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kernel/drivers/macintosh/via-cuda.c

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// SPDX-License-Identifier: GPL-2.0
/*
* Device driver for the Cuda and Egret system controllers found on PowerMacs
* and 68k Macs.
*
* The Cuda or Egret is a 6805 microcontroller interfaced to the 6522 VIA.
* This MCU controls system power, Parameter RAM, Real Time Clock and the
* Apple Desktop Bus (ADB) that connects to the keyboard and mouse.
*
* Copyright (C) 1996 Paul Mackerras.
*/
#include <linux/stdarg.h>
#include <linux/types.h>
#include <linux/errno.h>
#include <linux/kernel.h>
#include <linux/delay.h>
#include <linux/adb.h>
#include <linux/cuda.h>
#include <linux/spinlock.h>
#include <linux/interrupt.h>
#include <linux/of_address.h>
#include <linux/of_irq.h>
#ifdef CONFIG_PPC
#include <asm/machdep.h>
#include <asm/pmac_feature.h>
#else
#include <asm/macintosh.h>
#include <asm/macints.h>
#include <asm/mac_via.h>
#endif
#include <asm/io.h>
#include <linux/init.h>
static volatile unsigned char __iomem *via;
static DEFINE_SPINLOCK(cuda_lock);
/* 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 */
/*
* When the Cuda design replaced the Egret, some signal names and
* logic sense changed. They all serve the same purposes, however.
*
* VIA pin | Egret pin
* ----------------+------------------------------------------
* PB3 (input) | Transceiver session (active low)
* PB4 (output) | VIA full (active high)
* PB5 (output) | System session (active high)
*
* VIA pin | Cuda pin
* ----------------+------------------------------------------
* PB3 (input) | Transfer request (active low)
* PB4 (output) | Byte acknowledge (active low)
* PB5 (output) | Transfer in progress (active low)
*/
/* Bits in Port B data register */
#define TREQ 0x08 /* Transfer request */
#define TACK 0x10 /* Transfer acknowledge */
#define TIP 0x20 /* Transfer in progress */
/* 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 */
/* Duration of byte acknowledgement pulse (us) */
#define EGRET_TACK_ASSERTED_DELAY 300
#define EGRET_TACK_NEGATED_DELAY 400
/* Interval from interrupt to start of session (us) */
#define EGRET_SESSION_DELAY 450
#ifdef CONFIG_PPC
#define mcu_is_egret false
#else
static bool mcu_is_egret;
#endif
static inline bool TREQ_asserted(u8 portb)
{
return !(portb & TREQ);
}
static inline void assert_TIP(void)
{
if (mcu_is_egret) {
udelay(EGRET_SESSION_DELAY);
out_8(&via[B], in_8(&via[B]) | TIP);
} else
out_8(&via[B], in_8(&via[B]) & ~TIP);
}
static inline void assert_TIP_and_TACK(void)
{
if (mcu_is_egret) {
udelay(EGRET_SESSION_DELAY);
out_8(&via[B], in_8(&via[B]) | TIP | TACK);
} else
out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
}
static inline void assert_TACK(void)
{
if (mcu_is_egret) {
udelay(EGRET_TACK_NEGATED_DELAY);
out_8(&via[B], in_8(&via[B]) | TACK);
} else
out_8(&via[B], in_8(&via[B]) & ~TACK);
}
static inline void toggle_TACK(void)
{
out_8(&via[B], in_8(&via[B]) ^ TACK);
}
static inline void negate_TACK(void)
{
if (mcu_is_egret) {
udelay(EGRET_TACK_ASSERTED_DELAY);
out_8(&via[B], in_8(&via[B]) & ~TACK);
} else
out_8(&via[B], in_8(&via[B]) | TACK);
}
static inline void negate_TIP_and_TACK(void)
{
if (mcu_is_egret) {
udelay(EGRET_TACK_ASSERTED_DELAY);
out_8(&via[B], in_8(&via[B]) & ~(TIP | TACK));
} else
