summaryrefslogtreecommitdiff
path: root/nuttx/arch/z80/src/z8/z8_serial.c
blob: 553e3fb4008e16c99c44a068c91ec0f42bd99ff1 (plain) (blame)
1
2
3
4
5
6
7
8
9
10
11
12
13
14
15
16
17
18
19
20
21
22
23
24
25
26
27
28
29
30
31
32
33
34
35
36
37
38
39
40
41
42
43
44
45
46
47
48
49
50
51
52
53
54
55
56
57
58
59
60
61
62
63
64
65
66
67
68
69
70
71
72
73
74
75
76
77
78
79
80
81
82
83
84
85
86
87
88
89
90
91
92
93
94
95
96
97
98
99
100
101
102
103
104
105
106
107
108
109
110
111
112
113
114
115
116
117
118
119
120
121
122
123
124
125
126
127
128
129
130
131
132
133
134
135
136
137
138
139
140
141
142
143
144
145
146
147
148
149
150
151
152
153
154
155
156
157
158
159
160
161
162
163
164
165
166
167
168
169
170
171
172
173
174
175
176
177
178
179
180
181
182
183
184
185
186
187
188
189
190
191
192
193
194
195
196
197
198
199
200
201
202
203
204
205
206
207
208
209
210
211
212
213
214
215
216
217
218
219
220
221
222
223
224
225
226
227
228
229
230
231
232
233
234
235
236
237
238
239
240
241
242
243
244
245
246
247
248
249
250
251
252
253
254
255
256
257
258
259
260
261
262
263
264
265
266
267
268
269
270
271
272
273
274
275
276
277
278
279
280
281
282
283
284
285
286
287
288
289
290
291
292
293
294
295
296
297
298
299
300
301
302
303
304
305
306
307
308
309
310
311
312
313
314
315
316
317
318
319
320
321
322
323
324
325
326
327
328
329
330
331
332
333
334
335
336
337
338
339
340
341
342
343
344
345
346
347
348
349
350
351
352
353
354
355
356
357
358
359
360
361
362
363
364
365
366
367
368
369
370
371
372
373
374
375
376
377
378
379
380
381
382
383
384
385
386
387
388
389
390
391
392
393
394
395
396
397
398
399
400
401
402
403
404
405
406
407
408
409
410
411
412
413
414
415
416
417
418
419
420
421
422
423
424
425
426
427
428
429
430
431
432
433
434
435
436
437
438
439
440
441
442
443
444
445
446
447
448
449
450
451
452
453
454
455
456
457
458
459
460
461
462
463
464
465
466
467
468
469
470
471
472
473
474
475
476
477
478
479
480
481
482
483
484
485
486
487
488
489
490
491
492
493
494
495
496
497
498
499
500
501
502
503
504
505
506
507
508
509
510
511
512
513
514
515
516
517
518
519
520
521
522
523
524
525
526
527
528
529
530
531
532
533
534
535
536
537
538
539
540
541
542
543
544
545
546
547
548
549
550
551
552
553
554
555
556
557
558
559
560
561
562
563
564
565
566
567
568
569
570
571
572
573
574
575
576
577
578
579
580
581
582
583
584
585
586
587
588
589
590
591
592
593
594
595
596
597
598
599
600
601
602
603
604
605
606
607
608
609
610
611
612
613
614
615
616
617
618
619
620
621
622
623
624
625
626
627
628
629
630
631
632
633
634
635
636
637
638
639
640
641
642
643
644
645
646
647
648
649
650
651
652
653
654
655
656
657
658
659
660
661
662
663
664
665
666
667
668
669
670
671
672
673
674
675
676
677
678
679
680
681
682
683
684
685
686
687
688
689
690
691
692
693
694
695
696
697
698
699
700
701
702
703
704
705
706
707
708
709
710
711
712
713
714
715
716
717
718
719
720
721
722
723
724
725
726
727
728
729
730
731
732
733
734
735
736
737
738
739
740
741
742
743
744
745
746
747
748
749
750
751
752
753
754
755
756
757
758
759
760
761
762
763
764
765
766
767
768
769
770
771
772
773
774
775
776
777
778
779
780
781
782
783
784
785
786
787
788
789
790
791
792
793
794
795
796
797
798
799
800
801
802
803
804
805
806
807
808
809
810
811
812
813
814
815
816
817
818
819
820
821
822
823
824
825
826
827
828
829
830
831
832
833
834
835
836
837
838
839
840
841
842
843
844
845
846
847
848
849
850
851
852
853
854
855
856
857
858
/****************************************************************************
 * arch/z80/src/z8/z8_serial.c
 *
 *   Copyright (C) 2008-2009, 2012 Gregory Nutt. All rights reserved.
 *   Author: Gregory Nutt <gnutt@nuttx.org>
 *
 * Redistribution and use in source and binary forms, with or without
 * modification, are permitted provided that the following conditions
 * are met:
 *
 * 1. Redistributions of source code must retain the above copyright
 *    notice, this list of conditions and the following disclaimer.
 * 2. Redistributions in binary form must reproduce the above copyright
 *    notice, this list of conditions and the following disclaimer in
 *    the documentation and/or other materials provided with the
 *    distribution.
 * 3. Neither the name NuttX nor the names of its contributors may be
 *    used to endorse or promote products derived from this software
 *    without specific prior written permission.
 *
 * THIS SOFTWARE IS PROVIDED BY THE COPYRIGHT HOLDERS AND CONTRIBUTORS
 * "AS IS" AND ANY EXPRESS OR IMPLIED WARRANTIES, INCLUDING, BUT NOT
 * LIMITED TO, THE IMPLIED WARRANTIES OF MERCHANTABILITY AND FITNESS
 * FOR A PARTICULAR PURPOSE ARE DISCLAIMED. IN NO EVENT SHALL THE
 * COPYRIGHT OWNER OR CONTRIBUTORS BE LIABLE FOR ANY DIRECT, INDIRECT,
 * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING,
 * BUT NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS
 * OF USE, DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED
 * AND ON ANY THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT
 * LIABILITY, OR TORT (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN
 * ANY WAY OUT OF THE USE OF THIS SOFTWARE, EVEN IF ADVISED OF THE
 * POSSIBILITY OF SUCH DAMAGE.
 *
 ****************************************************************************/

