arch/sparc/cpu/leon2/serial.c

   1 /* GRLIB APBUART Serial controller driver
   2  *
   3  * (C) Copyright 2008, 2015
   4  * Daniel Hellstrom, Cobham Gaisler, daniel@gaisler.com.
   5  *
   6  * SPDX-License-Identifier:     GPL-2.0+
   7  */
   8
   9 #include <common.h>
  10 #include <asm/io.h>
  11 #include <serial.h>
  12 #include <watchdog.h>
  13
  14 DECLARE_GLOBAL_DATA_PTR;
  15
  16 static unsigned leon2_serial_calc_scaler(unsigned freq, unsigned baud)
  17 {
  18         return (((freq*10) / (baud*8)) - 5) / 10;
  19 }
  20
  21 static int leon2_serial_init(void)
  22 {
  23         LEON2_regs *leon2 = (LEON2_regs *)LEON2_PREGS;
  24         LEON2_Uart_regs *regs;
  25         unsigned int tmp;
  26
  27 #if LEON2_CONSOLE_SELECT == LEON_CONSOLE_UART1
  28         regs = (LEON2_Uart_regs *)&leon2->UART_Channel_1;
  29 #else
  30         regs = (LEON2_Uart_regs *)&leon2->UART_Channel_2;
  31 #endif
  32
  33         /* Set scaler / baud rate */
  34         tmp = leon2_serial_calc_scaler(CONFIG_SYS_CLK_FREQ, CONFIG_BAUDRATE);
  35         writel(tmp, &regs->UART_Scaler);
  36
  37         /* Let bit 11 be unchanged (debug bit for GRMON) */
  38         tmp = readl(&regs->UART_Control) & LEON2_UART_CTRL_DBG;
  39         tmp |= (LEON2_UART1_LOOPBACK_ENABLE << 7);
  40         tmp |= (LEON2_UART1_FLOWCTRL_ENABLE << 6);
  41         tmp |= (LEON2_UART1_PARITY_ENABLE << 5);
  42         tmp |= (LEON2_UART1_ODDPAR_ENABLE << 4);
  43         /* Receiver & transmitter enable */
  44         tmp |= (LEON2_UART_CTRL_RE | LEON2_UART_CTRL_TE);
  45         writel(tmp, &regs->UART_Control);
  46
  47         gd->arch.uart = regs;
  48         return 0;
  49 }
  50
  51 static inline LEON2_Uart_regs *leon2_get_uart_regs(void)
  52 {
  53         LEON2_Uart_regs *uart = gd->arch.uart;
  54
  55         return uart;
  56 }
  57
  58 static void leon2_serial_putc_raw(const char c)
  59 {
  60         LEON2_Uart_regs *uart = leon2_get_uart_regs();
  61
  62         if (!uart)
  63                 return;
  64
  65         /* Wait for last character to go. */
  66         while (!(readl(&uart->UART_Status) & LEON2_UART_STAT_THE))
  67                 WATCHDOG_RESET();
  68
  69         /* Send data */
  70         writel(c, &uart->UART_Channel);
  71
  72 #ifdef LEON_DEBUG
  73         /* Wait for data to be sent */
  74         while (!(readl(&uart->UART_Status) & LEON2_UART_STAT_TSE))
  75                 WATCHDOG_RESET();
  76 #endif
  77 }
  78
  79 static void leon2_serial_putc(const char c)
  80 {
  81         if (c == '\n')
  82                 leon2_serial_putc_raw('\r');
  83
  84         leon2_serial_putc_raw(c);
  85 }
  86
  87 static int leon2_serial_getc(void)
  88 {
  89         LEON2_Uart_regs *uart = leon2_get_uart_regs();
  90
  91         if (!uart)
  92                 return 0;
  93
  94         /* Wait for a character to arrive. */
  95         while (!(readl(&uart->UART_Status) & LEON2_UART_STAT_DR))
  96                 WATCHDOG_RESET();
  97
  98         /* Read character data */
  99         return readl(&uart->UART_Channel);
 100 }
 101
 102 static int leon2_serial_tstc(void)
 103 {
 104         LEON2_Uart_regs *uart = leon2_get_uart_regs();
 105
 106         if (!uart)
 107                 return 0;
 108
 109         return readl(&uart->UART_Status) & LEON2_UART_STAT_DR;
 110 }
 111
 112 static void leon2_serial_setbrg(void)
 113 {
 114         LEON2_Uart_regs *uart = leon2_get_uart_regs();
 115         unsigned int scaler;
 116
 117         if (!uart)
 118                 return;
 119
 120         if (!gd->baudrate)
 121                 gd->baudrate = CONFIG_BAUDRATE;
 122
 123         scaler = leon2_serial_calc_scaler(CONFIG_SYS_CLK_FREQ, gd->baudrate);
 124
 125         writel(scaler, &uart->UART_Scaler);
 126 }
 127
 128 static struct serial_device leon2_serial_drv = {
 129         .name   = "leon2_serial",
 130         .start  = leon2_serial_init,
 131         .stop   = NULL,
 132         .setbrg = leon2_serial_setbrg,
 133         .putc   = leon2_serial_putc,
 134         .puts   = default_serial_puts,
 135         .getc   = leon2_serial_getc,
 136         .tstc   = leon2_serial_tstc,
 137 };
 138
 139 void leon2_serial_initialize(void)
 140 {
 141         serial_register(&leon2_serial_drv);
 142 }
 143
 144 __weak struct serial_device *default_serial_console(void)
 145 {
 146         return &leon2_serial_drv;
 147 }