drivers/serial/serial_imx.c

   1 /*
   2  * (c) 2004 Sascha Hauer <sascha@saschahauer.de>
   3  *
   4  * SPDX-License-Identifier:     GPL-2.0+
   5  */
   6
   7 #include <common.h>
   8 #include <asm/arch/imx-regs.h>
   9 #include <serial.h>
  10 #include <linux/compiler.h>
  11
  12 #if defined CONFIG_IMX_SERIAL1
  13 #define UART_BASE IMX_UART1_BASE
  14 #elif defined CONFIG_IMX_SERIAL2
  15 #define UART_BASE IMX_UART2_BASE
  16 #else
  17 #error "define CONFIG_IMX_SERIAL1, CONFIG_IMX_SERIAL2 or CONFIG_IMX_SERIAL_NONE"
  18 #endif
  19
  20 struct imx_serial {
  21         volatile uint32_t urxd[16];
  22         volatile uint32_t utxd[16];
  23         volatile uint32_t ucr1;
  24         volatile uint32_t ucr2;
  25         volatile uint32_t ucr3;
  26         volatile uint32_t ucr4;
  27         volatile uint32_t ufcr;
  28         volatile uint32_t usr1;
  29         volatile uint32_t usr2;
  30         volatile uint32_t uesc;
  31         volatile uint32_t utim;
  32         volatile uint32_t ubir;
  33         volatile uint32_t ubmr;
  34         volatile uint32_t ubrc;
  35         volatile uint32_t bipr[4];
  36         volatile uint32_t bmpr[4];
  37         volatile uint32_t uts;
  38 };
  39
  40 DECLARE_GLOBAL_DATA_PTR;
  41
  42 static void imx_serial_setbrg(void)
  43 {
  44         serial_init();
  45 }
  46
  47 extern void imx_gpio_mode(int gpio_mode);
  48
  49 /*
  50  * Initialise the serial port with the given baudrate. The settings
  51  * are always 8 data bits, no parity, 1 stop bit, no start bits.
  52  *
  53  */
  54 static int imx_serial_init(void)
  55 {
  56         volatile struct imx_serial* base = (struct imx_serial *)UART_BASE;
  57         unsigned int ufcr_rfdiv;
  58         unsigned int refclk;
  59
  60 #ifdef CONFIG_IMX_SERIAL1
  61         imx_gpio_mode(PC11_PF_UART1_TXD);
  62         imx_gpio_mode(PC12_PF_UART1_RXD);
  63 #else
  64         imx_gpio_mode(PB30_PF_UART2_TXD);
  65         imx_gpio_mode(PB31_PF_UART2_RXD);
  66 #endif
  67
  68         /* Disable UART */
  69         base->ucr1 &= ~UCR1_UARTEN;
  70
  71         /* Set to default POR state */
  72
  73         base->ucr1 = 0x00000004;
  74         base->ucr2 = 0x00000000;
  75         base->ucr3 = 0x00000000;
  76         base->ucr4 = 0x00008040;
  77         base->uesc = 0x0000002B;
  78         base->utim = 0x00000000;
  79         base->ubir = 0x00000000;
  80         base->ubmr = 0x00000000;
  81         base->uts  = 0x00000000;
  82         /* Set clocks */
  83         base->ucr4 |= UCR4_REF16;
  84
  85         /* Configure FIFOs */
  86         base->ufcr = 0xa81;
  87
  88         /* set the baud rate.
