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/*
* Baud rate generator management functions.
*
* This file contains routines for allocating baud rate generators
* and clock sources to the SCCs and FCCs on the MPC8260. The
* allocation is a little more complex on this processor because
* there are restrictions on which brgs and clks can be assigned to
* a particular port. Rather than coming up with a fixed assignment
* these routines try to allocate resources sensibly.
*
* *** All attempts to allocate a BRG or CLK line should be made via
* calls to these routines or they simply won't work.
*
* Author: Andy Dachs <a.dachs@sstl.co.uk>
* Copyright Surrey Satellite Technology Limited (SSTL), 2001
*
* Derived in part from work by:
*
* Author: Jay Monkman (jmonkman@frasca.com)
* Copyright (C) 1998 by Frasca International, Inc.
* and
* W. Eric Norum
* Saskatchewan Accelerator Laboratory
* University of Saskatchewan
* Saskatoon, Saskatchewan, CANADA
* eric@skatter.usask.ca
*
* The license and distribution terms for this file may be
* found in the file LICENSE in this distribution or at
* http://www.rtems.com/license/LICENSE.
*/
#include <rtems.h>
#include <mpc8260.h>
#include <mpc8260/cpm.h>
#include <rtems/bspIo.h>
#define NUM_BRGS 8
#define NUM_CLKS 20
/* Used to track the usage of the baud rate generators */
/* (initialised to zeros) */
static unsigned long brg_spd[NUM_BRGS];
static unsigned int brg_use_count[NUM_BRGS];
/* Used to track the usage of the clock inputs */
/* (initialised to zeros) */
static unsigned int clk_use_count[NUM_BRGS];
/*
* Compute baud-rate-generator configuration register value
*/
int
m8xx_get_brg_cd (int baud)
{
int divisor;
int div16 = 0;
extern uint32_t bsp_serial_per_sec;
divisor = ((bsp_serial_per_sec) + (baud / 2)) / baud;
if (divisor > 4096) {
div16 = 1;
divisor = (divisor + 8) / 16;
}
return M8260_BRG_EN | M8260_BRG_EXTC_BRGCLK |
((divisor - 1) << 1) | div16;
}
/*
* Allocates an existing brg if one is already programmed for the same
* baud rate. Otherwise a new brg is assigned
* AFD: on the mpc8260 only some combinations of SCC/SMC and BRG are allowed
* so add a mask which specifies which of the BRGs we can choose from
*/
int
m8xx_get_brg(unsigned brgmask, int baud)
{
int i;
/* first try to find a BRG that is already at the right speed */
for ( i = 0; i < NUM_BRGS; i++ ) {
if( (1 << i) & brgmask ) /* is this brg allowed? */
if ( brg_spd[i] == baud ) {
break;
}
}
if ( i == NUM_BRGS ) { /* I guess we didn't find one */
for ( i = 0; i < NUM_BRGS; i++ ) {
if (((1<<i) & brgmask) && (brg_use_count[i] == 0)) {
break;
}
}
}
if (i != NUM_BRGS) {
brg_use_count[i]++;
brg_spd[i]=baud;
switch (i) {
case 0:
m8260.brgc1 = M8260_BRG_RST;
m8260.brgc1 = m8xx_get_brg_cd(baud);
break;
case 1:
m8260.brgc2 = M8260_BRG_RST;
m8260.brgc2 = m8xx_get_brg_cd(baud);
break;
case 2:
m8260.brgc3 = M8260_BRG_RST;
m8260.brgc3 = m8xx_get_brg_cd(baud);
break;
case 3:
m8260.brgc4 = M8260_BRG_RST;
m8260.brgc4 = m8xx_get_brg_cd(baud);
break;
case 4:
m8260.brgc5 = M8260_BRG_RST;
m8260.brgc5 = m8xx_get_brg_cd(baud);
break;
case 5:
m8260.brgc6 = M8260_BRG_RST;
m8260.brgc6 = m8xx_get_brg_cd(baud);
break;
case 6:
m8260.brgc7 = M8260_BRG_RST;
m8260.brgc7 = m8xx_get_brg_cd(baud);
break;
case 7:
m8260.brgc8 = M8260_BRG_RST;
m8260.brgc8 = m8xx_get_brg_cd(baud);
break;
}
return i;
}
else {
printk( "Could not assign a brg for %d\n", baud );
return -1;
}
}
/*
* When the brg is no longer needed call this routine to free the
* resource for re--use.
*/
void
m8xx_free_brg( int brg_num )
{
if( (brg_num>=0) && (brg_num<NUM_BRGS) )
if(brg_use_count[brg_num] > 0 )
brg_use_count[brg_num]--;
}
void m8xx_dump_brgs( void )
{
int i;
for(i=0; i<NUM_BRGS; i++ )
printk( "Brg[%d]: %d %d\n", i, brg_use_count[i], brg_spd[i] );
}
/*
* Reserve one of a range of clock inputs
*/
int
m8xx_get_clk( unsigned clkmask )
{
int i;
for ( i = 0; i < NUM_CLKS; i++ ) {
if (((1<<i) & clkmask) && (clk_use_count[i] == 0)) {
break;
}
}
if (i != NUM_CLKS) {
clk_use_count[i]++;
return i;
} else {
printk( "Could not assign clock in the range %X\n", clkmask );
return -1;
}
}
/*
* When the clock is no longer needed call this routine to free the
* resource for re--use.
*/
void
m8xx_free_clk( int clk_num )
{
if( (clk_num>=0) && (clk_num<NUM_BRGS) )
if(clk_use_count[clk_num] > 0 )
clk_use_count[clk_num]--;
}
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