEF currently includes support for 2 types of system events:
  1. SEF Ping. The event occurs every time RS sends a ping to figure out
  whether a system process is still alive. The default callback implementation
  provided by SEF is to notify RS back to let it know the process is alive
  and kicking.
  2. SEF Live update. The event occurs every time RS sends a prepare to update
  message to let a system process know an update is available and to prepare
  for it. The live update support is very basic for now. SEF only deals with
  verifying if the prepare state can be supported by the process, dumping the
  state for debugging purposes, and providing an event-driven programming
  model to the process to react to state changes check-in when ready to update.
- SEF should be extended in the future to integrate support for more types of
system events. Ideally, all the cross-cutting concerns should be integrated into
SEF to avoid duplicating code and ease extensibility. Examples include:
  * PM notify messages primarily used at shutdown.
  * SYSTEM notify messages primarily used for signals.
  * CLOCK notify messages used for system alarms.
  * Debug messages. IS could still be in charge of fkey handling but would
  forward the debug message to the target process (e.g. PM, if the user
  requested debug information about PM). SEF would then catch the message and
  do nothing unless the process has registered an appropriate callback to
  deal with the event. This simplifies the programming model to print debug
  information, avoids duplicating code, and reduces the effort to print
  debug information.

SYSTEM PROCESSES CHANGES:
- Every system process registers SEF callbacks it needs to override the default
system behavior and calls sef_startup() right after being started.
- sef_startup() does almost nothing now, but will be extended in the future to
support callbacks of its own to let RS control and synchronize with every
system process at initialization time.
- Every system process calls sef_receive() now rather than receive() directly,
to let SEF handle predefined system events.

RS CHANGES:
- RS supports a basic single-component live update protocol now, as follows:
  * When an update command is issued (via "service update *"), RS notifies the
  target system process to prepare for a specific update state.
  * If the process doesn't respond back in time, the update is aborted.
  * When the process responds back, RS kills it and marks it for refreshing.
  * The process is then automatically restarted as for a buggy process and can
  start running again.
  * Live update is currently prototyped as a controlled failure.
2009-12-21 14:12:21 +00:00

503 lines
18 KiB
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/* This file contains the printer driver. It is a fairly simple driver,
* supporting only one printer. Characters that are written to the driver
* are written to the printer without any changes at all.
*
* Changes:
* May 07, 2004 fix: wait until printer is ready (Jorrit N. Herder)
* May 06, 2004 printer driver moved to user-space (Jorrit N. Herder)
*
* The valid messages and their parameters are:
*
* DEV_OPEN: initializes the printer
* DEV_CLOSE: does nothing
* HARD_INT: interrupt handler has finished current chunk of output
* DEV_WRITE: a process wants to write on a terminal
* CANCEL: terminate a previous incomplete system call immediately
*
* m_type TTY_LINE IO_ENDPT COUNT ADDRESS
* |-------------+---------+---------+---------+---------|
* | DEV_OPEN | | | | |
* |-------------+---------+---------+---------+---------|
* | DEV_CLOSE | | proc nr | | |
* -------------------------------------------------------
* | HARD_INT | | | | |
* |-------------+---------+---------+---------+---------|
* | SYS_EVENT | | | | |
* |-------------+---------+---------+---------+---------|
* | DEV_WRITE |minor dev| proc nr | count | buf ptr |
* |-------------+---------+---------+---------+---------|
* | CANCEL |minor dev| proc nr | | |
* -------------------------------------------------------
*
* Note: since only 1 printer is supported, minor dev is not used at present.
*/
#include <minix/endpoint.h>
#include "../drivers.h"
/* Control bits (in port_base + 2). "+" means positive logic and "-" means
* negative logic. Most of the signals are negative logic on the pins but
* many are converted to positive logic in the ports. Some manuals are
* misleading because they only document the pin logic.
