/*
* I/O Processor (IOP) management
* Written and (C) 1999 by Joshua M. Thompson (funaho@jurai.org)
*
* Redistribution and use in source and binary forms, with or without
* modification, are permitted provided that the following conditions
* are met:
* 1. Redistributions of source code must retain the above copyright
* notice and this list of conditions.
* 2. Redistributions in binary form must reproduce the above copyright
* notice and this list of conditions in the documentation and/or other
* materials provided with the distribution.
*/
/*
* The IOP chips are used in the IIfx and some Quadras (900, 950) to manage
* serial and ADB. They are actually a 6502 processor and some glue logic.
*
* 990429 (jmt) - Initial implementation, just enough to knock the SCC IOP
* into compatible mode so nobody has to fiddle with the
* Serial Switch control panel anymore.
* 990603 (jmt) - Added code to grab the correct ISM IOP interrupt for OSS
* and non-OSS machines (at least I hope it's correct on a
* non-OSS machine -- someone with a Q900 or Q950 needs to
* check this.)
* 990605 (jmt) - Rearranged things a bit wrt IOP detection; iop_present is
* gone, IOP base addresses are now in an array and the
* globally-visible functions take an IOP number instead of an
* an actual base address.
* 990610 (jmt) - Finished the message passing framework and it seems to work.
* Sending _definitely_ works; my adb-bus.c mods can send
* messages and receive the MSG_COMPLETED status back from the
* IOP. The trick now is figuring out the message formats.
* 990611 (jmt) - More cleanups. Fixed problem where unclaimed messages on a
* receive channel were never properly acknowledged. Bracketed
* the remaining debug printk's with #ifdef's and disabled
* debugging. I can now type on the console.
* 990612 (jmt) - Copyright notice added. Reworked the way replies are handled.
* It turns out that replies are placed back in the send buffer
* for that channel; messages on the receive channels are always
* unsolicited messages from the IOP (and our replies to them
* should go back in the receive channel.) Also added tracking
* of device names to the listener functions ala the interrupt
* handlers.
* 990729 (jmt) - Added passing of pt_regs structure to IOP handlers. This is
* used by the new unified ADB driver.
*
* TODO:
*
* o Something should be periodically checking iop_alive() to make sure the
* IOP hasn't died.
* o Some of the IOP manager routines need better error checking and
* return codes. Nothing major, just prettying up.
*/
/*
* -----------------------
* IOP Message Passing 101
* -----------------------
*
* The host talks to the IOPs using a rather simple message-passing scheme via
* a shared memory area in the IOP RAM. Each IOP has seven "channels"; each
* channel is connected to a specific software driver on the IOP. For example
* on the SCC IOP there is one channel for each serial port. Each channel has
* an incoming and and outgoing message queue with a depth of one.
*
* A message is 32 bytes plus a state byte for the channel (MSG_IDLE, MSG_NEW,
* MSG_RCVD, MSG_COMPLETE). To send a message you copy the message into the
* buffer, set the state to MSG_NEW and signal the IOP by setting the IRQ flag
* in the IOP control to 1. The IOP will move the state to MSG_RCVD when it
* receives the message and then to MSG_COMPLETE when the message processing
* has completed. It is the host's responsibility at that point to read the
* reply back out of the send channel buffer and reset the channel state back
* to MSG_IDLE.
*
* To receive message from the IOP the same procedure is used except the roles
* are reversed. That is, the IOP puts message in the channel with a state of
* MSG_NEW, and the host receives the message and move its state to MSG_RCVD
* and then to MSG_COMPLETE when processing is completed and the reply (if any)
* has been placed back in the receive channel. The IOP will then reset the
* channel state to MSG_IDLE.
*
* Two sets of host interrupts are provided, INT0 and INT1. Both appear on one
* interrupt level; they are distinguished by a pair of bits in the IOP status
* register. The IOP will raise INT0 when one or more messages in the send
* channels have gone to the MSG_COMPLETE state and it will raise INT1 when one
* or more messages on the receive channels have gone to the MSG_NEW state.
*
* Since each channel handles only one message we have to implement a small
* interrupt-driven queue on our end. Messages to be sent are placed on the
* queue for sending and contain a pointer to an optional callback function.
* The handler for a message is called when the message state goes to
* MSG_COMPLETE.