/****************************************************************************
 * Included Files
 ****************************************************************************/

#include <nuttx/config.h>

#include <sys/types.h>
#include <stdint.h>
#include <stdbool.h>
#include <unistd.h>
#include <semaphore.h>
#include <string.h>
#include <errno.h>
#include <debug.h>
#include <ez8.h>

#include <nuttx/irq.h>
#include <nuttx/arch.h>
#include <nuttx/serial/serial.h>
#include <arch/serial.h>

#include "chip/chip.h"
#include "os_internal.h"
#include "up_internal.h"

#ifdef USE_SERIALDRIVER

extern uint32_t get_freq(void);

/****************************************************************************
 * Definitions
 ****************************************************************************/

/* System clock frequency value from ZDS target settings */

#define STATE_DISABLED   0
#define STATE_RXENABLED  1
#define STATE_TXENABLED  2

/****************************************************************************
 * Private Types
 ****************************************************************************/

struct z8_uart_s
{
  uint8_t volatile far* uartbase;		/* Base address of UART registers */
  uint32_t     baud;		/* Configured baud */
  bool         rxenabled;	/* RX interrupt enabled */
  bool         txenabled;	/* TX interrupt enabled */
  uint8_t      rxirq;		/* RX IRQ associated with this UART */
  uint8_t      txirq;		/* RX IRQ associated with this UART */
  uint8_t      parity;		/* 0=none, 1=odd, 2=even */
  bool         stopbits2;	/* true: Configure with 2 stop bits
							 * (instead of 1) */
};

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

static int  z8_setup(FAR struct uart_dev_s *dev);
static void z8_shutdown(FAR struct uart_dev_s *dev);
static int  z8_attach(FAR struct uart_dev_s *dev);
static void z8_detach(FAR struct uart_dev_s *dev);
static int  z8_rxinterrupt(int irq, FAR void *context);
static int  z8_txinterrupt(int irq, FAR void *context);
static int  z8_ioctl(FAR struct file *filep, int cmd, unsigned long arg);
static int  z8_receive(FAR struct uart_dev_s *dev, FAR uint32_t *status);
static void z8_rxint(FAR struct uart_dev_s *dev, bool enable);
static bool z8_rxavailable(FAR struct uart_dev_s *dev);
static void z8_send(FAR struct uart_dev_s *dev, int ch);
static void z8_txint(FAR struct uart_dev_s *dev, bool enable);
static bool z8_txready(FAR struct uart_dev_s *dev);
static bool z8_txempty(FAR struct uart_dev_s *dev);

