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
  20 static void start_serial_interrupt(int irq);
  21
  22 static const struct old_serial_port rs_table[] = {
  23         SERIAL_PORT_DFNS
  24 };
  25
  26 static const struct old_serial_port *serstate;
  27 static int timeouts;
  28
  29 static int spk_serial_out(struct spk_synth *in_synth, const char ch);
  30 static void spk_serial_send_xchar(char ch);
  31 static void spk_serial_tiocmset(unsigned int set, unsigned int clear);
  32 static unsigned char spk_serial_in(void);
  33 static unsigned char spk_serial_in_nowait(void);
  34 static void spk_serial_flush_buffer(void);
  35 static int spk_serial_wait_for_xmitr(struct spk_synth *in_synth);
  36
  37 struct 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 };
  46 EXPORT_SYMBOL_GPL(spk_serial_io_ops);
  47
  48 const 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
 114 static 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
 128 static 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
 153 static void spk_serial_send_xchar(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
 165 static void spk_serial_tiocmset(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
 172 int 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 }
 199 EXPORT_SYMBOL_GPL(spk_serial_synth_probe);
 200
 201 void 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 }
 214 EXPORT_SYMBOL_GPL(spk_stop_serial_interrupt);
 215
 216 static 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
 254 static unsigned char spk_serial_in(void)
 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
 268 static unsigned char spk_serial_in_nowait(void)
 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
 278 static void spk_serial_flush_buffer(void)
 279 {
 280         /* TODO: flush the UART 16550 buffer */
 281 }
 282
 283 static 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
 292 const 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 }
 308 EXPORT_SYMBOL_GPL(spk_serial_synth_immediate);
 309
 310 void spk_serial_release(void)
 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 }
 318 EXPORT_SYMBOL_GPL(spk_serial_release);