LXR linux/drivers/accessibility/speakup/serialio.c

   1// SPDX-License-Identifier: GPL-2.0
   2#include <linux/interrupt.h>
   3#include <linux/ioport.h>
   4
   5#include "spk_types.h"
   6#include "speakup.h"
   7#include "spk_priv.h"
   8#include "serialio.h"
   9
  10#include <linux/serial_core.h>
  11/* WARNING:  Do not change this to <linux/serial.h> without testing that
  12 * SERIAL_PORT_DFNS does get defined to the appropriate value.
  13 */
  14#include <asm/serial.h>
  15
  16#ifndef SERIAL_PORT_DFNS
  17#define SERIAL_PORT_DFNS
  18#endif
  19
  20static void start_serial_interrupt(int irq);
  21
  22static const struct old_serial_port rs_table[] = {
  23        SERIAL_PORT_DFNS
  24};
  25
  26static const struct old_serial_port *serstate;
  27static int timeouts;
  28
  29static int spk_serial_out(struct spk_synth *in_synth, const char ch);
  30static void spk_serial_send_xchar(struct spk_synth *in_synth, char ch);
  31static void spk_serial_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear);
  32static unsigned char spk_serial_in(struct spk_synth *in_synth);
  33static unsigned char spk_serial_in_nowait(struct spk_synth *in_synth);
  34static void spk_serial_flush_buffer(struct spk_synth *in_synth);
  35static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth);
  36
  37struct spk_io_ops spk_serial_io_ops = {
  38        .synth_out = spk_serial_out,
  39        .send_xchar = spk_serial_send_xchar,
  40        .tiocmset = spk_serial_tiocmset,
  41        .synth_in = spk_serial_in,
  42        .synth_in_nowait = spk_serial_in_nowait,
  43        .flush_buffer = spk_serial_flush_buffer,
  44        .wait_for_xmitr = spk_serial_wait_for_xmitr,
  45};
  46EXPORT_SYMBOL_GPL(spk_serial_io_ops);
  47
  48const struct old_serial_port *spk_serial_init(int index)
  49{
  50        int baud = 9600, quot = 0;
  51        unsigned int cval = 0;
  52        int cflag = CREAD | HUPCL | CLOCAL | B9600 | CS8;
  53        const struct old_serial_port *ser;
  54        int err;
  55
  56        if (index >= ARRAY_SIZE(rs_table)) {
  57                pr_info("no port info for ttyS%d\n", index);
  58                return NULL;
  59        }
  60        ser = rs_table + index;
  61
  62        /*      Divisor, bytesize and parity */
  63        quot = ser->baud_base / baud;
  64        cval = cflag & (CSIZE | CSTOPB);
  65#if defined(__powerpc__) || defined(__alpha__)
  66        cval >>= 8;
  67#else /* !__powerpc__ && !__alpha__ */
  68        cval >>= 4;
  69#endif /* !__powerpc__ && !__alpha__ */
  70        if (cflag & PARENB)
  71                cval |= UART_LCR_PARITY;
  72        if (!(cflag & PARODD))
  73                cval |= UART_LCR_EPAR;
  74        if (synth_request_region(ser->port, 8)) {
  75                /* try to take it back. */
  76                pr_info("Ports not available, trying to steal them\n");
  77                __release_region(&ioport_resource, ser->port, 8);
  78                err = synth_request_region(ser->port, 8);
  79                if (err) {
  80                        pr_warn("Unable to allocate port at %x, errno %i",
  81                                ser->port, err);
  82                        return NULL;
  83                }
  84        }
  85
  86        /*      Disable UART interrupts, set DTR and RTS high
  87         *      and set speed.
