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 <grlib/apbuart.h>
  13 #include <serial.h>
  14 #include <watchdog.h>
  15
  16 DECLARE_GLOBAL_DATA_PTR;
  17
  18 /* Select which UART that will become u-boot console */
  19 #ifndef CONFIG_SYS_GRLIB_APBUART_INDEX
  20 #define CONFIG_SYS_GRLIB_APBUART_INDEX 0
  21 #endif
  22
  23 static int leon3_serial_init(void)
  24 {
  25         ambapp_dev_apbuart *uart;
  26         ambapp_apbdev apbdev;
  27         unsigned int tmp;
  28
  29         /* find UART */
  30         if (ambapp_apb_find(&ambapp_plb, VENDOR_GAISLER, GAISLER_APBUART,
  31                 CONFIG_SYS_GRLIB_APBUART_INDEX, &apbdev) != 1) {
  32                 panic("%s: apbuart not found!\n", __func__);
  33                 return -1; /* didn't find hardware */
  34         }
  35
  36         /* found apbuart, let's init .. */
  37         uart = (ambapp_dev_apbuart *) apbdev.address;
  38
  39         /* Set scaler / baud rate */
  40         tmp = (((CONFIG_SYS_CLK_FREQ*10) / (CONFIG_BAUDRATE*8)) - 5)/10;
  41         writel(tmp, &uart->scaler);
  42
  43         /* Let bit 11 be unchanged (debug bit for GRMON) */
  44         tmp = readl(&uart->ctrl) & APBUART_CTRL_DBG;
  45         /* Receiver & transmitter enable */
  46         tmp |= APBUART_CTRL_RE | APBUART_CTRL_TE;
  47         writel(tmp, &uart->ctrl);
  48
  49         gd->arch.uart = uart;
  50         return 0;
  51 }
  52
  53 static inline ambapp_dev_apbuart *leon3_get_uart_regs(void)
  54 {
  55         ambapp_dev_apbuart *uart = gd->arch.uart;
  56         return uart;
  57 }
  58
  59 static void leon3_serial_putc_raw(const char c)
  60 {
  61         ambapp_dev_apbuart * const uart = leon3_get_uart_regs();
  62
  63         if (!uart)
  64                 return;
  65
  66         /* Wait for last character to go. */
  67         while (!(readl(&uart->status) & APBUART_STATUS_THE))
  68                 WATCHDOG_RESET();
  69
  70         /* Send data */
  71         writel(c, &uart->data);
  72
  73 #ifdef LEON_DEBUG
  74         /* Wait for data to be sent */
  75         while (!(readl(&uart->status) & APBUART_STATUS_TSE))
  76                 WATCHDOG_RESET();
  77 #endif
  78 }
  79
  80 static void leon3_serial_putc(const char c)
  81 {
  82         if (c == '\n')
  83                 leon3_serial_putc_raw('\r');
  84
  85         leon3_serial_putc_raw(c);
  86 }
  87
  88 static int leon3_serial_getc(void)
  89 {
  90         ambapp_dev_apbuart * const uart = leon3_get_uart_regs();
  91
  92         if (!uart)
  93                 return 0;
  94
  95         /* Wait for a character to arrive. */
  96         while (!(readl(&uart->status) & APBUART_STATUS_DR))
  97                 WATCHDOG_RESET();
  98
  99         /* Read character data */
 100         return readl(&uart->data);
 101 }
 102
 103 static int leon3_serial_tstc(void)
 104 {
 105         ambapp_dev_apbuart * const uart = leon3_get_uart_regs();
 106
 107         if (!uart)
 108                 return 0;
 109
 110         return readl(&uart->status) & APBUART_STATUS_DR;
 111 }
 112
 113 /* set baud rate for uart */
 114 static void leon3_serial_setbrg(void)
 115 {
 116         ambapp_dev_apbuart * const uart = leon3_get_uart_regs();
 117         unsigned int scaler;
 118
 119         if (!uart)
 120                 return;
 121
 122         if (!gd->baudrate)
 123                 gd->baudrate = CONFIG_BAUDRATE;
 124
 125         scaler = (((CONFIG_SYS_CLK_FREQ*10) / (gd->baudrate*8)) - 5)/10;
 126
 127         writel(scaler, &uart->scaler);
 128 }
 129
 130 static struct serial_device leon3_serial_drv = {
 131         .name   = "leon3_serial",
 132         .start  = leon3_serial_init,
 133         .stop   = NULL,
 134         .setbrg = leon3_serial_setbrg,
 135         .putc   = leon3_serial_putc,
 136         .puts   = default_serial_puts,
 137         .getc   = leon3_serial_getc,
 138         .tstc   = leon3_serial_tstc,
 139 };
 140
 141 void leon3_serial_initialize(void)
 142 {
 143         serial_register(&leon3_serial_drv);
 144 }
 145
 146 __weak struct serial_device *default_serial_console(void)
 147 {
 148         return &leon3_serial_drv;
 149 }
 150
 151 #ifdef CONFIG_DEBUG_UART_APBUART
 152
 153 #include <debug_uart.h>
 154
 155 static inline void _debug_uart_init(void)
 156 {
 157         ambapp_dev_apbuart *uart = (ambapp_dev_apbuart *)CONFIG_DEBUG_UART_BASE;
 158         uart->scaler = (((CONFIG_DEBUG_UART_CLOCK*10) / (CONFIG_BAUDRATE*8)) - 5)/10;
 159         uart->ctrl = APBUART_CTRL_RE | APBUART_CTRL_TE;
 160 }
 161
 162 static inline void _debug_uart_putc(int ch)
 163 {
 164         ambapp_dev_apbuart *uart = (ambapp_dev_apbuart *)CONFIG_DEBUG_UART_BASE;
 165         while (!(readl(&uart->status) & APBUART_STATUS_THE))
 166                 WATCHDOG_RESET();
 167         writel(ch, &uart->data);
 168 }
 169
 170 DEBUG_UART_FUNCS
 171
 172 #endif