  89          *
  90          * baud * 16   x
  91          * --------- = -
  92          *  refclk     y
  93          *
  94          * x - 1 = UBIR
  95          * y - 1 = UBMR
  96          *
  97          * each register is 16 bits wide. refclk max is 96 MHz
  98          *
  99          */
 100
 101         ufcr_rfdiv = ((base->ufcr) & UFCR_RFDIV) >> 7;
 102         if (ufcr_rfdiv == 6)
 103                 ufcr_rfdiv = 7;
 104         else
 105                 ufcr_rfdiv = 6 - ufcr_rfdiv;
 106
 107         refclk = get_PERCLK1();
 108         refclk /= ufcr_rfdiv;
 109
 110         /* Set the numerator value minus one of the BRM ratio */
 111         base->ubir = (gd->baudrate / 100) - 1;
 112
 113         /* Set the denominator value minus one of the BRM ratio */
 114         base->ubmr = (refclk/(16 * 100)) - 1;
 115
 116         /* Set to 8N1 */
 117         base->ucr2 &= ~UCR2_PREN;
 118         base->ucr2 |= UCR2_WS;
 119         base->ucr2 &= ~UCR2_STPB;
 120
 121         /* Ignore RTS */
 122         base->ucr2 |= UCR2_IRTS;
 123
 124         /* Enable UART */
 125         base->ucr1 |= UCR1_UARTEN | UCR1_UARTCLKEN;
 126
 127         /* Enable FIFOs */
 128         base->ucr2 |= UCR2_SRST | UCR2_RXEN | UCR2_TXEN;
 129
 130         /* Clear status flags */
 131         base->usr2 |= USR2_ADET  |
 132                       USR2_DTRF  |
 133                       USR2_IDLE  |
 134                       USR2_IRINT |
 135                       USR2_WAKE  |
 136                       USR2_RTSF  |
 137                       USR2_BRCD  |
 138                       USR2_ORE;
 139
 140         /* Clear status flags */
 141         base->usr1 |= USR1_PARITYERR |
 142                       USR1_RTSD      |
 143                       USR1_ESCF      |
 144                       USR1_FRAMERR   |
 145                       USR1_AIRINT    |
 146                       USR1_AWAKE;
 147         return (0);
 148 }
 149
 150 /*
 151  * Read a single byte from the serial port. Returns 1 on success, 0
 152  * otherwise. When the function is successful, the character read is
 153  * written into its argument c.
 154  */
 155 static int imx_serial_getc(void)
 156 {
 157         volatile struct imx_serial* base = (struct imx_serial *)UART_BASE;
 158         unsigned char ch;
 159
 160         while(base->uts & UTS_RXEMPTY);
 161
 162         ch = (char)base->urxd[0];
 163
 164         return ch;
 165 }
 166
 167 #ifdef CONFIG_HWFLOW
 168 static int hwflow = 0; /* turned off by default */
 169 int hwflow_onoff(int on)
 170 {
 171 }
 172 #endif
 173
 174 /*
 175  * Output a single byte to the serial port.
 176  */
 177 static void imx_serial_putc(const char c)
 178 {
 179         volatile struct imx_serial* base = (struct imx_serial *)UART_BASE;
 180
 181         /* Wait for Tx FIFO not full */
 182         while (base->uts & UTS_TXFULL);
 183
 184         base->utxd[0] = c;
 185
 186         /* If \n, also do \r */
 187         if (c == '\n')
 188                 serial_putc ('\r');
 189 }
 190
 191 /*
 192  * Test whether a character is in the RX buffer
 193  */
 194 static int imx_serial_tstc(void)
 195 {
 196         volatile struct imx_serial* base = (struct imx_serial *)UART_BASE;
 197
 198         /* If receive fifo is empty, return false */
 199         if (base->uts & UTS_RXEMPTY)
 200                 return 0;
 201         return 1;
 202 }
 203
 204 static struct serial_device imx_serial_drv = {
 205         .name   = "imx_serial",
 206         .start  = imx_serial_init,
 207         .stop   = NULL,
 208         .setbrg = imx_serial_setbrg,
 209         .putc   = imx_serial_putc,
 210         .puts   = default_serial_puts,
 211         .getc   = imx_serial_getc,
 212         .tstc   = imx_serial_tstc,
 213 };
 214
 215 void imx_serial_initialize(void)
 216 {
 217         serial_register(&imx_serial_drv);
 218 }
 219
 220 __weak struct serial_device *default_serial_console(void)
 221 {
 222         return &imx_serial_drv;
 223 }