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kernel/linux-imx6_3.14.28/arch/powerpc/boot/uartlite.c 1.74 KB
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  /*
   * Xilinx UARTLITE bootloader driver
   *
   * Copyright (C) 2007 Secret Lab Technologies Ltd.
   *
   * This file is licensed under the terms of the GNU General Public License
   * version 2. This program is licensed "as is" without any warranty of any
   * kind, whether express or implied.
   */
  
  #include <stdarg.h>
  #include <stddef.h>
  #include "types.h"
  #include "string.h"
  #include "stdio.h"
  #include "io.h"
  #include "ops.h"
  
  #define ULITE_RX		0x00
  #define ULITE_TX		0x04
  #define ULITE_STATUS		0x08
  #define ULITE_CONTROL		0x0c
  
  #define ULITE_STATUS_RXVALID	0x01
  #define ULITE_STATUS_TXFULL	0x08
  
  #define ULITE_CONTROL_RST_RX	0x02
  
  static void * reg_base;
  
  static int uartlite_open(void)
  {
  	/* Clear the RX FIFO */
  	out_be32(reg_base + ULITE_CONTROL, ULITE_CONTROL_RST_RX);
  	return 0;
  }
  
  static void uartlite_putc(unsigned char c)
  {
  	u32 reg = ULITE_STATUS_TXFULL;
  	while (reg & ULITE_STATUS_TXFULL) /* spin on TXFULL bit */
  		reg = in_be32(reg_base + ULITE_STATUS);
  	out_be32(reg_base + ULITE_TX, c);
  }
  
  static unsigned char uartlite_getc(void)
  {
  	u32 reg = 0;
  	while (!(reg & ULITE_STATUS_RXVALID)) /* spin waiting for RXVALID bit */
  		reg = in_be32(reg_base + ULITE_STATUS);
  	return in_be32(reg_base + ULITE_RX);
  }
  
  static u8 uartlite_tstc(void)
  {
  	u32 reg = in_be32(reg_base + ULITE_STATUS);
  	return reg & ULITE_STATUS_RXVALID;
  }
  
  int uartlite_console_init(void *devp, struct serial_console_data *scdp)
  {
  	int n;
  	unsigned long reg_phys;
  
  	n = getprop(devp, "virtual-reg", &reg_base, sizeof(reg_base));
  	if (n != sizeof(reg_base)) {
  		if (!dt_xlate_reg(devp, 0, &reg_phys, NULL))
  			return -1;
  
  		reg_base = (void *)reg_phys;
  	}
  
  	scdp->open = uartlite_open;
  	scdp->putc = uartlite_putc;
  	scdp->getc = uartlite_getc;
  	scdp->tstc = uartlite_tstc;
  	scdp->close = NULL;
  	return 0;
  }