out_8(&via[B], in_8(&via[B]) | TIP | TACK);
}
static enum cuda_state {
idle,
sent_first_byte,
sending,
reading,
read_done,
awaiting_reply
} cuda_state;
static struct adb_request *current_req;
static struct adb_request *last_req;
static unsigned char cuda_rbuf[16];
static unsigned char *reply_ptr;
static int reading_reply;
static int data_index;
static int cuda_irq;
#ifdef CONFIG_PPC
static struct device_node *vias;
#endif
static int cuda_fully_inited;
#ifdef CONFIG_ADB
static int cuda_probe(void);
static int cuda_send_request(struct adb_request *req, int sync);
static int cuda_adb_autopoll(int devs);
static int cuda_reset_adb_bus(void);
#endif /* CONFIG_ADB */
static int cuda_init_via(void);
static void cuda_start(void);
static irqreturn_t cuda_interrupt(int irq, void *arg);
static void cuda_input(unsigned char *buf, int nb);
void cuda_poll(void);
static int cuda_write(struct adb_request *req);
int cuda_request(struct adb_request *req,
void (*done)(struct adb_request *), int nbytes, ...);
#ifdef CONFIG_ADB
struct adb_driver via_cuda_driver = {
.name = "CUDA",
.probe = cuda_probe,
.send_request = cuda_send_request,
.autopoll = cuda_adb_autopoll,
.poll = cuda_poll,
.reset_bus = cuda_reset_adb_bus,
};
#endif /* CONFIG_ADB */
#ifdef CONFIG_MAC
int __init find_via_cuda(void)
{
struct adb_request req;
int err;
if (macintosh_config->adb_type != MAC_ADB_CUDA &&
macintosh_config->adb_type != MAC_ADB_EGRET)
return 0;
via = via1;
cuda_state = idle;
mcu_is_egret = macintosh_config->adb_type == MAC_ADB_EGRET;
err = cuda_init_via();
if (err) {
printk(KERN_ERR "cuda_init_via() failed\n");
via = NULL;
return 0;
}
/* enable autopoll */
cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
while (!req.complete)
cuda_poll();
return 1;
}
#else
int __init find_via_cuda(void)
{
struct adb_request req;
struct resource res;
int err;
if (vias)
return 1;
vias = of_find_node_by_name(NULL, "via-cuda");
if (!vias)
return 0;
err = of_address_to_resource(vias, 0, &res);
if (err) {
printk(KERN_ERR "via-cuda: Error getting \"reg\" property !\n");
goto fail;
}
via = ioremap(res.start, 0x2000);
if (via == NULL) {
printk(KERN_ERR "via-cuda: Can't map address !\n");
goto fail;
}
cuda_state = idle;
sys_ctrler = SYS_CTRLER_CUDA;
err = cuda_init_via();
if (err) {
printk(KERN_ERR "cuda_init_via() failed\n");
via = NULL;
return 0;
}
/* Clear and enable interrupts, but only on PPC. On 68K it's done */
/* for us by the main VIA driver in arch/m68k/mac/via.c */
out_8(&via[IFR], 0x7f); /* clear interrupts by writing 1s */
out_8(&via[IER], IER_SET|SR_INT); /* enable interrupt from SR */
/* enable autopoll */
cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, 1);
while (!req.complete)
cuda_poll();
return 1;
fail:
of_node_put(vias);
vias = NULL;
return 0;
}
#endif /* !defined CONFIG_MAC */
static int __init via_cuda_start(void)
{
if (via == NULL)
return -ENODEV;
#ifdef CONFIG_MAC
cuda_irq = IRQ_MAC_ADB;
#else
cuda_irq = irq_of_parse_and_map(vias, 0);
if (!cuda_irq) {
printk(KERN_ERR "via-cuda: can't map interrupts for %pOF\n",
vias);
return -ENODEV;
}
#endif
if (request_irq(cuda_irq, cuda_interrupt, 0, "ADB", cuda_interrupt)) {
printk(KERN_ERR "via-cuda: can't request irq %d\n", cuda_irq);
return -EAGAIN;
}
pr_info("Macintosh Cuda and Egret driver.\n");
cuda_fully_inited = 1;
return 0;
}
