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+/*
+ * 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 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 The SCC IOP has to be placed in bypass mode before the serial console
+ * gets initialized. iop_init() would be one place to do that. Or the
+ * bootloader could do that. For now, the Serial Switch control panel
+ * is needed for that -- contrary to the changelog above.
+ * 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 an 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>
+
+#ifdef DEBUG
+#define iop_pr_debug(fmt, ...) \
+ printk(KERN_DEBUG "%s: " fmt, __func__, ##__VA_ARGS__)
+#define iop_pr_cont(fmt, ...) \
+ printk(KERN_CONT fmt, ##__VA_ARGS__)
+#else
+#define iop_pr_debug(fmt, ...) \
+ no_printk(KERN_DEBUG "%s: " fmt, __func__, ##__VA_ARGS__)
+#define iop_pr_cont(fmt, ...) \
+ no_printk(KERN_CONT fmt, ##__VA_ARGS__)
+#endif
+
+/* 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_AUTOINC;
+}
+
+static __inline__ void iop_start(volatile struct mac_iop *iop)
+{
+ iop->status_ctrl = IOP_RUN | IOP_AUTOINC;
+}
+
+static __inline__ void iop_interrupt(volatile struct mac_iop *iop)
+{
+ iop->status_ctrl = IOP_IRQ | IOP_RUN | IOP_AUTOINC;
+}
+
+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_get_unused_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;
+}
+
+/*
+ * Initialize the IOPs, if present.
+ */
+
+void __init iop_init(void)
+{
+ int i;
+
+ 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_scc_present = 1;
+ pr_debug("SCC IOP detected at %p\n", iop_base[IOP_NUM_SCC]);
+ }
+ 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_ism_present = 1;
+ pr_debug("ISM IOP detected at %p\n", iop_base[IOP_NUM_ISM]);
+
+ iop_stop(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.
+ */
+
+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])) {
+ pr_warn("IOP: oh my god, they killed the ISM IOP!\n");
+ } else {
+ pr_warn("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;
+
+ iop_pr_debug("iop_num %d chan %d reply %*ph\n",
+ msg->iop_num, msg->channel, IOP_MSG_LEN, msg->reply);
+
+ 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]);
+
+ msg->status = IOP_MSGSTATUS_UNUSED;
+}
+
+/*
+ * 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;
+
+ iop_pr_debug("iop_num %d chan %d message %*ph\n",
+ msg->iop_num, msg->channel, IOP_MSG_LEN, msg->message);
+
+ 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;
+ int i,offset;
+
+ 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);
+ }
+ iop_pr_debug("iop_num %d chan %d reply %*ph\n",
+ iop_num, chan, IOP_MSG_LEN, msg->reply);
+
+ if (msg->handler) (*msg->handler)(msg);
+ msg->status = IOP_MSGSTATUS_UNUSED;
+ msg = msg->next;
+ iop_send_queue[iop_num][chan] = msg;
+ if (msg && iop_readb(iop, IOP_ADDR_SEND_STATE + chan) == IOP_MSG_IDLE)
+ 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;
+
+ msg = iop_get_unused_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_pr_debug("iop_num %d chan %d message %*ph\n",
+ iop_num, chan, IOP_MSG_LEN, msg->message);
+
+ 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 {
+ memset(msg->reply, 0, IOP_MSG_LEN);
+ 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_get_unused_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;
+ iop_do_send(msg);
+ } else {
+ while (q->next) q = q->next;
+ q->next = 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;
+ u8 events = iop->status_ctrl & (IOP_INT0 | IOP_INT1);
+
+ do {
+ iop_pr_debug("iop_num %d status %02X\n", iop_num,
+ iop->status_ctrl);
+
+ /* INT0 indicates state change on an outgoing message channel */
+ if (events & IOP_INT0) {
+ iop->status_ctrl = IOP_INT0 | IOP_RUN | IOP_AUTOINC;
+ for (i = 0; i < NUM_IOP_CHAN; i++) {
+ state = iop_readb(iop, IOP_ADDR_SEND_STATE + i);
+ if (state == IOP_MSG_COMPLETE)
+ iop_handle_send(iop_num, i);
+ else if (state != IOP_MSG_IDLE)
+ iop_pr_debug("chan %d send state %02X\n",
+ i, state);
+ }
+ }
+
+ /* INT1 for incoming messages */
+ if (events & IOP_INT1) {
+ iop->status_ctrl = IOP_INT1 | IOP_RUN | IOP_AUTOINC;
+ for (i = 0; i < NUM_IOP_CHAN; i++) {
+ state = iop_readb(iop, IOP_ADDR_RECV_STATE + i);
+ if (state == IOP_MSG_NEW)
+ iop_handle_recv(iop_num, i);
+ else if (state != IOP_MSG_IDLE)
+ iop_pr_debug("chan %d recv state %02X\n",
+ i, state);
+ }
+ }
+
+ events = iop->status_ctrl & (IOP_INT0 | IOP_INT1);
+ } while (events);
+
+ return IRQ_HANDLED;
+}
+
+void iop_ism_irq_poll(uint iop_num)
+{
+ unsigned long flags;
+
+ local_irq_save(flags);
+ iop_ism_irq(0, (void *)iop_num);
+ local_irq_restore(flags);
+}
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