/****************************************************************************
 * Private Variables
 ****************************************************************************/

static const struct uart_ops_s g_uart_ops =
{
  z8_setup,          /* setup */
  z8_shutdown,       /* shutdown */
  z8_attach,         /* attach */
  z8_detach,         /* detach */
  z8_ioctl,          /* ioctl */
  z8_receive,        /* receive */
  z8_rxint,          /* rxint */
  z8_rxavailable,    /* rxavailable */
  z8_send,           /* send */
  z8_txint,          /* txint */
  z8_txready,        /* txready */
  z8_txempty         /* txempty */
};

/* I/O buffers */

static char g_uart0rxbuffer[CONFIG_UART0_RXBUFSIZE];
static char g_uart0txbuffer[CONFIG_UART0_TXBUFSIZE];
static char g_uart1rxbuffer[CONFIG_UART1_RXBUFSIZE];
static char g_uart1txbuffer[CONFIG_UART1_TXBUFSIZE];

/* This describes the state of the DM320 uart0 port. */

static struct z8_uart_s g_uart0priv =
{
  Z8_UART0_BASE,            /* uartbase */
  CONFIG_UART0_BAUD,        /* baud */
  false,                    /* rxenabled */
  false,                    /* txenabled */
  Z8_UART0_RX_IRQ,          /* rxirq */
  Z8_UART0_TX_IRQ,          /* txirq */
  CONFIG_UART0_PARITY,      /* parity */
  CONFIG_UART0_2STOP        /* stopbits2 */
};

static uart_dev_t g_uart0port =
{
  0,                        /* open_count */
  false,                    /* xmitwaiting */
  false,                    /* recvwaiting */
#ifdef CONFIG_UART0_SERIAL_CONSOLE
  true,                     /* isconsole */
#else
  false,                    /* isconsole */
#endif
  { 0 },                    /* closesem */
  { 0 },                    /* xmitsem */
  { 0 },                    /* recvsem */
  {
    { 0 },                  /* xmit.sem */
    0,                      /* xmit.head */
    0,                      /* xmit.tail */
    CONFIG_UART0_TXBUFSIZE, /* xmit.size */
    g_uart0txbuffer,        /* xmit.buffer */
  },
  {
    { 0 },                  /* recv.sem */
    0,                      /* recv.head */
    0,                      /* recv.tail */
    CONFIG_UART0_RXBUFSIZE, /* recv.size */
    g_uart0rxbuffer,        /* recv.buffer */
  },
  &g_uart_ops,              /* ops */
  &g_uart0priv,             /* priv */
};

/* This describes the state of the DM320 uart1 port. */

static struct z8_uart_s g_uart1priv =
{
  Z8_UART1_BASE,            /* uartbase */
  CONFIG_UART1_BAUD,        /* baud */
  false,                    /* rxenabled */
  false,                    /* txenabled */
  Z8_UART1_RX_IRQ,          /* rxirq */
  Z8_UART1_TX_IRQ,          /* txirq */
  CONFIG_UART1_PARITY,      /* parity */
  CONFIG_UART1_2STOP        /* stopbits2 */
};

static uart_dev_t g_uart1port =
{
  0,                        /* open_count */
  false,                    /* xmitwaiting */
  false,                    /* recvwaiting */
#ifdef CONFIG_UART1_SERIAL_CONSOLE
  true,                     /* isconsole */
#else
  false,                    /* isconsole */
#endif
  { 0 },                    /* closesem */
  { 0 },                    /* xmitsem */
  { 0 },                    /* recvsem */
  {
    { 0 },                  /* xmit.sem */
    0,                      /* xmit.head */
    0,                      /* xmit.tail */
    CONFIG_UART1_TXBUFSIZE, /* xmit.size */
    g_uart1txbuffer,        /* xmit.buffer */
  },
  {
    { 0 },                  /* recv.sem */
    0,                      /* recv.head */
    0,                      /* recv.tail */
    CONFIG_UART1_RXBUFSIZE, /* recv.size */
    g_uart0rxbuffer,        /* recv.buffer */
  },
  &g_uart_ops,              /* ops */
  &g_uart1priv,             /* priv */
};

