drivers/serial/serial_max3100.c

   1 /*
   2  * (C) Copyright 2003
   3  *
   4  * Pantelis Antoniou <panto@intracom.gr>
   5  * Intracom S.A.
   6  *
   7  * See file CREDITS for list of people who contributed to this
   8  * project.
   9  *
  10  * This program is free software; you can redistribute it and/or
  11  * modify it under the terms of the GNU General Public License as
  12  * published by the Free Software Foundation; either version 2 of
  13  * the License, or (at your option) any later version.
  14  *
  15  * This program is distributed in the hope that it will be useful,
  16  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  17  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  18  * GNU General Public License for more details.
  19  *
  20  * You should have received a copy of the GNU General Public License
  21  * along with this program; if not, write to the Free Software
  22  * Foundation, Inc., 59 Temple Place, Suite 330, Boston,
  23  * MA 02111-1307 USA
  24  */
  25
  26 #include <common.h>
  27 #include <watchdog.h>
  28
  29 #ifdef CONFIG_MAX3100_SERIAL
  30
  31 DECLARE_GLOBAL_DATA_PTR;
  32
  33 /**************************************************************/
  34
  35 /* convienient macros */
  36 #define MAX3100_SPI_RXD() (MAX3100_SPI_RXD_PORT & MAX3100_SPI_RXD_BIT)
  37
  38 #define MAX3100_SPI_TXD(x) \
  39         do { \
  40                 if (x) \
  41                         MAX3100_SPI_TXD_PORT |=  MAX3100_SPI_TXD_BIT; \
  42                 else \
  43                         MAX3100_SPI_TXD_PORT &= ~MAX3100_SPI_TXD_BIT; \
  44         } while(0)
  45
  46 #define MAX3100_SPI_CLK(x) \
  47         do { \
  48                 if (x) \
  49                         MAX3100_SPI_CLK_PORT |=  MAX3100_SPI_CLK_BIT; \
  50                 else \
  51                         MAX3100_SPI_CLK_PORT &= ~MAX3100_SPI_CLK_BIT; \
  52         } while(0)
  53
  54 #define MAX3100_SPI_CLK_TOGGLE() (MAX3100_SPI_CLK_PORT ^= MAX3100_SPI_CLK_BIT)
  55
  56 #define MAX3100_CS(x) \
  57         do { \
  58                 if (x) \
  59                         MAX3100_CS_PORT |=  MAX3100_CS_BIT; \
  60                 else \
  61                         MAX3100_CS_PORT &= ~MAX3100_CS_BIT; \
  62         } while(0)
  63
  64 /**************************************************************/
  65
  66 /* MAX3100 definitions */
  67
  68 #define MAX3100_WC      (3 << 14)               /* write configuration */
  69 #define MAX3100_RC      (1 << 14)               /* read  configuration */
  70 #define MAX3100_WD      (2 << 14)               /* write data          */
  71 #define MAX3100_RD      (0 << 14)               /* read  data          */
  72
  73 /* configuration register bits */
  74 #define MAX3100_FEN     (1 << 13)               /* FIFO enable           */
  75 #define MAX3100_SHDN    (1 << 12)               /* shutdown bit          */
  76 #define MAX3100_TM      (1 << 11)               /* T bit irq mask        */
  77 #define MAX3100_RM      (1 << 10)               /* R bit irq mask        */
  78 #define MAX3100_PM      (1 <<  9)               /* P bit irq mask        */
  79 #define MAX3100_RAM     (1 <<  8)               /* mask for RA/FE bit    */
  80 #define MAX3100_IR      (1 <<  7)               /* IRDA timing mode      */
  81 #define MAX3100_ST      (1 <<  6)               /* transmit stop bit     */
  82 #define MAX3100_PE      (1 <<  5)               /* parity enable bit     */
  83 #define MAX3100_L       (1 <<  4)               /* Length bit            */