  88         */
  89        outb(cval | UART_LCR_DLAB, ser->port + UART_LCR);       /* set DLAB */
  90        outb(quot & 0xff, ser->port + UART_DLL);        /* LS of divisor */
  91        outb(quot >> 8, ser->port + UART_DLM);          /* MS of divisor */
  92        outb(cval, ser->port + UART_LCR);               /* reset DLAB */
  93
  94        /* Turn off Interrupts */
  95        outb(0, ser->port + UART_IER);
  96        outb(UART_MCR_DTR | UART_MCR_RTS, ser->port + UART_MCR);
  97
  98        /* If we read 0xff from the LSR, there is no UART here. */
  99        if (inb(ser->port + UART_LSR) == 0xff) {
 100                synth_release_region(ser->port, 8);
 101                serstate = NULL;
 102                return NULL;
 103        }
 104
 105        mdelay(1);
 106        speakup_info.port_tts = ser->port;
 107        serstate = ser;
 108
 109        start_serial_interrupt(ser->irq);
 110
 111        return ser;
 112}
 113
 114static irqreturn_t synth_readbuf_handler(int irq, void *dev_id)
 115{
 116        unsigned long flags;
 117        int c;
 118
 119        spin_lock_irqsave(&speakup_info.spinlock, flags);
 120        while (inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR) {
 121                c = inb_p(speakup_info.port_tts + UART_RX);
 122                synth->read_buff_add((u_char)c);
 123        }
 124        spin_unlock_irqrestore(&speakup_info.spinlock, flags);
 125        return IRQ_HANDLED;
 126}
 127
 128static void start_serial_interrupt(int irq)
 129{
 130        int rv;
 131
 132        if (!synth->read_buff_add)
 133                return;
 134
 135        rv = request_irq(irq, synth_readbuf_handler, IRQF_SHARED,
 136                         "serial", (void *)synth_readbuf_handler);
 137
 138        if (rv)
 139                pr_err("Unable to request Speakup serial I R Q\n");
 140        /* Set MCR */
 141        outb(UART_MCR_DTR | UART_MCR_RTS | UART_MCR_OUT2,
 142             speakup_info.port_tts + UART_MCR);
 143        /* Turn on Interrupts */
 144        outb(UART_IER_MSI | UART_IER_RLSI | UART_IER_RDI,
 145             speakup_info.port_tts + UART_IER);
 146        inb(speakup_info.port_tts + UART_LSR);
 147        inb(speakup_info.port_tts + UART_RX);
 148        inb(speakup_info.port_tts + UART_IIR);
 149        inb(speakup_info.port_tts + UART_MSR);
 150        outb(1, speakup_info.port_tts + UART_FCR);      /* Turn FIFO On */
 151}
 152
 153static void spk_serial_send_xchar(struct spk_synth *synth, char ch)
 154{
 155        int timeout = SPK_XMITR_TIMEOUT;
 156
 157        while (spk_serial_tx_busy()) {
 158                if (!--timeout)
 159                        break;
 160                udelay(1);
 161        }
 162        outb(ch, speakup_info.port_tts);
 163}
 164
 165static void spk_serial_tiocmset(struct spk_synth *in_synth, unsigned int set, unsigned int clear)
 166{
 167        int old = inb(speakup_info.port_tts + UART_MCR);
 168
 169        outb((old & ~clear) | set, speakup_info.port_tts + UART_MCR);
 170}
 171
 172int spk_serial_synth_probe(struct spk_synth *synth)
 173{
 174        const struct old_serial_port *ser;
 175        int failed = 0;
 176
 177        if ((synth->ser >= SPK_LO_TTY) && (synth->ser <= SPK_HI_TTY)) {
 178                ser = spk_serial_init(synth->ser);
 179                if (!ser) {
 180                        failed = -1;
 181                } else {
 182                        outb_p(0, ser->port);
 183                        mdelay(1);
 184                        outb_p('\r', ser->port);
 185                }
 186        } else {
 187                failed = -1;
 188                pr_warn("ttyS%i is an invalid port\n", synth->ser);
 189        }
 190        if (failed) {
 191                pr_info("%s: not found\n", synth->long_name);
 192                return -ENODEV;
 193        }
 194        pr_info("%s: ttyS%i, Driver Version %s\n",
 195                synth->long_name, synth->ser, synth->version);
 196        synth->alive = 1;
 197        return 0;
 198}
 199EXPORT_SYMBOL_GPL(spk_serial_synth_probe);