*
* For receiving message we maintain a list of handler functions to call when
* a message is received on that IOP/channel combination. The handlers are
* called much like an interrupt handler and are passed a copy of the message
* from the IOP. The message state will be in MSG_RCVD while the handler runs;
* it is the handler's responsibility to call iop_complete_message() when
* finished; this function moves the message state to MSG_COMPLETE and signals
* the IOP. This two-step process is provided to allow the handler to defer
* message processing to a bottom-half handler if the processing will take
* a significant amount of time (handlers are called at interrupt time so they
* should execute quickly.)
*/
#include <linux/types.h>
#include <linux/kernel.h>
#include <linux/mm.h>
#include <linux/delay.h>
#include <linux/init.h>
#include <linux/interrupt.h>
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/mac_iop.h>
/*#define DEBUG_IOP*/
/* Non-zero if the IOPs are present */
int iop_scc_present, iop_ism_present;
/* structure for tracking channel listeners */
struct listener {
const char *devname;
void (*handler)(struct iop_msg *);
};
/*
* IOP structures for the two IOPs
*
* The SCC IOP controls both serial ports (A and B) as its two functions.
* The ISM IOP controls the SWIM (floppy drive) and ADB.
*/
static volatile struct mac_iop *iop_base[NUM_IOPS];
/*
* IOP message queues
*/
static struct iop_msg iop_msg_pool[NUM_IOP_MSGS];
static struct iop_msg *iop_send_queue[NUM_IOPS][NUM_IOP_CHAN];
static struct listener iop_listeners[NUM_IOPS][NUM_IOP_CHAN];
irqreturn_t iop_ism_irq(int, void *);
/*
* Private access functions
*/
static __inline__ void iop_loadaddr(volatile struct mac_iop *iop, __u16 addr)
{
iop->ram_addr_lo = addr;
iop->ram_addr_hi = addr >> 8;
}
static __inline__ __u8 iop_readb(volatile struct mac_iop *iop, __u16 addr)
{
iop->ram_addr_lo = addr;
iop->ram_addr_hi = addr >> 8;
return iop->ram_data;
}
static __inline__ void iop_writeb(volatile struct mac_iop *iop, __u16 addr, __u8 data)
{
iop->ram_addr_lo = addr;
iop->ram_addr_hi = addr >> 8;
iop->ram_data = data;
}
static __inline__ void iop_stop(volatile struct mac_iop *iop)
{
iop->status_ctrl &= ~IOP_RUN;
}
static __inline__ void iop_start(volatile struct mac_iop *iop)
{
iop->status_ctrl = IOP_RUN | IOP_AUTOINC;
}
static __inline__ void iop_bypass(volatile struct mac_iop *iop)
{
iop->status_ctrl |= IOP_BYPASS;
}
static __inline__ void iop_interrupt(volatile struct mac_iop *iop)
{
iop->status_ctrl |= IOP_IRQ;
}
static int iop_alive(volatile struct mac_iop *iop)
{
int retval;
retval = (iop_readb(iop, IOP_ADDR_ALIVE) == 0xFF);
iop_writeb(iop, IOP_ADDR_ALIVE, 0);
return retval;
}
static struct iop_msg *iop_alloc_msg(void)
{
int i;
unsigned long flags;
local_irq_save(flags);
for (i = 0 ; i < NUM_IOP_MSGS ; i++) {
if (iop_msg_pool[i].status == IOP_MSGSTATUS_UNUSED) {
iop_msg_pool[i].status = IOP_MSGSTATUS_WAITING;
local_irq_restore(flags);
return &iop_msg_pool[i];
}
}
local_irq_restore(flags);
return NULL;
}
static void iop_free_msg(struct iop_msg *msg)
{
msg->status = IOP_MSGSTATUS_UNUSED;
}
/*
* This is called by the startup code before anything else. Its purpose
* is to find and initialize the IOPs early in the boot sequence, so that
* the serial IOP can be placed into bypass mode _before_ we try to
* initialize the serial console.
