| 1 | \author: Cesar Fuguet | 
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| 2 | \date  : July 24, 2014 | 
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| 3 |  | 
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| 4 | TSAR BOOT-LOADER | 
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| 5 |  | 
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| 6 | Files: | 
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| 7 | src/        Source files | 
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| 8 |             The entry point of this boot loader is the file reset.S | 
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| 9 |  | 
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| 10 | include/    Header files | 
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| 11 |  | 
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| 12 | driver/     Drivers source files and headers | 
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| 13 |  | 
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| 14 | conf/       Platform specific files | 
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| 15 |  | 
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| 16 |             For each platform, we must define a new directory. | 
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| 17 |             Mandatory files: | 
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| 18 |  | 
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| 19 |               - hard_config.h (can be generated using giet-vm genmap tool) | 
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| 20 |  | 
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| 21 |                 This file contains all physical segments addresses and sizes of | 
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| 22 |                 the hardware platform. It also contains other configuration | 
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| 23 |                 definitions as the disk controller type, mesh size, etc. | 
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| 24 |                 Examples can be found in the conf/ directory. | 
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| 25 |  | 
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| 26 |             Optional files: | 
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| 27 |  | 
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| 28 |               - platform.dts (platform device tree) | 
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| 29 |  | 
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| 30 | Makefile    Makefile to compile the boot loader. | 
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| 31 |             Mandatory arguments: | 
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| 32 |  | 
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| 33 |               - HARD_CONFIG_PATH=<platform_dir> | 
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| 34 |  | 
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| 35 |                 Defines the directory where to find the hard_config.h file | 
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| 36 |  | 
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| 37 |            Optional arguments: | 
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| 38 |  | 
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| 39 |               - USE_DT=<value> | 
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| 40 |  | 
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| 41 |                 Value can be 1 or 0. If a device tree file is not used, set | 
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| 42 |                 this flag to 0. It is set by default to 1. | 
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| 43 |  | 
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| 44 |               - SYSTEM_CLK=<platform clock frequency> | 
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| 45 |  | 
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| 46 |                 Platform clock frequency in KHz | 
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| 47 |  | 
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| 48 |               - DTS=<file.dts> | 
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| 49 |  | 
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| 50 |                 Platform device tree (by default is platform.dts) | 
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| 51 |  | 
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| 52 | Important characteristics of this preloader: | 
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| 53 |  | 
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| 54 |   - Processor 0 performs loading of Operating System Boot Loader which must | 
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| 55 |     be an ELF file located at the third block of the disk. | 
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| 56 |  | 
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| 57 |   - Other processors wait to be waken up through an interruption generated | 
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| 58 |     from a XICU mailbox. Each processor other than 0 has its own mailbox | 
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| 59 |     in the local XICU. | 
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| 60 |  | 
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| 61 |   - Stack allocation is only made for processor 0. The loaded Operating System | 
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| 62 |     boot loader or kernel must perform stack allocation for other processors. | 
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| 63 |  | 
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| 64 |   - Stack for processor 0 is allocated at the end of RAM segment in the cluster | 
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| 65 |     (0,0). | 
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| 66 |  | 
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| 67 | Examples: | 
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| 68 |  | 
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| 69 |     make HARD_CONFIG_PATH=<platform_dir> USE_DT=0 | 
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| 70 |  | 
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| 71 |         Compile for <platform_dir> and do not compile device tree file | 
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| 72 |  | 
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| 73 |     make HARD_CONFIG_PATH=<platform_dir> DTS=platform_fpga.dts SYSTEM_CLK=25000 | 
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| 74 |  | 
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| 75 |         Compile for <platform_dir> and compile the 'platform_dpga.dts' | 
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| 76 |         device tree file. System clock frequency is 25 MHz | 
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| 77 |  | 
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| 78 |     make HARD_CONFIG_PATH=<platform_conf> SYSTEM_CLK=25000 | 
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| 79 |  | 
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| 80 |         Compile for <platform_dir> and compile the 'platform.dts' | 
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| 81 |         device tree file (default name). System clock frequency is 25 MHz | 
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| 82 |  | 
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