*
* +0x01 Pin 1 -Strobe
* +0x02 Pin 14 -Auto Feed
* -0x04 Pin 16 -Initialize Printer
* +0x08 Pin 17 -Select Printer
* +0x10 IRQ7 Enable
*
* Auto Feed and Select Printer are always enabled. Strobe is enabled briefly
* when characters are output. Initialize Printer is enabled briefly when
* the task is started. IRQ7 is enabled when the first character is output
* and left enabled until output is completed (or later after certain
* abnormal completions).
*/
#define ASSERT_STROBE 0x1D /* strobe a character to the interface */
#define NEGATE_STROBE 0x1C /* enable interrupt on interface */
#define PR_SELECT 0x0C /* select printer bit */
#define INIT_PRINTER 0x08 /* init printer bits */
/* Status bits (in port_base + 2).
*
* -0x08 Pin 15 -Error
* +0x10 Pin 13 +Select Status
* +0x20 Pin 12 +Out of Paper
* -0x40 Pin 10 -Acknowledge
* -0x80 Pin 11 +Busy
*/
#define BUSY_STATUS 0x10 /* printer gives this status when busy */
#define NO_PAPER 0x20 /* status bit saying that paper is out */
#define NORMAL_STATUS 0x90 /* printer gives this status when idle */
#define ON_LINE 0x10 /* status bit saying that printer is online */
#define STATUS_MASK 0xB0 /* mask to filter out status bits */
#define MAX_ONLINE_RETRIES 120 /* about 60s: waits 0.5s after each retry */
/* Centronics interface timing that must be met by software (in microsec).
*
* Strobe length: 0.5u to 100u (not sure about the upper limit).
* Data set up: 0.5u before strobe.
* Data hold: 0.5u after strobe.
* Init pulse length: over 200u (not sure).
*
* The strobe length is about 50u with the code here and function calls for
* sys_outb() - not much to spare. The 0.5u minimums will not be violated
* with the sys_outb() messages exchanged.
*/
PRIVATE int caller; /* process to tell when printing done (FS) */
PRIVATE int revive_pending; /* set to true if revive is pending */
PRIVATE int revive_status; /* revive status */
PRIVATE int done_status; /* status of last output completion */
PRIVATE int oleft; /* bytes of output left in obuf */
PRIVATE unsigned char obuf[128]; /* output buffer */
PRIVATE unsigned char *optr; /* ptr to next char in obuf to print */
PRIVATE int orig_count; /* original byte count */
PRIVATE int port_base; /* I/O port for printer */
PRIVATE int proc_nr; /* user requesting the printing */
PRIVATE cp_grant_id_t grant_nr; /* grant on which print happens */
PRIVATE int user_left; /* bytes of output left in user buf */
PRIVATE vir_bytes user_vir_g; /* start of user buf (address or grant) */
PRIVATE vir_bytes user_vir_d; /* offset in user buf */
PRIVATE int user_safe; /* address or grant? */
PUBLIC int writing; /* nonzero while write is in progress */
PRIVATE int irq_hook_id; /* id of irq hook at kernel */
extern int errno; /* error number */
FORWARD _PROTOTYPE( void do_cancel, (message *m_ptr) );
FORWARD _PROTOTYPE( void output_done, (void) );
FORWARD _PROTOTYPE( void do_write, (message *m_ptr, int safe) );
FORWARD _PROTOTYPE( void do_status, (message *m_ptr) );
FORWARD _PROTOTYPE( void prepare_output, (void) );
FORWARD _PROTOTYPE( void do_initialize, (void) );
FORWARD _PROTOTYPE( void reply, (int code,int replyee,int proc,int status));
FORWARD _PROTOTYPE( void do_printer_output, (void) );
FORWARD _PROTOTYPE( void do_signal, (void) );
/* SEF functions and variables. */
FORWARD _PROTOTYPE( void sef_local_startup, (void) );
EXTERN _PROTOTYPE( void sef_cb_lu_prepare, (int state) );
EXTERN _PROTOTYPE( int sef_cb_lu_state_isvalid, (int state) );
EXTERN _PROTOTYPE( void sef_cb_lu_state_dump, (int state) );
PUBLIC int is_status_msg_expected = FALSE;
/*===========================================================================*
* printer_task *
*===========================================================================*/
PUBLIC void main(void)
{
/* Main routine of the printer task. */
