git.sur5r.net Git - u-boot/blob - arch/sparc/cpu/leon3/serial.c

   1 /* GRLIB APBUART Serial controller driver
   2  *
   3  * (C) Copyright 2007, 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 <ambapp.h>
  12 #include <serial.h>
  13 #include <watchdog.h>
  14
  15 DECLARE_GLOBAL_DATA_PTR;
  16
  17 /* Select which UART that will become u-boot console */
  18 #ifndef CONFIG_SYS_GRLIB_APBUART_INDEX
  19 #define CONFIG_SYS_GRLIB_APBUART_INDEX 0
  20 #endif
  21
  22 static int leon3_serial_init(void)
  23 {
  24         ambapp_dev_apbuart *uart;
  25         ambapp_apbdev apbdev;
  26         unsigned int tmp;
  27
  28         /* find UART */
  29         if (ambapp_apb_find(&ambapp_plb, VENDOR_GAISLER, GAISLER_APBUART,
  30                 CONFIG_SYS_GRLIB_APBUART_INDEX, &apbdev) != 1)
  31                 return -1; /* didn't find hardware */
  32
  33         /* found apbuart, let's init .. */
  34         uart = (ambapp_dev_apbuart *) apbdev.address;
  35
  36         /* Set scaler / baud rate */
  37         tmp = (((CONFIG_SYS_CLK_FREQ*10) / (CONFIG_BAUDRATE*8)) - 5)/10;
  38         writel(tmp, &uart->scaler);
  39
  40         /* Let bit 11 be unchanged (debug bit for GRMON) */
  41         tmp = readl(&uart->ctrl) & LEON_REG_UART_CTRL_DBG;
  42         /* Receiver & transmitter enable */
  43         tmp |= LEON_REG_UART_CTRL_RE | LEON_REG_UART_CTRL_TE;
  44         writel(tmp, &uart->ctrl);
  45
  46         gd->arch.uart = uart;
  47         return 0;
  48 }
  49
  50 static inline ambapp_dev_apbuart *leon3_get_uart_regs(void)
  51 {
  52         ambapp_dev_apbuart *uart = gd->arch.uart;
  53         return uart;
  54 }
  55
  56 static void leon3_serial_putc_raw(const char c)
  57 {
  58         ambapp_dev_apbuart * const uart = leon3_get_uart_regs();
  59
  60         if (!uart)
  61                 return;
  62
  63         /* Wait for last character to go. */
  64         while (!(readl(&uart->status) & LEON_REG_UART_STATUS_THE))
  65                 WATCHDOG_RESET();
  66
  67         /* Send data */
  68         writel(c, &uart->data);
  69
  70 #ifdef LEON_DEBUG
  71         /* Wait for data to be sent */
  72         while (!(readl(&uart->status) & LEON_REG_UART_STATUS_TSE))
  73                 WATCHDOG_RESET();
  74 #endif
  75 }
  76
  77 static void leon3_serial_putc(const char c)
  78 {
  79         if (c == '\n')
  80                 leon3_serial_putc_raw('\r');
  81
  82         leon3_serial_putc_raw(c);
  83 }
  84
  85 static int leon3_serial_getc(void)
  86 {
  87         ambapp_dev_apbuart * const uart = leon3_get_uart_regs();
  88
  89         if (!uart)
  90                 return 0;
  91
  92         /* Wait for a character to arrive. */
  93         while (!(readl(&uart->status) & LEON_REG_UART_STATUS_DR))
  94                 WATCHDOG_RESET();
  95
  96         /* Read character data */
  97         return readl(&uart->data);
  98 }
  99
 100 static int leon3_serial_tstc(void)
 101 {
 102         ambapp_dev_apbuart * const uart = leon3_get_uart_regs();
 103
 104         if (!uart)
 105                 return 0;
 106
 107         return readl(&uart->status) & LEON_REG_UART_STATUS_DR;
 108 }
 109
 110 /* set baud rate for uart */
 111 static void leon3_serial_setbrg(void)
 112 {
 113         ambapp_dev_apbuart * const uart = leon3_get_uart_regs();
 114         unsigned int scaler;
 115
 116         if (!uart)
 117                 return;
 118
 119         if (!gd->baudrate)
 120                 gd->baudrate = CONFIG_BAUDRATE;
 121
 122         scaler = (((CONFIG_SYS_CLK_FREQ*10) / (gd->baudrate*8)) - 5)/10;
 123
 124         writel(scaler, &uart->scaler);
 125 }
 126
 127 static struct serial_device leon3_serial_drv = {
 128         .name   = "leon3_serial",
 129         .start  = leon3_serial_init,
 130         .stop   = NULL,
 131         .setbrg = leon3_serial_setbrg,
 132         .putc   = leon3_serial_putc,
 133         .puts   = default_serial_puts,
 134         .getc   = leon3_serial_getc,
 135         .tstc   = leon3_serial_tstc,
 136 };
 137
 138 void leon3_serial_initialize(void)
 139 {
 140         serial_register(&leon3_serial_drv);
 141 }
 142
 143 __weak struct serial_device *default_serial_console(void)
 144 {
 145         return &leon3_serial_drv;
 146 }