/* Now, which one with be tty0/console and which tty1? */

#ifdef CONFIG_UART1_SERIAL_CONSOLE
# define CONSOLE_DEV     g_uart1port
# define TTYS0_DEV       g_uart1port
# define TTYS1_DEV       g_uart0port
#else
# define CONSOLE_DEV     g_uart0port
# define TTYS0_DEV       g_uart0port
# define TTYS1_DEV       g_uart1port
#endif

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: z8_putuart
 ****************************************************************************/
 
static inline void z8_putuart(FAR struct z8_uart_s *priv, uint8_t value,
                              uint8_t offset)
{
  putreg8(value, *(priv->uartbase + offset));
}

/****************************************************************************
 * Name: z8_getuart
 ****************************************************************************/
 
static inline uint8_t z8_getuart(FAR struct z8_uart_s *priv, uint8_t offset)
{
  return getreg8(*(priv->uartbase + offset));
}

/****************************************************************************
 * Name: z8_disableuartirq
 ****************************************************************************/

static uint8_t z8_disableuartirq(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv  = (struct z8_uart_s*)dev->priv;
  irqstate_t          flags = irqsave();
  uint8_t             state = priv->rxenabled ? STATE_RXENABLED : STATE_DISABLED | \
                              priv->txenabled ? STATE_TXENABLED : STATE_DISABLED;

  z8_txint(dev, false);
  z8_rxint(dev, false);

  irqrestore(flags);
  return state;
}

/****************************************************************************
 * Name: z8_restoreuartirq
 ****************************************************************************/

static void z8_restoreuartirq(FAR struct uart_dev_s *dev, uint8_t state)
{
  struct z8_uart_s *priv  = (struct z8_uart_s*)dev->priv;
  irqstate_t          flags = irqsave();

  z8_txint(dev, (state & STATE_TXENABLED) ? true : false);
  z8_rxint(dev, (state & STATE_RXENABLED) ? true : false);

  irqrestore(flags);
}

/****************************************************************************
 * Name: z8_consoleput
 ****************************************************************************/

static void z8_consoleput(uint8_t ch)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)CONSOLE_DEV.priv;
  int tmp;

  for (tmp = 1000 ; tmp > 0 ; tmp--)
    {
      if (z8_txready(&CONSOLE_DEV))
        {
          break;
        }
    }
  z8_putuart(priv, ch,  Z8_UART_TXD);
}

/****************************************************************************
 * Name: z8_uartconfigure
 *
 * Description:
 *   Configure hardware for UART functionality
 *
 ****************************************************************************/

void z8_uartconfigure(void)
{
  uint16_t brg;
  uint8_t  val;

  /* Configure GPIO Port A pins 4 & 5 for alternate function */

  putreg8(0x02, PAADDR);
  val = getreg8(PACTL) | 0x30;    /* Set bits in alternate function register */
  putreg8(val, PACTL);
  putreg8(0x07, PAADDR);
  val = getreg8(PACTL) & 0xcf;    /* Reset bits in alternate function set-1 register */
  putreg8(val, PACTL);
  putreg8(0x08, PAADDR);
  val = getreg8(PACTL) & 0xcf;    /* Reset bits in alternate function set-2 register */
  putreg8(val, PACTL);
  putreg8(0x00, PAADDR);

#ifdef EZ8_UART1
  /* Configure GPIO Port D pins 4 & 5 for alternate function */
  
  putreg8(0x02, PAADDR);
  val = getreg8(PDCTL) | 0x30;    /* Set bits in alternate function register */
  putreg8(val, PDCTL);
  putreg8(0x07, PDADDR);
  val = getreg8(PDCTL) & 0xcf;    /* Reset bits in alternate function set-1 register */
  putreg8(val, PDCTL);
  putreg8(0x08, PDADDR);
  val = getreg8(PDCTL) & 0xcf;    /* Reset bits in alternate function set-2 register */
  putreg8(val, PDCTL);
  putreg8(0x00, PDADDR);
#endif
}