  84 #define MAX3100_B_MASK  (0x000F)                /* baud rate bits mask   */
  85 #define MAX3100_B(x)    ((x) & 0x000F)  /* baud rate select bits */
  86
  87 /* data register bits (write) */
  88 #define MAX3100_TE      (1 << 10)               /* transmit enable bit (active low)        */
  89 #define MAX3100_RTS     (1 <<  9)               /* request-to-send bit (inverted ~RTS pin) */
  90
  91 /* data register bits (read) */
  92 #define MAX3100_RA      (1 << 10)               /* receiver activity when in shutdown mode */
  93 #define MAX3100_FE      (1 << 10)               /* framing error when in normal mode       */
  94 #define MAX3100_CTS     (1 <<  9)               /* clear-to-send bit (inverted ~CTS pin)   */
  95
  96 /* data register bits (both directions) */
  97 #define MAX3100_R       (1 << 15)               /* receive bit    */
  98 #define MAX3100_T       (1 << 14)               /* transmit bit   */
  99 #define MAX3100_P       (1 <<  8)               /* parity bit     */
 100 #define MAX3100_D_MASK  0x00FF                  /* data bits mask */
 101 #define MAX3100_D(x)    ((x) & 0x00FF)          /* data bits      */
 102
 103 /* these definitions are valid only for fOSC = 3.6864MHz */
 104 #define MAX3100_B_230400        MAX3100_B(0)
 105 #define MAX3100_B_115200        MAX3100_B(1)
 106 #define MAX3100_B_57600         MAX3100_B(2)
 107 #define MAX3100_B_38400         MAX3100_B(9)
 108 #define MAX3100_B_19200         MAX3100_B(10)
 109 #define MAX3100_B_9600          MAX3100_B(11)
 110 #define MAX3100_B_4800          MAX3100_B(12)
 111 #define MAX3100_B_2400          MAX3100_B(13)
 112 #define MAX3100_B_1200          MAX3100_B(14)
 113 #define MAX3100_B_600           MAX3100_B(15)
 114
 115 /**************************************************************/
 116
 117 static inline unsigned int max3100_transfer(unsigned int val)
 118 {
 119         unsigned int rx;
 120         int b;
 121
 122         MAX3100_SPI_CLK(0);
 123         MAX3100_CS(0);
 124
 125         rx = 0; b = 16;
 126         while (--b >= 0) {
 127                 MAX3100_SPI_TXD(val & 0x8000);
 128                 val <<= 1;
 129                 MAX3100_SPI_CLK_TOGGLE();
 130                 udelay(1);
 131                 rx <<= 1;
 132                 if (MAX3100_SPI_RXD())
 133                         rx |= 1;
 134                 MAX3100_SPI_CLK_TOGGLE();
 135                 udelay(1);
 136         }
 137
 138         MAX3100_SPI_CLK(1);
 139         MAX3100_CS(1);
 140
 141         return rx;
 142 }
 143
 144 /**************************************************************/
 145
 146 /* must be power of 2 */
 147 #define RXFIFO_SZ       16
 148
 149 static int rxfifo_cnt;
 150 static int rxfifo_in;
 151 static int rxfifo_out;
 152 static unsigned char rxfifo_buf[16];
 153
 154 static void max3100_putc(int c)
 155 {
 156         unsigned int rx;
 157
 158         while (((rx = max3100_transfer(MAX3100_RC)) & MAX3100_T) == 0)
 159                 WATCHDOG_RESET();
 160
 161         rx = max3100_transfer(MAX3100_WD | (c & 0xff));
 162         if ((rx & MAX3100_RD) != 0 && rxfifo_cnt < RXFIFO_SZ) {
 163                 rxfifo_cnt++;
 164                 rxfifo_buf[rxfifo_in++] = rx & 0xff;
 165                 rxfifo_in &= RXFIFO_SZ - 1;
 166         }
 167 }
 168
 169 static int max3100_getc(void)
 170 {
 171         int c;
 172         unsigned int rx;
 173
 174         while (rxfifo_cnt == 0) {
 175                 rx = max3100_transfer(MAX3100_RD);
 176                 if ((rx & MAX3100_R) != 0) {
 177                         do {
