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alistair23-linux/drivers/macintosh/via-cuda.c
Finn Thain 458c77f3de macintosh/via-cuda: Don't rely on Cuda to end a transfer 
Certain Cuda transfers have to be ended by the driver. According
to Apple's open source Cuda driver, as found in mkLinux and XNU, this
applies to any "open ended request such as PRAM read". This fixes an
infinite polling loop in cuda_pram_read_byte().

Tested-by: Stan Johnson <userm57@yahoo.com>
Signed-off-by: Finn Thain <fthain@telegraphics.com.au>
Signed-off-by: Greg Kroah-Hartman <gregkh@linuxfoundation.org>
2019-01-22 10:21:45 +01:00

806 lines
19 KiB
C
Raw Blame History

// 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 <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>
#ifdef CONFIG_PPC
#include <asm/prom.h>
#include <asm/machdep.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;
phys_addr_t taddr;
const u32 *reg;
int err;
if (vias != 0)
return 1;
vias = of_find_node_by_name(NULL, "via-cuda");
if (vias == 0)
return 0;
reg = of_get_property(vias, "reg", NULL);
if (reg == NULL) {
printk(KERN_ERR "via-cuda: No \"reg\" property !\n");
goto fail;
}
taddr = of_translate_address(vias, reg);
if (taddr == 0) {
printk(KERN_ERR "via-cuda: Can't translate address !\n");
goto fail;
}
via = ioremap(taddr, 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 != 0) {
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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