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Diffstat (limited to 'doc/README.at91-soc')
| -rw-r--r-- | doc/README.at91-soc | 41 |
1 files changed, 41 insertions, 0 deletions
diff --git a/doc/README.at91-soc b/doc/README.at91-soc new file mode 100644 index 000000000..bed035c88 --- /dev/null +++ b/doc/README.at91-soc @@ -0,0 +1,41 @@ + New C structure AT91 SoC access +================================= + +The goal +-------- + +Currently the at91 arch uses hundreds of address defines and special +at91_xxxx_write/read functions to access the SOC. +The u-boot project perferred method is to access memory mapped hw +regisister via a c structure. + +e.g. old + + *AT91C_PIOA_IDR = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK; + *AT91C_PIOC_PUDR = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK; + *AT91C_PIOC_PER = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK; + *AT91C_PIOC_OER = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK; + *AT91C_PIOC_PIO = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK; + + at91_sys_write(AT91_RSTC_CR, + AT91_RSTC_KEY | AT91_RSTC_PROCRST | AT91_RSTC_PERRST); + +e.g new + pin = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK; + writel(pin, &pio->pioa.idr); + writel(pin, &pio->pioa.pudr); + writel(pin, &pio->pioa.per); + writel(pin, &pio->pioa.oer); + writel(pin, &pio->pioa.sodr); + + writel(AT91_RSTC_KEY | AT91_RSTC_CR_PROCRST | + AT91_RSTC_CR_PERRST, &rstc->cr); + +The method for updating +------------------------ + +1. add's the temporary CONFIG_AT91_LEGACY to all at91 board configs +2. Display a compile time warning, if the board has not been converted +3. add new structures for SoC access +4. Convert arch, driver and boards file to new SoC +5. remove legacy code, if all boards and drives are ready |