1 | #ifndef _mmu_405_h |
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2 | #define _mmu_405_h |
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3 | |
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4 | /* |
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5 | Simple interface to the PowerPC 405 MMU |
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6 | |
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7 | The intention here is just to allow the MMU to be used to define cacheability and |
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8 | read/write/execute permissions in a simple enough way to fit entirely into the |
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9 | 64-entry TLB cache. |
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10 | |
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11 | This code does not do address relocation and does not generate any MMU-related interrupts. |
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12 | |
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13 | The process ID support is there for a possible future extension where RTEMS supports |
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14 | setting the process ID on task switches, which allows per-process stack protection |
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15 | |
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16 | This code will call fatal_error() if your add_space() calls overrun the 64 entries |
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17 | |
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18 | Michael Hamel ADInstruments 2008 |
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19 | |
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20 | */ |
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21 | |
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22 | |
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23 | #ifdef __cplusplus |
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24 | extern "C" { |
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25 | #endif |
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26 | |
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27 | #include "stdint.h" |
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28 | |
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29 | enum { |
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30 | kAllProcessIDs = 0 |
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31 | }; |
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32 | |
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33 | typedef enum MMUAccessType { |
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34 | executable, |
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35 | readOnlyData, |
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36 | readOnlyNoCache, |
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37 | readWriteData, |
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38 | readWriteNoCache, |
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39 | readWriteExecutable |
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40 | } MMUAccessType; |
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41 | |
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42 | /* Initialise and clear the MMU */ |
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43 | void mmu_initialise(void); |
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44 | |
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45 | /* Turn on/off data access translation */ |
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46 | bool mmu_enable_data(bool enable); |
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47 | |
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48 | /* Turn on instruction translation */ |
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49 | bool mmu_enable_code(bool enable); |
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50 | |
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51 | /* Define properties for an area of memory (must be 1K-aligned) */ |
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52 | void mmu_add_space(uint32_t startAddr, uint32_t endAddr, MMUAccessType permissions, uint8_t processID); |
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53 | |
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54 | /* Delete a memory property definition */ |
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55 | void mmu_remove_space(uint32_t startAddr, uint32_t endAddr); |
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56 | |
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57 | /* Return number of TLB entries out of total in use */ |
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58 | int mmu_get_tlb_count(void); |
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59 | |
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60 | /* Allocate a new process ID and return it */ |
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61 | uint8_t mmu_new_processID(void); |
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62 | |
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63 | /* Free a process ID that has been in use */ |
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64 | void mmu_free_processID(uint8_t freeThis); |
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65 | |
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66 | /* Return the current process ID */ |
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67 | uint8_t mmu_current_processID(void); |
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68 | |
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69 | /* Change the process ID to ID and return the old value */ |
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70 | uint8_t mmu_set_processID(uint8_t toID); |
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71 | |
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72 | |
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73 | #ifdef __cplusplus |
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74 | } |
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75 | #endif |
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76 | |
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77 | #endif //_mmu_405.h |
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