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kernel/linux-imx6_3.14.28/arch/powerpc/boot/ns16550.c 1.94 KB
6b13f685e   김민수   BSP 최초 추가
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  /*
   * 16550 serial console support.
   *
   * Original copied from <file:arch/ppc/boot/common/ns16550.c>
   * (which had no copyright)
   * Modifications: 2006 (c) MontaVista Software, Inc.
   *
   * Modified by: Mark A. Greer <mgreer@mvista.com>
   */
  #include <stdarg.h>
  #include <stddef.h>
  #include "types.h"
  #include "string.h"
  #include "stdio.h"
  #include "io.h"
  #include "ops.h"
  
  #define UART_DLL	0	/* Out: Divisor Latch Low */
  #define UART_DLM	1	/* Out: Divisor Latch High */
  #define UART_FCR	2	/* Out: FIFO Control Register */
  #define UART_LCR	3	/* Out: Line Control Register */
  #define UART_MCR	4	/* Out: Modem Control Register */
  #define UART_LSR	5	/* In:  Line Status Register */
  #define UART_LSR_THRE	0x20	/* Transmit-hold-register empty */
  #define UART_LSR_DR	0x01	/* Receiver data ready */
  #define UART_MSR	6	/* In:  Modem Status Register */
  #define UART_SCR	7	/* I/O: Scratch Register */
  
  static unsigned char *reg_base;
  static u32 reg_shift;
  
  static int ns16550_open(void)
  {
  	out_8(reg_base + (UART_FCR << reg_shift), 0x06);
  	return 0;
  }
  
  static void ns16550_putc(unsigned char c)
  {
  	while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_THRE) == 0);
  	out_8(reg_base, c);
  }
  
  static unsigned char ns16550_getc(void)
  {
  	while ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) == 0);
  	return in_8(reg_base);
  }
  
  static u8 ns16550_tstc(void)
  {
  	return ((in_8(reg_base + (UART_LSR << reg_shift)) & UART_LSR_DR) != 0);
  }
  
  int ns16550_console_init(void *devp, struct serial_console_data *scdp)
  {
  	int n;
  	u32 reg_offset;
  
  	if (dt_get_virtual_reg(devp, (void **)&reg_base, 1) < 1)
  		return -1;
  
  	n = getprop(devp, "reg-offset", &reg_offset, sizeof(reg_offset));
  	if (n == sizeof(reg_offset))
  		reg_base += reg_offset;
  
  	n = getprop(devp, "reg-shift", &reg_shift, sizeof(reg_shift));
  	if (n != sizeof(reg_shift))
  		reg_shift = 0;
  
  	scdp->open = ns16550_open;
  	scdp->putc = ns16550_putc;
  	scdp->getc = ns16550_getc;
  	scdp->tstc = ns16550_tstc;
  	scdp->close = NULL;
  
  	return 0;
  }