*/
void __init iop_preinit(void)
{
if (macintosh_config->scc_type == MAC_SCC_IOP) {
if (macintosh_config->ident == MAC_MODEL_IIFX) {
iop_base[IOP_NUM_SCC] = (struct mac_iop *) SCC_IOP_BASE_IIFX;
} else {
iop_base[IOP_NUM_SCC] = (struct mac_iop *) SCC_IOP_BASE_QUADRA;
}
iop_base[IOP_NUM_SCC]->status_ctrl = 0x87;
iop_scc_present = 1;
} else {
iop_base[IOP_NUM_SCC] = NULL;
iop_scc_present = 0;
}
if (macintosh_config->adb_type == MAC_ADB_IOP) {
if (macintosh_config->ident == MAC_MODEL_IIFX) {
iop_base[IOP_NUM_ISM] = (struct mac_iop *) ISM_IOP_BASE_IIFX;
} else {
iop_base[IOP_NUM_ISM] = (struct mac_iop *) ISM_IOP_BASE_QUADRA;
}
iop_base[IOP_NUM_ISM]->status_ctrl = 0;
iop_ism_present = 1;
} else {
iop_base[IOP_NUM_ISM] = NULL;
iop_ism_present = 0;
}
}
/*
* Initialize the IOPs, if present.
*/
void __init iop_init(void)
{
int i;
if (iop_scc_present) {
printk("IOP: detected SCC IOP at %p\n", iop_base[IOP_NUM_SCC]);
}
if (iop_ism_present) {
printk("IOP: detected ISM IOP at %p\n", iop_base[IOP_NUM_ISM]);
iop_start(iop_base[IOP_NUM_ISM]);
iop_alive(iop_base[IOP_NUM_ISM]); /* clears the alive flag */
}
/* Make the whole pool available and empty the queues */
for (i = 0 ; i < NUM_IOP_MSGS ; i++) {
iop_msg_pool[i].status = IOP_MSGSTATUS_UNUSED;
}
for (i = 0 ; i < NUM_IOP_CHAN ; i++) {
iop_send_queue[IOP_NUM_SCC][i] = NULL;
iop_send_queue[IOP_NUM_ISM][i] = NULL;
iop_listeners[IOP_NUM_SCC][i].devname = NULL;
iop_listeners[IOP_NUM_SCC][i].handler = NULL;
iop_listeners[IOP_NUM_ISM][i].devname = NULL;
iop_listeners[IOP_NUM_ISM][i].handler = NULL;
}
}
/*
* Register the interrupt handler for the IOPs.
* TODO: might be wrong for non-OSS machines. Anyone?
*/
void __init iop_register_interrupts(void)
{
if (iop_ism_present) {
if (macintosh_config->ident == MAC_MODEL_IIFX) {
if (request_irq(IRQ_MAC_ADB, iop_ism_irq, 0,
"ISM IOP", (void *)IOP_NUM_ISM))
pr_err("Couldn't register ISM IOP interrupt\n");
} else {
if (request_irq(IRQ_VIA2_0, iop_ism_irq, 0, "ISM IOP",
(void *)IOP_NUM_ISM))
pr_err("Couldn't register ISM IOP interrupt\n");
}
if (!iop_alive(iop_base[IOP_NUM_ISM])) {
printk("IOP: oh my god, they killed the ISM IOP!\n");
} else {
printk("IOP: the ISM IOP seems to be alive.\n");
}
}
}
/*
* Register or unregister a listener for a specific IOP and channel
*
* If the handler pointer is NULL the current listener (if any) is
* unregistered. Otherwise the new listener is registered provided
* there is no existing listener registered.
*/
int iop_listen(uint iop_num, uint chan,
void (*handler)(struct iop_msg *),
const char *devname)
{
if ((iop_num >= NUM_IOPS) || !iop_base[iop_num]) return -EINVAL;
if (chan >= NUM_IOP_CHAN) return -EINVAL;
if (iop_listeners[iop_num][chan].handler && handler) return -EINVAL;
iop_listeners[iop_num][chan].devname = devname;
iop_listeners[iop_num][chan].handler = handler;
return 0;
}
/*
* Complete reception of a message, which just means copying the reply
* into the buffer, setting the channel state to MSG_COMPLETE and
* notifying the IOP.