message pr_mess; /* buffer for all incoming messages */
struct sigaction sa;
int s;
/* SEF local startup. */
sef_local_startup();
/* Install signal handlers. Ask PM to transform signal into message. */
sa.sa_handler = SIG_MESS;
sigemptyset(&sa.sa_mask);
sa.sa_flags = 0;
if (sigaction(SIGTERM,&sa,NULL)<0) panic("PRN","sigaction failed", errno);
while (TRUE) {
sef_receive(ANY, &pr_mess);
if (is_notify(pr_mess.m_type)) {
switch (_ENDPOINT_P(pr_mess.m_source)) {
case HARDWARE:
do_printer_output();
break;
case PM_PROC_NR:
do_signal();
break;
default:
reply(TASK_REPLY, pr_mess.m_source,
pr_mess.IO_ENDPT, EINVAL);
}
continue;
}
switch(pr_mess.m_type) {
case DEV_OPEN:
do_initialize(); /* initialize */
/* fall through */
case DEV_CLOSE:
reply(TASK_REPLY, pr_mess.m_source, pr_mess.IO_ENDPT, OK);
break;
case DEV_WRITE_S: do_write(&pr_mess, 1); break;
case DEV_STATUS: do_status(&pr_mess); break;
case CANCEL: do_cancel(&pr_mess); break;
default:
reply(TASK_REPLY, pr_mess.m_source, pr_mess.IO_ENDPT, EINVAL);
}
}
}
/*===========================================================================*
* sef_local_startup *
*===========================================================================*/
PRIVATE void sef_local_startup()
{
/* Register live update callbacks. */
sef_setcb_lu_prepare(sef_cb_lu_prepare);
sef_setcb_lu_state_isvalid(sef_cb_lu_state_isvalid);
sef_setcb_lu_state_dump(sef_cb_lu_state_dump);
/* Let SEF perform startup. */
sef_startup();
}
/*===========================================================================*
* do_signal *
*===========================================================================*/
PRIVATE void do_signal()
{
sigset_t sigset;
if (getsigset(&sigset) != 0) return;
/* Expect a SIGTERM signal when this server must shutdown. */
if (sigismember(&sigset, SIGTERM)) {
exit(0);
}
/* Ignore all other signals. */
}
/*===========================================================================*
* do_write *
*===========================================================================*/
PRIVATE void do_write(m_ptr, safe)
register message *m_ptr; /* pointer to the newly arrived message */
int safe; /* use virtual addresses or grant id's? */
{
/* The printer is used by sending DEV_WRITE messages to it. Process one. */
register int r = SUSPEND;
int retries;
unsigned long status;
/* Reject command if last write is not yet finished, the count is not
* positive, or the user address is bad.
*/
if (writing) r = EIO;
else if (m_ptr->COUNT <= 0) r = EINVAL;
/* Reply to FS, no matter what happened, possible SUSPEND caller. */
reply(TASK_REPLY, m_ptr->m_source, m_ptr->IO_ENDPT, r);
/* If no errors occurred, continue printing with SUSPENDED caller.
* First wait until the printer is online to prevent stupid errors.
*/
if (SUSPEND == r) {
caller = m_ptr->m_source;
proc_nr = m_ptr->IO_ENDPT;
user_left = m_ptr->COUNT;
orig_count = m_ptr->COUNT;
user_vir_g = (vir_bytes) m_ptr->ADDRESS; /* Address or grant id. */
user_vir_d = 0; /* Offset. */
user_safe = safe; /* Address or grant? */
writing = TRUE;
grant_nr = safe ? (cp_grant_id_t) m_ptr->ADDRESS : GRANT_INVALID;
retries = MAX_ONLINE_RETRIES + 1;
while (--retries > 0) {
if(sys_inb(port_base + 1, &status) != OK) {
printf("printer: sys_inb of %x failed\n", port_base+1);
panic(__FILE__,"sys_inb failed", NO_NUM);
}
if ((status & ON_LINE)) { /* printer online! */
prepare_output();
do_printer_output();
return;
}
micro_delay(500000); /* wait before retry */
}
/* If we reach this point, the printer was not online in time. */
done_status = status;
output_done();
}
}
/*===========================================================================*
* output_done *
*===========================================================================*/
PRIVATE void output_done()
{
/* Previous chunk of printing is finished. Continue if OK and more.
