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https://github.com/AsahiLinux/u-boot
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41 lines
1.3 KiB
Text
41 lines
1.3 KiB
Text
New C structure AT91 SoC access
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=================================
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The goal
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--------
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Currently the at91 arch uses hundreds of address defines and special
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at91_xxxx_write/read functions to access the SOC.
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The u-boot project perferred method is to access memory mapped hw
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regisister via a c structure.
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e.g. old
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*AT91C_PIOA_IDR = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
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*AT91C_PIOC_PUDR = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
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*AT91C_PIOC_PER = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
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*AT91C_PIOC_OER = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
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*AT91C_PIOC_PIO = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
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at91_sys_write(AT91_RSTC_CR,
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AT91_RSTC_KEY | AT91_RSTC_PROCRST | AT91_RSTC_PERRST);
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e.g new
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pin = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
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writel(pin, &pio->pioa.idr);
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writel(pin, &pio->pioa.pudr);
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writel(pin, &pio->pioa.per);
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writel(pin, &pio->pioa.oer);
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writel(pin, &pio->pioa.sodr);
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writel(AT91_RSTC_KEY | AT91_RSTC_CR_PROCRST |
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AT91_RSTC_CR_PERRST, &rstc->cr);
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The method for updating
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------------------------
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1. add's the temporary CONFIG_AT91_LEGACY to all at91 board configs
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2. Display a compile time warning, if the board has not been converted
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3. add new structures for SoC access
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4. Convert arch, driver and boards file to new SoC
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5. remove legacy code, if all boards and drives are ready
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