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29 | jermar | 1 | /* |
2 | * Copyright (C) 2005 Jakub Jermar |
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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 | #include <arch/acpi/acpi.h> |
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32 | jermar | 30 | #include <arch/bios/bios.h> |
29 | jermar | 31 | |
32 | jermar | 32 | #define RSDP_SIGNATURE "RSD PTR " |
33 | #define RSDP_REVISION_OFFS 15 |
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34 | |||
29 | jermar | 35 | struct acpi_rsdp *acpi_rsdp = NULL; |
36 | |||
32 | jermar | 37 | int rsdp_check(__u8 *rsdp) { |
38 | struct acpi_rsdp *r = (struct acpi_rsdp *) rsdp; |
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39 | __u8 sum = 0; |
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40 | int i; |
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41 | |||
42 | for (i=0; i<20; i++) |
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43 | sum += rsdp[i]; |
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44 | |||
45 | if (sum) |
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46 | return 0; /* bad checksum */ |
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47 | |||
48 | if (r->revision == 0) |
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49 | return 1; /* ACPI 1.0 */ |
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50 | |||
51 | for (; i<r->length; i++) |
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52 | sum += rsdp[i]; |
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53 | |||
54 | return !sum; |
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55 | |||
56 | } |
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57 | |||
29 | jermar | 58 | void acpi_init(void) |
59 | { |
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32 | jermar | 60 | __u8 *addr[2] = { NULL, (__u8 *) 0xe0000 }; |
61 | int i, j, length[2] = { 1024, 128*1024 }; |
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62 | __u64 *sig = (__u64 *) RSDP_SIGNATURE; |
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63 | |||
64 | /* |
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65 | * Find Root System Description Pointer |
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66 | * 1. search first 1K of EBDA |
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67 | * 2. search 128K starting at 0xe0000 |
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68 | */ |
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69 | |||
70 | addr[0] = (__u8 *) ebda; |
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71 | for (i = (ebda ? 0 : 1); i < 2; i++) { |
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72 | for (j = 0; j < length[i]; j += 16) { |
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73 | if (*((__u64 *) &addr[i][j]) == *sig && rsdp_check(&addr[i][j])) { |
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74 | acpi_rsdp = (struct acpi_rsdp *) &addr[i][j]; |
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75 | goto rsdp_found; |
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76 | } |
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77 | } |
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78 | } |
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79 | |||
80 | return; |
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81 | |||
82 | rsdp_found: |
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83 | printf("%L: ACPI Root System Description Pointer\n", acpi_rsdp); |
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29 | jermar | 84 | } |