* Otherwise, reply to caller (FS).
*/
register int status;
if (!writing) return; /* probably leftover interrupt */
if (done_status != OK) { /* printer error occurred */
status = EIO;
if ((done_status & ON_LINE) == 0) {
printf("Printer is not on line\n");
} else if ((done_status & NO_PAPER)) {
printf("Printer is out of paper\n");
status = EAGAIN;
} else {
printf("Printer error, status is 0x%02X\n", done_status);
}
/* Some characters have been printed, tell how many. */
if (status == EAGAIN && user_left < orig_count) {
status = orig_count - user_left;
}
oleft = 0; /* cancel further output */
}
else if (user_left != 0) { /* not yet done, continue! */
prepare_output();
return;
}
else { /* done! report back to FS */
status = orig_count;
}
is_status_msg_expected = TRUE;
revive_pending = TRUE;
revive_status = status;
notify(caller);
}
/*===========================================================================*
* do_status *
*===========================================================================*/
PRIVATE void do_status(m_ptr)
register message *m_ptr; /* pointer to the newly arrived message */
{
if (revive_pending) {
m_ptr->m_type = DEV_REVIVE; /* build message */
m_ptr->REP_ENDPT = proc_nr;
m_ptr->REP_STATUS = revive_status;
m_ptr->REP_IO_GRANT = grant_nr;
writing = FALSE; /* unmark event */
revive_pending = FALSE; /* unmark event */
} else {
m_ptr->m_type = DEV_NO_STATUS;
is_status_msg_expected = FALSE;
}
send(m_ptr->m_source, m_ptr); /* send the message */
}
/*===========================================================================*
* do_cancel *
*===========================================================================*/
PRIVATE void do_cancel(m_ptr)
register message *m_ptr; /* pointer to the newly arrived message */
{
/* Cancel a print request that has already started. Usually this means that
* the process doing the printing has been killed by a signal. It is not
* clear if there are race conditions. Try not to cancel the wrong process,
* but rely on FS to handle the EINTR reply and de-suspension properly.
*/
if (writing && m_ptr->IO_ENDPT == proc_nr) {
oleft = 0; /* cancel output by interrupt handler */
writing = FALSE;
revive_pending = FALSE;
}
reply(TASK_REPLY, m_ptr->m_source, m_ptr->IO_ENDPT, EINTR);
}
/*===========================================================================*
* reply *
*===========================================================================*/
PRIVATE void reply(code, replyee, process, status)
int code; /* TASK_REPLY or REVIVE */
int replyee; /* destination for message (normally FS) */
int process; /* which user requested the printing */
int status; /* number of chars printed or error code */
{
/* Send a reply telling FS that printing has started or stopped. */
message pr_mess;
pr_mess.m_type = code; /* TASK_REPLY or REVIVE */
pr_mess.REP_STATUS = status; /* count or EIO */
pr_mess.REP_ENDPT = process; /* which user does this pertain to */
send(replyee, &pr_mess); /* send the message */
}
/*===========================================================================*
* do_initialize *
*===========================================================================*/
PRIVATE void do_initialize()
{
/* Set global variables and initialize the printer. */
static int initialized = FALSE;
if (initialized) return;
initialized = TRUE;
/* Get the base port for first printer. */
if(sys_vircopy(SELF, BIOS_SEG, LPT1_IO_PORT_ADDR,
SELF, D, (vir_bytes) &port_base, LPT1_IO_PORT_SIZE) != OK) {
panic(__FILE__, "do_initialize: sys_vircopy failed", NO_NUM);
}
if(sys_outb(port_base + 2, INIT_PRINTER) != OK) {
printf("printer: sys_outb of %x failed\n", port_base+2);
panic(__FILE__, "do_initialize: sys_outb init failed", NO_NUM);