 178                                 rxfifo_cnt++;
 179                                 rxfifo_buf[rxfifo_in++] = rx & 0xff;
 180                                 rxfifo_in &= RXFIFO_SZ - 1;
 181
 182                                 if (rxfifo_cnt >= RXFIFO_SZ)
 183                                         break;
 184                         } while (((rx = max3100_transfer(MAX3100_RD)) & MAX3100_R) != 0);
 185                 }
 186                 WATCHDOG_RESET();
 187         }
 188
 189         rxfifo_cnt--;
 190         c = rxfifo_buf[rxfifo_out++];
 191         rxfifo_out &= RXFIFO_SZ - 1;
 192         return c;
 193 }
 194
 195 static int max3100_tstc(void)
 196 {
 197         unsigned int rx;
 198
 199         if (rxfifo_cnt > 0)
 200                 return 1;
 201
 202         rx = max3100_transfer(MAX3100_RD);
 203         if ((rx & MAX3100_R) == 0)
 204                 return 0;
 205
 206         do {
 207                 rxfifo_cnt++;
 208                 rxfifo_buf[rxfifo_in++] = rx & 0xff;
 209                 rxfifo_in &= RXFIFO_SZ - 1;
 210
 211                 if (rxfifo_cnt >= RXFIFO_SZ)
 212                         break;
 213         } while (((rx = max3100_transfer(MAX3100_RD)) & MAX3100_R) != 0);
 214
 215         return 1;
 216 }
 217
 218 int serial_init(void)
 219 {
 220         unsigned int wconf, rconf;
 221         int i;
 222
 223         wconf = 0;
 224
 225         /* Set baud rate */
 226         switch (gd->baudrate) {
 227                 case 1200:
 228                         wconf = MAX3100_B_1200;
 229                         break;
 230                 case 2400:
 231                         wconf = MAX3100_B_2400;
 232                         break;
 233                 case 4800:
 234                         wconf = MAX3100_B_4800;
 235                         break;
 236                 case 9600:
 237                         wconf = MAX3100_B_9600;
 238                         break;
 239                 case 19200:
 240                         wconf = MAX3100_B_19200;
 241                         break;
 242                 case 38400:
 243                         wconf = MAX3100_B_38400;
 244                         break;
 245                 case 57600:
 246                         wconf = MAX3100_B_57600;
 247                         break;
 248                 default:
 249                 case 115200:
 250                         wconf = MAX3100_B_115200;
 251                         break;
 252                 case 230400:
 253                         wconf = MAX3100_B_230400;
 254                         break;
 255         }
 256
 257         /* try for 10ms, with a 100us gap */
 258         for (i = 0; i < 10000; i += 100) {
 259
 260                 max3100_transfer(MAX3100_WC | wconf);
 261                 rconf = max3100_transfer(MAX3100_RC) & 0x3fff;
 262
 263                 if (rconf == wconf)
 264                         break;
 265                 udelay(100);
 266         }
 267
 268         rxfifo_in = rxfifo_out = rxfifo_cnt = 0;
 269
 270         return (0);
 271 }
 272
 273 void serial_putc(const char c)
 274 {
 275         if (c == '\n')
 276                 max3100_putc('\r');
 277
 278         max3100_putc(c);
 279 }
 280
 281 void serial_puts(const char *s)
 282 {
 283         while (*s)
 284                 serial_putc (*s++);
 285 }
 286
 287 int serial_getc(void)
 288 {
 289         return max3100_getc();
 290 }
 291
 292 int serial_tstc(void)
 293 {
 294         return max3100_tstc();
 295 }
 296
 297 /* XXX WTF? */
 298 void serial_setbrg(void)
 299 {
 300 }
 301
 302 #endif