--- /dev/null
+/*
+ * 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/mac_via.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 reply_buf or req->reply */
+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, 0, "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;
+}
Code Review / kvmfornfv.git / blobdiff