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