/****************************************************************************
 * Name: z8_setup
 *
 * Description:
 *   Configure the UART baud, parity, etc. This method is called the first
 *   time that the serial port is opened.
 *
 ****************************************************************************/

static int z8_setup(FAR struct uart_dev_s *dev)
{
#ifndef CONFIG_SUPPRESS_UART_CONFIG
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  uint32_t freq = get_freq();
  uint16_t brg;
  uint8_t ctl0;
  uint8_t ctl1;

  /* Calculate and set the baud rate generation register.
   * BRG = (freq + baud * 8)/(baud * 16)
   */

  brg = (freq + (priv->baud << 3))/(priv->baud << 4);
  z8_putuart(priv, brg >> 8, Z8_UART_BRH);
  z8_putuart(priv, brg & 0xff, Z8_UART_BRL);

  /* Configure STOP bits */

  ctl0 = ctl1 = 0;
  if (priv->stopbits2)
    {
      ctl0 |= Z8_UARTCTL0_STOP;
    }

  /* Configure parity */

  if (priv->parity == 1)
    {
      ctl0 |= (Z8_UARTCTL0_PEN|Z8_UARTCTL0_PSEL);
    }
  else if (priv->parity == 2)
    {
      ctl0 |= Z8_UARTCTL0_PEN;
    }

  z8_putuart(priv, ctl0, Z8_UART_CTL0);
  z8_putuart(priv, ctl1, Z8_UART_CTL1);

  /* Enable UART receive (REN) and transmit (TEN) */

  ctl0 |= (Z8_UARTCTL0_TEN|Z8_UARTCTL0_REN);
  z8_putuart(priv, ctl0, Z8_UART_CTL0);
#endif
  return OK;
}

/****************************************************************************
 * Name: z8_shutdown
 *
 * Description:
 *   Disable the UART.  This method is called when the serial
 *   port is closed
 *
 ****************************************************************************/

static void z8_shutdown(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  (void)z8_disableuartirq(dev);
}

/****************************************************************************
 * Name: z8_attach
 *
 * Description:
 *   Configure the UART to operation in interrupt driven mode.  This method is
 *   called when the serial port is opened.  Normally, this is just after the
 *   the setup() method is called, however, the serial console may operate in
 *   a non-interrupt driven mode during the boot phase.
 *
 *   RX and TX interrupts are not enabled when by the attach method (unless the
 *   hardware supports multiple levels of interrupt enabling).  The RX and TX
 *   interrupts are not enabled until the txint() and rxint() methods are called.
 *
 ****************************************************************************/

static int z8_attach(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  int ret;

  /* Attach the RX IRQ */

  ret = irq_attach(priv->rxirq, z8_rxinterrupt);
  if (ret == OK)
    {
      /* Attach the TX IRQ */

      ret = irq_attach(priv->txirq, z8_txinterrupt);
      if (ret != OK)
        {
          irq_detach(priv->rxirq);
        }
    }
  return ret;
}

/****************************************************************************
 * Name: z8_detach
 *
 * Description:
 *   Detach UART interrupts.  This method is called when the serial port is
 *   closed normally just before the shutdown method is called.  The exception is
 *   the serial console which is never shutdown.
 *
 ****************************************************************************/

static void z8_detach(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  up_disable_irq(priv->rxirq);
  up_disable_irq(priv->txirq);
  irq_detach(priv->rxirq);
  irq_detach(priv->txirq);
}

/****************************************************************************
 * Name: z8_rxinterrupt
 *
 * Description:
 *   This is the UART interrupt handler.  It will be invoked when an RX
 *   event occurs at the z8's LIN-UART.
 *
 ****************************************************************************/

static int z8_rxinterrupt(int irq, FAR void *context)
{
  struct uart_dev_s  *dev = NULL;
  struct z8_uart_s *priv;
  uint8_t            status;

  if (g_uart1priv.rxirq == irq)
    {
      dev = &g_uart1port;
    }
  else if (g_uart0priv.rxirq == irq)
    {
      dev = &g_uart0port;
    }
  else
    {
      PANIC();
    }

  priv = (struct z8_uart_s*)dev->priv;