}
micro_delay(1000000/20); /* easily satisfies Centronics minimum */
if(sys_outb(port_base + 2, PR_SELECT) != OK) {
printf("printer: sys_outb of %x failed\n", port_base+2);
panic(__FILE__, "do_initialize: sys_outb select failed", NO_NUM);
}
irq_hook_id = 0;
if(sys_irqsetpolicy(PRINTER_IRQ, 0, &irq_hook_id) != OK ||
sys_irqenable(&irq_hook_id) != OK) {
panic(__FILE__, "do_initialize: irq enabling failed", NO_NUM);
}
}
/*==========================================================================*
* prepare_output *
*==========================================================================*/
PRIVATE void prepare_output()
{
/* Start next chunk of printer output. Fetch the data from user space. */
int s;
register int chunk;
if ( (chunk = user_left) > sizeof obuf) chunk = sizeof obuf;
if(user_safe) {
s=sys_safecopyfrom(proc_nr, user_vir_g, user_vir_d,
(vir_bytes) obuf, chunk, D);
} else {
s=sys_datacopy(proc_nr, user_vir_g, SELF, (vir_bytes) obuf, chunk);
}
if(s != OK) {
done_status = EFAULT;
output_done();
return;
}
optr = obuf;
oleft = chunk;
}
/*===========================================================================*
* do_printer_output *
*===========================================================================*/
PRIVATE void do_printer_output()
{
/* This function does the actual output to the printer. This is called on an
* interrupt message sent from the generic interrupt handler that 'forwards'
* interrupts to this driver. The generic handler did not reenable the printer
* IRQ yet!
*/
unsigned long status;
pvb_pair_t char_out[3];
if (oleft == 0) {
/* Nothing more to print. Turn off printer interrupts in case they
* are level-sensitive as on the PS/2. This should be safe even
* when the printer is busy with a previous character, because the
* interrupt status does not affect the printer.
*/
if(sys_outb(port_base + 2, PR_SELECT) != OK) {
printf("printer: sys_outb of %x failed\n", port_base+2);
panic(__FILE__,"sys_outb failed", NO_NUM);
}
if(sys_irqenable(&irq_hook_id) != OK) {
panic(__FILE__,"sys_irqenable failed", NO_NUM);
}
return;
}
do {
/* Loop to handle fast (buffered) printers. It is important that
* processor interrupts are not disabled here, just printer interrupts.
*/
if(sys_inb(port_base + 1, &status) != OK) {
printf("printer: sys_inb of %x failed\n", port_base+1);
panic(__FILE__,"sys_inb failed", NO_NUM);
}
if ((status & STATUS_MASK) == BUSY_STATUS) {
/* Still busy with last output. This normally happens
* immediately after doing output to an unbuffered or slow
* printer. It may happen after a call from prepare_output or
* pr_restart, since they are not synchronized with printer
* interrupts. It may happen after a spurious interrupt.
*/
if(sys_irqenable(&irq_hook_id) != OK) {
panic(__FILE__, "sys_irqenable failed\n", NO_NUM);
}
return;
}
if ((status & STATUS_MASK) == NORMAL_STATUS) {
/* Everything is all right. Output another character. */
pv_set(char_out[0], port_base, *optr);
optr++;
pv_set(char_out[1], port_base+2, ASSERT_STROBE);
pv_set(char_out[2], port_base+2, NEGATE_STROBE);
if(sys_voutb(char_out, 3) != OK) {
/* request series of port outb */
panic(__FILE__, "sys_voutb failed\n", NO_NUM);
}
user_vir_d++;
user_left--;
} else {
/* Error. This would be better ignored (treat as busy). */
done_status = status;
output_done();
if(sys_irqenable(&irq_hook_id) != OK) {
panic(__FILE__, "sys_irqenable failed\n", NO_NUM);
}
return;
}
}
while (--oleft != 0);
/* Finished printing chunk OK. */
done_status = OK;
output_done();
if(sys_irqenable(&irq_hook_id) != OK) {
panic(__FILE__, "sys_irqenable failed\n", NO_NUM);
}
}
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