arch/sparc/cpu/leon3/serial.c

   1 /* GRLIB APBUART Serial controller driver
   2  *
   3  * (C) Copyright 2007
   4  * Daniel Hellstrom, Gaisler Research, daniel@gaisler.com.
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <asm/processor.h>
  11 #include <asm/leon.h>
  12 #include <ambapp.h>
  13 #include <serial.h>
  14 #include <linux/compiler.h>
  15
  16 DECLARE_GLOBAL_DATA_PTR;
  17
  18 ambapp_dev_apbuart *leon3_apbuart = NULL;
  19
  20 static int leon3_serial_init(void)
  21 {
  22         ambapp_apbdev apbdev;
  23         unsigned int tmp;
  24
  25         /* find UART */
  26         if (ambapp_apb_first(VENDOR_GAISLER, GAISLER_APBUART, &apbdev) == 1) {
  27
  28                 leon3_apbuart = (ambapp_dev_apbuart *) apbdev.address;
  29
  30                 /* found apbuart, let's init...
  31                  *
  32                  * Set scaler / baud rate
  33                  *
  34                  * Receiver & transmitter enable
  35                  */
  36                 leon3_apbuart->scaler = CONFIG_SYS_GRLIB_APBUART_SCALER;
  37
  38                 /* Let bit 11 be unchanged (debug bit for GRMON) */
  39                 tmp = READ_WORD(leon3_apbuart->ctrl);
  40
  41                 leon3_apbuart->ctrl = ((tmp & LEON_REG_UART_CTRL_DBG) |
  42                                        LEON_REG_UART_CTRL_RE |
  43                                        LEON_REG_UART_CTRL_TE);
  44
  45                 return 0;
  46         }
  47         return -1;              /* didn't find hardware */
  48 }
  49
  50 static void leon3_serial_putc_raw(const char c)
  51 {
  52         if (!leon3_apbuart)
  53                 return;
  54
  55         /* Wait for last character to go. */
  56         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_THE)) ;
  57
  58         /* Send data */
  59         leon3_apbuart->data = c;
  60
  61 #ifdef LEON_DEBUG
  62         /* Wait for data to be sent */
  63         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_TSE)) ;
  64 #endif
  65 }
  66
  67 static void leon3_serial_putc(const char c)
  68 {
  69         if (c == '\n')
  70                 leon3_serial_putc_raw('\r');
  71
  72         leon3_serial_putc_raw(c);
  73 }
  74
  75 static int leon3_serial_getc(void)
  76 {
  77         if (!leon3_apbuart)
  78                 return 0;
  79
  80         /* Wait for a character to arrive. */
  81         while (!(READ_WORD(leon3_apbuart->status) & LEON_REG_UART_STATUS_DR)) ;
  82
  83         /* read data */
  84         return READ_WORD(leon3_apbuart->data);
  85 }
  86
  87 static int leon3_serial_tstc(void)
  88 {
  89         if (leon3_apbuart)
  90                 return (READ_WORD(leon3_apbuart->status) &
  91                         LEON_REG_UART_STATUS_DR);
  92         return 0;
  93 }
  94
  95 /* set baud rate for uart */
  96 static void leon3_serial_setbrg(void)
  97 {
  98         /* update baud rate settings, read it from gd->baudrate */
  99         unsigned int scaler;
 100         if (leon3_apbuart && (gd->baudrate > 0)) {
 101                 scaler =
 102                     (((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
 103                      5) / 10;
 104                 leon3_apbuart->scaler = scaler;
 105         }
 106         return;
 107 }
 108
 109 static struct serial_device leon3_serial_drv = {
 110         .name   = "leon3_serial",
 111         .start  = leon3_serial_init,
 112         .stop   = NULL,
 113         .setbrg = leon3_serial_setbrg,
 114         .putc   = leon3_serial_putc,
 115         .puts   = default_serial_puts,
 116         .getc   = leon3_serial_getc,
 117         .tstc   = leon3_serial_tstc,
 118 };
 119
 120 void leon3_serial_initialize(void)
 121 {
 122         serial_register(&leon3_serial_drv);
 123 }
 124
 125 __weak struct serial_device *default_serial_console(void)
 126 {
 127         return &leon3_serial_drv;
 128 }