drivers/serial/serial_mxc.c

   1 /*
   2  * (c) 2007 Sascha Hauer <s.hauer@pengutronix.de>
   3  *
   4  * This program is free software; you can redistribute it and/or modify
   5  * it under the terms of the GNU General Public License as published by
   6  * the Free Software Foundation; either version 2 of the License, or
   7  * (at your option) any later version.
   8  *
   9  * This program is distributed in the hope that it will be useful,
  10  * but WITHOUT ANY WARRANTY; without even the implied warranty of
  11  * MERCHANTABILITY or FITNESS FOR A PARTICULAR PURPOSE.  See the
  12  * GNU General Public License for more details.
  13  *
  14  * You should have received a copy of the GNU General Public License
  15  * along with this program; if not, write to the Free Software
  16  * Foundation, Inc., 59 Temple Place, Suite 330, Boston, MA  02111-1307  USA
  17  *
  18  */
  19
  20 #include <common.h>
  21 #include <watchdog.h>
  22 #include <asm/arch/imx-regs.h>
  23 #include <asm/arch/clock.h>
  24 #include <serial.h>
  25 #include <linux/compiler.h>
  26
  27 #define __REG(x)     (*((volatile u32 *)(x)))
  28
  29 #ifndef CONFIG_MXC_UART_BASE
  30 #error "define CONFIG_MXC_UART_BASE to use the MXC UART driver"
  31 #endif
  32
  33 #define UART_PHYS       CONFIG_MXC_UART_BASE
  34
  35 /* Register definitions */
  36 #define URXD  0x0  /* Receiver Register */
  37 #define UTXD  0x40 /* Transmitter Register */
  38 #define UCR1  0x80 /* Control Register 1 */
  39 #define UCR2  0x84 /* Control Register 2 */
  40 #define UCR3  0x88 /* Control Register 3 */
  41 #define UCR4  0x8c /* Control Register 4 */
  42 #define UFCR  0x90 /* FIFO Control Register */
  43 #define USR1  0x94 /* Status Register 1 */
  44 #define USR2  0x98 /* Status Register 2 */
  45 #define UESC  0x9c /* Escape Character Register */
  46 #define UTIM  0xa0 /* Escape Timer Register */
  47 #define UBIR  0xa4 /* BRM Incremental Register */
  48 #define UBMR  0xa8 /* BRM Modulator Register */
  49 #define UBRC  0xac /* Baud Rate Count Register */
  50 #define UTS   0xb4 /* UART Test Register (mx31) */
  51
  52 /* UART Control Register Bit Fields.*/
  53 #define  URXD_CHARRDY    (1<<15)
  54 #define  URXD_ERR        (1<<14)
  55 #define  URXD_OVRRUN     (1<<13)
  56 #define  URXD_FRMERR     (1<<12)
  57 #define  URXD_BRK        (1<<11)
  58 #define  URXD_PRERR      (1<<10)
  59 #define  URXD_RX_DATA    (0xFF)
  60 #define  UCR1_ADEN       (1<<15) /* Auto dectect interrupt */
  61 #define  UCR1_ADBR       (1<<14) /* Auto detect baud rate */
  62 #define  UCR1_TRDYEN     (1<<13) /* Transmitter ready interrupt enable */
  63 #define  UCR1_IDEN       (1<<12) /* Idle condition interrupt */
  64 #define  UCR1_RRDYEN     (1<<9)  /* Recv ready interrupt enable */
  65 #define  UCR1_RDMAEN     (1<<8)  /* Recv ready DMA enable */
  66 #define  UCR1_IREN       (1<<7)  /* Infrared interface enable */
  67 #define  UCR1_TXMPTYEN   (1<<6)  /* Transimitter empty interrupt enable */
  68 #define  UCR1_RTSDEN     (1<<5)  /* RTS delta interrupt enable */
  69 #define  UCR1_SNDBRK     (1<<4)  /* Send break */
  70 #define  UCR1_TDMAEN     (1<<3)  /* Transmitter ready DMA enable */
  71 #define  UCR1_UARTCLKEN  (1<<2)  /* UART clock enabled */
  72 #define  UCR1_DOZE       (1<<1)  /* Doze */
  73 #define  UCR1_UARTEN     (1<<0)  /* UART enabled */
  74 #define  UCR2_ESCI       (1<<15) /* Escape seq interrupt enable */
  75 #define  UCR2_IRTS       (1<<14) /* Ignore RTS pin */
  76 #define  UCR2_CTSC       (1<<13) /* CTS pin control */
