[8ef3818] | 1 | /* |
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| 2 | * dpram.c |
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| 3 | * |
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| 4 | * MPC8xx dual-port RAM allocation routines |
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| 5 | * |
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| 6 | * Based on code (alloc860.c in eth_comm port) by |
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| 7 | * Jay Monkman (jmonkman@frasca.com), |
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| 8 | * which, in turn, is based on code by |
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| 9 | * W. Eric Norum (eric@skatter.usask.ca). |
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| 10 | * |
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| 11 | * |
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| 12 | * Modifications : |
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| 13 | * Copyright (c) 1999, National Research Council of Canada |
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| 14 | */ |
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| 15 | |
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[61bd0301] | 16 | #include <rtems.h> |
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| 17 | #include <mpc8xx.h> |
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| 18 | #include <mpc8xx/cpm.h> |
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[8ef3818] | 19 | |
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| 20 | /* |
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| 21 | * Allocation order: |
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| 22 | * - Dual-Port RAM section 0 |
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| 23 | * - Dual-Port RAM section 1 |
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| 24 | * - Dual-Port RAM section 2 |
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| 25 | * - Dual-Port RAM section 3 |
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| 26 | * - Dual-Port RAM section 4 |
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| 27 | */ |
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| 28 | static struct { |
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| 29 | unsigned8 *base; |
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| 30 | unsigned int size; |
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| 31 | unsigned int used; |
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| 32 | } dpram_regions[] = { |
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| 33 | { (char *)&m8xx.dpram0[0], sizeof m8xx.dpram0, 0 }, |
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| 34 | { (char *)&m8xx.dpram1[0], sizeof m8xx.dpram1, 0 }, |
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| 35 | { (char *)&m8xx.dpram2[0], sizeof m8xx.dpram2, 0 }, |
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| 36 | { (char *)&m8xx.dpram3[0], sizeof m8xx.dpram3, 0 }, |
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| 37 | { (char *)&m8xx.dpram4[0], sizeof m8xx.dpram4, 0 }, |
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| 38 | }; |
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| 39 | |
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| 40 | #define NUM_DPRAM_REGIONS (sizeof(dpram_regions) / sizeof(dpram_regions[0])) |
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| 41 | |
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| 42 | void * |
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| 43 | m8xx_dpram_allocate( unsigned int byte_count ) |
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| 44 | { |
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| 45 | unsigned int i; |
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| 46 | ISR_Level level; |
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| 47 | void *blockp = NULL; |
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| 48 | |
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| 49 | byte_count = (byte_count + 3) & ~0x3; |
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| 50 | |
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| 51 | /* |
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| 52 | * Running with interrupts disabled is usually considered bad |
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| 53 | * form, but this routine is probably being run as part of an |
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| 54 | * initialization sequence so the effect shouldn't be too severe. |
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| 55 | */ |
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| 56 | _ISR_Disable (level); |
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| 57 | |
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| 58 | for ( i = 0; i < NUM_DPRAM_REGIONS; i++ ) { |
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| 59 | /* |
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| 60 | * Verify that the region is available for use. |
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| 61 | * This test is necessary because if extra microcode modules |
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| 62 | * are installed, some regions are locked and unavailable. |
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| 63 | * See MPC860 User's Manual Pages 19-9 to 19-11. |
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| 64 | */ |
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| 65 | if (dpram_regions[i].used == 0) { |
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| 66 | volatile unsigned char *cp = dpram_regions[i].base; |
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| 67 | *cp = 0xAA; |
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| 68 | if (*cp != 0xAA) |
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| 69 | dpram_regions[i].used = dpram_regions[i].size; |
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| 70 | else { |
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| 71 | *cp = 0x55; |
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| 72 | if (*cp != 0x55) |
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| 73 | dpram_regions[i].used = dpram_regions[i].size; |
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| 74 | } |
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| 75 | *cp = 0x0; |
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| 76 | } |
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| 77 | if (dpram_regions[i].size - dpram_regions[i].used >= byte_count) { |
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| 78 | blockp = dpram_regions[i].base + dpram_regions[i].used; |
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| 79 | dpram_regions[i].used += byte_count; |
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| 80 | break; |
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| 81 | } |
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| 82 | } |
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| 83 | |
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| 84 | _ISR_Enable(level); |
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| 85 | |
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| 86 | if (blockp == NULL) |
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| 87 | rtems_panic("Can't allocate %d bytes of dual-port RAM.\n", byte_count); |
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| 88 | return blockp; |
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| 89 | } |
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