[1ec501c] | 1 | /* |
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| 2 | * Baud rate generator management functions. |
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| 3 | * |
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| 4 | * This file contains routines for allocating baud rate generators |
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| 5 | * and clock sources to the SCCs and FCCs on the MPC8260. The |
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| 6 | * allocation is a little more complex on this processor because |
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| 7 | * there are restrictions on which brgs and clks can be assigned to |
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| 8 | * a particular port. Rather than coming up with a fixed assignment |
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| 9 | * these routines try to allocate resources sensibly. |
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| 10 | * |
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| 11 | * *** All attempts to allocate a BRG or CLK line should be made via |
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| 12 | * calls to these routines or they simply won't work. |
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[7ec9bd59] | 13 | */ |
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| 14 | |
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| 15 | /* |
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[1ec501c] | 16 | * Author: Andy Dachs <a.dachs@sstl.co.uk> |
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| 17 | * Copyright Surrey Satellite Technology Limited (SSTL), 2001 |
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| 18 | * |
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| 19 | * Derived in part from work by: |
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| 20 | * |
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| 21 | * Author: Jay Monkman (jmonkman@frasca.com) |
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| 22 | * Copyright (C) 1998 by Frasca International, Inc. |
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| 23 | * and |
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| 24 | * W. Eric Norum |
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| 25 | * Saskatchewan Accelerator Laboratory |
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| 26 | * University of Saskatchewan |
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| 27 | * Saskatoon, Saskatchewan, CANADA |
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| 28 | * eric@skatter.usask.ca |
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| 29 | * |
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| 30 | * The license and distribution terms for this file may be |
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| 31 | * found in the file LICENSE in this distribution or at |
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[c499856] | 32 | * http://www.rtems.org/license/LICENSE. |
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[1ec501c] | 33 | */ |
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| 34 | |
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[7ec9bd59] | 35 | #include <bsp.h> |
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[1ec501c] | 36 | #include <mpc8260.h> |
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| 37 | #include <mpc8260/cpm.h> |
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[5c76213] | 38 | #include <rtems/bspIo.h> |
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[1ec501c] | 39 | |
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| 40 | #define NUM_BRGS 8 |
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| 41 | #define NUM_CLKS 20 |
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| 42 | |
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| 43 | /* Used to track the usage of the baud rate generators */ |
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| 44 | /* (initialised to zeros) */ |
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| 45 | static unsigned long brg_spd[NUM_BRGS]; |
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| 46 | static unsigned int brg_use_count[NUM_BRGS]; |
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| 47 | |
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| 48 | /* Used to track the usage of the clock inputs */ |
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| 49 | /* (initialised to zeros) */ |
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| 50 | static unsigned int clk_use_count[NUM_BRGS]; |
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| 51 | |
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| 52 | /* |
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| 53 | * Compute baud-rate-generator configuration register value |
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| 54 | */ |
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| 55 | int |
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| 56 | m8xx_get_brg_cd (int baud) |
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| 57 | { |
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| 58 | int divisor; |
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| 59 | int div16 = 0; |
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| 60 | |
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[c4cc8199] | 61 | divisor = ((bsp_serial_per_sec) + (baud / 2)) / baud; |
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[1ec501c] | 62 | if (divisor > 4096) { |
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| 63 | div16 = 1; |
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| 64 | divisor = (divisor + 8) / 16; |
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| 65 | } |
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| 66 | return M8260_BRG_EN | M8260_BRG_EXTC_BRGCLK | |
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| 67 | ((divisor - 1) << 1) | div16; |
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| 68 | } |
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| 69 | |
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| 70 | /* |
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| 71 | * Allocates an existing brg if one is already programmed for the same |
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| 72 | * baud rate. Otherwise a new brg is assigned |
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| 73 | * AFD: on the mpc8260 only some combinations of SCC/SMC and BRG are allowed |
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| 74 | * so add a mask which specifies which of the BRGs we can choose from |
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| 75 | */ |
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| 76 | int |
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| 77 | m8xx_get_brg(unsigned brgmask, int baud) |
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| 78 | { |
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| 79 | int i; |
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| 80 | |
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| 81 | /* first try to find a BRG that is already at the right speed */ |
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| 82 | for ( i = 0; i < NUM_BRGS; i++ ) { |
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[7ec9bd59] | 83 | if ( (1 << i) & brgmask ) /* is this brg allowed? */ |
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[1ec501c] | 84 | if ( brg_spd[i] == baud ) { |
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| 85 | break; |
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| 86 | } |
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| 87 | } |
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| 88 | |
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| 89 | if ( i == NUM_BRGS ) { /* I guess we didn't find one */ |
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| 90 | for ( i = 0; i < NUM_BRGS; i++ ) { |
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| 91 | if (((1<<i) & brgmask) && (brg_use_count[i] == 0)) { |
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| 92 | break; |
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| 93 | } |
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| 94 | } |
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| 95 | } |
