diff options
Diffstat (limited to 'c/src/lib/libcpu/powerpc/mpc8260/cpm/brg.c')
| -rw-r--r-- | c/src/lib/libcpu/powerpc/mpc8260/cpm/brg.c | 204 |
1 files changed, 204 insertions, 0 deletions
diff --git a/c/src/lib/libcpu/powerpc/mpc8260/cpm/brg.c b/c/src/lib/libcpu/powerpc/mpc8260/cpm/brg.c new file mode 100644 index 0000000000..c6e48be0b0 --- /dev/null +++ b/c/src/lib/libcpu/powerpc/mpc8260/cpm/brg.c @@ -0,0 +1,204 @@ +/* + * 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.OARcorp.com/rtems/license.html. + * + * $Id$ + */ + +#include <rtems.h> +#include <mpc8260.h> +#include <mpc8260/cpm.h> +#include <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]; + + +extern rtems_cpu_table Cpu_table; + +/* + * Compute baud-rate-generator configuration register value + */ +int +m8xx_get_brg_cd (int baud) +{ + int divisor; + int div16 = 0; + + divisor = ((Cpu_table.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]--; +} |