LXR linux/arch/powerpc/boot/uartlite.c

   1/*
   2 * Xilinx UARTLITE bootloader driver
   3 *
   4 * Copyright (C) 2007 Secret Lab Technologies Ltd.
   5 *
   6 * This file is licensed under the terms of the GNU General Public License
   7 * version 2. This program is licensed "as is" without any warranty of any
   8 * kind, whether express or implied.
   9 */
  10
  11#include <stdarg.h>
  12#include <stddef.h>
  13#include "types.h"
  14#include "string.h"
  15#include "stdio.h"
  16#include "io.h"
  17#include "ops.h"
  18
  19#define ULITE_RX                0x00
  20#define ULITE_TX                0x04
  21#define ULITE_STATUS            0x08
  22#define ULITE_CONTROL           0x0c
  23
  24#define ULITE_STATUS_RXVALID    0x01
  25#define ULITE_STATUS_TXFULL     0x08
  26
  27#define ULITE_CONTROL_RST_RX    0x02
  28
  29static void * reg_base;
  30
  31static int uartlite_open(void)
  32{
  33        /* Clear the RX FIFO */
  34        out_be32(reg_base + ULITE_CONTROL, ULITE_CONTROL_RST_RX);
  35        return 0;
  36}
  37
  38static void uartlite_putc(unsigned char c)
  39{
  40        u32 reg = ULITE_STATUS_TXFULL;
  41        while (reg & ULITE_STATUS_TXFULL) /* spin on TXFULL bit */
  42                reg = in_be32(reg_base + ULITE_STATUS);
  43        out_be32(reg_base + ULITE_TX, c);
  44}
  45
  46static unsigned char uartlite_getc(void)
  47{
  48        u32 reg = 0;
  49        while (!(reg & ULITE_STATUS_RXVALID)) /* spin waiting for RXVALID bit */
  50                reg = in_be32(reg_base + ULITE_STATUS);
  51        return in_be32(reg_base + ULITE_RX);
  52}
  53
  54static u8 uartlite_tstc(void)
  55{
  56        u32 reg = in_be32(reg_base + ULITE_STATUS);
  57        return reg & ULITE_STATUS_RXVALID;
  58}
  59
  60int uartlite_console_init(void *devp, struct serial_console_data *scdp)
  61{
  62        int n;
  63        unsigned long reg_phys;
  64
  65        n = getprop(devp, "virtual-reg", &reg_base, sizeof(reg_base));
  66        if (n != sizeof(reg_base)) {
  67                if (!dt_xlate_reg(devp, 0, &reg_phys, NULL))
  68                        return -1;
  69
  70                reg_base = (void *)reg_phys;
  71        }
  72
  73        scdp->open = uartlite_open;
  74        scdp->putc = uartlite_putc;
  75        scdp->getc = uartlite_getc;
  76        scdp->tstc = uartlite_tstc;
  77        scdp->close = NULL;
  78        return 0;
  79}
  80