projects / u-boot.git / blame
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1 | |
| 2 | U-Boot for ARM Integrator Development Platforms | |
| 3 | ||
| 4 | Peter Pearse, ARM Ltd. | |
| 5 | [email protected] | |
| 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. | |
| 21 | ||
| 22 | Boot Methods : | |
| 23 | ------------ | |
| 24 | Integrator platforms can be configured to use U-Boot in at least three ways :- | |
| 25 | a) Run ARM boot monitor, manually run U-Boot image from flash | |
| 26 | b) Run ARM boot monitor, automatically run U-Boot image from flash | |
| 27 | c) Run U-Boot image direct from flash. | |
| 28 | ||
| fe7eb5d8 | 29 | In cases a) and b) the ARM boot monitor will have configured the CM and mapped |
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30 | writeable memory to 0x00000000 in the Integrator address space. |
| 31 | U-Boot has to carry out minimal configration before standard code is run. | |
| 32 | ||
| 33 | In case c) it may be necessary for U-Boot to perform CM dependent initialization. | |
| 34 | ||
| 35 | Configuring U-Boot : | |
| fe7eb5d8 | 36 | ------------------ |
| 74f4304e | 37 | The makefile contains targets for Integrator platforms of both types |
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38 | fitted with all current variants of CM. If these targets are to be used with |
| 39 | boot process c) above then CONFIG_INIT_CRITICAL may need to be defined to ensure | |
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40 | that the CM is correctly configured. |
| 41 | ||
| 42 | There are also targets independent of CM. These may not be suitable for | |
| fe7eb5d8 | 43 | boot process c) above. They have been preserved for backward compatibility with |
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44 | existing build processes. |
| 45 | ||
| 46 | Code Hierarchy Applied : | |
| 47 | ---------------------- | |
| fe7eb5d8 | 48 | Code specific to initialization of a particular ARM processor has been placed in |
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49 | cpu/arm<>/start.S so that it may be used by other boards. |
| 50 | ||
| fe7eb5d8 | 51 | However, to avoid duplicating code through all processor files, a generic core |
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52 | for ARM Integrator CMs has been added |
| 53 | ||
| 54 | cpu/arm_intcm | |
| 55 | ||
| 56 | Otherwise. for example, the standard CM reset via the CM control register would | |
| 57 | need placing in each CM processor file...... | |
| 58 | ||
| 59 | Code specific to the initialization of the CM, rather than the cpu, and initialization | |
| fe7eb5d8 | 60 | of the Integrator board itself, has been placed in |
| 74f4304e | 61 | |
| fe7eb5d8 | 62 | board/integrator<>/platform.S |
| 74f4304e | 63 | board/integrator<>/integrator<>.c |