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| 3467 | rimsky | 1 | /* |
| 2 | * Copyright (c) 2006 Pavel Rimsky |
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| 3 | * All rights reserved. |
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| 4 | * |
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| 5 | * Redistribution and use in source and binary forms, with or without |
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| 6 | * modification, are permitted provided that the following conditions |
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| 7 | * are met: |
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| 8 | * |
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| 9 | * - Redistributions of source code must retain the above copyright |
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| 10 | * notice, this list of conditions and the following disclaimer. |
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| 11 | * - Redistributions in binary form must reproduce the above copyright |
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| 12 | * notice, this list of conditions and the following disclaimer in the |
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| 13 | * documentation and/or other materials provided with the distribution. |
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| 14 | * - The name of the author may not be used to endorse or promote products |
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| 15 | * derived from this software without specific prior written permission. |
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| 16 | * |
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| 17 | * THIS SOFTWARE IS PROVIDED BY THE AUTHOR ``AS IS'' AND ANY EXPRESS OR |
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| 18 | * IMPLIED WARRANTIES, INCLUDING, BUT NOT LIMITED TO, THE IMPLIED WARRANTIES |
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| 19 | * OF MERCHANTABILITY AND FITNESS FOR A PARTICULAR PURPOSE ARE DISCLAIMED. |
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| 20 | * IN NO EVENT SHALL THE AUTHOR BE LIABLE FOR ANY DIRECT, INDIRECT, |
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| 21 | * INCIDENTAL, SPECIAL, EXEMPLARY, OR CONSEQUENTIAL DAMAGES (INCLUDING, BUT |
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| 22 | * NOT LIMITED TO, PROCUREMENT OF SUBSTITUTE GOODS OR SERVICES; LOSS OF USE, |
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| 23 | * DATA, OR PROFITS; OR BUSINESS INTERRUPTION) HOWEVER CAUSED AND ON ANY |
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| 24 | * THEORY OF LIABILITY, WHETHER IN CONTRACT, STRICT LIABILITY, OR TORT |
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| 25 | * (INCLUDING NEGLIGENCE OR OTHERWISE) ARISING IN ANY WAY OUT OF THE USE OF |
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| 26 | * THIS SOFTWARE, EVEN IF ADVISED OF THE POSSIBILITY OF SUCH DAMAGE. |
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| 27 | */ |
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| 28 | |||
| 29 | /** @addtogroup sparc64 |
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| 30 | * @{ |
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| 31 | */ |
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| 32 | /** |
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| 33 | * @file |
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| 34 | * @brief Routines for writing characters directly to Simics CLI. |
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| 35 | * |
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| 36 | */ |
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| 37 | |||
| 38 | #include <console/chardev.h> |
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| 39 | #include <console/console.h> |
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| 40 | #include <synch/spinlock.h> |
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| 41 | #include <arch/drivers/simics_output.h> |
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| 42 | |||
| 43 | /** maximum number of characters stored before printed */ |
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| 44 | #define BUFSIZE 512 |
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| 45 | |||
| 46 | /* %g2 will store a magic value used during initialization */ |
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| 47 | asm (".register %g2, #scratch"); |
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| 48 | |||
| 49 | /* %g3 will store the address (to be passed to Simics) of the buffer */ |
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| 50 | asm (".register %g3, #scratch"); |
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| 51 | |||
| 52 | /* lock protecting the character buffer */ |
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| 53 | SPINLOCK_INITIALIZE(simics_buf_lock); |
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| 54 | |||
| 55 | static void simics_putchar(struct chardev * cd, char c); |
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| 56 | |||
| 57 | /** character device operations - only writing will be supported */ |
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| 58 | static chardev_operations_t simics_stdout_ops = { |
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| 59 | .suspend = NULL, |
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| 60 | .resume = NULL, |
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| 61 | .write = simics_putchar, |
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| 62 | .read = NULL |
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| 63 | }; |
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| 64 | |||
| 65 | /** Simics character device */ |
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| 66 | chardev_t simics_stdout; |
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| 67 | |||
| 68 | /** |
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| 69 | * buffer to which output characters are stored before they're printed by Simics |
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| 70 | */ |
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| 71 | static volatile char buffer[BUFSIZE]; |
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| 72 | |||
| 73 | /** Writes a single character to the Simics CLI. |
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| 74 | * |
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| 75 | * The character is not written immediately, but it is stored to the first free |
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| 3477 | rimsky | 76 | * position in the buffer, waiting for Simics' Python routine to read it |
| 3467 | rimsky | 77 | * and print it. |
| 78 | */ |
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| 79 | static void simics_putchar(struct chardev * cd, char c) |
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| 80 | { |
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| 81 | /* the first free position in the buffer */ |
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| 82 | static uint16_t current = 0; |
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| 83 | |||
| 84 | /* '\0' terminates a contiguous block of characters to be printed! */ |
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| 85 | if (c == '\0') |
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| 86 | return; |
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| 87 | |||
| 88 | /* wait till buffer is non-full and other processors aren't writing to it */ |
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| 89 | while (1) { |
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| 90 | while (buffer[current] != 0) |
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| 91 | ; |
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| 92 | if (spinlock_trylock(&simics_buf_lock)) |
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| 93 | break; |
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| 94 | } |
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| 95 | |||
| 96 | buffer[current] = c; |
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| 97 | |||
| 98 | current = (current + 1) % BUFSIZE; |
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| 99 | membar(); |
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| 100 | |||
| 101 | spinlock_unlock(&simics_buf_lock); |
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| 102 | } |
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| 103 | |||
| 104 | /** Initializes the Simics output. |
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| 105 | * |
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| 106 | * Passes the address of the buffer to the Simics' Python script and |
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| 107 | * redirects kernel output to the Simics CLI. |
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| 108 | */ |
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| 109 | void simics_output_init(void) |
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| 110 | { |
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| 111 | /* all buffer positions are free at the beginning */ |
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| 112 | uint16_t i; |
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| 113 | for (i = 0; i < BUFSIZE; i++) { |
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| 114 | buffer[i] = '\0'; |
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| 115 | } |
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| 116 | |||
| 117 | /* |
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| 118 | * pass the address of the buffer to the Simics' Python script |
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| 119 | * - write it to the %g3 register |
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| 120 | * - write the magic value to the %g2 register |
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| 121 | * (so that the script knows that the value in %g3 is valid) |
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| 122 | * - loop until the value is read |
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| 123 | * (the script notifies us by setting %g2 to 0) |
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| 124 | */ |
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| 125 | asm volatile ( |
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| 126 | "or %0, 0, %%g3\n" |
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| 127 | |||
| 128 | "set 0x18273645, %%g2\n" |
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| 129 | |||
| 130 | "0: cmp %%g2, 0\n" |
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| 131 | "bnz 0b\n" |
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| 132 | "nop" |
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| 133 | :: "r" (buffer) |
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| 134 | ); |
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| 135 | |||
| 136 | /* redirect kernel output */ |
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| 137 | chardev_initialize("simics_output", &simics_stdout, &simics_stdout_ops); |
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| 138 | stdout = &simics_stdout; |
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| 139 | } |
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| 140 | |||
| 141 | /** @} |
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| 142 | */ |