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| 96 | if (i != NUM_BRGS) { |
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| 97 | brg_use_count[i]++; |
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| 98 | brg_spd[i]=baud; |
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| 99 | switch (i) { |
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[7ec9bd59] | 100 | case 0: |
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| 101 | m8260.brgc1 = M8260_BRG_RST; |
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| 102 | m8260.brgc1 = m8xx_get_brg_cd(baud); |
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| 103 | break; |
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| 104 | case 1: |
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| 105 | m8260.brgc2 = M8260_BRG_RST; |
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| 106 | m8260.brgc2 = m8xx_get_brg_cd(baud); |
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| 107 | break; |
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| 108 | case 2: |
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| 109 | m8260.brgc3 = M8260_BRG_RST; |
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| 110 | m8260.brgc3 = m8xx_get_brg_cd(baud); |
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| 111 | break; |
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| 112 | case 3: |
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| 113 | m8260.brgc4 = M8260_BRG_RST; |
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| 114 | m8260.brgc4 = m8xx_get_brg_cd(baud); |
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| 115 | break; |
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| 116 | case 4: |
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| 117 | m8260.brgc5 = M8260_BRG_RST; |
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| 118 | m8260.brgc5 = m8xx_get_brg_cd(baud); |
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| 119 | break; |
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| 120 | case 5: |
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| 121 | m8260.brgc6 = M8260_BRG_RST; |
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| 122 | m8260.brgc6 = m8xx_get_brg_cd(baud); |
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| 123 | break; |
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| 124 | case 6: |
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| 125 | m8260.brgc7 = M8260_BRG_RST; |
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| 126 | m8260.brgc7 = m8xx_get_brg_cd(baud); |
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| 127 | break; |
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| 128 | case 7: |
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| 129 | m8260.brgc8 = M8260_BRG_RST; |
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| 130 | m8260.brgc8 = m8xx_get_brg_cd(baud); |
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| 131 | break; |
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[1ec501c] | 132 | } |
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| 133 | return i; |
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| 134 | } |
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| 135 | |
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| 136 | else { |
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| 137 | printk( "Could not assign a brg for %d\n", baud ); |
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| 138 | return -1; |
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| 139 | } |
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| 140 | } |
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| 141 | |
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| 142 | |
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| 143 | /* |
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| 144 | * When the brg is no longer needed call this routine to free the |
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| 145 | * resource for re--use. |
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| 146 | */ |
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| 147 | void |
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| 148 | m8xx_free_brg( int brg_num ) |
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| 149 | { |
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[7ec9bd59] | 150 | if ( (brg_num>=0) && (brg_num<NUM_BRGS) ) |
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| 151 | if (brg_use_count[brg_num] > 0 ) |
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| 152 | brg_use_count[brg_num]--; |
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[1ec501c] | 153 | } |
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| 154 | |
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[7ec9bd59] | 155 | #ifdef DEBUG_BRG |
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| 156 | static void m8xx_dump_brgs( void ) |
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[1ec501c] | 157 | { |
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| 158 | int i; |
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[7ec9bd59] | 159 | for (i=0; i<NUM_BRGS; i++ ) |
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[1ec501c] | 160 | printk( "Brg[%d]: %d %d\n", i, brg_use_count[i], brg_spd[i] ); |
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| 161 | } |
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[7ec9bd59] | 162 | #endif |
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[1ec501c] | 163 | |
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| 164 | /* |
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| 165 | * Reserve one of a range of clock inputs |
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| 166 | */ |
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| 167 | int |
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| 168 | m8xx_get_clk( unsigned clkmask ) |
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| 169 | { |
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| 170 | int i; |
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| 171 | |
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| 172 | for ( i = 0; i < NUM_CLKS; i++ ) { |
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| 173 | if (((1<<i) & clkmask) && (clk_use_count[i] == 0)) { |
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| 174 | break; |
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| 175 | } |
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| 176 | } |
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| 177 | |
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| 178 | if (i != NUM_CLKS) { |
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| 179 | clk_use_count[i]++; |
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| 180 | return i; |
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| 181 | } else { |
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| 182 | printk( "Could not assign clock in the range %X\n", clkmask ); |
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| 183 | return -1; |
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| 184 | } |
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| 185 | } |
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| 186 | |
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| 187 | |
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| 188 | /* |
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| 189 | * When the clock is no longer needed call this routine to free the |
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| 190 | * resource for re--use. |
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| 191 | */ |
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| 192 | void |
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| 193 | m8xx_free_clk( int clk_num ) |
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| 194 | { |
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[7ec9bd59] | 195 | if ( (clk_num>=0) && (clk_num<NUM_BRGS) ) |
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| 196 | if (clk_use_count[clk_num] > 0 ) |
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[1ec501c] | 197 | clk_use_count[clk_num]--; |
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| 198 | } |
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