  77 #define  UCR2_CTS        (1<<12) /* Clear to send */
  78 #define  UCR2_ESCEN      (1<<11) /* Escape enable */
  79 #define  UCR2_PREN       (1<<8)  /* Parity enable */
  80 #define  UCR2_PROE       (1<<7)  /* Parity odd/even */
  81 #define  UCR2_STPB       (1<<6)  /* Stop */
  82 #define  UCR2_WS         (1<<5)  /* Word size */
  83 #define  UCR2_RTSEN      (1<<4)  /* Request to send interrupt enable */
  84 #define  UCR2_TXEN       (1<<2)  /* Transmitter enabled */
  85 #define  UCR2_RXEN       (1<<1)  /* Receiver enabled */
  86 #define  UCR2_SRST       (1<<0)  /* SW reset */
  87 #define  UCR3_DTREN      (1<<13) /* DTR interrupt enable */
  88 #define  UCR3_PARERREN   (1<<12) /* Parity enable */
  89 #define  UCR3_FRAERREN   (1<<11) /* Frame error interrupt enable */
  90 #define  UCR3_DSR        (1<<10) /* Data set ready */
  91 #define  UCR3_DCD        (1<<9)  /* Data carrier detect */
  92 #define  UCR3_RI         (1<<8)  /* Ring indicator */
  93 #define  UCR3_TIMEOUTEN  (1<<7)  /* Timeout interrupt enable */
  94 #define  UCR3_RXDSEN     (1<<6)  /* Receive status interrupt enable */
  95 #define  UCR3_AIRINTEN   (1<<5)  /* Async IR wake interrupt enable */
  96 #define  UCR3_AWAKEN     (1<<4)  /* Async wake interrupt enable */
  97 #define  UCR3_REF25      (1<<3)  /* Ref freq 25 MHz */
  98 #define  UCR3_REF30      (1<<2)  /* Ref Freq 30 MHz */
  99 #define  UCR3_INVT       (1<<1)  /* Inverted Infrared transmission */
 100 #define  UCR3_BPEN       (1<<0)  /* Preset registers enable */
 101 #define  UCR4_CTSTL_32   (32<<10) /* CTS trigger level (32 chars) */
 102 #define  UCR4_INVR       (1<<9)  /* Inverted infrared reception */
 103 #define  UCR4_ENIRI      (1<<8)  /* Serial infrared interrupt enable */
 104 #define  UCR4_WKEN       (1<<7)  /* Wake interrupt enable */
 105 #define  UCR4_REF16      (1<<6)  /* Ref freq 16 MHz */
 106 #define  UCR4_IRSC       (1<<5)  /* IR special case */
 107 #define  UCR4_TCEN       (1<<3)  /* Transmit complete interrupt enable */
 108 #define  UCR4_BKEN       (1<<2)  /* Break condition interrupt enable */
 109 #define  UCR4_OREN       (1<<1)  /* Receiver overrun interrupt enable */
 110 #define  UCR4_DREN       (1<<0)  /* Recv data ready interrupt enable */
 111 #define  UFCR_RXTL_SHF   0       /* Receiver trigger level shift */
 112 #define  UFCR_RFDIV      (7<<7)  /* Reference freq divider mask */
 113 #define  UFCR_TXTL_SHF   10      /* Transmitter trigger level shift */
 114 #define  USR1_PARITYERR  (1<<15) /* Parity error interrupt flag */
 115 #define  USR1_RTSS       (1<<14) /* RTS pin status */
 116 #define  USR1_TRDY       (1<<13) /* Transmitter ready interrupt/dma flag */
 117 #define  USR1_RTSD       (1<<12) /* RTS delta */
 118 #define  USR1_ESCF       (1<<11) /* Escape seq interrupt flag */
 119 #define  USR1_FRAMERR    (1<<10) /* Frame error interrupt flag */
 120 #define  USR1_RRDY       (1<<9)  /* Receiver ready interrupt/dma flag */
 121 #define  USR1_TIMEOUT    (1<<7)  /* Receive timeout interrupt status */
 122 #define  USR1_RXDS       (1<<6)  /* Receiver idle interrupt flag */
 123 #define  USR1_AIRINT     (1<<5)  /* Async IR wake interrupt flag */
 124 #define  USR1_AWAKE      (1<<4)  /* Aysnc wake interrupt flag */
 125 #define  USR2_ADET       (1<<15) /* Auto baud rate detect complete */
 126 #define  USR2_TXFE       (1<<14) /* Transmit buffer FIFO empty */
 127 #define  USR2_DTRF       (1<<13) /* DTR edge interrupt flag */
 128 #define  USR2_IDLE       (1<<12) /* Idle condition */
 129 #define  USR2_IRINT      (1<<8)  /* Serial infrared interrupt flag */