device_initcall(via_cuda_start);
#ifdef CONFIG_ADB
static int
cuda_probe(void)
{
#ifdef CONFIG_PPC
if (sys_ctrler != SYS_CTRLER_CUDA)
return -ENODEV;
#else
if (macintosh_config->adb_type != MAC_ADB_CUDA &&
macintosh_config->adb_type != MAC_ADB_EGRET)
return -ENODEV;
#endif
if (via == NULL)
return -ENODEV;
return 0;
}
#endif /* CONFIG_ADB */
static int __init sync_egret(void)
{
if (TREQ_asserted(in_8(&via[B]))) {
/* Complete the inbound transfer */
assert_TIP_and_TACK();
while (1) {
negate_TACK();
mdelay(1);
(void)in_8(&via[SR]);
assert_TACK();
if (!TREQ_asserted(in_8(&via[B])))
break;
}
negate_TIP_and_TACK();
} else if (in_8(&via[B]) & TIP) {
/* Terminate the outbound transfer */
negate_TACK();
assert_TACK();
mdelay(1);
negate_TIP_and_TACK();
}
/* Clear shift register interrupt */
if (in_8(&via[IFR]) & SR_INT)
(void)in_8(&via[SR]);
return 0;
}
#define WAIT_FOR(cond, what) \
do { \
int x; \
for (x = 1000; !(cond); --x) { \
if (x == 0) { \
pr_err("Timeout waiting for " what "\n"); \
return -ENXIO; \
} \
udelay(100); \
} \
} while (0)
static int
__init cuda_init_via(void)
{
#ifdef CONFIG_PPC
out_8(&via[IER], 0x7f); /* disable interrupts from VIA */
(void)in_8(&via[IER]);
#else
out_8(&via[IER], SR_INT); /* disable SR interrupt from VIA */
#endif
out_8(&via[DIRB], (in_8(&via[DIRB]) | TACK | TIP) & ~TREQ); /* TACK & TIP out */
out_8(&via[ACR], (in_8(&via[ACR]) & ~SR_CTRL) | SR_EXT); /* SR data in */
(void)in_8(&via[SR]); /* clear any left-over data */
if (mcu_is_egret)
return sync_egret();
negate_TIP_and_TACK();
/* delay 4ms and then clear any pending interrupt */
mdelay(4);
(void)in_8(&via[SR]);
out_8(&via[IFR], SR_INT);
/* sync with the CUDA - assert TACK without TIP */
assert_TACK();
/* wait for the CUDA to assert TREQ in response */
WAIT_FOR(TREQ_asserted(in_8(&via[B])), "CUDA response to sync");
/* wait for the interrupt and then clear it */
WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (2)");
(void)in_8(&via[SR]);
out_8(&via[IFR], SR_INT);
/* finish the sync by negating TACK */
negate_TACK();
/* wait for the CUDA to negate TREQ and the corresponding interrupt */
WAIT_FOR(!TREQ_asserted(in_8(&via[B])), "CUDA response to sync (3)");
WAIT_FOR(in_8(&via[IFR]) & SR_INT, "CUDA response to sync (4)");
(void)in_8(&via[SR]);
out_8(&via[IFR], SR_INT);
return 0;
}
#ifdef CONFIG_ADB
/* Send an ADB command */
static int
cuda_send_request(struct adb_request *req, int sync)
{
int i;
if ((via == NULL) || !cuda_fully_inited) {
req->complete = 1;
return -ENXIO;
}
req->reply_expected = 1;
i = cuda_write(req);
if (i)
return i;
if (sync) {
while (!req->complete)
cuda_poll();
}
return 0;
}
/* Enable/disable autopolling */
static int
cuda_adb_autopoll(int devs)
{
struct adb_request req;
if ((via == NULL) || !cuda_fully_inited)
return -ENXIO;
cuda_request(&req, NULL, 3, CUDA_PACKET, CUDA_AUTOPOLL, (devs? 1: 0));
while (!req.complete)
cuda_poll();
return 0;
}
/* Reset adb bus - how do we do this?? */
static int
cuda_reset_adb_bus(void)
{
struct adb_request req;
if ((via == NULL) || !cuda_fully_inited)
return -ENXIO;
cuda_request(&req, NULL, 2, ADB_PACKET, 0); /* maybe? */
while (!req.complete)
cuda_poll();
return 0;
}
#endif /* CONFIG_ADB */
/* Construct and send a cuda request */
int
cuda_request(struct adb_request *req, void (*done)(struct adb_request *),
int nbytes, ...)