  /* Check the LIN-UART status 0 register to determine whether the source of
   * the interrupt is error, break, or received data
   */

  status = z8_getuart(priv, Z8_UART_STAT0);

  /* REVISIT error and break handling */

  /* Check if received data is available  */

  if (status & Z8_UARTSTAT0_RDA)
    {
      /* Handline an incoming, receive byte */

      uart_recvchars(dev);
    }
  return OK;
}

/****************************************************************************
 * Name: z8_txinterrupt
 *
 * Description:
 *   This is the UART TX interrupt handler.  This interrupt handler will
 *   be invoked when the X16F LIN UART transmit data register is empty.
 *
 ****************************************************************************/

static int z8_txinterrupt(int irq, FAR void *context)
{
  struct uart_dev_s  *dev = NULL;
  struct z8_uart_s *priv;
  uint8_t            status;

  if (g_uart1priv.txirq == irq)
    {
      dev = &g_uart1port;
    }
  else if (g_uart0priv.txirq == irq)
    {
      dev = &g_uart0port;
    }
  else
    {
      PANIC();
    }

  priv = (struct z8_uart_s*)dev->priv;

  /* Verify that the transmit data register is empty */

  status = z8_getuart(priv, Z8_UART_STAT0);
  if (status & Z8_UARTSTAT0_TDRE)
    {
      /* Handle outgoing, transmit bytes */

      uart_xmitchars(dev);
    }
  return OK;
}

/****************************************************************************
 * Name: z8_ioctl
 *
 * Description:
 *   All ioctl calls will be routed through this method
 *
 ****************************************************************************/

static int z8_ioctl(FAR struct file *filep, int cmd, unsigned long arg)
{
  return -ENOTTY;
}

/****************************************************************************
 * Name: z8_receive
 *
 * Description:
 *   Called (usually) from the interrupt level to receive one character from
 *   the UART.  Error bits associated with the receipt are provided in the
 *   return 'status'.
 *
 ****************************************************************************/

static int z8_receive(FAR struct uart_dev_s *dev, FAR uint32_t *status)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  uint8_t  rxd;
  uint8_t  stat0;

  rxd     = z8_getuart(priv, Z8_UART_RXD);
  stat0   = z8_getuart(priv, Z8_UART_STAT0);
  *status = (uint32_t)rxd | (((uint32_t)stat0) << 8);
  return rxd;
}

/****************************************************************************
 * Name: z8_rxint
 *
 * Description:
 *   Call to enable or disable RX interrupts
 *
 ****************************************************************************/

static void z8_rxint(FAR struct uart_dev_s *dev, bool enable)
{
  struct z8_uart_s *priv  = (struct z8_uart_s*)dev->priv;
  irqstate_t          flags = irqsave();

  if (enable)
    {
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
      up_enable_irq(priv->rxirq);
#endif
    }
  else
    {
      up_disable_irq(priv->rxirq);
    }

  priv->rxenabled = enable;
  irqrestore(flags);
}

/****************************************************************************
 * Name: z8_rxavailable
 *
 * Description:
 *   Return true if the receive fifo is not empty
 *
 ****************************************************************************/

static bool z8_rxavailable(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  return ((z8_getuart(priv, Z8_UART_STAT0) & Z8_UARTSTAT0_RDA) != 0);
}

/****************************************************************************
 * Name: z8_send
 *
 * Description:
 *   This method will send one byte on the UART
 *
 ****************************************************************************/

static void z8_send(FAR struct uart_dev_s *dev, int ch)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  z8_putuart(priv, ch, Z8_UART_TXD);
}

/****************************************************************************
 * Name: z8_txint
 *
 * Description:
 *   Call to enable or disable TX interrupts
 *
 ****************************************************************************/

static void z8_txint(FAR struct uart_dev_s *dev, bool enable)
{
  struct z8_uart_s *priv  = (struct z8_uart_s*)dev->priv;
  irqstate_t          flags = irqsave();

  if (enable)
    {
#ifndef CONFIG_SUPPRESS_SERIAL_INTS
      up_enable_irq(priv->txirq);
#endif
    }
  else
    {
      up_disable_irq(priv->txirq);
    }

  priv->txenabled = enable;
  irqrestore(flags);
}

/****************************************************************************
 * Name: z8_txready
 *
 * Description:
 *   Return true if the tranmsit fifo is not full
 *
 ****************************************************************************/

static bool z8_txready(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  return ((z8_getuart(priv, Z8_UART_STAT0) & Z8_UARTSTAT0_TDRE) != 0);
}