 130 #define  USR2_WAKE       (1<<7)  /* Wake */
 131 #define  USR2_RTSF       (1<<4)  /* RTS edge interrupt flag */
 132 #define  USR2_TXDC       (1<<3)  /* Transmitter complete */
 133 #define  USR2_BRCD       (1<<2)  /* Break condition */
 134 #define  USR2_ORE        (1<<1)  /* Overrun error */
 135 #define  USR2_RDR        (1<<0)  /* Recv data ready */
 136 #define  UTS_FRCPERR     (1<<13) /* Force parity error */
 137 #define  UTS_LOOP        (1<<12) /* Loop tx and rx */
 138 #define  UTS_TXEMPTY     (1<<6)  /* TxFIFO empty */
 139 #define  UTS_RXEMPTY     (1<<5)  /* RxFIFO empty */
 140 #define  UTS_TXFULL      (1<<4)  /* TxFIFO full */
 141 #define  UTS_RXFULL      (1<<3)  /* RxFIFO full */
 142 #define  UTS_SOFTRST     (1<<0)  /* Software reset */
 143
 144 DECLARE_GLOBAL_DATA_PTR;
 145
 146 static void mxc_serial_setbrg(void)
 147 {
 148         u32 clk = imx_get_uartclk();
 149
 150         if (!gd->baudrate)
 151                 gd->baudrate = CONFIG_BAUDRATE;
 152
 153         __REG(UART_PHYS + UFCR) = 4 << 7; /* divide input clock by 2 */
 154         __REG(UART_PHYS + UBIR) = 0xf;
 155         __REG(UART_PHYS + UBMR) = clk / (2 * gd->baudrate);
 156
 157 }
 158
 159 static int mxc_serial_getc(void)
 160 {
 161         while (__REG(UART_PHYS + UTS) & UTS_RXEMPTY)
 162                 WATCHDOG_RESET();
 163         return (__REG(UART_PHYS + URXD) & URXD_RX_DATA); /* mask out status from upper word */
 164 }
 165
 166 static void mxc_serial_putc(const char c)
 167 {
 168         __REG(UART_PHYS + UTXD) = c;
 169
 170         /* wait for transmitter to be ready */
 171         while (!(__REG(UART_PHYS + UTS) & UTS_TXEMPTY))
 172                 WATCHDOG_RESET();
 173
 174         /* If \n, also do \r */
 175         if (c == '\n')
 176                 serial_putc ('\r');
 177 }
 178
 179 /*
 180  * Test whether a character is in the RX buffer
 181  */
 182 static int mxc_serial_tstc(void)
 183 {
 184         /* If receive fifo is empty, return false */
 185         if (__REG(UART_PHYS + UTS) & UTS_RXEMPTY)
 186                 return 0;
 187         return 1;
 188 }
 189
 190 /*
 191  * Initialise the serial port with the given baudrate. The settings
 192  * are always 8 data bits, no parity, 1 stop bit, no start bits.
 193  *
 194  */
 195 static int mxc_serial_init(void)
 196 {
 197         __REG(UART_PHYS + UCR1) = 0x0;
 198         __REG(UART_PHYS + UCR2) = 0x0;
 199
 200         while (!(__REG(UART_PHYS + UCR2) & UCR2_SRST));
 201
 202         __REG(UART_PHYS + UCR3) = 0x0704;
 203         __REG(UART_PHYS + UCR4) = 0x8000;
 204         __REG(UART_PHYS + UESC) = 0x002b;
 205         __REG(UART_PHYS + UTIM) = 0x0;
 206
 207         __REG(UART_PHYS + UTS) = 0x0;
 208
 209         serial_setbrg();
 210
 211         __REG(UART_PHYS + UCR2) = UCR2_WS | UCR2_IRTS | UCR2_RXEN | UCR2_TXEN | UCR2_SRST;
 212
 213         __REG(UART_PHYS + UCR1) = UCR1_UARTEN;
 214
 215         return 0;
 216 }
 217
 218 static struct serial_device mxc_serial_drv = {
 219         .name   = "mxc_serial",
 220         .start  = mxc_serial_init,
 221         .stop   = NULL,
 222         .setbrg = mxc_serial_setbrg,
 223         .putc   = mxc_serial_putc,
 224         .puts   = default_serial_puts,
 225         .getc   = mxc_serial_getc,
 226         .tstc   = mxc_serial_tstc,
 227 };
 228
 229 void mxc_serial_initialize(void)
 230 {
 231         serial_register(&mxc_serial_drv);
 232 }
 233
 234 __weak struct serial_device *default_serial_console(void)
 235 {
 236         return &mxc_serial_drv;
 237 }