{
va_list list;
int i;
if (via == NULL) {
req->complete = 1;
return -ENXIO;
}
req->nbytes = nbytes;
req->done = done;
va_start(list, nbytes);
for (i = 0; i < nbytes; ++i)
req->data[i] = va_arg(list, int);
va_end(list);
req->reply_expected = 1;
return cuda_write(req);
}
EXPORT_SYMBOL(cuda_request);
static int
cuda_write(struct adb_request *req)
{
unsigned long flags;
if (req->nbytes < 2 || req->data[0] > CUDA_PACKET) {
req->complete = 1;
return -EINVAL;
}
req->next = NULL;
req->sent = 0;
req->complete = 0;
req->reply_len = 0;
spin_lock_irqsave(&cuda_lock, flags);
if (current_req) {
last_req->next = req;
last_req = req;
} else {
current_req = req;
last_req = req;
if (cuda_state == idle)
cuda_start();
}
spin_unlock_irqrestore(&cuda_lock, flags);
return 0;
}
static void
cuda_start(void)
{
/* assert cuda_state == idle */
if (current_req == NULL)
return;
data_index = 0;
if (TREQ_asserted(in_8(&via[B])))
return; /* a byte is coming in from the CUDA */
/* set the shift register to shift out and send a byte */
out_8(&via[ACR], in_8(&via[ACR]) | SR_OUT);
out_8(&via[SR], current_req->data[data_index++]);
if (mcu_is_egret)
assert_TIP_and_TACK();
else
assert_TIP();
cuda_state = sent_first_byte;
}
void
cuda_poll(void)
{
cuda_interrupt(0, NULL);
}
EXPORT_SYMBOL(cuda_poll);
#define ARRAY_FULL(a, p) ((p) - (a) == ARRAY_SIZE(a))
static irqreturn_t
cuda_interrupt(int irq, void *arg)
{
unsigned long flags;
u8 status;
struct adb_request *req = NULL;
unsigned char ibuf[16];
int ibuf_len = 0;
int complete = 0;
bool full;
spin_lock_irqsave(&cuda_lock, flags);
/* On powermacs, this handler is registered for the VIA IRQ. But they use
* just the shift register IRQ -- other VIA interrupt sources are disabled.
* On m68k macs, the VIA IRQ sources are dispatched individually. Unless
* we are polling, the shift register IRQ flag has already been cleared.
*/
#ifdef CONFIG_MAC
if (!arg)
#endif
{
if ((in_8(&via[IFR]) & SR_INT) == 0) {
spin_unlock_irqrestore(&cuda_lock, flags);
return IRQ_NONE;
} else {
out_8(&via[IFR], SR_INT);
}
}
status = in_8(&via[B]) & (TIP | TACK | TREQ);
switch (cuda_state) {
case idle:
/* System controller has unsolicited data for us */
(void)in_8(&via[SR]);
idle_state:
assert_TIP();
cuda_state = reading;
reply_ptr = cuda_rbuf;
reading_reply = 0;
break;
case awaiting_reply:
/* System controller has reply data for us */
(void)in_8(&via[SR]);
assert_TIP();
cuda_state = reading;
reply_ptr = current_req->reply;
reading_reply = 1;
break;
case sent_first_byte:
if (TREQ_asserted(status)) {
/* collision */
out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
(void)in_8(&via[SR]);
negate_TIP_and_TACK();
cuda_state = idle;
/* Egret does not raise an "aborted" interrupt */
if (mcu_is_egret)
goto idle_state;
} else {
out_8(&via[SR], current_req->data[data_index++]);
toggle_TACK();
if (mcu_is_egret)
assert_TACK();
cuda_state = sending;
}
break;
case sending:
req = current_req;
if (data_index >= req->nbytes) {
out_8(&via[ACR], in_8(&via[ACR]) & ~SR_OUT);
(void)in_8(&via[SR]);
negate_TIP_and_TACK();
req->sent = 1;
if (req->reply_expected) {
cuda_state = awaiting_reply;
} else {
current_req = req->next;
complete = 1;
/* not sure about this */
cuda_state = idle;
cuda_start();
}
} else {
out_8(&via[SR], req->data[data_index++]);
toggle_TACK();
if (mcu_is_egret)
assert_TACK();
}
break;
case reading:
full = reading_reply ? ARRAY_FULL(current_req->reply, reply_ptr)
: ARRAY_FULL(cuda_rbuf, reply_ptr);