/****************************************************************************
 * Name: z8_txempty
 *
 * Description:
 *   Return true if the transmit fifo is empty
 *
 ****************************************************************************/

static bool z8_txempty(FAR struct uart_dev_s *dev)
{
  struct z8_uart_s *priv = (struct z8_uart_s*)dev->priv;
  return ((z8_getuart(priv, Z8_UART_STAT0) & Z8_UARTSTAT0_TXE) != 0);
}

/****************************************************************************
 * Public Funtions
 ****************************************************************************/

/****************************************************************************
 * Name: up_serialinit
 *
 * Description:
 *   Register serial console and serial ports.
 *
 ****************************************************************************/

void up_serialinit(void)
{
   /* Disable all UART interrupts */

  (void)z8_disableuartirq(&TTYS0_DEV);
  (void)z8_disableuartirq(&TTYS1_DEV);

  /* Initialize the console for early use */
  CONSOLE_DEV.isconsole = true;
  z8_setup(&CONSOLE_DEV);

  /* Reigster console and tty devices */

  (void)uart_register("/dev/console", &CONSOLE_DEV);
  (void)uart_register("/dev/ttyS0", &TTYS0_DEV);
  (void)uart_register("/dev/ttyS1", &TTYS1_DEV);
}

/****************************************************************************
 * Name: up_putc
 *
 * Description:
 *   Provide priority, low-level access to support OS debug
 *   writes
 *
 ****************************************************************************/

int up_putc(int ch)
{
  uint8_t  state;

  /* Keep interrupts disabled so that we do not interfere with normal
   * driver operation 
   */

  state = z8_disableuartirq(&CONSOLE_DEV);

  /* Check for LF */

  if (ch == '\n')
    {
      /* Add CR before LF */

      z8_consoleput('\r');
    }

  /* Output the character */

  z8_consoleput((uint8_t)ch);

  /* It is important to restore the TX interrupt while the send is pending.
   * otherwise, TRDE interrupts can be lost since they do not pend after the
   * TRDE false->true transition.
   */

  z8_restoreuartirq(&CONSOLE_DEV, state);
  return ch;
}

#else /* USE_SERIALDRIVER */

/****************************************************************************
 * Definitions
 ****************************************************************************/

#ifdef CONFIG_UART1_SERIAL_CONSOLE
# define z8_contrde() \
  ((getreg8(*(Z8_UART1_BASE+Z8_UART_STAT0)) & Z8_UARTSTAT0_TDRE) != 0)
# define z8_contxd(ch) \
  putreg8((uint8_t)(ch), *(Z8_UART1_BASE+Z8_UART_TXD))
#else
# define z8_contrde() \
  ((getreg8(*(Z8_UART0_BASE+Z8_UART_STAT0)) & Z8_UARTSTAT0_TDRE) != 0)
# define z8_contxd(ch) \
  putreg8((uint8_t)(ch), *(Z8_UART0_BASE+Z8_UART_TXD))
#endif

/****************************************************************************
 * Private Function Prototypes
 ****************************************************************************/

/****************************************************************************
 * Private Variables
 ****************************************************************************/

/****************************************************************************
 * Private Functions
 ****************************************************************************/

/****************************************************************************
 * Name: z8_putc
 ****************************************************************************/

static void z8_putc(int ch)
{
  int tmp;
  for (tmp = 1000 ; tmp > 0 && !z8_contrde(); tmp--);
  z8_contxd(ch);
}

/****************************************************************************
 * Public Functions
 ****************************************************************************/

/****************************************************************************
 * Name: up_putc
 ****************************************************************************/

int up_putc(int ch)
{
  /* Check for LF */

  if (ch == '\n')
    {
      /* Output CR before LF */

      z8_putc('\r');
    }

  /* Output character */

  z8_putc(ch);
  return ch;
}

#endif /* USE_SERIALDRIVER */