*/
void iop_complete_message(struct iop_msg *msg)
{
int iop_num = msg->iop_num;
int chan = msg->channel;
int i,offset;
#ifdef DEBUG_IOP
printk("iop_complete(%p): iop %d chan %d\n", msg, msg->iop_num, msg->channel);
#endif
offset = IOP_ADDR_RECV_MSG + (msg->channel * IOP_MSG_LEN);
for (i = 0 ; i < IOP_MSG_LEN ; i++, offset++) {
iop_writeb(iop_base[iop_num], offset, msg->reply[i]);
}
iop_writeb(iop_base[iop_num],
IOP_ADDR_RECV_STATE + chan, IOP_MSG_COMPLETE);
iop_interrupt(iop_base[msg->iop_num]);
iop_free_msg(msg);
}
/*
* Actually put a message into a send channel buffer
*/
static void iop_do_send(struct iop_msg *msg)
{
volatile struct mac_iop *iop = iop_base[msg->iop_num];
int i,offset;
offset = IOP_ADDR_SEND_MSG + (msg->channel * IOP_MSG_LEN);
for (i = 0 ; i < IOP_MSG_LEN ; i++, offset++) {
iop_writeb(iop, offset, msg->message[i]);
}
iop_writeb(iop, IOP_ADDR_SEND_STATE + msg->channel, IOP_MSG_NEW);
iop_interrupt(iop);
}
/*
* Handle sending a message on a channel that
* has gone into the IOP_MSG_COMPLETE state.
*/
static void iop_handle_send(uint iop_num, uint chan)
{
volatile struct mac_iop *iop = iop_base[iop_num];
struct iop_msg *msg,*msg2;
int i,offset;
#ifdef DEBUG_IOP
printk("iop_handle_send: iop %d channel %d\n", iop_num, chan);
#endif
iop_writeb(iop, IOP_ADDR_SEND_STATE + chan, IOP_MSG_IDLE);
if (!(msg = iop_send_queue[iop_num][chan])) return;
msg->status = IOP_MSGSTATUS_COMPLETE;
offset = IOP_ADDR_SEND_MSG + (chan * IOP_MSG_LEN);
for (i = 0 ; i < IOP_MSG_LEN ; i++, offset++) {
msg->reply[i] = iop_readb(iop, offset);
}
if (msg->handler) (*msg->handler)(msg);
msg2 = msg;
msg = msg->next;
iop_free_msg(msg2);
iop_send_queue[iop_num][chan] = msg;
if (msg) iop_do_send(msg);
}
/*
* Handle reception of a message on a channel that has
* gone into the IOP_MSG_NEW state.
*/
static void iop_handle_recv(uint iop_num, uint chan)
{
volatile struct mac_iop *iop = iop_base[iop_num];
int i,offset;
struct iop_msg *msg;
#ifdef DEBUG_IOP
printk("iop_handle_recv: iop %d channel %d\n", iop_num, chan);
#endif
msg = iop_alloc_msg();
msg->iop_num = iop_num;
msg->channel = chan;
msg->status = IOP_MSGSTATUS_UNSOL;
msg->handler = iop_listeners[iop_num][chan].handler;
offset = IOP_ADDR_RECV_MSG + (chan * IOP_MSG_LEN);
for (i = 0 ; i < IOP_MSG_LEN ; i++, offset++) {
msg->message[i] = iop_readb(iop, offset);
}
iop_writeb(iop, IOP_ADDR_RECV_STATE + chan, IOP_MSG_RCVD);
/* If there is a listener, call it now. Otherwise complete */
/* the message ourselves to avoid possible stalls. */
if (msg->handler) {
(*msg->handler)(msg);
} else {
#ifdef DEBUG_IOP
printk("iop_handle_recv: unclaimed message on iop %d channel %d\n", iop_num, chan);
printk("iop_handle_recv:");
for (i = 0 ; i < IOP_MSG_LEN ; i++) {
printk(" %02X", (uint) msg->message[i]);
}
printk("\n");
#endif
iop_complete_message(msg);
}
}
/*
* Send a message
*
* The message is placed at the end of the send queue. Afterwards if the
* channel is idle we force an immediate send of the next message in the
* queue.
