projects / people / ms / u-boot.git / blame
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1 | |
| 2 | U-Boot for ARM Integrator Development Platforms | |
| 3 | ||
| 4 | Peter Pearse, ARM Ltd. | |
| 5 | peter.pearse@arm.com | |
| 6 | www.arm.com | |
| 7 | ||
| 8 | Manuals available from :- | |
| 9 | http://www.arm.com/products/DevTools/Hardware_Platforms.html | |
| 10 | ||
| 11 | Overview : | |
| 12 | -------- | |
| 13 | There are two Integrator variants - Integrator/AP and Integrator/CP. | |
| 14 | Each may be fitted with a variety of core modules (CMs). | |
| fe7eb5d8 | 15 | Each CM consists of a ARM processor core and associated hardware e.g |
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16 | FPGA implementing various controllers and/or register |
| 17 | SSRAM | |
| 18 | SDRAM | |
| 19 | RAM controllers | |
| 20 | clock generators etc. | |
| 9b880bd4 | 21 | CMs may be fitted with varying amounts of SDRAM using a DIMM socket. |
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22 | |
| 23 | Boot Methods : | |
| 24 | ------------ | |
| 25 | Integrator platforms can be configured to use U-Boot in at least three ways :- | |
| 26 | a) Run ARM boot monitor, manually run U-Boot image from flash | |
| 27 | b) Run ARM boot monitor, automatically run U-Boot image from flash | |
| 28 | c) Run U-Boot image direct from flash. | |
| 29 | ||
| fe7eb5d8 | 30 | In cases a) and b) the ARM boot monitor will have configured the CM and mapped |
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31 | writeable memory to 0x00000000 in the Integrator address space. |
| 32 | U-Boot has to carry out minimal configration before standard code is run. | |
| 33 | ||
| 34 | In case c) it may be necessary for U-Boot to perform CM dependent initialization. | |
| 35 | ||
| 36 | Configuring U-Boot : | |
| fe7eb5d8 | 37 | ------------------ |
| 74f4304e | 38 | The makefile contains targets for Integrator platforms of both types |
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39 | fitted with all current variants of CM. If these targets are to be used with |
| 40 | boot process c) above then CONFIG_INIT_CRITICAL may need to be defined to ensure | |
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41 | that the CM is correctly configured. |
| 42 | ||
| 43 | There are also targets independent of CM. These may not be suitable for | |
| fe7eb5d8 | 44 | boot process c) above. They have been preserved for backward compatibility with |
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45 | existing build processes. |
| 46 | ||
| 47 | Code Hierarchy Applied : | |
| 48 | ---------------------- | |
| fe7eb5d8 | 49 | Code specific to initialization of a particular ARM processor has been placed in |
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50 | cpu/arm<>/start.S so that it may be used by other boards. |
| 51 | ||
| fe7eb5d8 | 52 | However, to avoid duplicating code through all processor files, a generic core |
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53 | for ARM Integrator CMs has been added |
| 54 | ||
| 55 | cpu/arm_intcm | |
| 56 | ||
| 57 | Otherwise. for example, the standard CM reset via the CM control register would | |
| 58 | need placing in each CM processor file...... | |
| 59 | ||
| 60 | Code specific to the initialization of the CM, rather than the cpu, and initialization | |
| fe7eb5d8 | 61 | of the Integrator board itself, has been placed in |
| 74f4304e | 62 | |
| fe7eb5d8 | 63 | board/integrator<>/platform.S |
| 74f4304e | 64 | board/integrator<>/integrator<>.c |