async.h

Ibmstb02500 miniboot 源码

/* openbios/arch/pallas/redwood5/async.h, redbios, redbios_iii_1.0 6/14/99 14:34:35 */
/*-----------------------------------------------------------------------------+
|
|       This source code has been made available to you by IBM on an AS-IS
|       basis.  Anyone receiving this source is licensed under IBM
|       copyrights to use it in any way he or she deems fit, including
|       copying it, modifying it, compiling it, and redistributing it either
|       with or without modifications.  No license under IBM patents or
|       patent applications is to be implied by the copyright license.
|
|       Any user of this software should understand that IBM cannot provide
|       technical support for this software and will not be responsible for
|       any consequences resulting from the use of this software.
|
|       Any person who transfers this source code or any derivative work
|       must include the IBM copyright notice, this paragraph, and the
|       preceding two paragraphs in the transferred software.
|
|       COPYRIGHT   I B M   CORPORATION 1995
|       LICENSED MATERIAL  -  PROGRAM PROPERTY OF I B M
+-----------------------------------------------------------------------------*/
/*-----------------------------------------------------------------------------+
|
|  File Name:   async.h
|
|  Function:    Platform specific asynchronous port basic functions.
|
|  Author:      Bill DeStein, Maciej P. Tyrlik.
|
|  Change Activity-
|
|  Date        Description of Change                                       BY
|  ---------   ---------------------                                       ---
|  13-Aug-93   Created                                                     WCD
|  27-May-94   Port to Oak                                                 MPT
|  14-Jun-99   Added s1setbaud                                             pag
|  29-Dec-01   Added getline/askchar                                       YYD
|  09-Jan-02   Splitted platform specific ones                             YYD
+-----------------------------------------------------------------------------*/

/*-----------------------------------------------------------------------------+
| Line Status Register.
+-----------------------------------------------------------------------------*/
#define asyncLSRport1           0x40040005
#define asyncLSRDataReady1            0x01
#define asyncLSROverrunError1         0x02
#define asyncLSRParityError1          0x04
#define asyncLSRFramingError1         0x08
#define asyncLSRBreakInterrupt1       0x10
#define asyncLSRTxHoldEmpty1          0x20
#define asyncLSRTxShiftEmpty1         0x40
#define asyncLSRRxFifoError1          0x80

/*-----------------------------------------------------------------------------+
| Miscellanies defines.
+-----------------------------------------------------------------------------*/
#define asyncTxBufferport1      0x40040000
#define asyncRxBufferport1      0x40040000


/*-----------------------------------------------------------------------------+
| Getchar.
+-----------------------------------------------------------------------------*/
int getchar()
{

   unsigned char        status=0;

   while(1) {
      status=in8(asyncLSRport1);
      if ((status&asyncLSRDataReady1)!=0x0) {
         break;
      } else if ((status&(asyncLSRFramingError1|asyncLSROverrunError1|
                 asyncLSRParityError1|asyncLSRBreakInterrupt1))!=0) {
         (void)out8(asyncLSRport1, asyncLSRFramingError1|asyncLSROverrunError1|
         asyncLSRParityError1|asyncLSRBreakInterrupt1);
      }
   }
   return(0x000000ff&(int)in8(asyncRxBufferport1));
}

/*-----------------------------------------------------------------------------+
| Kbhit.
+-----------------------------------------------------------------------------*/
int kbhit()
{

   unsigned char        status;

   status=in8(asyncLSRport1);
   if ((status&asyncLSRDataReady1)!=0x0) {
      return(1);
   }
   if ((status&(asyncLSRFramingError1|asyncLSROverrunError1|asyncLSRParityError1|
        asyncLSRBreakInterrupt1))!=0) {
      (void)out8(asyncLSRport1, asyncLSRFramingError1|asyncLSROverrunError1|
                 asyncLSRParityError1|asyncLSRBreakInterrupt1);
   }
   return 0;
}


unsigned long   scc_clk = 20000000;

void init_s1port_divisor()
{
   unsigned long                temp_value;
   unsigned long                Mult, RangeA, RangeB, scc_div;


   /*--------------------------------------------------------------------------+
   | Calculate the serial port clock speed.  This code really ought to be put
   | somewhere else (like in ramcheck where the clock computations are done).
   | The update the baud rate (which will use the new scc_clk variable).
   +--------------------------------------------------------------------------*/

   temp_value = ppcMfclkgpcr();
   Mult = temp_value & 0xf;
   if (Mult == 0)
   {
      Mult = 16;
   }
   scc_clk = BOARD_CLOCK * Mult;
   if ((temp_value & 0x00000080) == 0)
   {
      RangeB = 8 - ((temp_value >> 8) & 0x7);
      RangeA = 8 - ((temp_value >> 4) & 0x7);
      scc_clk = scc_clk * RangeA / RangeB;
   }
   if ((temp_value & 0x00400000) == 0)
   {
      scc_clk *= 2;
   }
   scc_div = (temp_value >> 18 ) & 0x0000003f;
   if (scc_div == 0)
   {
      scc_div = 16;
   }
   scc_clk /= scc_div;

   s1setbaud(1);

#if 0
   /* debug print out of serial port clock speed */
   s1printf("Serial port speed: %d\n", scc_clk);
   s1printf(" Control reg: 0x%x, Mult: %d, A: %d, B: %d, scc_div: %d\n",
                                  temp_value, Mult, RangeA, RangeB, scc_div);
#endif
}