*/
int iop_send_message(uint iop_num, uint chan, void *privdata,
uint msg_len, __u8 *msg_data,
void (*handler)(struct iop_msg *))
{
struct iop_msg *msg, *q;
if ((iop_num >= NUM_IOPS) || !iop_base[iop_num]) return -EINVAL;
if (chan >= NUM_IOP_CHAN) return -EINVAL;
if (msg_len > IOP_MSG_LEN) return -EINVAL;
msg = iop_alloc_msg();
if (!msg) return -ENOMEM;
msg->next = NULL;
msg->status = IOP_MSGSTATUS_WAITING;
msg->iop_num = iop_num;
msg->channel = chan;
msg->caller_priv = privdata;
memcpy(msg->message, msg_data, msg_len);
msg->handler = handler;
if (!(q = iop_send_queue[iop_num][chan])) {
iop_send_queue[iop_num][chan] = msg;
} else {
while (q->next) q = q->next;
q->next = msg;
}
if (iop_readb(iop_base[iop_num],
IOP_ADDR_SEND_STATE + chan) == IOP_MSG_IDLE) {
iop_do_send(msg);
}
return 0;
}
/*
* Upload code to the shared RAM of an IOP.
*/
void iop_upload_code(uint iop_num, __u8 *code_start,
uint code_len, __u16 shared_ram_start)
{
if ((iop_num >= NUM_IOPS) || !iop_base[iop_num]) return;
iop_loadaddr(iop_base[iop_num], shared_ram_start);
while (code_len--) {
iop_base[iop_num]->ram_data = *code_start++;
}
}
/*
* Download code from the shared RAM of an IOP.
*/
void iop_download_code(uint iop_num, __u8 *code_start,
uint code_len, __u16 shared_ram_start)
{
if ((iop_num >= NUM_IOPS) || !iop_base[iop_num]) return;
iop_loadaddr(iop_base[iop_num], shared_ram_start);
while (code_len--) {
*code_start++ = iop_base[iop_num]->ram_data;
}
}
/*
* Compare the code in the shared RAM of an IOP with a copy in system memory
* and return 0 on match or the first nonmatching system memory address on
* failure.
*/
__u8 *iop_compare_code(uint iop_num, __u8 *code_start,
uint code_len, __u16 shared_ram_start)
{
if ((iop_num >= NUM_IOPS) || !iop_base[iop_num]) return code_start;
iop_loadaddr(iop_base[iop_num], shared_ram_start);
while (code_len--) {
if (*code_start != iop_base[iop_num]->ram_data) {
return code_start;
}
code_start++;
}
return (__u8 *) 0;
}
/*
* Handle an ISM IOP interrupt
*/
irqreturn_t iop_ism_irq(int irq, void *dev_id)
{
uint iop_num = (uint) dev_id;
volatile struct mac_iop *iop = iop_base[iop_num];
int i,state;
#ifdef DEBUG_IOP
printk("iop_ism_irq: status = %02X\n", (uint) iop->status_ctrl);
#endif
/* INT0 indicates a state change on an outgoing message channel */
if (iop->status_ctrl & IOP_INT0) {
iop->status_ctrl = IOP_INT0 | IOP_RUN | IOP_AUTOINC;
#ifdef DEBUG_IOP
printk("iop_ism_irq: new status = %02X, send states",
(uint) iop->status_ctrl);
#endif
for (i = 0 ; i < NUM_IOP_CHAN ; i++) {
state = iop_readb(iop, IOP_ADDR_SEND_STATE + i);
#ifdef DEBUG_IOP
printk(" %02X", state);
#endif
if (state == IOP_MSG_COMPLETE) {
iop_handle_send(iop_num, i);
}
}
#ifdef DEBUG_IOP
printk("\n");
#endif
}
if (iop->status_ctrl & IOP_INT1) { /* INT1 for incoming msgs */
iop->status_ctrl = IOP_INT1 | IOP_RUN | IOP_AUTOINC;
#ifdef DEBUG_IOP
printk("iop_ism_irq: new status = %02X, recv states",
(uint) iop->status_ctrl);
#endif
for (i = 0 ; i < NUM_IOP_CHAN ; i++) {
state = iop_readb(iop, IOP_ADDR_RECV_STATE + i);
#ifdef DEBUG_IOP
printk(" %02X", state);
#endif
if (state == IOP_MSG_NEW) {
iop_handle_recv(iop_num, i);
}
}
#ifdef DEBUG_IOP
printk("\n");
#endif
}
return IRQ_HANDLED;
}