if (full)
(void)in_8(&via[SR]);
else
*reply_ptr++ = in_8(&via[SR]);
if (!TREQ_asserted(status) || full) {
if (mcu_is_egret)
assert_TACK();
/* that's all folks */
negate_TIP_and_TACK();
cuda_state = read_done;
/* Egret does not raise a "read done" interrupt */
if (mcu_is_egret)
goto read_done_state;
} else {
toggle_TACK();
if (mcu_is_egret)
negate_TACK();
}
break;
case read_done:
(void)in_8(&via[SR]);
read_done_state:
if (reading_reply) {
req = current_req;
req->reply_len = reply_ptr - req->reply;
if (req->data[0] == ADB_PACKET) {
/* Have to adjust the reply from ADB commands */
if (req->reply_len <= 2 || (req->reply[1] & 2) != 0) {
/* the 0x2 bit indicates no response */
req->reply_len = 0;
} else {
/* leave just the command and result bytes in the reply */
req->reply_len -= 2;
memmove(req->reply, req->reply + 2, req->reply_len);
}
}
current_req = req->next;
complete = 1;
reading_reply = 0;
} else {
/* This is tricky. We must break the spinlock to call
* cuda_input. However, doing so means we might get
* re-entered from another CPU getting an interrupt
* or calling cuda_poll(). I ended up using the stack
* (it's only for 16 bytes) and moving the actual
* call to cuda_input to outside of the lock.
*/
ibuf_len = reply_ptr - cuda_rbuf;
memcpy(ibuf, cuda_rbuf, ibuf_len);
}
reply_ptr = cuda_rbuf;
cuda_state = idle;
cuda_start();
if (cuda_state == idle && TREQ_asserted(in_8(&via[B]))) {
assert_TIP();
cuda_state = reading;
}
break;
default:
pr_err("cuda_interrupt: unknown cuda_state %d?\n", cuda_state);
}
spin_unlock_irqrestore(&cuda_lock, flags);
if (complete && req) {
void (*done)(struct adb_request *) = req->done;
mb();
req->complete = 1;
/* Here, we assume that if the request has a done member, the
* struct request will survive to setting req->complete to 1
*/
if (done)
(*done)(req);
}
if (ibuf_len)
cuda_input(ibuf, ibuf_len);
return IRQ_HANDLED;
}
static void
cuda_input(unsigned char *buf, int nb)
{
switch (buf[0]) {
case ADB_PACKET:
#ifdef CONFIG_XMON
if (nb == 5 && buf[2] == 0x2c) {
extern int xmon_wants_key, xmon_adb_keycode;
if (xmon_wants_key) {
xmon_adb_keycode = buf[3];
return;
}
}
#endif /* CONFIG_XMON */
#ifdef CONFIG_ADB
adb_input(buf+2, nb-2, buf[1] & 0x40);
#endif /* CONFIG_ADB */
break;
case TIMER_PACKET:
/* Egret sends these periodically. Might be useful as a 'heartbeat'
* to trigger a recovery for the VIA shift register errata.
*/
break;
default:
print_hex_dump(KERN_INFO, "cuda_input: ", DUMP_PREFIX_NONE, 32, 1,
buf, nb, false);
}
}
/* Offset between Unix time (1970-based) and Mac time (1904-based) */
#define RTC_OFFSET 2082844800
time64_t cuda_get_time(void)
{
struct adb_request req;
u32 now;
if (cuda_request(&req, NULL, 2, CUDA_PACKET, CUDA_GET_TIME) < 0)
return 0;
while (!req.complete)
cuda_poll();
if (req.reply_len != 7)
pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
now = (req.reply[3] << 24) + (req.reply[4] << 16) +
(req.reply[5] << 8) + req.reply[6];
return (time64_t)now - RTC_OFFSET;
}
int cuda_set_rtc_time(struct rtc_time *tm)
{
u32 now;
struct adb_request req;
now = lower_32_bits(rtc_tm_to_time64(tm) + RTC_OFFSET);
if (cuda_request(&req, NULL, 6, CUDA_PACKET, CUDA_SET_TIME,
now >> 24, now >> 16, now >> 8, now) < 0)
return -ENXIO;
while (!req.complete)
cuda_poll();
if ((req.reply_len != 3) && (req.reply_len != 7))
pr_err("%s: got %d byte reply\n", __func__, req.reply_len);
return 0;
}
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