uboot/doc/README.at91-soc
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   1 New C structure AT91 SoC access
   2=================================
   3
   4The goal
   5--------
   6
   7Currently the at91 arch uses hundreds of address defines and special
   8at91_xxxx_write/read functions to access the SOC.
   9The u-boot project perferred method is to access memory mapped hw
  10regisister via a c structure.
  11
  12e.g. old
  13
  14        *AT91C_PIOA_IDR = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
  15        *AT91C_PIOC_PUDR = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
  16        *AT91C_PIOC_PER = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
  17        *AT91C_PIOC_OER = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
  18        *AT91C_PIOC_PIO = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
  19
  20        at91_sys_write(AT91_RSTC_CR,
  21                AT91_RSTC_KEY | AT91_RSTC_PROCRST | AT91_RSTC_PERRST);
  22
  23e.g new
  24        pin = AT91_PMX_AA_TWD | AT91_PMX_AA_TWCK;
  25        writel(pin, &pio->pioa.idr);
  26        writel(pin, &pio->pioa.pudr);
  27        writel(pin, &pio->pioa.per);
  28        writel(pin, &pio->pioa.oer);
  29        writel(pin, &pio->pioa.sodr);
  30
  31        writel(AT91_RSTC_KEY | AT91_RSTC_CR_PROCRST |
  32                AT91_RSTC_CR_PERRST, &rstc->cr);
  33
  34The method for updating
  35------------------------
  36
  371. add's the temporary CONFIG_AT91_LEGACY to all at91 board configs
  382. Display a compile time warning, if the board has not been converted
  393. add new structures for SoC access
  404. Convert arch, driver and boards file to new SoC
  415. remove legacy code, if all boards and drives are ready
  42
  432013-10-30 Andreas Bießmann <andreas@biessmann.org>:
  44
  45The goal is almost reached, we could remove the CONFIG_AT91_LEGACY switch but
  46remain the CONFIG_ATMEL_LEGACY switch until the GPIO disaster is fixed. The
  47AT91 spi driver has also some CONFIG_ATMEL_LEGACY stuff left, so another point
  48to fix until this README can be removed.
  49