diff options
| author | fishsoupisgood <github@madingley.org> | 2019-04-29 01:17:54 +0100 |
|---|---|---|
| committer | fishsoupisgood <github@madingley.org> | 2019-05-27 03:43:43 +0100 |
| commit | 3f2546b2ef55b661fd8dd69682b38992225e86f6 (patch) | |
| tree | 65ca85f13617aee1dce474596800950f266a456c /roms/u-boot/doc/README.at91-soc | |
| download | qemu-master.tar.gz qemu-master.tar.bz2 qemu-master.zip | |
Diffstat (limited to 'roms/u-boot/doc/README.at91-soc')
| -rw-r--r-- | roms/u-boot/doc/README.at91-soc | 48 |
1 files changed, 48 insertions, 0 deletions
diff --git a/roms/u-boot/doc/README.at91-soc b/roms/u-boot/doc/README.at91-soc new file mode 100644 index 00000000..ab3f7134 --- /dev/null +++ b/roms/u-boot/doc/README.at91-soc @@ -0,0 +1,48 @@ + 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 + +2013-10-30 Andreas Bießmann <andreas.devel@googlemail.com>: + +The goal is almost reached, we could remove the CONFIG_AT91_LEGACY switch but +remain the CONFIG_ATMEL_LEGACY switch until the GPIO disaster is fixed. The +AT91 spi driver has also some CONFIG_ATMEL_LEGACY stuff left, so another point +to fix until this README can be removed. |