 200
 201void spk_stop_serial_interrupt(void)
 202{
 203        if (speakup_info.port_tts == 0)
 204                return;
 205
 206        if (!synth->read_buff_add)
 207                return;
 208
 209        /* Turn off interrupts */
 210        outb(0, speakup_info.port_tts + UART_IER);
 211        /* Free IRQ */
 212        free_irq(serstate->irq, (void *)synth_readbuf_handler);
 213}
 214EXPORT_SYMBOL_GPL(spk_stop_serial_interrupt);
 215
 216static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth)
 217{
 218        int tmout = SPK_XMITR_TIMEOUT;
 219
 220        if ((in_synth->alive) && (timeouts >= NUM_DISABLE_TIMEOUTS)) {
 221                pr_warn("%s: too many timeouts, deactivating speakup\n",
 222                        in_synth->long_name);
 223                in_synth->alive = 0;
 224                /* No synth any more, so nobody will restart TTYs, and we thus
 225                 * need to do it ourselves.  Now that there is no synth we can
 226                 * let application flood anyway
 227                 */
 228                speakup_start_ttys();
 229                timeouts = 0;
 230                return 0;
 231        }
 232        while (spk_serial_tx_busy()) {
 233                if (--tmout == 0) {
 234                        pr_warn("%s: timed out (tx busy)\n",
 235                                in_synth->long_name);
 236                        timeouts++;
 237                        return 0;
 238                }
 239                udelay(1);
 240        }
 241        tmout = SPK_CTS_TIMEOUT;
 242        while (!((inb_p(speakup_info.port_tts + UART_MSR)) & UART_MSR_CTS)) {
 243                /* CTS */
 244                if (--tmout == 0) {
 245                        timeouts++;
 246                        return 0;
 247                }
 248                udelay(1);
 249        }
 250        timeouts = 0;
 251        return 1;
 252}
 253
 254static unsigned char spk_serial_in(struct spk_synth *in_synth)
 255{
 256        int tmout = SPK_SERIAL_TIMEOUT;
 257
 258        while (!(inb_p(speakup_info.port_tts + UART_LSR) & UART_LSR_DR)) {
 259                if (--tmout == 0) {
 260                        pr_warn("time out while waiting for input.\n");
 261                        return 0xff;
 262                }
 263                udelay(1);
 264        }
 265        return inb_p(speakup_info.port_tts + UART_RX);
 266}
 267
 268static unsigned char spk_serial_in_nowait(struct spk_synth *in_synth)
 269{
 270        unsigned char lsr;
 271
 272        lsr = inb_p(speakup_info.port_tts + UART_LSR);
 273        if (!(lsr & UART_LSR_DR))
 274                return 0;
 275        return inb_p(speakup_info.port_tts + UART_RX);
 276}
 277
 278static void spk_serial_flush_buffer(struct spk_synth *in_synth)
 279{
 280        /* TODO: flush the UART 16550 buffer */
 281}
 282
 283static int spk_serial_out(struct spk_synth *in_synth, const char ch)
 284{
 285        if (in_synth->alive && spk_serial_wait_for_xmitr(in_synth)) {
 286                outb_p(ch, speakup_info.port_tts);
 287                return 1;
 288        }
 289        return 0;
 290}
 291
 292const char *spk_serial_synth_immediate(struct spk_synth *synth,
 293                                       const char *buff)
 294{
 295        u_char ch;
 296
 297        while ((ch = *buff)) {
 298                if (ch == '\n')
 299                        ch = synth->procspeech;
 300                if (spk_serial_wait_for_xmitr(synth))
 301                        outb(ch, speakup_info.port_tts);
 302                else
 303                        return buff;
 304                buff++;
 305        }
 306        return NULL;
 307}
 308EXPORT_SYMBOL_GPL(spk_serial_synth_immediate);
 309
 310void spk_serial_release(struct spk_synth *synth)
 311{
 312        spk_stop_serial_interrupt();
 313        if (speakup_info.port_tts == 0)
 314                return;
 315        synth_release_region(speakup_info.port_tts, 8);
 316        speakup_info.port_tts = 0;
 317}
 318EXPORT_SYMBOL_GPL(spk_serial_release);
 319