66 lines
3.8 KiB
Plaintext
66 lines
3.8 KiB
Plaintext
[video member=miotatsu stream_platform=twitch project=riscy title="Studying GPIO & The Config String" vod_platform=youtube id=LS_pE0zp4gs annotator=Miblo]
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[0:08][Recap some off-stream work looking for the definition of __start()[ref
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title="ISO/IEC 9899:201x"
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url=http://open-std.org/JTC1/SC22/WG14/www/docs/n1570.pdf]]
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[1:38][Recap what we discovered about handle_m_time_interrupt() last time][:research]
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[3:59][TODO: Dive into __start + entry.S][:blackboard]
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[5:05][Set the stage for the day]
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[6:13][@hossein1387][I had a look at link.lds (located at freedom-e-sdk/bsp/env/freedom-e300-hifive1 which provides stack size and other stuff) but it does call _start]
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[6:54][Consult link.lds][:research]
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[8:44][Come to understand handle_m_ext_interrupt()[ref
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site="RISC-V"
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page="Draft Privileged ISA Specification v1.9.1"
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url=https://riscv.org/specifications/privileged-isa/]][:research]
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[15:59][:Research the GPIO[ref
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site="SiFive Developers"
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page="Platform Reference Manual"
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url=https://www.sifive.com/documentation/freedom-soc/freedom-e300-platform-reference-manual/]]
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[17:24][Consult the GPIO pin layout[ref
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site="SiFive Developers"
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page="Freedom E310-G000 Manual"
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url=https://www.sifive.com/documentation/chips/freedom-e310-g000-manual/]][:research]
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[19:31][Determine to understand the GPIO_REG macro][:research]
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[21:37][Point out the GPIO pins on the HiFive1][:hardware]
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[23:10][Continue reading env/hifive1.h][:research]
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[25:05][Find the GPIO_REG() and _REG32() macros in env/freedom-e300-hifive1/platform.h][:research]
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[27:09][Read about the General Purpose Input/Output Controller (GPIO)[ref
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site="SiFive Developers"
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page="Freedom E310-G000 Manual"
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url=https://www.sifive.com/documentation/chips/freedom-e310-g000-manual/]][:research]
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[29:47][Read the Machine Configuration Description[ref
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site="RISC-V"
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page="Draft Privileged ISA Specification v1.9.1"
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url=https://riscv.org/specifications/privileged-isa/]][:research]
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[37:28][@hossein1387][From what I know, device tree is the way to tell Linux / OS what hardware we are using]
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[38:12][Read about Device Tree[ref
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site="Embedded Linux Wiki"
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page="Device Tree Usage"
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url=http://elinux.org/Device_Tree_Usage]][:research]
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[43:41][Continue reading about the Configuration String[ref
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site="RISC-V"
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page="Draft Privileged ISA Specification v1.9.1"
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url=https://riscv.org/specifications/privileged-isa/]][:research]
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[45:18][Consult the table detailing the overall memory map of the E3 Coreplex[ref
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site="SiFive Developers"
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page="E3 Coreplex Manual"
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url=https://static.dev.sifive.com/pdfjs/web/viewer.html?file=https://static.dev.sifive.com/SiFive-E3-Coreplex-v1.2.pdf]]
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[45:55][Enable print_instructions() to print the information following the configuration string address]
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[51:13][Continue studying the GPIO[ref
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site="SiFive Developers"
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page="Platform Reference Manual"
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url=https://www.sifive.com/documentation/freedom-soc/freedom-e300-platform-reference-manual/]][:research]
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[54:21][Using XOR to invert][:blackboard]
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[56:57][Briefly consult the diagram detailing the structure of a single GPIO Pin with Control Registers before reading on about the GPIO[ref
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site="SiFive Developers"
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page="Platform Reference Manual"
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url=https://www.sifive.com/documentation/freedom-soc/freedom-e300-platform-reference-manual/]][:hardware :research]
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[1:01:56][GPIO][:blackboard]
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[1:03:52][We are out of time for today]
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[1:05:32][@hossein1387][I tried to print the config]
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[1:05:53][@hossein1387][It didn't work out]
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[1:06:33][@hossein1387][It's all garbage]
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[1:07:01][@hossein1387][{ model = "SiFive,FE310G-0000-Z0"; compatible = "sifive,fe300"; /include/ 0x20004;};]
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[1:08:42][@hossein1387][Can you also try? I want to know if there is a serial number or something]
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[1:09:11][Wind it down]
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[/video]
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