arch/sparc/cpu/leon2/serial.c

   1 /* GRLIB APBUART Serial controller driver
   2  *
   3  * (C) Copyright 2008
   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 <serial.h>
  13 #include <linux/compiler.h>
  14
  15 DECLARE_GLOBAL_DATA_PTR;
  16
  17 static int leon2_serial_init(void)
  18 {
  19         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
  20         LEON2_Uart_regs *regs;
  21         unsigned int tmp;
  22
  23         /* Init LEON2 UART
  24          *
  25          * Set scaler / baud rate
  26          *
  27          * Receiver & transmitter enable
  28          */
  29 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
  30         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
  31 #else
  32         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
  33 #endif
  34
  35         regs->UART_Scaler = CONFIG_SYS_LEON2_UART1_SCALER;
  36
  37         /* Let bit 11 be unchanged (debug bit for GRMON) */
  38         tmp = READ_WORD(regs->UART_Control);
  39
  40         regs->UART_Control = ((tmp & LEON2_UART_CTRL_DBG) |
  41                               (LEON2_UART1_LOOPBACK_ENABLE << 7) |
  42                               (LEON2_UART1_FLOWCTRL_ENABLE << 6) |
  43                               (LEON2_UART1_PARITY_ENABLE << 5) |
  44                               (LEON2_UART1_ODDPAR_ENABLE << 4) |
  45                               LEON2_UART_CTRL_RE | LEON2_UART_CTRL_TE);
  46
  47         return 0;
  48 }
  49
  50 static void leon2_serial_putc_raw(const char c)
  51 {
  52         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
  53         LEON2_Uart_regs *regs;
  54
  55 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
  56         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
  57 #else
  58         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
  59 #endif
  60
  61         /* Wait for last character to go. */
  62         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_THE)) ;
  63
  64         /* Send data */
  65         regs->UART_Channel = c;
  66
  67 #ifdef LEON_DEBUG
  68         /* Wait for data to be sent */
  69         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_TSE)) ;
  70 #endif
  71 }
  72
  73 static void leon2_serial_putc(const char c)
  74 {
  75         if (c == '\n')
  76                 leon2_serial_putc_raw('\r');
  77
  78         leon2_serial_putc_raw(c);
  79 }
  80
  81 static int leon2_serial_getc(void)
  82 {
  83         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
  84         LEON2_Uart_regs *regs;
  85
  86 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
  87         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
  88 #else
  89         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
  90 #endif
  91
  92         /* Wait for a character to arrive. */
  93         while (!(READ_WORD(regs->UART_Status) & LEON2_UART_STAT_DR)) ;
  94
  95         /* read data */
  96         return READ_WORD(regs->UART_Channel);
  97 }
  98
  99 static int leon2_serial_tstc(void)
 100 {
 101         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
 102         LEON2_Uart_regs *regs;
 103
 104 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
 105         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
 106 #else
 107         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
 108 #endif
 109
 110         return (READ_WORD(regs->UART_Status) & LEON2_UART_STAT_DR);
 111 }
 112
 113 /* set baud rate for uart */
 114 static void leon2_serial_setbrg(void)
 115 {
 116         /* update baud rate settings, read it from gd->baudrate */
 117         unsigned int scaler;
 118         LEON2_regs *leon2 = (LEON2_regs *) LEON2_PREGS;
 119         LEON2_Uart_regs *regs;
 120
 121 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
 122         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_1;
 123 #else
 124         regs = (LEON2_Uart_regs *) & leon2->UART_Channel_2;
 125 #endif
 126
 127         if (gd->baudrate > 0) {
 128                 scaler =
 129                     (((CONFIG_SYS_CLK_FREQ * 10) / (gd->baudrate * 8)) -
 130                      5) / 10;
 131                 regs->UART_Scaler = scaler;
 132         }
 133 }
 134
 135 static struct serial_device leon2_serial_drv = {
 136         .name   = "leon2_serial",
 137         .start  = leon2_serial_init,
 138         .stop   = NULL,
 139         .setbrg = leon2_serial_setbrg,
 140         .putc   = leon2_serial_putc,
 141         .puts   = default_serial_puts,
 142         .getc   = leon2_serial_getc,
 143         .tstc   = leon2_serial_tstc,
 144 };
 145
 146 void leon2_serial_initialize(void)
 147 {
 148         serial_register(&leon2_serial_drv);
 149 }
 150
 151 __weak struct serial_device *default_serial_console(void)
 152 {
 153         return &leon2_serial_drv;
 154 }